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Industrial Training Fund INDUSTRIAL SKILL TRAINING CENTRE, IKEJA
Dangote Academy
INDUSTRIAL SAFETY
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Lockout/Tagout (LOTO)
(Safe shut down of Hazardous Energy Sources)
Employees servicing or maintaining machines or equipment may be exposed to serious physical
harm or death if hazardous energy is not properly controlled. Craft workers, machine operators,
and maintenance personnel are among the workers who service equipment and face the greatest
risk. Lockout/tagout program establishes the minimum requirements for the lockout or tagout
of energy isolating devices. It will ensure that machines or equipment are isolated from all
potentially hazardous energy, and locked out or tagged out before employees perform any
servicing or maintenance. Workplace activities considered to be “Servicing and/or
maintenance” of machinery and equipment” include: adjusting, inspecting, modifying,
constructing, re-tooling, lubricating, removing jams, cleaning etc.
Lockout/tagout is a method of controlling personnel injury/equipment damage associated
with repairs and maintenance of equipment by de-energizing machines that use electricity or
other sources of energy to prevent the operator from being exposed to serious and life
threatening situations. Such accidental exposures can cause severe scalding or burns,
extremities or clothing to be caught in a machine’s moving parts, or fatal electric shock. A
wide variety of energy sources may need to be locked out during service or maintenance.
This includes but is not limited to:
a. Electrical equipment
b. Hydraulic
c. Pneumatic
d. Mechanical
e. Gravity
f. Thermal
g. Chemical
h. Fluids and Gases
i. Water under pressure
j. Steam
The goal of any employer is to maintain a safe and healthy work environment in order to
protect each employee from potentially hazardous or unsafe conditions. Requirements and
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regulations pertaining to Lockout/tagout are found in the Occupational Safety and Health
Standards for General Industry (OSHA 29 CFR 1910.147). Guidelines and procedures
outlined in this section have been developed to ensure that a machine or piece of equipment is
isolated from all potentially hazardous energy sources before servicing is performed. The
above standard does not apply to:
a. Work on cord and plug connected equipment - Work on cord and plug connected
electric equipment for which exposure to the hazards of unexpected energizing or start up
of the equipment is controlled by the unplugging of the equipment from the energy source
and by the plug being under the exclusive control of the employee performing
maintenance or repair. b. Hot tap operations, under special conditions - Hot tap operations involving transmission
and distribution systems when they are performed on pressurized pipelines
c. Oil and gas well drilling and servicing. Lockout Device: A device that utilizes a lock and key to hold an energy isolating device in the
safe position and prevents a machine or equipment from being energized.
Lockout Devices
Tagout Device: A prominent warning device, such as a tag, that can be securely attached to
equipment or machinery for the purpose of warning personnel not to operate an energy isolating
device and identifying the applier or authority who has control of the procedure.
Tagout Devices
Lockout/Tagout: The placement of a lock and tag on the energy isolating device in accordance
with an established procedure, indicating that the energy isolating device shall not be operated
until removal of the lock/tag in accordance with an established procedure. (The term "lockout/
tagout requires the combination of a lockout device and a tagout device).
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Lockout/tagout device
The objectives of the Lockout/tagout Program include:
a. To insure that specific lockout/tagout procedures are developed for all pieces of
equipment and machinery in which the unexpected energization, start up or release of
stored energy could cause injury to employees.
b. To insure that “Affected Employees” recognize the various types of equipment used by
“Authorized Employees” and understand the use and purpose of lockout/tagout
equipment.
c. To insure that “Authorized Employees” are properly trained and implement the
lockout/tagout system according to developed procedures.
d. To insure that only “Authorized Employees” lockout or tagout machines or equipment.
e. To insure that every new or transferred employee, and any other employee, whose work
operations may be in the area, are instructed in the purpose and use of lockout/tagout
procedures.
f. To insure that contracting employees are given correct and proper notification of required
lockout/tagout procedures used in area of engagement and that the contracting company
adheres to these guidelines.
Responsibility/Resources Employed
Safety Manager/ Maintenance Manager Safety manager/Maintenance manager is responsible for developing the written
lockout/tagout program and ensuring that training is scheduled. He/she serves as the first
contact for issues concerning the lockout/tagout program.
Maintenance Supervisor The maintenance supervisor will develop written equipment specific procedures and review
the proficiency of their subordinates in following developed procedures. The Maintenance
supervisor will also be responsible for following emergency procedures for lock and tag
removal in the absence of an employee who attached the lock and tag.
Authorized Employees “Authorized Employees” are responsible for locking and tagging out equipment and
machinery in accordance with procedures outlined in this section. Also,“Authorized
Employees” are responsible for notifying “Affected Employees” before these procedures are
implemented, and when the equipment is placed back into service.
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Affected Employees “Affected Employees” are responsible for recognizing the various types of lockout/tagout
equipment used by “Authorized Employees” and ensuring that this equipment is not tampered
with or removed by anyone but the “Authorized Employee”.
OHS Department OHS is responsible for auditing departments that have implemented lockout/tagout programs.
Upon request, OHS will assist departments in developing equipment specific lockout/tagout
procedures, train "Affected" and "Authorized Employees", and assist with lockout/tagout
equipment selection.
Rules for Lockout/Tag-outs You must attach a danger tag before starting work on any equipment that could injure you if
it is energised. To do this you, or your supervisor, must isolate the equipment from its energy
source, and safely discharge any stored energy. Your danger tag is then filled out and
attached to the correct isolating device (such as a valve or switch).
a. Only the name of the person tagging the equipment should be on the danger tag.
b. You must NEVER touch a device, which has a danger tag attached to it.
c. You can only remove YOUR OWN danger tag. You MUST NEVER remove someone
else’s danger tag.
d. You must remove your danger tag when you have finished work on the repair.
The lockout/tagout rule covers the following employees 1. Authorized Employee
2. Affected Employee
3. Other Employee
Authorized employee: An employee who services or performs maintenance on
machines or equipment i.e maintenance personnel
Affected employee: An employee who normally works on or near a machine that
must be locked out for maintenance. i.e machine operators
Other Employee: Person who works in an area where lockout/tagout procedures
are being used.
Application of Lockout/tagout Lockout/tagout program applies to the control of hazardous energy during schedule
maintenance of machines and equipment or during normal machine operations if there is
likelihood:
a. That an employee is required to remove or bypass a guard or other safety device;
b. That an employee is required to place any part of their body into an area on a machine or
piece of equipment where work is actually performed upon the material being processed
(point of operation) or where an associated danger zone exists during a machine operating
cycle.
Conditions for using lockout
Machinery or equipment is “capable of being locked out” if the following conditions are
met: a. It has a hasp or other means to attach a lock; or
b. It has a built in locking mechanism
c. Does not have to be dismantled or altered to achieve lockout.
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Conditions for using tagout a. When an energy isolating device is not capable of being “locked out”.
b. If employer can demonstrate (prove) that using a tagout system will provide full
employee protection.
Requirements for lock-out/tag out devices The locks, tags, and other hardware that are identified and required will be the only devices
used to lockout or tagout for personnel protection. The locks and tags used for personnel
protection will be:
a. Standardized according to one or more of the following: colour, shape, size, type, or
format
b. Distinctive in appearance, easily recognizable, clearly visible
c. Designed to convey all information required for the application
d. Designed to deter accidental or unauthorized removal
e. Designed to withstand environmental conditions for the duration of their application
The employer will provide the locks, tags, chains, wedges, key blocks, adaptor pins, self-
locking fasteners, or other hardware. Lockout/tagout devices are to be singularly identified;
and the only devices used for controlling energy. Do not be use these for other purposes.
Labelled Lockout Hasp Ball Valve Lockout Devices Plug lockout devices
Floor mounted tagout
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Circuit circuit-breaker-lockout-device
Qualities of Tags and Locks
Durable a. Capable of withstanding environmental conditions for the maximum period of use
b. Constructed and printed so exposure will not cause deterioration of the message on the
tag, and
c. Tags shall not deteriorate when used in a corrosive environment.
Substantial a. Must prevent removal without excessive force or unusual techniques such as bolt cutter
or cutting tools
b. Must be substantial enough to prevent inadvertent or accidental removal
a) Non-reusable type
b) Attachable by hand
c) Self-locking
d) Non-releasing with a minimum unlocking strength of less than 50 pounds, and
e) Similar to the general design and basic characteristics of being at least equivalent
to a one-piece, all environment-tolerant nylon cable tie.
Identifiable Lockout/tagout devices must have the identity of the employee and must warn against
hazardous conditions. Messages must include:
a. DO NOT START
b. DO NOT OPEN
c. DO NOT CLOSE
d. DO NOT ENERGIZE, OR
e. DO NOT OPERATE
General Energy Control Procedures OSHA regulations state that it is not necessary to document a specific procedure for a
particular machine or piece of equipment when all of the following conditions are met:
1. The machine has no potential for stored or residual energy or re-accumulation of stored
energy after shut down which could injure employees.
2. The machine or equipment has a single energy source which can readily be identified and
isolated.
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3. The isolation and locking out that energy source will completely deengerize and
deactivate the machine or equipment.
4. The machine or equipment is isolated from that energy source and locked out during
servicing or maintenance.
5. A single lockout device will achieve a locked-out condition.
6. The lockout device is under the exclusive control of the Authorized Employee performing
the servicing or maintenance.
7. The servicing and maintenance does not create hazards for other employees.
8. No accident involving the unexpected activation or re-energization of the machine or
equipment during servicing or maintenance.
Procedure for Equipment/Machinery Not Requiring a Specific Procedure: STEP 1: Notify all “Affected Employees” that lockout/tagout is going to be utilized and
the reason why.
STEP 2: If the machine or equipment is operating, shut it down by the normal stopping
procedure (depress stop button, open toggle switch, etc.).
STEP 3: Operate the switch, valve, or other energy isolating device(s) so that the
equipment is isolated from its energy source.
STEP 4: Lockout/Tagout the energy isolating devices.
STEP 5: After insuring that no personnel are exposed, and as a check on having
disconnected the energy source, operate the push button or other normal
operating control to make certain the equipment will not operate.
STEP 6: Return the operating control to the "neutral" of "off" position after the test.
The equipment is now locked/tagged out.
Procedures for Multiple Employee Lockout/Tagout: Employees may at times be required to repair/service equipment that requires the expertise of
more than one (1) person. For these applications, a Multiple Employee Lockout procedure
will be used. The following steps will be followed to properly lockout/tagout equipment that
has more than one employee performing maintenance and service:
Multiple Employee Lockout using a multi-lock hasp
A multi – lock hasp will be placed on the equipment and each employee may put its own
locks and tags by following a written procedure developed for the particular piece of
equipment. Once an employee has completed their work on the locked out piece of
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equipment, they will remove their lock and tag from the equipment. The equipment will be
put into use when the last employee may have removed his/her lock.
Procedures for Lock or Tag Removal: Each lockout or tagout device will be removed from energy isolating source by the employee
who put the device on the equipment. EXCEPTION: When the employee who applied the
lock or tag is not available to remove it, the following procedures will be followed:
1. Supervisor will be contacted and notified of the situation
2. Verification that the employee who applied the lock or tag is not at work.
3. An attempt will be made to phone the employee who applied the lock or tag. If
telephone contact is made with the employee, he/she will be instructed that their lock or
tag needs to be removed and that they must report to work to remove the lock or tag. If
telephone contact is not made, the course of action will continue to Step 4.
4. The Supervisor will inspect the work area to ensure that non-essential items have been
removed, machine components are operationally intact, all employees have been safely
positioned or removed, and that affected employees in the area have been notified that
the lock and tag are being removed.
5. No employee may remove a lock or tag belonging to another employee or contractor,
unless specifically directed by maintenance supervisor.
6. Before the employee who applied the lock or tag that has been removed returns to work,
they will be retrained on proper lockout/tagout procedures, instructed on the situation
that arose and the steps taken to remove the lock and tag.
Checklist for Lockout/Tagout
Have all energy sources been identified (many types of equipment have more than one)?
Have all energy sources been shut off or released?
Have all lines been bled of air or hydraulic pressure?
Have all valves or switches been locked in the off position?
Are adequate tags and labels posted to notify other worker and inform area of authorized
person’s name?
Have employees and supervisors in the area been informed of shutdown?
Have brakes been applied or time been given to stop all centrifugal movement before
guard is removed?
Has equipment been blocked appropriately?
Is there a plan for re-energizing the equipment when work is finished?
Has all staff that operate or are performing work on the equipment been trained in
Lockout/tagout?
The most common problems of lockout/tagout
1. Lack of procedures.
Specific procedures should be written for each piece of equipment.
2. Training for all employees.
The staff that do normal repairs or operate the machines daily are usually well trained, it
is the other staff you need to look in to
3. Wrong use of tags.
Do not use these danger tags for anything except servicing and maintenance.
4. Wrong use of lock.
Special lockout locks are not to be used on toolboxes, lockers, etc.
5. Working under someone else’s lock.
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If the lock on the equipment is not yours you are violating the law and putting yourself at
risk of injury.
6. Not identifying all energy sources.
You turn off the electricity, but not the steam!
7. Annual audit of procedures and review of findings.
This is for your safety to make sure no new energy sources have been added and that all
energy sources have been identified.)
8. Maintenance vs. minor, routine tool changes.
Employees need to know the difference between service/maintenance and routine
adjustment/normal operations
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HAND TOOL SAFETY
Introduction A hand tool may be powered or not powered. These tools allow us to work faster and increase
the number of different jobs that we can accomplish. However, the greatest hazards posed by
thesetools results from misuse and improper maintenance. Also when a tools is not put away
safely then
accidents can occur. The correct way is the safe way. The incorrect way is wrong. By using
protective equipment, and following proper work practices, you can operate hand tools safely
and with confidence.
Always have it in mind, that the time and effort taken in fetching the correct tool from the
stores or in servicing a worn tool is considerably less than the time taken in convalescing
from an injury.
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Hand tools can cause many types of injuries:
a. Cuts, abrasions, amputations, and punctures. If hand tools are designed to cut or move
metal and wood, remember what a single slip can do to fragile human flesh.
b. Repetitive motion injuries. Using the same tool in the same way all day long, day after
day, can stress human muscles and ligaments. Carpal tunnel syndrome (inflammation of
the nerve sheath in the wrist) and injuries to muscles, joints and ligaments are
increasingly common if the wrong tool is used, or the right tool is used improperly. Injury
from continuous vibration can also cause numbness or poor circulation in hands and arms.
c. Eye injuries. Flying chips of wood or metal are a common hazard, often causing needless
and permanent blindness.
d. Broken bones and bruises. Tools can slip, fall from heights, or even be thrown by careless
employees, causing severe injuries. A hammer that falls from a ladder is a lethal weapon.
To avoid such injuries, remember the following safety procedures:
1. Use the right tool for the job. Don't use your wrench as a hammer. Don't use a
screwdriver as a chisel, etc. Go back to the tool house and get the right tool in the right
size for the job.
2. Don't use broken or damaged tools, dull cutting tools, or screwdrivers with worn tips.
3. Cut in a direction away from your body.
4. Make sure your grip and footing are secure when using large tools.
5. Carry tools securely in a tool belt or box. Don't carry tools up ladders. Use a hoist or rope.
6. Keep close track of tools when working at heights. A falling tool can kill a co-worker.
7. Pass a tool to another person by the handle; never toss it to them.
8. Use the right personal protective equipment (PPE) for the job. Follow company
instructions for selecting and using safety eyewear, steel toed shoes, gloves, hard hats,
etc.
9. Never carry sharp or pointed tools such as a screwdriver in your pocket.
10. Select ergonomic tools for your work task when movements are repetitive and forceful.
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1. Be on the lookout for signs of repetitive stress. Early detection might prevent a
serious injury.
2. Always keep your tools in top condition. A dull blade or blunt point can lead to
injury.
3. Store tools properly when you stop work.
By following these precautions, you can help prevent injuries and provide a better workplace
for everyone. Remember, an ounce of prevention is worth a pound of cure!
The type of personal protective equipment (PPE) you need when using hand tools depends on
the tool being used. At a minimum, eye protection—in the form of safety glasses or
goggles—must be worn at all times. It is also important to protect your hands from cuts,
abrasion, and repeated impact. Cut-resistant gloves made of stainless steel can help protect
against the effects of a misplaced blade. On jobs that require long periods of hammering,
impact-resistant gloves with gel or rubber palms can reduce vibration. When using hand
tools, the following apply:
a. Select the right tools designed for specific purposes, e.g. screwdrivers-are for driving
screws, chisels are for chiselling etc. a tools must be used only to perform the job, which
it is designed.
b. Tools should be used in the correct manner. Like other machines, there should be a proper
way (also the safe way) of using a certain piece of tools.
c. Tools should be properly stored. Improper storage of tools can cause damage to tools and
injuries to people, especially those sharp edged or sharp-pointed tools; they should be
properly secured during transport.
d. Hand tools should not be left lying in places where persons have to work or pass, or on
scaffolds or other elevations from which they might fall on persons below.
e. Only insulated or non-conducting tools should be used on or near live electrical
installations if there is any risk of electrical shock.
f. Make sure saw blades, knives, or other tools are directed away from aisle areas and other
employees working in close proximity.
g. Replace or repair all wooden handles that are loose, splintered, or cracked.
h. Do not use impact tools such as chisels, wedges, or drift pins that have mushroomed
heads.
i. Handling and use of sharp-edged and sharp-pointed tools should not: -
• Be thrown from person to person;
• Be used in dangerous proximity to other persons or moving machinery.
Storage of hand tools a. When not in use, sharp tools should be kept in sheaths, shields, chests or other suitable
containers.
b. Unless adequately protected, sharp-edged and sharp-pointed tools should not be carried in
pockets. Tools should not be carried in manner that the sharp edges or the sharp points
facing you or other persons.
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Do not carry tools in your pockets.
c. Sharp edges or points of tools to be carried or stored, should be protected
d. Sharp-edged and sharp-pointed hand tools should be stored in such a way that:
• They cannot fall; and
• They cannot cause danger to the person removing them.
Wrenches Wrenches come in an endless variety of styles such as socket, open-end, combination,
adjustable and torque, just to name a few. Wrenches are designed to turn or hold bolts, nuts or
multiple threaded fasteners. They are sized to keep the leverage and load in an acceptable
balance.
a. Choose a wrench that properly fits the fastener you wish to turn. Use metric wrenches for
metric bolts and American inch wrenches for inch-sized bolts. By using the correct size,
the wrench is less prone to slip or round off the fastener corners.
b. Avoid using an extension to improve the leverage of a wrench.
c. Do not use open-end or adjustable wrenches for final tightening or loosening frozen
fasteners. These wrenches do not have the strength of a box-end or socket wrench.
d. Apply penetrating oil on frozen fasteners before using a striking face box, socket or
heavy-duty box wrench.
e. Do not expose a wrench to temperatures that could weaken tool hardness.
f. Always try to pull on a wrench (instead of pushing) in case the fastener loosens.
g. Adjustable wrenches must be adjusted tightly to the fasteners and then pulled, putting the
force on the fixed end.
h. Turn power off and use electrically insulated wrenches when working on or around
electrical components.
i. Never alter a wrench.
j. Do not over torque a fastener. Use a torque wrench to tighten the fastener to the exact
torque required.
k. Inspect wrenches periodically for damage, such as cracking, severe wear or distortion.
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Always try to pull on a wrench (instead of pushing)
Do not use oversize spanner and packing
Hammers, wrenches, chisels, pliers, screwdrivers, and other hand tools are often underrated
as sources of potential danger. Hand tools may look harmless, but they are the cause of many
injuries. In fact, an estimated 8 per cent of all workplace compensable injuries are caused by
incidents associated with hand tools. These injuries can be serious, including loss of fingers
or eyesight.
Pliers Pliers come in all shapes and sizes, such as lineman, diagonal cutting, needle nose, slip joint,
locking tongue and groove. Plier uses include gripping, cutting, turning and bending. Pliers
are a versatile tool, but must be used according to how they are designed.
a. Do not increases a plier’s handle length to gain more leverage, instead choose larger sized
pliers.
b. Never subject pliers to temperatures that could decrease tool hardness.
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c. Cut hardened wire only with pliers designed for that purpose.
d. Do not substitute a plier for a wrench when turning nuts and bolts.
e. Be sure the plier’s jaws can grasp properly when bending rigid wire.
f. Do not hammer with pair of pliers.
g. Always use non-sparking pliers when in the presence of flammable vapours or dusts.
Hammers and Striking Tools Hammers are one of the most used tools in our toolboxes. (Unfortunately, they are also the
most abused tools.) Nail, soft-face, ball-peen, chipping, sledge and setting are just a few of
the hammers we use in the workplace and home. Hammers are designed according to the
intended purpose.
a. Always use a hammer of the proper weight and size for the task.
b. Hammers handles shall be well fitted and securely fastened by wedges or other acceptable
means.
c. Do not use one hammer to strike another hammer, stones or concrete.
d. Look behind and above you before swinging the hammer.
e. Watch the object you are hitting.
f. Do not use one hammer to strike another hammer, stones or concrete.
g. Look behind and above you before swinging the hammer.
h. Watch the object you are hitting.
i. Hold the hammer with your wrist straight and your hand firmly wrapped around the
handle.
j. Strike a hammer blow squarely.
Strike a hammer blow squarely.
Hammer with cracked head and Hammer with a loose handle.
Screwdrivers Screwdrivers are intended for turning a variety of threaded fasteners, such as machine or
wood screws, in or out of materials. Screwdriver tips come in a variety of different shapes
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and sizes. The slotted tips are the most common; however, hex, square and various others are
also used. As with any tool, it is important to match the type of screwdriver you use to the
type of job you are doing.
Safety Tips To Know When Using Screwdrivers are stated below.
a. Never use a screwdriver as a pry bar, chisel, punch, stirrer or scraper.
b. Always use a screwdriver tip that properly fits the slot of the screw.
c. Throw away screwdrivers with broken or worn handles.
d. Never expose screwdrivers to temperatures that could reduce tip hardness.
e. e. Turn power off and use electrically insulated screwdrivers when working on or around
electrical components.
f. f. Straighten tips or redress rounded edges with file.
g. Use magnetic or screw-holding screwdrivers to start fasteners in tight areas.
h. Use both hands when using a screwdriver—one guides the tip and the other to turn the
handle. Final tightening requires both hands on the screwdriver handle.
i. Always use non-sparking screwdrivers in the presence of flammable vapours
j. Use a screw-holding screwdriver (with screw-holding clips or magnetic blades) to get
screws started in awkward, hard-to-reach areas. Square-tipped screwdrivers (e.g.,
Robertson) that hold screws with recessed square holes are also useful in such situations.
Files a. Files must never be used without a proper handle.
b. Keep files in racks and avoid the chipping of the teeth which will result in poor quality
workmanship
c. Files should be provided with well-fitting handles.
d. Wooden handles should be renewed if they show signs of splitting.
e. Check that the work piece is firmly gripped in the vice.
f. Hold the file correctly and distribute the weight evenly over its whole length. Apply
pressure only on the cutting strokes.
g. File narrow surfaces diagonally. Always remove sharp edges and tidy up the job.
h. Always check that the handle is firmly attached to the tang.
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Do not use a file without a proper handle
Chisels a. Always wear safety glasses or goggles when using chisels.
b. The proper type and size of chisel should be selected for the job.
c. Cold chisels for cutting metal should not be used for cutting timber.
d. Never use chisels for prying opening lids.
e. Always drive chisels outward and away from your body.
f. The head of the chisel must be free of grease and burrs. The mushroomed heads must be
properly rounded off.
g. Use the tools only if they are in good condition (i.e., cutting edges are sharp, struck head
is not mushroomed or chipped).
h. Hold the chisel, for shearing and chipping, at an angle, which permits the bevel of the
cutting edge to lie flat against the shearing plane.
i. Chisels should be fitted with hand protection.
Chisels should be fitted with hand protection
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Hacksaws a. Use the right type of saws for cutting different materials (e.g. timber, steel, etc.).
b. All saws should be kept sharp and clean.
c. When cutting, use slow, deliberate strokes. Forcing the cut can make the blade buckle and
snap and/or jump out onto your hand.
d. Don’t hold work pieces in your hand when using a saw. Securely place work piece in a
vise or other suitable support.
Marking Out Tools a. Keep all marking – out clean and slightly oiled, and well away from all other tools.
b. Take care to clean the tools and the work piece before starting to mark out.
c. Handle the tools carefully – no knocking or rubbing of the surface.
d. Check that the clamps are tight on the scribing block
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Hydraulic Tools Safety Fluid powers hydraulic tools, the fluid used to power hydraulic tools must be approved and
fire resistant.
It also must retain its same operating characteristics at the highest temperature to which it is
exposed. For example, if a hydraulic tool is used in a very hot environment, the fluid must
retain its same characteristics, even with the extreme temperature change. Any limitations set
forth by the manufacturer on the fluid or equipment must not be exceeded.
Fuel-powered Tools Safety Fuel-powered tools usually are operated with gasoline. The most serious hazards associated
with these types of tools are the inhalation of fumes and the risk of explosion. In
environments where fuel-powered tools are used, effective ventilation is mandatory. To
reduce the chance of fire or explosion, do not use these tools near flames or flammable
materials, and store gas in approved containers only. Always turn off a tool and allow it to
cool before refueling.
Powder Tool Safety A powder tool works like a loaded gun. A powder tool is often used to shoot nails into a
work-piece. Only approved, trained employees may operate powder tools because they pose
many safety risks. To use them, you must follow the manufacturer recommendations and
wear eye, ear, and face protection. In addition, most manufacturers of powder tools require
employees to wear hard hats because of the ricochet possibility. Some manufacturers
also require signs to be posted in areas where the tools are used.
Abrasive Wheel Tool Safety Grinding, cutting, polishing, and wire buffing wheels create special safety problems since
they may discharge particles. Even worse, they may become disengaged from the mounting.
Abrasive wheel tool.
Before an abrasive wheel is mounted, it should be inspected closely and sound-tested or ring-
tested to be sure it is free from cracks or defects. Many types of grinding wheels will emit a
high-pitched ringing sound when tapped with a light, non-metallic tool. When wheels are
cracked or damaged, the sound will be dull or “dead.” Do not use damaged or “dead”
abrasive wheels. If a wheel is defective, it could fly apart in operation. When mounting, the
wheel must be tightened with a nut without distorting the flange, and the wheel must be able
to move freely.
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Mounting of abrasive wheel.
Pneumatic Tool Safety Pneumatic tools are powered by compressed air. Examples of pneumatic tools include drills,
hammers, grinders, nail guns, riveting guns, and sanders. Fig. 5.54 shows a pneumatic nail
gun.
A type of pneumatic tool and Pneumatic unit.
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OSHA requires that each pneumatic tool must have a tool retainer installed on each piece of
pneumatic utilization equipment. The retainer protects the tool from being ejected during
operation. Also, “the hose and hose connections used for conducting compressed air to
utilization equipment shall be designed for the pressure and service to which they are
subjected.” In other words, the equipment you use for the hose and its corresponding
equipment must be designed specifically for the pneumatic tool you are using.
For air hoses more than 1/2 inch (12mm) in diameter, a safety excess flow valve must be
installed at the air supply to reduce pressure in the event of hose failure. Pneumatic tools that
shoot nails, rivets, staples, or similar fasteners and operate at pressures greater than 100 psi
must have a safety device to keep fasteners from being accidentally ejected, unless the
muzzle is pressed against the work surface. Airless spray guns that spray fluids such as paint
at 100 psi or greater must have safety devices that prevent accidental pulling of the trigger.
Pneumatic Nail Gun.
a. Portable pneumatic tools should be used only for the work for which they are designed.
b. Wear safety glasses or a face shield and, where necessary, safety shoes or boots and
hearing protection.
c. Pneumatic shock tools should be equipped with safety clips or retainers to prevent dies
and tools from being accidentally expelled from the barrel.
d. Restrict the use of pneumatic tools to the competent persons who have been given
adequate instructions and training on proper use of such tools.
e. Post warning signs where pneumatic tools are used. Set up screens or shields in areas
where nearby workers may be exposed to flying fragments, chips, dust, and excessive
noise.
f. Cleaning with compressed air is dangerous. You should not use the compressed air for
cleaning.
25
Do not use compressed air to blow debris or to clean dirt from clothes
26
Material handling Safety
Introduction Materials handling embraces the movement of all the materials used in the workshops. It
should be apparent that any piece of material used in engineering workshops has to be moved
about many times. This shows the importance of material movement in the workshops,
especially when it is recognized that there is some danger involved every time material is
moved.
Many of the accidents that happen in workshops are caused by mishaps during handling and
moving materials. This should indicate the need for caution when lifting and carrying
materials- the aim being to make your work easier and much safer. The objective of material
handling should be the speedy movement of materials between all operation stages
throughout the workshops. Material handling involves lifting, moving and placing of objects.
It can be done manually (MANUAL material handling) or with the aids of equipment
(MECHANICAL material handling) such as trolleys, forklift trucks, chain blocks etc.
Manual Handling Operations Manual handling covers a wide range of activities including lifting, pushing, pulling, holding,
throwing, carrying and supporting of loads by way of physical effort. It includes repetitive
tasks such as packing, typing, assembling, cleaning and sorting, using hand-tools, and
operating machinery and equipment. Most jobs involve some form of manual handling; most
workers are at risk of manual handling injury. Of course, not all manual handling tasks are
hazardous. But it is significant that around a quarter of all workplace injuries are caused by
manual handling. The first consideration when looking at an activity involving manual
handling should be whether the manual handling is necessary. Quite often it is only being
done in the way that it is because, “it has always been done that way”. It may be possible to
change the system of work to remove the need for the manual handling.
Power Zone The power zone for lifting is close to the body, between mid-thigh and mid-chest height. This
zone is where arms and back can lift the most loads with the least amount of effort.
Power zone
27
Hazards Accidents related to manual material handling can result in a variety of injuries such as
crushed fingers, broken toes, cuts, and brushes to the legs and feet, strained sprained backs
etc. However, back injuries are far the most serious and common problem in manual material
handling. Back injuries are not limited to industrial or construction activities, but are
widespread among many occupational environments including office work.
Causes of Injuries a. Manual material handling injuries can be attributed to a number of factors:
b. Incorrect lifting techniques.
c. Carrying too heavy a load.
d. Incorrect gripping.
e. Failure to wear protective clothing.
f. Poor job design.
g. Physical conditions of individuals.
Control Measures Applying both administrative and engineering control measures should minimize the
potential for injury cause by manual material handling.
Administrative Controls These refer mainly to items such as training, the provision of personal protection equipment
and proper job assignment. The provision of proper training is very important in reducing
injuries resulting from manual material handling. Training should include the recognition of
dangers in manual material handling, learning of proper lifting practice to avoid unnecessary
stress to the body.
Engineering Controls Engineering controls refer to items such as improvement on mechanical, visual, and thermal
environments, alternatives for material handling systems, minimization of potential
ergonomic problems etc. The mechanical controls include container design, handle and
handhold designs, and floor worker interfaces. The visual environment refers to lighting,
colour and labelling. Material handling alternatives include various equipment and job aids,
such as the use of trolleys, chain blocks, hooks, bars, and other devices. Potential ergonomic
problems minimized through proper design or workstations.
28
Proper Handholds Proper handholds make lifting easier and reduce the risk of injury. Handholds should be
made large enough to accommodate larger hands and should not dig into fingers and palms.
Assessment of Work Procedure for Manual Handling
The Task a. Does the task involve holding loads away from the trunk?
b. Does the task involve large vertical movement?
c. Does the task involve long carrying distances?
d. Does the task involve strenuous pushing or pulling of the load
Manual Handling and Lifting Techniques
Lifting Heavy Loads How much weight a worker can safely lift depends on a number of factors. When the factors
are such that the worker can assume an “ideal” body posture during the lift, the worker is able
to lift greater loads. Factors affecting how much weight a worker can safely lift include:
Lifting factors More weight can be safely lifted when:
The amount of weight that can safely be lifted is reduced when:
How far from the body the load is held (horizontal distance).
The load is close to the body and not too large/bulky, which allows the arms and elbows to
be close to the torso during the lift.
The load is farther away from the body or is large/bulky, forcing the
arms and elbows away from the torso during the lift.
How high or low is the lift (vertical distance).
The lift is at waist height. The lift must be made from below the knees or above the shoulder.
How much the worker must twist to lift and move the load.
The lift is performed in front of the body.
The worker must twist the torso to lift and move the load.
How often the lift is repeated.
The lift is performed only occasionally.
The lift is performed repeatedly (several times a minute).
How far the load is carried. The lift does not involve carrying.
The load must be carried a distance (more than 3 feet).
How the load is gripped. The load has handles. The load does not have handles or is slippery.
(b). Team lifting Team lifting is employed when manhandling heavy loads, but remembers there can be only
ONE captain to the team and only he gives the orders. All members of the team should lift
together to spread the load evenly. All the men in the team should be of similar physique and
build.
29
Some Proper Lifting Practices are recommended below:
a. Gets firm footings make sure that the floor is not slippery.
b. Determine how heavy it weighs. If the load is too big or too heavy for one person to
carry, ask somebody to help or use team lifting.
c. Make sure the load is free, not locked down or struck.
d. Watch out for the fingers and hands when carrying a load so that they will not struck
against other objects.
e. Inspect the route over which the load is to be carried. Make sure it is in plain view with
adequate lighting and is free of obstructions or spillage that could cause tripping or
slipping.
f. Inspect the load to be lifted for sharp edges, and wet or greasy spots.
g. Wear gloves when lifting or handling objects with sharp or splintered edges. Make sure
the gloves are free from oil, grease, or other agents that may cause a poor grip.
h. Consider the distance the load is to be carried. Recognize the fact that gripping power will
weaken over long distances. DO NOT continue lifting when the load is too heavy.
i. Size up the load and make a preliminary “heft” to be sure the load is easily within lifting
capacity. If it is not, get help or use a mechanical lifting device.
j. If team lifting is required, make sure that personnel are similar in size and physique. One
person should act as leader and give the commands to lift, lower, etc.
k. Never overexert yourself when lifting. If the load is thought to be more than one person
can handle, an additional person shall be assigned to the job.
l. Bend your knees and keep your back straight.
m. Lift gradually with your legs (not your back), without jerking, to minimize the effects of
acceleration.
n. Keep the load close to the body.
o. Lift without twisting the body.
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General Lifting Principles
General Lifting Principles
a. Get a firm footing. Keep your feet apart for a stable base. Point feet in the direction of
travel.
b. Bend your hips and knees instead of bending at the waist. This allows the leg muscles
to take the
load and not the spine.
c. Tighten abdominal muscles. Abdominal muscles support the spine when lifting.
d. Ensure correct hold. Select a secure grip so that there is no danger of slipping during
the lift.
e. Brace yourself for the lift, continue to breathe normally through the lift, concentrate
on the lift and
not on the breathing. vi. Lift steadily don't jerk the load.
f. Keep your back straight and avoid twisting or bending to the side.
g. Keep the load close. The closer it is to your spine the less force it exerts on your back.
How to Lift Safely Before lifting, take a moment to think about what you're about to do. Examine the object for
sharp corners, slippery spots or other potential hazards. Know your limit and don't try to
exceed it. Ask for help if needed, or if possible, divide the load to make it lighter. Know
where you are going to set the item down and make sure it and your path are free of
obstructions. Then follow these steps.
1. Stand close to the load with your feet spread apart
about shoulder width, with one foot slightly in front
of the other for balance.
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2. Squat down bending at the knees (not your waist).
Tuck your chin while keeping your back as vertical as
possible.
3. Get a firm grasp of the object before beginning the lift.
4. Begin slowly lifting with your LEGS by straightening
them. Never twist your body during this step.
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5. Once the lift is complete, keep the object as close to
the body as possible. As the load's center of gravity
moves away from the body, there is a dramatic
increase in stress to the lumbar region of the back.
If you must turn while carrying the load, turn using your
feet-not your torso. To place the object below the level of
your waist, follow the same procedures in reverse order.
Remember, keep your back as vertical as possible and
bend at the knees.
Non-Powered Hand Trucks When not in use, trucks should be parked in a designated area, not in the aisles or in other
places where they constitute tripping hazards or obstruct traffic
Manual Pallet Jack
Pallet + walk + no stack + manual
Manual lifting and/or travel
Floor Hand Truck
Four or more wheeled hand truck with handles
for pushing or hitches for pulling
33
Guidelines for using a hand truck. a) Keep the centre of gravity of the load as low as possible. Place heavy objects below
lighter objects.
b) Place the load well forward so the axle will carry the weight.
c) Position the load so it will not slip, shift, or fall. Load only to a height that will allow
a clear view ahead.
d) Let the truck carry the load. The operator should only balance and push.
e) Never walk backwards with a hand truck.
f) When going down an incline, keep the truck in front of you. When going up, keep the
truck behind you.
g) Move the truck at a safe speed. Do not run. Keep the truck under control at all times.
Guidelines for using a wheelbarrow.
a. Keep the centre of gravity of the load as low as possible.
b. Centre the load so the axle will carry the weight.
c. Position the load so it will not slip, shift, or fall.
d. Make sure the tires are inflated and at the proper pounds per square inch (p.s.i.).
e. Position your body between the handles, using your right hand for the right handle and
left hand for the left handle.
f. To properly lift the load, bend your knees, while keeping your back straight.
Two-Wheeled Hand Truck
Non-pallet + manual + no stack
Load tilted during travel
Dolly
Three or more wheeled hand truck with a flat platform
in which, since it has no handles, the load is used for
pushing
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g. Let the wheelbarrow carry the load. The operator should only balance and push.
Mechanical Handling Operations
Introduction The aim of lifting equipment is to lift material effectively, without waste of time or effort,
and without causing damage or injury to man or machine. Almost every workplace contains
parts or tools that are too heavy to lift safely by hand. Lifting equipment can be defined as
“work equipment used at work for lifting and lowering loads includes attachments used for
anchoring or supporting the load. “Such a definition covers a wide range of equipment.
Key Requirements of Lifting Equipment
a. Strength and Stability The lifting equipment must be sufficiently strong, stable for the proposed use. Similarly
the load and anything attached to it must be suitable and of adequate strength.
b. Positioning and Installation Lifting equipment must be positioned or installed to prevent risk of injury, e.g. from the
equipment or the load falling or striking people.
c. Marking of Lifting Equipment Lifting equipment, including accessories, must be visibly marked with any appropriate
information to be taken into account for its safe use, e.g. safe working load. Equipment
for lifting people must be appropriately marked, as must equipment, which must not be
used for lifting people but might be in error.
d. Organization of Lifting Operations Lifting operations must be planned, supervised, and carried out in a safe manner by
people who are competent to do so.
e. Lifting Equipment for Lifting Persons Such equipment must not present a risk of crushing or tripping, nor must people be at risk
of falling from the equipment or struck by it.
Types of Lifting Devices for Material Handling The most common lifting devices used today for handling material are stated below.
a. Cranes.
b. Portable lifting stands.
c. Chain Blocks.
d. Forklift Trucks.
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Principles of lifting device
Portable lifiting Stand
Chain Blocks
Mobile Crane
Forklift
Gantry Crane
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Overhead Crane
Chain Blocks (Tackle) Although a crane is necessary to lift heavy loads, chain blocks are frequently used in
workshops for the overhead lifting of smaller loads. To lift a load with chain blocks, it is
necessary to have a support above the load, to which the block can be fixed. Often a special
lifting jib is fixed over the place where most of the lifting needs to be done. In selecting the
support to be used, remember that any roof attachment used has to carry the total load to be
lifted plus the weight of the block, and manual pull exerted.
Forklift trucks Forklift trucks are commonly used in the workplace and industry in moving and stacking
goods on pallets. Forklift trucks can be powered by different kinds of fuels such as LPG
batteries, diesel. Forklift trucks have one major difference from ordinary road vehicles that
they are operated with rear wheel steering. As a result, both the forks and the rear of the
vehicle swing wide on corners. Forklift truck drivers have to be trained and practice for some
time before they can get used to the difference.
Mobile Cranes Mobile cranes are used to hoist loads to meet various construction and industrial needs. All
cranes use cables and pulleys or hydraulics to raise and lower the desired load. Mobile Cranes
are used in many industries and construction sites to move heavy and oversized object that
other material handling methods cannot.
The basic operational characteristics of all mobile cranes as follows:
a. Ability to lift and lower loads.
b. Ability to swing loads around an axis of rotation.
c. Adjustable boom lengths.
d. Adjustable boom angles.
e. Ability to travel about the job site under their own power.
Overhead Cranes Overhead cranes are among the most commonly used lifting devices in many industrial
workplaces. They provide both vertical and horizontal movement of heavy and oversized
loads. Overhead travelling cranes usually have three main drive mechanisms for:
a. Lifting.
b. Crane travel.
c. Hoist trolley travel.
Overhead cranes have a railed support structure called a bridge and a wheeled trolley that
travels across the bridge horizontally. A hoisting mechanism attaches to the trolley and exerts
37
force for raising and lowering. The load is attached to the hoist with an attachment such as a
sling or a hoist chain. There are several types of overhead cranes, including gantry cranes,
storage bridge cranes, mobile cranes and wall cranes. These cranes are powered similarly to
hoists, manually, electrically, or by air. Overhead cranes are used in shop environments to
maximize the use of overhead space.
Gantry Cranes Gantry Cranes are similar to overhead cranes, except that the bridge carrying the trolley is
supported on two or more legs running parallel on fixed rails; also, the legs of a gantry crane
are secured to the ground, or movable. Otherwise, the setup is basically the same with the
overhead crane.
Lifting Equipment and Lifting Gears There are many kinds of lifting equipment such as cranes, hoists, winches; chain blocks etc.,
which are used for moving materials vertically. Lifting equipment also, include devices such
as ropes, chains, slings, shackles, eyebolts etc.
Hazards
Hazards involving the use of lifting equipment include:
a. Failing down of elevated materials due to improper fixing, tying, slinging etc
b. Structural failure of lifting equipment due to overloading.
c. Overturning of mobile cranes due to improper operations.
d. Striking of persons or objects by the load as a result of inadequate visibility of the
operator.
Safety Precautions in the use of Lifting Devices
Always ensure that all lifting equipment is:
a. Sufficiently strong, stable and suitable for the proposed use. Similarly, the load and
anything attached (eg timber pallets, lifting points) must be suitable;
b. positioned or installed to prevent the risk of injury, eg from the equipment or the load
falling or striking people;
c. Visibly marked with any appropriate information to be taken into account for its safe use,
eg safe working loads. Accessories, eg slings, clamps etc, should be similarly marked.
Never exceed any safe working loads.
Additionally, you must ensure that:
a. lifting operations are planned, supervised and carried out in a safe manner by people who
are competent;
b. where equipment is used for lifting people it is marked accordingly, and it should be safe
for such a purpose, eg all necessary precautions have been taken to eliminate or reduce
any risk;
c. Where appropriate, before lifting equipment (including accessories) is used for the first
time, it is thoroughly examined.
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Chemical Safety Introduction Over the past decade there has been a vast increase in the use of chemicals, and this trend will
continue as chemicals have a direct impact on the improved quality of life. There are,
however, many risks associated with the unsafe use of chemicals at work. Therefore safety
and health in the use of chemicals offers a challenge to governments, and to employers and
workers and their representatives. Fifty years ago only 1 million tons of chemical were
produced annually. Little was known, and little was done, about the hazards associated with
chemicals and chemical processes. Today over 400 million tons of chemicals are produced
annually, and of the 5-7 million known chemical substances over 80,000 are marketed. Over
1,000 new chemicals are produced each year. It is estimated that 5,000-10,000 commercial
chemicals are hazardous, of which 150-200 are considered likely to cause cancer. It is
imperative that everyone who could potentially come into contact with chemicals should
know and understand the risks, and the methods available for reducing them. This section
covers the following topics:
a. Health risks resulting from exposure to chemical hazards at work;
b. Chemical fire and explosion hazards;
c. Basic principles of prevention;
d. Chemical emergency procedures;
e. The management of a chemical control programme.
What is a Chemical? What is a chemical? Everything is a chemical. Chemistry is the study of matter and its
interactions with other matter. Anything made of matter is therefore a chemical be it liquid,
solid, or gas, any pure substance or any mixture. Chemicals are available either in natural or
synthetic form. These chemicals are mostly found as mixtures in commercial products such as
39
agricultural chemicals, food additives, fuels for power production, chemical consumer
products, etc. One to two million of such products or trade names are available.
What is a hazardous chemical? A hazardous chemical is a chemical for which there is significant evidence that acute or
chronic health effects may occur in exposed employees.
The following properties contribute to risk to health resulting from acute, repeated or
prolonged exposure:
a. very toxic or toxic
b. harmful
c. corrosive
d. irritant
e. cancer causing
f. hazards to reproduction
g. can cause non-heritable birth defects
h. sensitizing
What is Toxicity?
Toxicity is the degree to which a substance is able to damage an exposed organism. There are no safe substances, all chemicals can be poisonous and cause injury or death. But
they can be used safely: the effect depends on the dose and exposure. It is possible by
limiting these to handle and benefit from the properties of chemical substances in an
`acceptably safe' way.
The toxic effects can be immediate or delayed, reversible or irreversible, local or systemic.
The toxic effects vary from mild and reversible (e.g., a headache from a single episode of
inhaling the vapours of ethyl acetate that disappears when the victim inhales fresh air) to
serious and irreversible (e.g., birth defects from excessive exposure to a teratogen during
pregnancy or cancer from excessive exposure to a carcinogen).
Toxic Entities There are generally three types of toxic entities; chemical, biological and physical:
a. Chemicals include inorganic substances such as lead, mercury, asbestos, hydrofluoric
acid, and chlorine gas, organic compounds such as methyl alcohol, most medications, and
poisons from living things.
b. Biological toxic entities include those bacteria and viruses that are able to induce disease
in living organisms. Biological toxicity can be complicated to measure because the
"threshold dose" may be a single organism. Theoretically one virus, bacterium or worm
can reproduce to cause a serious infection. However, in a host with an intact immune
system the inherent toxicity of the organism is balanced by the host's ability to fight back;
the effective toxicity is then a combination of both parts of the relationship. A similar
situation is also present with other types of toxic agents.
c. Physically toxic entities include things not usually thought of under the heading of
"toxic" by many people: direct blows, concussion, sound and vibration, heat and cold,
non-ionizing electromagnetic radiation such as infrared and visible light, and ionizing
radiation such as X-rays and alpha, beta, and gamma radiation.
How chemicals affect us The harmful effects of chemical substances depend on the toxicity and the exposure to that
chemical. Toxicity is a property of the chemical substance, while the exposure depends on the
way the chemical is used. For a chemical to exert an effect there has first to be exposure. If
40
there is no contact between a living organism and a chemical, no matter how toxic the
chemical, the organism cannot possibly be harmed.
Exposure to chemicals: dose-effect relationship
Chemical health hazard Chemicals have become a part of our life, sustaining many of our activities, preventing and
controlling diseases, and increasing agricultural productivity. However, one can not ignore
that these chemicals may, especially if not properly used, endanger our health and poison our
environment. Chemical health hazard is the potential of a chemical to cause harm or adversely
affect health of people in the workplace. Adverse health effect ranges from fatality, permanent
and serious health impairment to mild skin irritation at the other end. To prevent chemical risks, it
is necessary to:
a. Identify the substances present in the workplace;
b. Be aware of their risks for health and the environment;
c. Understand both employers’ and employees’ perception of risk;
d. Identify alternatives that bear lesser risk; and
e. Evaluate the advantages and inconveniences that these alternatives may present from a
legal, environmental, occupational and economic perspective, before implementing them.
Fig 1. Factors that determine the chemical effects on a worker
Acute effects - Chronic effects The effects may be acute: after a short exposure an immediate effect may be experienced.
Chronic effects usually require repeated exposure and a delay is observed between the first
41
exposure and appearance of adverse health effects. A substance may have acute and chronic
effects. Both acute and chronic conditions can result in permanent injury.
Local effects - Systemic effects Hazardous substances may cause local effects. Acute local effects may include corrosive
injuries from acids and bases or lung injuries from inhaled gases such as ozone, phosgene and
nitrogen oxides. Systemic effect refers to an adverse health effect that takes place at a
location distant from the body's initial point of contact and presupposes absorption has taken
place.
a. Local effects - stomach irritation and stomach upset.
b. Systemic effects - an increase in the blood alcohol level, which can cause damage to
brain cells.
c. Acute effects - drunkenness, headache and a hangover.
d. Chronic effects - permanent liver damage, which can have a latency period of many
years.
Fig, 2. Local and Systemic effects
Routes of entry of workplace chemicals into the body a. Inhalation (breathing in)
b. Absorption (through the skin or eyes)
c. Ingestion (eating, swallowing)
Other routes of entry include
a. Transfer across the placenta to the unborn baby
b. Intravenous (injection into the vein)
42
c. Intramuscular (injection into the muscle)
d. Subcutaneous (injection under the skin)
Fig. 3. Routes of entry of chemical into the body
Table 1. The physical form, route of entry, affected organ and type of toxicity of some
common industrial chemicals.
Chemical Physical
form Method of
entry Organ(s)
that
can be
affected
Class of
toxicity Symptoms Examples of
industries
where the
chemicals are
used
Cadmium
metal and
some of its
compounds
Dusts,
vapours, Inhalation Lungs,
throat,
kidneys
Poisonous,
causing
damage to
lungs, kidneys
on chronic
exposure.
Dry burning
throat, chest
pain, vomiting,
headaches
Metal
industries,
welding
processes,
heavy
chemicals
Dusts Ingestion
Toluene di-
isocyanate Vapour
Inhalation
Lungs
Allergenic
Industrial
asthma due to
lung effects
Industrial
processes
involving
polyureth
ane
manufact
ure,
paints and inks
Solid Spillage on
skin Skin Allergenic Dermatitis
43
Target Organ Effects of Chemicals 1. Hepatotoxins damage the liver.
2. Nephrotoxins damage the kidneys.
3. Neurotoxins adversely affect the nervous system.
4. Hematopoietic Agents decrease haemoglobin function and deprive the body tissues of
oxygen.
5. Agents which damage the lung irritate or damage pulmonary tissue.
6. Reproductive toxins affect reproductive capabilities including chromosomal damage
(mutations) and effects on foetuses (teratogens).
7. Cutaneous hazards affect the skin, or dermal layer, of the body.
8. Eye hazards affect the eye or visual capacity.
Fig.4. Target organ of chemical
Forms of chemical found in the workplace The physical form of a chemical can affect how it enters your body and to some extent, the
damage it causes. The main physical forms are stated below.
a. Solid. This form is the least likely to cause chemical poisoning. However, certain
chemical solids can cause poisoning if they get onto your skin, or into food;
44
b. Dust. Dust is made of tiny particles of solids. Exposure can be either from materials that
normally exist in dust form (for example, bags of cement), or from work processes that
create dust (for example, handling glass fibres that produce toxic dust);
c. Liquid. Many hazardous substances, such as acids and solvents, are liquids when they are
at normal temperature;
d. Vapour. This is the gas phase of a material that is found as a liquid under normal
conditions. Tiny droplets of liquid which are suspended in the air are called mists; and
e. Gases. Some chemical substances exist as a gas when they are at a normal temperature.
However, some chemicals in liquid or solid form become gases when they are heated.
Other physical forms are aerosols, fumes, smokes, and fogs.
Fig. 5, Chemicals can change their physical form, e.g. wood into sawdust.
Common forms of Chemical That Cause Health Risks a. Dusts
b. Acids and bases
c. Fumes/vapour
d. Solvents
e. Pesticides
f. Gases
g. Metals
Labels
45
The hazard classification and labelling process is an essential tool for establishing an
effective information transfer so that the degree of the hazard the chemical represents for man
and the environment can be recognized, the correct preventive actions be chosen, and safe use
achieved. The label is the basic tool to keep the user informed on the classification of a
product’s hazard and the most important safety precautions. Labels must be attached to the
container, and correspond to the exact chemical that can be found in the container.
Fig. 7 Labelling of chemicals
It is important to know that most industrial chemicals have two names: (1) a trade name by
which the chemical is commonly known, for example “Wonderglu” or “Supabat”, which does
not tell you anything about the chemical — it is simply the brand name used to advertise the
chemical; and (2) the chemical (generic) name which tells you the exact ingredients (the
ingredients are often in small writing on the label).
SODIUMTRICHLOROACETATE
(NaTA)
Dangerous to health
safety - hazards: dangerous to
health, especially
when swallowed!
may decompose above
110����C (230����F) and
form poisonous gases
safety - directions
1. keep container tightly closed and store in cool, dry area
2. keep material away from food
3. avoid contact with skin and eyes
4. rinse contaminated articles and floors thoroughly with
water
5. avoid elevated temperatures in case of fire do not inhale
smoke
Labelling systems International, regional, and national classification and labelling systems are already
established some of them are stated below:
46
a. The United Nations Recommendations on the Transport of Dangerous Goods is widely
recognized and used among the UN member states;
b. The classification and labelling system of the European Union which is used beyond the
EU countries; and
c. Several functioning national systems, such as those of Canada and USA, may also be
used as models for national systems.
d. The globally harmonized system of classification and labelling of chemicals (GHS)
Fig.9. Label under EU regulation
The globally harmonized system of classification and labelling of chemicals (GHS) The globally harmonized system of classification and labelling of chemicals (GHS) is an
internationally recognized system set to replace the various classification and labelling
standards used in different countries. The GHS establishes consistent criteria for
classification and labelling of chemicals on a global scale. It covers all hazardous chemicals,
including substances and mixtures.
Information on GHS labels The required information in the GHS labels includes:
a. Symbols (hazard pictograms)
b. Signal Words: “Danger” or “Warning”
c. Hazard Statements: Additional label elements included in the GHS are:
a. Precautionary statements:
b. Product identifier:
c. Supplemental information.
Safety data sheets (MSDS) Safety data sheet (or SDS) is the name given to the Material Safety Data Sheet of the
Globally Harmonized System of Classification and Labelling of Chemicals (GHS).
Safety Data Sheets contain identification information about the substance (composition,
physical, chemical and toxicological hazards), information on specific protection and
prevention measures throughout the whole process (production, storage, transport, etc.),
measures to undertake in case of an accident (spillage, fire-fighting measures, etc.), as well as
47
contact details of the supplier. The information in the SDS should be presented using the
following 16 headings in the order given below:
1. Identification 2. Hazard identification
3. Composition/information on ingredients
4. First-aid measures
5. Fire-fighting measures
6. Accidental release measures
7. Handling and storage
8. Exposure controls/personal protection
9. Physical and chemical properties
10. Stability and reactivity
11. Toxicological information
12. Ecological information
13. Disposal considerations
14. Transport information
15. Regulatory information
16. Other information
PREVENTIVE MEASURES
1. Substitution
Replace the hazardous chemical with another less dangerous one
2. Engineering control
Enclosed process
Ventilation
3. Safe working procedures - Codes of Practice
4. Reducing exposure
The number of exposed workers
Reducing the length of time and/or frequency of exposure
5. Personal protective equipment
6. Monitoring
Working environment
Medical monitoring of workers
7. Hazard communication
Labelling of chemicals
Chemical Safety Data Sheets
8. Training
Use of chemicals
Emergency situation
First aid training
Provisions and legislation concern
Substitution Substitution of a less toxic material
Change in process to minimize contact with hazardous chemicals
Isolation or enclosure of a process or operation
Use of wet methods to reduce generation of dusts or other particulates
Engineering Controls General dilution ventilation
Local exhaust, including the use of fume hoods
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Closed system
Housekeeping
Management controls
a. Restricted entries
b. Special attention to high-risk groups
c. Job rotation
d. Observing re-entry intervals in sprayed places
Use of personal protective equipment and personal hygiene Personal protective equipment against chemicals includes:
a. Face shields, goggles and safety glasses;
b. Gloves;
c. Rubber boots;
d. Plastic or rubber overalls and aprons;
e. Hard hats;
f. Respirators; and
g. Dust masks.
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Machinery Hazards, Prevention and Protection Measures
Introduction In the manufacturing industry, production consists of processing, assembling, and
transporting materials. In modern times, machines use large amounts of energy to absorb the
burden from workers to assist in production. Trained workers based on experience in
operating the machines create more stable quality, causing the relationship between machines
and production to continue and evolve into many forms today. Machinery has the potential to
cause severe and fatal injuries. It is estimated that half of machinery accidents arise during
maintenance. This means that all dangerous parts must be guarded.
Concept of Machine Safety The relationship between workers and machines and the environment in which they operate
has thus changed on a global scale. And yet, manufacturing is not possible until a worker
operates a machine. Across changes in the operating environment, safety demands that
machines and production facilities should be used safely regardless of where they are used or
who uses them. This is required not only in the workers, but also in the machines and
hardware technology. As a result, global standards for safety are required for today's
production sites.
Hazards Generated by Machinery Hazards occur in areas where machine work areas (machine operating output) and human
work areas overlap. Danger from machinery can arise in two main ways.
1. Firstly by machinery hazards, including traps, impact, contact, entanglement or through
ejection of materials or machine parts.
2. Secondly through non machinery hazards, which include electrical failure, exposure to
chemicals, pressure, extremes of temperature, noise, vibration and radiation. Danger can
also arise from the software element; computer control and human error by the person
carrying out the task at the machine
Fig 1. Hazards occur in areas where machine work areas and human work areas overlap
Human Workspace
Machine Workspace
Hazard Zone
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Source: http://www.ia.omron.com
Fig. 2. Safety Procedure for Machinery
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Fig. 3. Risk Reduction Processes from the Designer’s Perspective
Typical Machinery Hazards
1. Mechanical Hazards
2. Electrical Hazards
3. Thermal Hazards
4. Hazards Generated by Noise
5. Hazards Generated by Vibration
6. Hazards Generated by Radiation
7. Hazards Generated by Materials and Substances
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8. Hazards Generated by Neglecting Ergonomic Principles in Machine Design
9. Hazards associated with the environment in which the machine is used
10. Hazards combinations
Machinery Hazards Injuries Many serious accidents at work involve the use of machinery. People can be injured by
machinery in five different ways. Some machines can injure in more than one way. The five
ways are:
1. Traps: The body or limb(s) become trapped between closing or passing motions of the
machine. In some cases the trap occurs when the limb(s) are drawn into a closing motion,
for example in-running nips.
2. Impact: Injuries can result from being struck by moving parts of the machine.
3. Contact: Injuries can result from contact of the operator with sharp and abrasive surfaces.
Alternatively, contact with hot or electrically live components will cause injury on
contact.
4. Entanglement: Injuries resulting from the entanglement of hair, jewellery, items of
clothing in moving (particularly rotating) parts of machinery.
5. Ejection: Injuries can result from elements of the work-piece or components of machinery
being thrown out during the operation of the machine, for example sparks, swarf, chips,
molten metal splashes and broken components
Causes of Machinery Accidents
a. Reaching in to remove debris or loosen a jam
b. Not using lockout/tagout
c. Unauthorized persons doing maintenance or using the machines.
d. Missing or loose machine guards.
e. Operators/users not properly trained.
Contact with Dangerous Parts of machinery can be achieved by:
1. Unsafe (Unauthorised) Behaviours :
(i). Violations - deliberate deviation from rules/procedures
(ii). Errors - of commission (failure to perform an act correctly)
(iii). Errors of omission (failure to act e.g not turning off power)
2. Authorised Behaviours :
Maintenance, Repair, Inspection activities
3. Accidental Events: e.g. tripping / slipping –collision with or falling into equipment
Machinery Hazards Prevention Preventing machinery hazards begins by eliminating mechanisms that facilitate hazardous
conditions. The following strategies are generally used to achieve this goal:
1. Spatial separation between human and machine workspaces (Isolation principle, Safety
protection like guards, machine layout)
2. Temporal separation (stoppage principle: Safety by Design)
3. Safe Systems of Working
4. Operator training and supervision
5. Machine maintenance and inspection
6. The provision of personal protective equipment.
Safety by Design
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Safety by design is the process by which the designer of the work equipment eliminates
hazards at the design stage with consideration for the elimination of dangerous parts or
making dangerous parts inaccessible, reducing the need to handle work pieces in the danger
area, provision of automatic feed devices, and enclosure of the moving parts of the machine.
Other areas, which should be covered at the design stage, include:
Controls: The design and provision of controls which:
a. Are in the correct position;
b. Are of the correct type;
c. Remove the risk of accidental start up;
d. Have a directional link (control movement matched to machinery movement);
e. Distinguished by direction of movement;
f. Have distinguishing features (size, colour, feel e.t.c).
Failure to Safety: Designers should ensure that machines fail to safety and not to danger.
Examples of this are; provision of arrestor devices to prevent unexpected strokes and
movements, fitting of catches and fall back devices, and fail safe electrical limit switches.
Safe Systems of Working Where machinery is in operation systems of working must be put in place that prevents
danger to operators or other persons who may be exposed. Permit to work systems should be
in place where individuals may have to enter hazardous environments. Safe systems should
be designed to ensure that people exposed to the work activities are not at risk.
Operator training and supervision Training should take account of the nature of the hazard, the experience of the operator and
any other points of vulnerability such as young people, pregnancy or disability. Supervision
should be such that best practice is always complied with.
Machine Maintenance and Inspection Depending upon the use equipment is put to; it should be regularly inspected and maintained.
Such maintenance should be part of systematic schedules of work. In some cases,
particularly lifting equipment and air receivers there is a statutory duty to carry out
inspections. The safety of operatives during cleaning and maintenance operations should be
designed into machinery. Positive lock off devices should be provided to prevent
unintentional restarting of machinery.
Machine Layout: The way in which machines are arranged in the workplace can reduce
accidents significantly. A safe layout will take account of:
a. Spacing - to facilitate access for operation, supervision, maintenance, adjustment and
cleaning.
b. Lighting - both general lighting to the workplace (natural or artificial, but avoiding glare)
and localised for specific operations at machines.
c. Cables and pipes - should be placed to allow safe access and avoid tripping, with
sufficient headroom.
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Machine Guards
A machine guard is a rigid cover that shields workers from moving machine parts and flying
debris. Injuries arising from exposure to unprotected moving machine parts include Crushed
hands and arms, severed fingers, blindness etc, These injuries may range from minor to
severe and cause the employee pain, suffering, lost wages and lost work time. It is important
for employees to understand that guards are provided to protect them from injury.
In effective guard Effective guard
Most modern machine designs incorporate proper machine guards to prevent access to
dangerous parts of the machine. Guards are engineered to give as much protection as
possible. However, many older and rebuilt machines do not necessarily offer the proper
protection from moving parts. Also, when workers are servicing and maintaining machines,
they are often exposed to areas that are typically guarded, such as the motor connections and
nip points. For this reason, employers must do everything they can to properly guard
machinery, and employees must be trained to recognize machine hazards and prevent injuries
whether or not guards are in place. Machine guards must meet the following minimum general
requirements to protect workers against mechanical hazards:
1. Be securely attached
2. Create no new hazards
3. Withstand operational conditions
4. Allow for safe routine maintenance
5. Allow for safe operator adjustments
6. Withstand environmental conditions
7. Provide protection from falling objects
8. Prevent contact with hazardous conditions
9. Create no interference in the conduct of work
Hierarchy of Control to be used for the selection of machine guards The type of machine guard used will depend very much on the type of machine part which
needs guarding, the access requirements to the part and the feasibility of the guard. The
following gives a hierarchy to be used for the selection of machine guards/controls:
1. Where access to the danger area is not required during normal operation:
a. Fixed guard, where practicable
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b. Distance guard
c. Trip device
2. Where access to the danger area is required during normal operation:
a. Interlocked guard
b. Automatic guard
c. Trip device
d. Adjustable guard
e. Self-adjusting guard
f. Two-handed control
3. Parts of machine to be guarded
Parts of Machine to be safeguarded include:
1. Where Mechanical Hazards Occur
a. The Point of Operation:
b. Power Transmission Apparatus:
c. Other Moving Parts:
2. The Point of Operation: Where work is performed on the
material, such as:
a. Cutting
b. Shaping
c. Boring
d. Forming of stock
3. Power Transmission Apparatus: All components of the
mechanical system which transmit energy to the part of the
machine performing the work such as:
a. Rotating parts
b. Feed mechanisms
c. Reciprocating parts
d. Transverse moving parts
e. Auxiliary parts of the machine
�
�
�
Hazardous Mechanical Motions and Actions A wide variety of mechanical motions and actions may present hazards to the worker:
56
a. Rotating members
b. Reciprocating arms
c. Moving belts
d. Meshing gears
e. Cutting teeth
f. Any parts that impact or shear
�
�
�
The basic types of hazardous mechanical motions and actions
Motions a. Rotating
b. In-running Nip Points c. Reciprocating d. Transversing
NIP POINT
Actions a. Cutting
b. Punching
c. Shearing
d. Bending
SHEARITE
CUTTING BLADES
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Hazardous Mechanical Motions
Rotating motion
a. Collars
b. Couplings
c. Cams
d. Spindles
e. Meshing gears
f. Fans
g. Clutches
h. Flywheels
i. Shafts
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Rotating and fixed parts Rotating and tangentially moving
Parts rotating in opposite direction
Reciprocating motion
Transverse motion
Examples:
Conveyor lines
Lengthy belts
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Hazardous Mechanical Actions
Cutting Bending
Punching Shearing
Methods of Machine Guarding There are many ways to safeguard machines. The type of operation, the size or shape of
stock, the method of handling, and the physical layout of the work area, the type of material,
and production requirements or limitations will help determine the appropriate safeguarding
method for the individual machine. The two principal methods of guards are stated below:
Guards Devices
a. Fixed
b. Interlocked
c. Adjustable
d. Self-adjusting
a. Presence-Sensing Devices
b. Photoelectric (optical)
c. Radiofrequency (capacitance)
d. Electromechanical
e. Pullbacks
f. Restraints
g. Gates
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Other safeguarding strategies may include: a. Location/Distance
Miscellaneous aids can help reduce exposure a. Awareness barriers Protective shields
b. Hand-feeding tools and holding fixtures
Guards Guards are physical barriers which prevent access to danger areas.
1. Fixed
2. Interlocked
3. Adjustable
4. Self-adjusting
Fixed Guards a. Permanent part of the machine.
b. Not dependent upon moving parts to perform its intended function.
c. Constructed of sheet metal, screen, wire cloth, bars, plastic, or other substantial material
d. Usually preferable to all other types because of its relative simplicity and permanence.
Interlocked Guards a. When opened or removed, the tripping mechanism and/or power automatically shuts off
or disengages
b. Machine cannot cycle or be started until the guard is back in place
c. Electrical, mechanical, hydraulic, or pneumatic power
d. Replacing the guard should not automatically restart the machine
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Adjustable Guards Allow flexibility in accommodating various sizes of stock
Self-adjusting Guards a. Openings are determined by the movement of stock
b. Guard is pushed away as stock is introduced;
c. Opening is only large enough to admit the stock;
d. Guard returns to rest position after stock passes through.
Devices A safety device may perform one of several functions.
a. It may stop the machine if a hand or any part of the body is inadvertently placed in the
danger area;
b. Restrain or withdraw the operator's hands from the danger area during operation;
c. Require the operator to use both hands on machine controls; or
d. Provide a barrier which is synchronized with the operating cycle of the machine in order
to prevent entry to the danger area during the hazardous part of the cycle.
Type of Safety Devices
a. Presence-Sensing Devices
b. Photoelectric (optical)
c. Radiofrequency (capacitance)
d. Electromechanical
e. Pullback
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f. Restraint
g. Safety Trip Controls
h. Two-Hand Controls
i. Gate
Location & Distance The machine or its dangerous moving parts are positioned so that the hazardous areas are not
accessible or do not present a hazard during normal operation
a. Walls
b. Barriers/Fences
c. Height above worker
d. Size of stock (single end feed, punching)
e. Controls (positioned at a safe distance)
Miscellaneous Aids May not give complete protection from machine hazards, but may provide the operator with
an extra margin of safety. Examples:
a. Awareness barriers
b. Ropes
c. Shields
d. Holding tools
e. Push sticks or blocks
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Quiz a. Machine guarding protects operators and prevents injury from……
b. Three basic areas require machine safeguarding. Name them:
c. What are the three types of equipment/machine motions that present hazards to the
worker?
d. What are the four types of equipment/machine actions that can injure the worker?
e. List the four general types of guards.
f. List at least two types of safeguard devices.
g. What are the requirements for effective guards?
h. Describe at least two of the main causes of machine accidents.
i. List three of the requirements for safeguards.
j. List 5 machinery parts that pose hazards when unguarded or improperly guarded.
k. List at least five types of machine guards
l. List at least three types of devices used to safeguard machines.
GUIDANCE AND STANDARDS There are numerous standards for machine guarding and machine specific standards.
Standards should be researched and consulted where they exist. The main standards are:
1. BS EN ISO14121-1:2007, “Safety of machinery – Principles for risk assessment”
2. BS-EN953:1998, “Safety of machinery – Guards – General requirements for the design
and construction of fixed and movable guards”.
3. BS EN294:1992, “Safety of machinery – Safety distances to prevent danger zones being
reached by the upper limbs”.
4. BS EN811: 1997, “Safety of machinery – Safety distances to prevent danger zones being
reached by the lower limbs”.
5. BS EN1088:1995, amended in 2007, “Safety of machinery – Interlocking devices
associated with guards, principles for design and selection”.
6. PD5304:2005, “Guidance on safe use of machinery” – although not a standard this is a
BSI published documented based on BS5304:1998 and contains a wealth of useful
guidance and practical examples of guard designs.
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NOISE SAFETY Introduction Not all sound is noise — noise is sound that people do not like. Noise can be annoying and it
can interfere with your ability to work by causing stress and disturbing your concentration.
Noise can cause accidents by interfering with communication and warning signals. Noise can
cause chronic health problems. Noise can also cause you to lose your hearing.
Hearing loss from exposure to noise in the workplace is one of the most common of all
industrial diseases. Workers can be exposed to high noise levels in workplaces as varied as
construction industries, foundries and textile industries. Short-term exposure to excessive (too
much) noise can cause temporary hearing loss, lasting from a few seconds to a few days.
Exposure to noise over a long period of time can cause permanent hearing loss. Hearing loss
that occurs over time is not always easy to recognize and unfortunately, most workers do not
realize they are going deaf until their hearing is permanently damaged. Industrial noise
exposure can be controlled — often for minimal costs and without technical difficulty. The
goal in controlling industrial noise is to eliminate or reduce the noise at the source producing
it.
1. Health effects of noise exposure What are the health effects of exposure to too much noise?
The health effects of noise exposure depend on the level of the noise and the length of the
exposure.
A. Temporary hearing loss After spending a short time in a noisy workplace, you may have noticed that you cannot hear
very well and you have a ringing in your ears. This condition is called temporary threshold
shift. The ringing and the feeling of deafness normally wear off after you have been away
from the noise for a short time. However, the longer you are exposed to the noise, the longer
it takes for your hearing to return to “normal”. After leaving work, it may take several hours
for a worker's ears to recover. This may cause social problems because the worker may find it
difficult to hear what other people are saying or may want the radio or television on louder
than the rest of the family.
Suspect hearing loss if a person complains that he or she cannot hear something when you
can.
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B. Permanent hearing loss Eventually, after you have been exposed to excessive noise for too long, your ears does not
recover and the hearing loss becomes permanent. Permanent hearing loss can never be
repaired. This type of damage to the ear can be caused by long-term exposure to loud noise
or, in some cases, by short exposures to very loud noises.
When a worker begins to lose his or her hearing, he or she may first notice that normal
talking or other sounds, such as warning signals, are becoming unclear. Workers often adapt
themselves (“get used to”) to hearing loss produced by harmful noises at work. For example,
they may begin to read lips as people talk, but have difficulty listening to someone in a crowd
or on the telephone. In order to hear the radio or television they may need to turn up the
volume so much that it deafens the rest of the family. “Getting used to” noise means you are
slowly losing your hearing.
Hearing tests are the only reliable way to find out whether a worker is suffering from hearing
loss. Unfortunately, hearing tests can be difficult to obtain and need to be performed by a
trained health-care professional. The reactions of new workers or visitors to a noisy
workplace can be indicators of a noise problem, for example if they have to shout, cover their
ears, or leave “in a hurry”.
C. Other effects In addition to hearing loss, exposure to noise in the workplace can cause a variety of other
problems, including chronic health problems:
a. Exposure to noise over a long period of time decreases coordination and concentration.
This increases the chance of accidents happening.
b. Noise increases stress, which can lead to a number of health problems, including heart,
stomach and nervous disorders. Noise is suspected of being one of the causes of heart
disease and stomach ulcers.
c. Workers exposed to noise may complain of nervousness, sleeping problems and fatigue
(feeling tired all the time).
d. Excessive exposure to noise can also reduce job performance and may cause high rates of
absenteeism.
Masking noise
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2. Measuring noise Noise in the workplace may be disturbing because of its frequency as well as its volume. For
example, a high-pitched noise, such as a whistle, irritates the ears much more than a noise
with a low pitch, even if the volume is the same in both cases.
A. Decibels Sounds have different intensities (loudness). For example, if you shout at someone instead of
whispering, your voice has more energy and can travel a great distance, therefore it has more
intensity (loudness). Intensity is measured in units which are calls decibels (dB) or dB(A).
The decibel scale is not a typical scale — it is a logarithmic scale. Basically this means that a
small increase in the decibel level is, in reality, a big increase in the noise level.
For example, if sound is increased by 3 dB at any level, your ears will tell you that the sound
has approximately doubled in volume. Similarly, if sound is reduced by 3 dB, your ears will
feel that the volume has been cut in half. Therefore, an increase of 3 dB from 90 dB to 93 dB
means the volume of the noise has doubled. However, a 10 dB increase at any level (for
example, from 80 dB to 90 dB) means the noise intensity has increased ten times.
Inside a typical workplace, noise comes from different sources, such as tools (machinery and
materials handling), compressors, background noise, etc. If you want to identify all of the
noise problems in the workplace, then you must measure the noise from each source
separately. For example, if two different sources of noise in a workplace each create 80 dB by
themselves, the level of noise they make together is 83 dB (not 160 dB). Therefore when you
consider the amount of noise the two sources make together, the level of noise has doubled.
An effective way to measure the noise in your workplace is with a sound meter.
Unfortunately, it can be difficult to get the meters and the trained personnel to use them.
However, there is a simple method that will help you to understand if there is a noise problem
in your workplace:
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Simple method for assessing noise exposure Stand at arm's length from a co-worker. If you cannot speak in a normal tone and have to
shout to communicate, then the noise level in your workplace is too high and should be
reduced!
B. Safe noise levels Is there a safe level of noise?
A safe level of noise basically depends on two things:
(1) the level (volume) of the noise; and
(2) how long you are exposed to the noise.
The level of noise allowed by most countries' noise standards is generally 85-90 dB over an
eight-hour workday (although some countries recommend that noise levels be even lower
than this).
Exposure to higher noise levels may be allowed for periods of less than eight hours of
exposure time. For example, workers should not be exposed to noise levels above 95 dB for
more than four hours per day. Exposed workers should be provided with ear protection while
exposed at this level and rotated out of the noise areas after four hours of continuous work.
Of course before using ear protection and rotation every effort should be made to reduce
noise using engineering controls.
The eight-hour per day exposure limit found in a noise standard is the total amount of noise
that a worker may be exposed to over an eight-hour period. The exposure may be from
continuous (constant) noise, or from intermittent noise (noise that is periodic at regular
intervals but not continuous). Therefore, you must add up the levels of noise you are exposed
to throughout the day and see if they exceed 85-90 dB. Note: workers should never be
exposed to more than 140 dB of impulse noise (usually a very loud noise that occurs only
once) at any time. The following chart gives recommended limits of noise exposure for the
number of hours exposed.
No. of hours exposed Sound level dB
8 90
6 92
4 95
3 97
2 100
1.5 102
1 105
0.5 110
0.25 or less 115
3. Methods of noise control
How can noise be controlled? Workplace noise can be controlled: (1) at the source; (2) through the use of barriers; and (3)
at the worker.
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A. At the source As with other types of exposures, the best method of prevention is to eliminate the hazard.
Therefore controlling noise at its source is the best method of noise control. It can also often
be cheaper than other methods of noise control. This method of control may require that some
noisy machinery be replaced. Noise can be controlled at the source by the manufacturer, so
that noisy devices never reach your workplace. Many machines are now required to conform
to noise standards. Therefore before new machines (such as presses, drills, etc.) are
purchased, checks should be made to see that they conform to noise standards. Unfortunately,
many used machines producing high noise levels (which have been replaced with quieter
models) are often exported to developing countries, causing workers to pay the price with
hearing loss, stress, etc.
Put a silencer on the machine instead of ear protectors on the workers.
Noise control at the source can also be engineered into an existing device by making
adjustments to parts or a whole machine that reduce noise. For example, the noise level from
a pneumatic drill can be reduced by placing a sound-reducing blanket around the drill. A
length of tubing on the exhaust of the drill will also reduce the noise level. A rubber covering
can be used to reduce noise from metal falling on to metal. Other engineering methods to
reduce noise include:
a. preventing or reducing impact between machine parts;
b. reducing speeds gently between forward and reverse movements;
c. replacing metal parts with quieter plastic parts;
d. enclosing particularly noisy machine parts;
e. providing mufflers for the air outlets of pneumatic valves;
f. changing the type of pump in hydraulic systems;
g. changing to quieter types of fans or placing mufflers in the ducts of ventilation systems;
h. providing mufflers for electric motors;
i. providing mufflers for intakes of air compressors.
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Noise - insulated air compressors. The principle is that the noise should be contained under the hood. The hood is made of hard
material with a soft, absorbent lining.
Regular maintenance, lubrication and replacement of worn or defective parts can also be
effective ways to reduce noise levels. Noise from the way materials are handled can be
reduced by measures such as:
a. reducing the dropping height of goods being collected in bins and boxes;
b. increasing the rigidity of containers receiving impact from goods, or damping them
with damping materials;
c. using soft rubber or plastic to receive hard impacts;
d. reducing the speed of conveyor systems;
e. using belt conveyors rather than the roller type.
A machine vibrating on a hard floor is a common source of noise. Mounting vibrating
machines on rubber mats or other damping material will reduce the noise problem.
B. Barriers If it is not possible to control the noise at the source, then it may be necessary to enclose the
machine, place sound-reducing barriers between the source and the worker, or increase the
distance between the worker and the source. (However, this can be difficult in many cases.)
The following chart is a simple method of knowing how much sound is reduced by distance.
If a small sound source produces a sound level of 90 dB at a distance of 1 meter, the sound
level at a 2-meter distance is 84 dB, at 4 meters 78 dB, etc.
Here are a few points to remember when controlling noise with barriers:
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a. an enclosure should not be in contact with any part of the machine;
b. holes in the enclosure should be minimized;
c. access doors and holes for wiring and piping should be fitted with rubber gaskets;
d. panels of insulating enclosures must be covered inside with sound-absorbent material;
e. exhausts and air vents must be silenced and directed away from operators;
f. the noise source should be separated from other work areas;
g. the noise should be deflected away from work areas with a sound-insulating or reflecting
barrier;
h. Sound-absorbent materials should be used, if possible, on walls, floors and ceilings.
C. At the worker Controlling noise at the worker, by using ear protection (sometimes called hearing protection)
is, unfortunately, the most common yet least effective form of noise control. Forcing the
worker to adapt to the workplace is always the least desirable form of protection from any
hazard. Generally there are two types of ear protection: earplugs and earmuffs. Both are
designed to prevent excessive noise from reaching the inner ear.
Earplugs are worn inside the ear and come in a variety of materials, including rubber, plastic,
or any material that will fit tightly in the ear. Earplugs are the least desirable type of hearing
protection because they do not provide very effective protection against noise and they can
cause ear infection if pieces of the plug are left in the ear or if a dirty plug is used. Cotton
wool should not be used as ear protection.
Earplugs and earmuffs:
(1) Formable wadding-acoustical fibres;
(2) Plastic-covered acoustical fibres;
(3) Expandable plastics;
(4) Reusable plastic earplugs;
(5) Earmuffs.
Earmuffs are more protective than earplugs if they are used correctly. They are worn over the
whole ear and protect the ear from noise. Earmuffs are less efficient if they do not fit tightly
or if glasses are worn with them.
Ear protection is the least acceptable method of controlling an occupational noise problem
because:
a. the noise is still present: it has not been reduced;
b. in hot, humid conditions workers often prefer earplugs (which are less effective) because
earmuffs make the ears sweaty and uncomfortable;
c. management does not always provide the correct type of ear protection: often it is a case
of “the cheaper the better”;
d. workers cannot communicate with each other and cannot hear warning signals;
e. if ear protection is provided instead of controlling the noise at source, then management is
putting the responsibility on the worker — it becomes the worker's fault if he or she
becomes deaf.
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Summary Temporary or permanent hearing loss from occupational noise exposure is one of the most
common of all industrial diseases. Occupational noise exposure can cause a number of
chronic health problems in addition to hearing loss. However, noise can be controlled by a
variety of methods, the most effective of which is controlling noise at the source; the least
acceptable method is relying on ear protection.
Generally 85-90 dB over an eight-hour workday is the allowable level of noise, although it is
better to reduce noise even further, whenever possible. There are a number of steps you and
your union can take towards controlling noise in your workplace.
Exercise. Case-study on occupational noise
The following case - studies are based on real situations.
Case 1
The problem Company XYZ is a manufacturer with five power presses producing noise levels of 102 - 104
dB. Even when only one or two presses are operating, the noise levels are still as high as 98
dB. This is painful for the workers and puts them in serious danger of losing their hearing.
Question (1) What solutions to this problem can you suggest?
How the problem was solved To solve the problem, the power presses were moved to a distance of 20 metres from the
place where most of the workers were located. In this way, the workers were exposed to
acceptable noise levels of 75-80 dB. Workers who operated the power presses were provided
with earmuffs and rotated to a quieter section of the factory after a maximum of four hours'
continuous work in the power press area.
Questions a. Were these actions good solutions to the problem? Why or why not?
b. Are workers safe if they are exposed to excessive noise for only four hours?
c. Do you think there was still noise exposure for the workers even after the changes were
made?
d. Can you think of any better solutions to the problem?
e. Why are earmuffs not an acceptable solution to noise exposure?
Case 2
The problem Company ABC produces nails. The machines that cut the nails produce a noise level of 95
dB. These machines are all in a row in one section of the factory and need to be operated by a
worker for eight hours a day. All workers have been given ear protectors but they do not wear
them because it is too hot and uncomfortable.
Question (1) What solutions to this problem can you suggest?
How the problem was solved The union and the employer discussed the noise problem and decided that enclosing the nail-
cutting machines would cost less than buying ear protectors for all of the workers.
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Inexpensive, local materials were used to build a full enclosure around the machines. The
enclosure reached from the floor to the ceiling, with no holes except the door to enter the
machine area. The enclosure reduced the noise level outside the machine area to 85 dB.
Workers operating the nail-cutting machines were required to wear earmuffs and were also
rotated out of that area after four hours of continuous work there. A sign was placed on the
door to the enclosed area reminding workers to put on their earmuffs before entering the
noisy area.
Questions a. Were these actions good solutions to the problem? Why or why not?
b. Why were the workers rotated out of the enclosed area after four hours of continuous
work there?
c. Can you think of any better solutions to the problem?
d. Are the solutions to this case better than the solutions that were used for the first case?
Why or why not?
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Confined Space Safety
Introduction Many workers are injured and killed each year while working in confined spaces. An
estimated 60% of the fatalities have been among the would-be rescuers without proper
training and equipment. A confined space can be more hazardous than regular workspaces for
many reasons. To effectively control the risks associated with working in a confined space, a
Confined Space Hazard Assessment and Control Program should be implemented for your
workplace.
What Is a Confined Space? Confined Space it’s an enclosed space large enough for employee to bodily enter and perform
assigned work, has limited or constricted means of entry or exit, and is not designed for
continuous employee occupancy. Generally speaking, a confined space is an enclosed or
partially enclosed space that:
a. Contains or has the potential to contain a hazardous atmosphere.
b. Contains a material that has the potential for engulfment of the entrant.
c. Has an internal configuration such that an entrant could be trapped or asphyxiated (such
as sloping walls or floors that reduce the area to a point of constriction.
d. Contains any other recognized serious safety or health hazard.
Confined spaces can be below or above ground. Confined spaces can be found in almost any
workplace. Examples of confined spaces include:
a. Storage tanks,
b. Process vessels, dikes
c. Pits, vats, and vaults,
d. Sewage digesters and sewer silos,
e. Tunnels, manholes, utility vaults,
f. Pumping stations and enclosed grit chambers.
g. Ditches and trenches may also be a confined space when access or egress is limited.
h. Silos, and hoppers, etc.
It is not possible to provide a comprehensive list of confined spaces. Some places may
become confined spaces when work is carried out, or during their construction, fabrication or
subsequent modification.
Reasons for Entering Confined Space Entering a confined space as part of the industrial activity may be done for various reasons.
a. It is done usually to perform a necessary function, such as inspection, repair, maintenance
(cleaning or painting), or similar operations, which would be an infrequent or irregular
function of the total industrial activity.
b. Entry may also be made during new construction. Potential hazards should be easier to
recognize during construction since the confined space has not been used. The types of
hazards involved will be limited by the specific work practices. When the area meets the
criteria for a confined space, all ventilation and other requirements should be enforced.
c. One of the most difficult entries to control is that of unauthorized entry, especially when
there are large numbers of workers and trades involved, such as welders, painters,
electricians, and safety monitors.
d. A final and most important reason for entry would be emergency rescue.
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This, and all other reasons for entry, must be well planned before initial entry is made and the
hazards must be thoroughly reviewed. The standby person and all rescue personnel should be
aware of the structural design of the space, emergency exit procedures, and life support
systems required.
Categories of Confined Spaces There are generally two categories of confined spaces.
a. Open – top confined space or
b. A limited-access confined space.
Open-Top Confined Open-top confined spaces have an entry on the top, with or without a cover. For example, pits
and some storage tanks are considered open-top confined spaces. These spaces generally
have a depth that restricts the normal movement of air. When certain substances are present,
the quality or even the amount of air that is present in the tank may be affected, posing a
breathing hazard to anyone entering. Even the interior of a water tank can be hazardous
because of the possible build-up of certain gases.
Limited-Access Limited-access confined spaces are those that are enclosed and have a very small opening for
entry and exit. For example, sewers and silos are considered limited-access confined spaces.
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Open-top and Limited-Access confined spaces
Both types of confined spaces also can contain mechanical equipment, such as a pump or
mixing device, which could cause additional hazards. For example, someone could
accidentally start the equipment while an employee is inside the space, causing injury or
death.
Because movement is so restricted in confined spaces, employees can become stuck, or they
can be injured by the tools they take into the space with them. Also, the small openings can
restrict the flow of air into the space. Even a space that contains air can be deadly if a worker
spends too much time in the space and the worker’s breathing causes carbon dioxide to build
up.
Types of Confined Space
The employer is required to determine if there are any confined spaces that present or could
pose a hazard in the workplace. Confined spaces are of two types:
a. Permit-required
b. Non-permit required.
Permit-Required Confined Space has any of these dangers:
a. A dangerous or potentially hazardous atmosphere, contains material that could bury
(engulf) workers,
b. Has a shape that could cause workers to be trapped, or
c. Has any other recognized serious health hazards.
Non-Permit Required Confined Space is an area that does not contain any hazards capable
of causing death or serious physical harm. Employers must make sure that there are no
atmospheric or other major dangers.
Permit System
Written Permit System: It is basically just common sense “ideas” that result from
knowledge and experience gained through studying the dangers of confined space work. A
Written Permit System contains all the conditions that must be evaluated to ensure safe entry
into a Permit-Require Confined-Space.
Employers must develop a written permit-required confined space programme and train and
certify employees required to enter a permit-required space. Training should include
information about specific types of confined spaces and hazards employees will encounter at
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their worksite. Permit-required confined space entry requires a team of employees filling
clearly defined roles. These are the authorized entrant, attendant, entry supervisor, and rescue
personnel.
For a permit-required confined space to be safe, employers must ensure that certain work
practices are followed, including atmospheric testing, purging, decontaminating, isolating,
and record keeping. Employees must protect themselves by wearing proper PPE and by using
specialized equipment that does not cause additional hazards, such as fires. At the least, the
written Permit System should contain:
a. Hazards present- a list of the hazards present in the confined space must be identified.
This includes atmospheric hazards as well as mechanical, explosive, and engulfment
hazards.
b. Means of isolation- the means by which the hazards will be isolated from the confined
space. This includes “lock out/tag out,” when you physically disable a potential energy
source (i.e. an electric or power switch), then lock or tag it so the energy cannot be
restored until it’s safe to do so. Or, in the case of pipes, like Danny’s situation, you would
double block and bleed or line break the pipe and then lock and tag it so it can’t be
reopened until the confined space work is completed. Once isolation methods are used,
you may be required to purge and/or ventilate the PRCS to establish acceptable
conditions for entry.
c. Acceptable environmental conditions – List the acceptable environmental conditions
that must be maintained during entry. These conditions will vary depending on the
hazardous, toxic, and explosive materials and mechanical processes commonly found at
your worksite. It would also include the usual concern of LEL and oxygen content along
with work performed in the confined space that could alter the environmental conditions.
Actions such as cleaning, Purging, and welding may affect the conditions in a confined
space. The Permit System must acknowledge these actions in the written procedures and
provide guidelines for maintaining safe working conditions while they are being
performed.
Entry permits must contain the following information: a. Any test results, such as levels of breathable air, and the tester’s initials or signature.
b. Name and signature of the supervisor authorizing the entry.
c. Name of permit space to be entered, names of authorized entrants, and names of others
involved in the entry.
d. Purpose of entry and known hazards of the space.
e. Measures taken to isolate the space and control hazards, such as lockout/tagout or
ventilation procedures.
f. Date and authorized duration of work.
g. Acceptable entry procedures.
h. Communication procedures and equipment
i. Additional permits needed, such as for hot work, before entering the space.
j. Special equipment and procedures, including personal protective equipment (PPE).
In general, the duration of the permit must not exceed the time required to complete the
assigned task or job identified on the permit. Also, the entry supervisor must terminate the
permit as soon as the operations covered by the permit are completed or when a condition
arises that is not covered by the permit. For example, if the purpose of the entry is to inspect
the space, and the inspection uncovers the need for a repair, the employer must issue a second
permit for repair work.
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Personnel Authorised to enter into Confined Space Permit-required confined space entry requires a team of employees filling clearly defined
roles. Each role has specific duties that help ensure everyone involved in the process remains
safe. These roles are the authorized entrant, authorized attendant, entry supervisor, and rescue
team.
Authorized Entrant An authorized entrant is an employee who actually has permission to enter the workspace.
OSHA is very specific about the skills and duties required of authorized entrants, including
requirements that entrants should:
a. Know the hazards they may face during entry, including information on the mode of entry
for the hazard and the signs, symptoms, and effects of exposure.
b. Properly use appropriate PPE, including eye and ear protection.
c. Maintain communication with attendants.
d. Alert the attendant when a prohibited condition exists or when warning signs or
symptoms of exposure exist.
e. Exit from the permit space as soon as possible when ordered, when the warning signs or
symptoms of exposure exist, when a prohibited condition exists, or when an alarm is
activated.
More than one authorized entrant is allowed to enter a confined space at a time. However,
there must be adequate space for all entrants. Also, the amount of time it takes to exit the
space in the event of an emergency must be taken into account when determining the number
of occupants.
Authorized Attendant The authorized attendant is essentially a guard who helps keep the authorized entrant safe.
However, this person should be completely trained in the hazards that the entrant may
encounter within the space. The authorized attendant is the authorized entrant’s primary
safety device. The importance of this person’s duties cannot be overstated.
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The authorized attendant helps ensure the safety of the authorized entrant.
The duties outlined for the authorized attendant include requirements that this person must:
a. Remain outside the permit space during entry operations unless relieved by another
authorized attendant.
b. Perform no-entry rescues when specified by the employer’s rescue procedure.
c. Know existing and potential hazards, including the signs and symptoms of exposure and
their behavioural effects.
d. Maintain communication with and keep an accurate account of those employees entering
the permit-required space.
e. Order evacuation of the permit space when a prohibited condition exists or when a worker
shows signs of exposure.
f. Summon rescue and other service during an emergency.
g. Ensure that unauthorized persons stay away from the permit spaces.
h. Inform the authorized entrant and the entry supervisor in the event that unauthorized
persons have entered the space.
i. Perform no other duties that interfere with the task of attending the space.
Entry Supervisor The entry supervisor is the person most responsible for verifying that the space is as safe as
possible to enter. In addition to knowing the hazards that may be faced during entry and the
signs and symptoms of exposure, the supervisor’s duties include:
a. Verifying that specified entry conditions, such as permits, tests, procedures, and
equipment, are in place.
b. Terminating entry and cancelling permits when entry operations are completed or if a
new condition exists.
c. Taking appropriate measures to remove unauthorized entrants.
d. Ensuring that entry operations remain consistent with the entry permit and that acceptable
entry conditions are maintained.
e. Verifying that rescue services are available and that the means of summoning them, such
as telephones or radios, are in working order.
The employer, supervisor or foreman often fills the role of the entry supervisor. An entry
supervisor may also serve as an attendant or as an authorized entrant, as long as they are
properly trained and equipped for these other roles. Also, the role of entry supervisor may be
passed from one individual to another during the course of a single entry situation.
Confined Space Hazards The hazards encountered and associated with entering and working in confined spaces is
capable of causing bodily injury, illness, and death to the worker. Accidents occur among
workers because of failure to recognize that a confined space is a potential hazard. It should
therefore be considered that the most unfavourable situation existing every case and that the
danger of explosion, poisoning, and asphyxiation will be present at the onset of entry. All
hazards found in a regular workspace can also be found in a confined space. However, they
can be even more hazardous in a confined space than in a regular worksite. There are three
types of confined space hazards:
a. General hazards,
b. Physical hazards, and
c. Atmospheric hazards.
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General Hazards General hazards are further broken down into mechanical hazards,
communication hazards, and entry and exit hazards.
Mechanical hazards Mechanical hazards are those that occur when electrical or mechanical equipment is
accidentally activated. To protect against these types of hazards, electrical and mechanical
devices must be put under lockout or tag-out to alert others that the device should remain off.
Alternatively, or in addition to lockout/tag-out, devices must be isolated. Isolation may be
accomplished by physically or manually blocking components so that they cannot
accidentally start up or by disconnecting pipes or feed lines to prevent the flow of substances.
Communication hazards Communication hazards occur when the person inside the confined space is unable to
communicate with those on the outside and vice versa. When workers cannot speak to or
signal each other, accidents can occur. In dark areas, a type of lighting that is safe for the
environment must be used so that the worker is visible to those on the outside. When visual
contact is impossible, another means of communication must be used, such as a radio or
alarm system.
Entry and exit hazards Entry and exit hazards Entry and exit time is of major significance as a physical limitation
and is directly related to the potential hazard of the confined space. This hazard occurs when
insufficient preparations are made to ensure that the employee on the inside can exit quickly.
All possible means of entry and exit must be examined, and an emergency plan for removing
injured or incapacitated workers must be in place. The extent of precautions taken and the
standby equipment needed to maintain a safe work area will be determined by the means of
access and rescue. The following should be considered: type of confined space to be entered,
access to the entrance, number and size of openings, barriers within the space, the occupancy
load, and the time requirement for exiting in event of fire, or vapour incursion, and the time
required to rescue injured workers.
Atmospheric Hazards Atmospheric hazards are hazards in the environment of the confined space that may
incapacitate, injure, or impair an employee’s self-rescue or lead to acute illness or death to
workers and rescuers who enter confined spaces. Generally, atmospheric hazards are
categorized as:
a. Flammable hazards,
b. Toxic hazards, (Chemical Exposures)
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c. Irritant hazards, and
d. Asphyxiating hazards.
.
Flammable hazards, A flammable atmosphere generally arises from enriched oxygen
(above 21%) atmospheres, vaporization of flammable liquids, and by-products of work,
chemical reactions, concentrations of combustible dusts. An atmosphere becomes flammable
when the ratio of oxygen to combustible material in the air is neither too rich nor too lean for
combustion to occur. Combustible gases or vapours will accumulate when there is inadequate
ventilation in areas such as a confined space.
Flammable gases such as acetylene, butane, propane, hydrogen, methane, natural or
manufactured gases or vapours from liquid hydrocarbons can be trapped in confined spaces,
and since many gases are heavier than air, they will seek lower levels as in pits, sewers, and
various types of storage tanks and vessels. In a closed top tank, it should also be noted that
lighter than air gases may rise and develop a flammable concentration if trapped above the
opening. Often the smallest spark from a tool can ignite the atmosphere within a tank,
causing burns, explosions, and death. Also, many substances will spontaneously ignite when
exposed to air or water.
.
Toxic hazards, the substances to be regarded as toxic in a confined space can cover the
entire spectrum of gases, vapours, and finely divided airborne dust in industry. The sources of
toxic atmospheres encountered may arise from the following:
a. The manufacturing process (for example, in producing polyvinyl chloride, hydrogen
chloride is used as well as vinyl chloride monomer which is carcinogenic).
b. The product stored (removing decomposed organic material from a tank can liberate toxic
substances such as hydrogen sulphide [H2S]).
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c. The operation performed in the confined space (for example, welding or brazing with
metals capable of producing toxic fumes
The three most commonly found toxic gases in confined spaces are stated below:
a. Carbon monoxide (CO) results from incomplete combustion processes in equipment
such as gasoline engines. CO is a colourless and odourless gas that displaces oxygen in
the blood and can cause headaches, dizziness, unconsciousness, asphyxiation, and death.
b. Hydrogen sulphide (H2S) is encountered in sewers, sewage treatment plants, and other
locations where organic material (dead animals, leaves, etc.) decomposes. It has a distinct
odour of rotten eggs at low concentrations but can cause olfactory fatigue (a deadened
sense of smell) at high levels. H2S can block respiration, causing rapid loss of
consciousness, and possible death.
c. Methane (CH4) is a natural gas produced from the decay of organic matter. It is a
flammable, explosive, colourless, and odourless gas. It can displace oxygen to the point
of oxygen deficiency in a confined space, causing dizziness, unconsciousness, and
asphyxiation.
These substances may be inhaled, absorbed through the skin or eyes, or may enter the body
through a cut in the skin. Toxic substances can cause illness, disease, and death. Be aware of
any chemicals used in or generated by your specific industry, such as carbon dioxide in
bakeries and breweries. Cleaning solvents and residues remaining in vessels can also be
dangerous.
Irritant Hazards Irritants are found in many forms, including liquids or gases. Primary irritants cause no
systemic effects, meaning they harm only the parts that they touch, such as the skin, without
harming the entire body. Secondary irritants can harm the parts they touch, as well as the
entire body. For example, a chemical can cause skin problems and be absorbed into the body
and cause diseases like cancer or infertility. Irritant gases vary widely among all areas of
industrial activity. They can be found in plastics plants, chemical plants, the petroleum
industry, tanneries, refrigeration industries, paint manufacturing, and mining operations
Asphyxiating Hazards The normal atmosphere is composed approximately of 20.9% oxygen and 78.1% nitrogen,
and 1% argon with small amounts of various other gases. Asphyxiating atmospheres are those
that lack oxygen and/or contain excessive levels of harmful, breathable substances. An
oxygen-deficient
oxygen and/or contain excessive levels of harmful, breathable substances. An oxygen-
deficient atmosphere has less than 19.5% available oxygen. The oxygen level in a confined
space can decrease because of work being done, such as welding, cutting, or brazing; or, it
can be decreased by certain chemical reactions (rusting) or through bacterial action
(fermentation). The oxygen level is also decreased if oxygen is displaced by another gas, such
as carbon dioxide or nitrogen. This type of environment occurs naturally in sewers, wells, and
storage bins. Any atmosphere with less than 19.5% oxygen should not be entered without an
approved self-contained breathing apparatus (SCBA).
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Physical hazards Physical Hazards are non-chemical hazards that affect the body, including vibration, too
much noise, poor visibility, falls, radiation, becoming stuck in a tight spot, or being buried by
material stored in the space, structural hazards, entanglement, slips, temperature extremes
including atmospheric and surface, barrier failure resulting in a flood or release of free-
flowing solid etc.
Causes of Confined Space Hazards Hazards specific to confined spaces generally have three causes:
a. The material stored or used in the confined space,
b. The activity carried out in the space, and
c. The external environment.
The Material Stored or Used in the Confined Space. The material stored or used in a confined space might be an obvious hazard, such as a caustic
chemical, or an unrecognized hazard, such as a carbon filter in a water tank. While some
substances have an odor that would warn you of their presence, many do not. For example,
most employees would not suspect that the carbon filters in a water tank are capable of
absorbing available oxygen, thus creating a breathing hazard.
The Activity Carried Out in the Confined Space The activity carried out in a confined space also can create a number of problems. For
example, if a tank is used for fermenting organic materials, decomposition can create a
number of hazardous vapours. Also, when work, such as welding, is performed inside a
confined space, fumes, heat, explosions, and other hazards can affect workers.
The External Environment The external environment also can create hazards. For example, floods or tides can affect
sewer systems, and a worker entering an empty pipe may be engulfed by water rushing into
the pipe. Similarly, a storage tank that is entered at dawn may turn deadly when the rising sun
raises the interior temperature. Again, all of these hazards may be increased by the addition
of moving parts or mechanical equipment inside. Employees entering these spaces must be
aware of all possible sources of injury or death.
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Equipment for Confined Spaces Equipment used in confined spaces includes the PPE that authorized entrants and rescuers
must wear, as well as any tools that are used inside the space. Because of the hazards that
exist in confined spaces, equipment must be specialized. For example, typical ear, eye, and
head protection is often appropriate in confined spaces. However, caustic chemicals or fire
and explosion hazards may require you to wear special protective suits, gloves, and
facemasks. To facilitate rescue, entrants must often wear a harness with a hoist that allows
workers to be pulled to safety.
When atmospheres cannot be purged or when safe environments cannot be maintained,
authorized entrants must wear breathing equipment. An air-purifying respirator is used when
air exists in the atmosphere but is too contaminated to breadth without filtering. An air-
supplying respirator is used when there is not enough air to safely filter and breathe. This
device may have an air tank that the entrant wears or a supply line leading to an external tank.
Work tools used inside the space must not create additional hazards. For example, tools used
in explosive atmospheres must not create sparks or flames. Also, wet atmospheres require
electrical tools that use low voltage or are plugged into power sources that have circuits
equipped with ground fault interrupters. Employers are responsible for providing necessary
equipment, but it is your responsibility to use it. To successfully perform work in confined
spaces, you must strictly follow the requirements for entry, including using the proper
equipment. Disregarding the rules because you will be in the space for “just a minute” can be
fatal.
Safe Systems of Work If you cannot avoid entry into a confined space make sure you have a safe system for
working inside the space. Use the results of your risk assessment to help identify the
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necessary precautions to reduce the risk of injury. These will depend on the nature of the
confined space, the associated risk and the work involved.
Make sure that the safe system of work, including the precautions identified, is developed and
put into practice. Everyone involved will need to be properly trained and instructed to make
sure they know what to do and how to do it safely. The following checklist is not intended to
be exhaustive but includes many of the essential elements to help prepare a safe system of
work.
a. Record keeping includes securing proper permits and recording the details of any
problems or accidents that occur.
b. Is A ‘Permit-To-Work’ Necessary? A permit-to-work ensures a formal check is
undertaken to ensure all the elements of a safe system of work are in place before people
are allowed to enter or work in the confined space. It is also a means of communication
between site management, supervisors, and those carrying out the hazardous work.
Essential features of a permit-to work are:
1. Clear identification of who may authorise particular jobs (and any limits to their
authority) and who is responsible for specifying the necessary precautions (e.g.
isolation, air testing, emergency arrangements e.t.c);
2. Provision for ensuring that contractors engaged to carry out work are included;
3. Training and instruction in the issue of permits;
4. Monitoring and auditing to ensure that the system works as intended.
c. Suitability of Personnel: Do they have sufficient experience of the type of work to be
carried out, and what training have they received? Where risk assessment highlights
exceptional constraints as a result of the physical layout, are individuals of suitable build?
The competent person may need to consider other factors, e.g. concerning claustrophobia
or fitness to wear breathing apparatus, and medical advice on an individual’s suitability
may be needed.
d. Isolation: Mechanical and electrical isolation of equipment is essential if it could
otherwise operate, or be operated, inadvertently. If gas, fume or vapour could enter the
confined space, physical isolation of pipe work etc needs to be made. Isolation can
include lockout/tagout of power sources, blanking and bleeding feed lines, disconnecting
belt and chain drives, and securing moving parts with chains or blocks. In all cases a
check should be made to ensure isolation is effective.
e. Decontaminating by various cleaning methods removes hazardous substances.
f. Cleaning Before Entry (Purging): This may be necessary to ensure fumes do not
develop from residues etc while the work is being done. Purging clears the existing
atmosphere by displacing it with water, vapour, or forced air. Ventilation with an exhaust
fan maintains the atmosphere. Purging or ventilating with pure oxygen, however, is a
serious fire and explosion hazard and is prohibited.
g. Check the Size of The Entrance: Is the entrance big enough to allow workers wearing
all the necessary equipment to climb in and out easily, and provide ready access and
egress in an emergency? For example, the size of the opening may mean choosing airline-
breathing apparatus in place of self-contained equipment, which is more bulky and
therefore likely to restrict ready passage.
h. Air Quality Testing This may be necessary to check that it is free from both toxic and
flammable vapours and that it is fit to breathe. You should never trust your senses to
determine the safety of the atmosphere. The air within the confined space should be tested
from outside of the confined space before entry into the confined space. Care should be
taken to ensure that air is tested throughout the confined space side-to-side and top to
bottom. Qualified personnel with specialized testing equipment must perform
atmospheric testing. The sampling should show that:
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� The oxygen content is within safe limits - not too little and not too much.
� A hazardous atmosphere (toxic gases, flammable atmosphere) is not present.
� Ventilation equipment is operating properly.
i. Provision of Mechanical Ventilation: Natural ventilation (natural air currents) is usually
not reliable and not sufficient to maintain the air quality in confined space. Mechanical
ventilation (blowers, fans) is usually necessary to maintain air quality. This is essential
where portable gas cylinders and diesel-fuelled equipment are used inside the space
because of the dangers from build-up of engine exhaust.
� If mechanical ventilation is provided, there should be a warning system in place to
immediately notify the worker in the event of a hazard or a failure in the ventilation
equipment
� Care should be taken to make sure the air being provided by the ventilation system to
the confined space is ‘clean’.
� Ease of air movement throughout the confined space should be considered because of
the danger of pockets of toxic gases still remaining even with the use of mechanical
ventilation.
� Do not substitute oxygen for fresh air. Increasing the oxygen content will significantly
increase the risk of fire and explosion.
� The use of mechanical ventilation should be noted on the entry permit.
Warning: carbon monoxide in the exhaust from petrol-fuelled engines is so dangerous
Confined Space Atmospheric Testing Continuous Monitoring
Permissible Record Monitoring Results/Time
CONTINUOUS
MONITORING TEST(S) TO BE TAKEN
PERMISSIBLE ENTRY LEVEL
1. Percent of Oxygen 19.5% to 23.5%
2. Lower flammable limit Under 10%
3. Carbon Monoxide 25 ppm
4. Aromatic Hydrocarbon 1 ppm - 5 ppm
5. Hydrogen Cyanide 4.7 ppm (S)
6. Hydrogen Sulphide 10 ppm* 15 ppm**
7. Sulphur Dioxide 2 ppm* 5 ppm**
8. Ammonia 25 ppm* 35 ppm**
9. Other(s) To be stated
a. 8 hr. time-weighted avg.: Employee can work in area 8 hrs (longer
with appropriate respiratory protection). a. **Short-term exposure
limit: Employee can work in the area up to 15 minutes.
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that use of such equipment in confined spaces should never be allowed.
j. Provision of Special Tools and Lighting: Non-sparking tools and specially protected
lighting are essential where flammable or potentially explosive atmospheres are likely. In
certain confined spaces (e.g. inside metal tanks) suitable precautions to prevent electric
shock include use of extra low voltage equipment (typically less than 25 V) and, where
necessary, residual current devices.
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k. Provision of Breathing Apparatus: This is essential if the air inside the space cannot be
made fit to breathe because of gas, fume or vapour present, or lack of oxygen. Never try
to ‘sweeten’ the air in a confined space with oxygen as this can greatly increase the risk
of a fire or explosion.
l. Preparation of Emergency Arrangements: This will need to cover the necessary
equipment, training and practice drills.
m. Provision of Rescue Harnesses: In addition to using ventilation and other measures to
get rid of hazards, workers need protective gear. This includes a full body or chest
harness and may also require respirators, hard hats, goggles, earplugs or muffs, gloves,
boots, or other protective clothing. Lifelines attached to harnesses should run back to a
point outside the confined space.
Once spaces are cleared of hazards, they should be checked and monitored repeatedly for
problems. For example, a poor atmosphere could be caused by a very small amount of
chemical residue or an on-going chemical reaction. Clearing the space once is not enough.
Control of Hazards in Confined Space The traditional hazard control methods found in regular worksites can be effective in a
confined space. These include engineering controls, administrative controls and personal
protective equipment. Engineering controls are designed to remove the hazard while
administrative controls and personal protective equipment try to minimize the contact with
the hazard. However, often because of the nature of the confined space and depending on the
hazard, special precautions not normally required in a regular worksite may also need to be
taken. The engineering control commonly used in confined spaces is mechanical ventilation.
The Entry Permit system is an example of an administrative control used in confined spaces.
Personal protective equipment (respirators, gloves, ear plugs) is commonly used in confined
spaces as well.
Fire and Explosion Prevention Work where a flame is used or a source of ignition may be produced (hot work) should
not normally be performed in a confined space unless:
a. All flammable gases, liquids and vapours are removed prior to the start of any hot work.
Mechanical ventilation is usually used to Keep the concentration of any explosive or
flammable hazardous substance less than 10% of its Lower Explosive Limit AND
b. Make sure that the oxygen content in the confined space is not enriched. Oxygen content
should be less than 23% but maintained at levels greater than 18%. (These numbers can
vary slightly from jurisdiction to jurisdiction.)
If a potential flammable atmosphere hazards are identified during the initial testing, the
confined space should be cleaned or purged and ventilated and tested again before entry to
the confined space is allowed. Only after the air testing is within allowable limits should
entry occur, as the gases used for purging can be extremely hazardous.
Emergency Procedures in Confined Space When things go wrong, people may be exposed to serious and immediate danger. Effective
arrangements for raising the alarm and carrying out rescue operations in an emergency are
essential. Contingency plans will depend on the nature of the confined space, the risks
identified and consequently the likely nature of an emergency rescue. Emergency
arrangements will depend on the risks. You should consider:
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a. Communications: It is necessary to station someone outside to keep watch and to
communicate with anyone inside, raise the alarm quickly in an emergency, and take
charge of the rescue procedures. Attendants can perform a rescue that does NOT require
entry. They may only enter to perform a rescue if they are trained and another attendant is
present outside the space.
b. Rescue and Resuscitation: Equipment: Suitable rescue and resuscitation equipment
should be readily available. Where such equipment is provided for use by rescuers,
training in correct operation is essential.
c. Rescuers Capabilities: There is need to have a properly trained people, sufficiently fit to
carry out their task, ready at hand, and capable of using any equipment provided for
rescue, e.g. breathing apparatus, lifelines and fire fighting equipment. Rescuers also need
to be protected against the cause of the emergency.
d. Shut down: It may be necessary to shut down adjacent plant before attempting
emergency rescue.
e. First-aid Procedures: Trained first aiders need to be available to make proper use of any
necessary first-aid equipment provided.
f. Local emergency services: Local emergency services (e.g., fire brigade) should be
contacted. Information about the particular dangers in the confined space should be given to
them on their arrival.
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Work Permit System
Introduction
Definition of Safe Work Permit A Safe Work Permit is a written record that authorizes specific work, at a specific location,
for a specific period of time. A Safe Work Permit is an agreement between the issuer and the
receiver, which documents the conditions, preparations, precautions and limitations before
work commences.
The Work Permit is a tool that is used to plan and control work that may have particularly
high risks attached to either:
a. The type of work that is being undertaken;
b. The persons undertaking the work; or
c. The area/plant/persons in the vicinity where the work is being undertaken.
Therefore the Work Permit Procedure applies to the following:
a. Work that is unusual or out of the ordinary that does not form part of the usual work for
employees.
b. Work that is normally undertaken by employees, but has a particularly high element of
risk (e.g entering confined spaces or excavating).
Therefore the Work Permit Procedure provides a means for adequate planning and control for
work that would otherwise, through the unusual nature of the work, have little or no planning
or control. That is, the Work Permit Procedure provides for safe working procedures to be
implemented where there may be no formal procedures in place due to the short term or
unusual nature of the work. In these situations, it is through the application of formal Work
Permit Procedures that the employer is able to prove diligence in ensuring:
a. The safety of activity; and
b. The safety of the persons involved in the activity.
The person authorised to issue a Work Permit is known as the Authorised Personnel and is
responsible for defining work precautions and work conditions and ensuring that they are
adhered to.
The person(s) who receives a Work Permit is known as the Permit Holder and is responsible
for complying with the conditions of the Work Permit.
A Safe Work Permit must identify: a. The work to be done - a brief description of it.
b. The location where the work will be done - as specific as possible.
c. The hazards involved in the work - any toxic, corrosive, flammable materials in the work
area.
d. The length of the work - date and time the work will commence and finish.
e. The precautions to be taken to do the work - equipment and/or procedures that must be
worn/followed; isolation, ventilation and testing requirements.
f. All hazards and precautions related to the work have to be determined before the work
starts.
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A Safe Work Permit must also outline: a. The date the permit was issued and the name of the issuer.
b. The date the permit was received and the name of the receiver.
c. All the steps to prepare the equipment, building or area to be worked on.
d. The emergency and rescue plan, if it is necessary.
e. The date and time when the permit was returned and name of the person who signed it
off.
Use of Safe Work Permits Safe work permits should be used by:
a. Any industry that has a significant risk because of a particular hazard.
b. Any organization that has its own maintenance program and personnel.
c. Any contractor who allows sub-contractors work to do maintenance or other hazardous
work.
d. Organizations that have individual employees working in isolated areas.
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Safe Work Permits should be used in activities such as:
a. Maintenance
b. Work in confined spaces
c. Work in flammable or explosive atmospheres
d. Exposure to harmful substances
e. Work with high voltage
f. Excavations
g. Blasting
h. Use internal combustion engines in enclosed areas
Types of Safe Work Permits: The range of work activities and locations makes impossible for a single type of permit to suit
all situations. For this reason, there are several different types of Safe Work Permits.
The most appropriate type is determined according to the nature of the work to be performed
and the hazards to be eliminated or controlled.
a. Work Clearance – used when the work to be done requires no preparation by the
operations personnel. For example: oiling, greasing, garbage pickup/removal, meter
reading, etc.
b. Hot Work Permit – used when heat or sparks are present due to the work activities. For
example: welding, cutting, grinding, etc. The heat or sparks can ignite flammable or
explosive materials/vapours that may be present close to the work place.
c. Cold Work Permit – used in maintenance work that does not involve hot work. Cold
work permits are issued when there is no reasonable source of ignition and all contact
with harmful substances have been eliminated or appropriate precautions been taken.
d. Confined Space Entry Permit – used when entering confined spaces.
e. Special Permits – used to cover special hazards, such as radioactive materials, PCBs, etc.
f. Working At Heights Permit- used when working at height.
Responsibility
Employees It is the responsibility of all persons working at Company workplaces to ensure that the relevant Work Permit is issued where appropriate.
Manager/Supervisor It is the responsibility of Managers and Supervisors to ensure that the Work Permit System is
implemented and maintained.
It is also the responsibility of Managers and Supervisors to ensure that employees are trained
appropriately prior to becoming a Permit Authority and that the relevant Authorisation Form
has been completed.
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Each one of the five types of permits described above provides a checklist for the person
preparing the equipment, a list of the hazards involved in the activity and the precautions to
be taken.
Safe Work Permits are usually made out in three copies: one retained by the issuer, the
second for the workers directly involved in the task and the third for the safety department.
The workers’ copy is returned to the issuer when the work is completed.
A Safe Work Permit should be issued only by a competent person, who is completely familiar
with the work and the work area. The issuer should review the place where the work will be
performed prior to issuing the permit.
Written instructions alone are often insufficient in the effective use of a permit. Practical
training exercises for the people who issue and receive permits should be considered.
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Work at Height Safety
The majority of serious and fatal industrial accidents involve falling from heights. In
workplaces, a fall can occur on any walking and working surface. Walking and working
surfaces include any areas where workers must place their feet to travel from one place to the
next, such as floors, platforms, stairs, temporary working platforms, ladders etc. Employer
must make every effort to prevent this type of accidents.
Hazard Management There are three levels of hazard management working at height
1. Elimination or how hazard can be remove altogether? For example, do as much work on
the ground. This should always be the first option.
2. Isolation or how can the hazard be separated from employees? For example, install
guardrails. If there is no way that you can eliminate a fall hazard, then you have to isolate
it.
3. Minimisation or what to be done to minimise the impact should an accident occur? For
example use of safety harnesses. Only when the first two methods of managing a height
hazard are impossible that minimisation option is chosen. Following are just five common
systems used when working at height.
a. Ladders
b. Scaffolding
c. Machine-Lifted Work Platforms
d. Handrails, Guardrails And Toe-boards
e. Fall Arrest Devices
Hazards There are four main types of hazard associated with work at height:
1. falls of persons
2. falling objects
3. falls from collapsing structures
4. access to normally inaccessible hazards (e.g. overhead power cables).
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Safety precautions to be observe on elevated workplaces.
a. Stop working at an elevated spot if possible, and do operations on the ground if you can
by devising appropriate working procedures.
b. Always have some breakfast or at least a hot drink such as a cup of tea or coffee before
you go to work – AN EMPTY STOMACH CAN OFTEN RESULT IN A SUDDEN
ATTACK OF FAINTNESS in even the healthiest person
c. Put on a prescribed protective outfit and do not act recklessly.
d. Secure a work floor that is wide enough not to cause inconvenience in working and fasten
it firmly to supports to keep it from sliding down.
e. When circumstances do not allow handrails to be placed on a work floor, use such safety
precautions as wearing a safety belt, and setting up a safety net for preventing an
accidental fall.
f. Do not put articles on a work floor because such things restrict the space and workers
may stumble over them and drop something they carry.
g. Let two workers do operations that require the use of a ladder or Stepladders if possible,
and have one worker support the ladder or stepladders and keep watch while the other is
at work.
h. Pay attention to weather conditions, including rain and wind, and avoid doing operations
at an elevated spot in bad weather.
Ladders A ladder is a steps consisting of two parallel members connected by rungs; for climbing up or
down. Ladders are made from different materials such as Aluminium, Fibre Glass, wood and
in a multitude of designs to be used in a variety of circumstances. The checklist below will
assist in choosing a ladder.
a. know when to use a ladder;
b. decide how to go about selecting the right sort of ladder for the particular job;
c. understand how to use it;
d. know how to look after it; and
e. Take sensible safety precautions.
Types of ladder a. Single Ladders
b. Extension Ladders
c. Fixed Ladders
d. Step Ladders
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Do’s: 1. Use the ladder at a safe angle – ‘four up, one out’.
2. Allow at least a 1 metre extension above the step off point (unless some other form of
hand hold is provided).
3. Set the ladder up on a firm, even surface (unless a secure method is used to ensure an
even distribution of weight between the stiles).
4. Secure the ladder against sliding at the top and bottom while in use (get someone to hold
the ladder until another can secure the top).
5. Make sure you have removed any loose tools or other items from the steps or rungs
before you move the ladder.
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6. Consider the need to place cones or barricading where the ladder encroaches onto a
passage or roadway.
Don’ts: 7. Don’t use the rung or step of a ladder to support a plank on which a person has to work.
8. Don’t use a ladder horizontally as a work platform.
9. Don’t carry a load that will prevent both hands from being able to hold or grab the rungs.
10. Don’t over-reach – your waist should remain within the stiles of the ladder at all times.
Remember: ladders and steps are designed for the use of one person only at any one time
Scaffolding A scaffold is an elevated, temporary work platform. Scaffolding can be defined as a
temporary structure supporting one or more platforms and which is used either as a
workplace or for the storage of materials in the course of any type of construction work,
including both maintenance and demolition work. Scaffolds can be used on most sites to
provide a good working platform at any height. Make sure all scaffolding is suitable and safe
to use. The following are the checklist to consider when working with scaffolds.
1. Is it erected on a firm foundation?
2. Are all guardrails in position and at the correct height?
3. Are there enough planks to form the work platform and are they secured in position?
4. How far is it from the closest plank to the workface, and also to the outer edge of the
scaffold?
5. What access is provided between platforms?
6. Is a safety belt or harness needed?
7. Are all scaffold ties in place?
Types of Scaffolds a. Supported Scaffolds
b. Suspended Scaffolds
c. Independent (Tower) scaffolds
d. Manually Propelled Mobile Ladder Stand (Rolling Towers)
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Independent (Tower) scaffolds
Supported Scaffold
Independent scaffold Suspended scaffold
Ensure that a certified scaffolder is in direct charge of erection, modification or dismantling
of any scaffold more than 5 metres above the ground (and a register kept for general
inspection).
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Machine-Lifted Work Platforms
Work platforms provide a permanent or temporary surface for people to carry out work.
These are power operated rolling tower. They may be powered either by electricity or
Hydraulic engine. The platform should be secured against a structure for stability and be
installed with an edge protection system. The surface of the working platform should be of a
size and strength to safely support the tools, materials and people who may be working on it.
The surface should be non-slip, free from trip hazards and traps and of an easily negotiable
gradient. Safe access and egress must be provided to the work platform. These machines
include elevating work platforms, cherry pickers, scissor hoists, crane lift platforms and
building maintenance units. Before using such a machine, you must:
a. Checked that the machine is the correct type and is fit for the intended work?
b. Be trained to set up and operate that particular type of machine?
c. Made sure the machine will not be overloaded?
The following are the precautions to be observed on the use of the elevating platform.
a) Follow the manufacturer’s operating instructions.
b) Follow manufacturer’s guidelines for maintenance and operation of the engine and
hydraulic systems.
c) Ensure that operator controls are at platform level. Place emergency override controls at
ground level.
d) Lock wheels and use outriggers with adequate sole plates.
e) Place on a firm and level surface only.
Handrails, Guardrails and Toe-boards Remember, handrails are to assist balance, guardrails are to prevent falls.
Have you:
1. Made sure the top rail for both types of rail is between 0.9 and 1.1 metres above the floor
or front of the stair nosing?
2. Ensured a midrail has been fitted for guardrails?
3. Fitted a toe-board of sufficient height anywhere there is a danger of tools or materials
being lost over the edge?
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Fall Protection Systems Fall protection systems can consist of devices that arrest a free fall or devices that restrain a
worker in position to prevent a fall from occurring. Protection against falls must be provided
when working on elevated surfaces or when a 1.2-metre or more fall hazard exists. Fall
arresting systems are often used when guardrails, floors, nets, and other means cannot control
fall hazards or where guardrails or other protection is not in place. Workers must use a fall
protection system if there is danger of falling
a. more than 1.2 metres
b. into operating machinery
c. into water or another liquid
d. Into or onto a hazardous substance or object.
The two basic types of fall protection are:
a. Personal fall arrest
b. Travel restraint.
Use of belts, harnesses, fall arrest devices and the related rigging of static lines, anchorage
lines and restraints is a skilled and specialised area, and should be relied on only as a last
resort for fall prevention. Only use these systems if you have been fully trained and there are
emergency procedures in place which enable a rescue within a few minutes. Where a fall has
been arrested (the worker is held having fallen), faintness and serious blood circulation
problems can occur which can lead to brain damage or death in under 10 minutes.
Fall Arrest System Fall arrest system is employed when a worker is at risk of falling from an elevated position.
Personal fall arrest systems consist of an anchorage, connectors, a body harness, and may
include a lanyard, deceleration device, lifeline, or suitable combinations of these items. These
systems are designed to stop a free fall of up to 1.2-metre while limiting the forces imposed
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on the wearer. Any time a worker is at a height of 1.8-metre or more, the worker is at risk and
needs to be protected.
Personal Fall Arrest Systems These systems must include 4 elements referred to as ABCD's of Fall Arrest:
a. A - Anchorage - a fixed structure or structural adaptation, often including an anchorage
connector, to which the other components of the PFAS are rigged.
b. B - Body Wear - a full body harness worn by the worker.
c. C - Connector - a subsystem component connecting the harness to the anchorage - such
as a lanyard.
d. D - Deceleration Device - a subsystem component designed to dissipate the forces
associated with a fall arrest event.
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Travel Restraint Travel-restraint systems prevent falls by restraining a worker from getting too close to an
unprotected edge. A travel restraint system must be arranged to keep the worker back from
the fall hazard area. The system usually consists of
a. safety belt of full body harness
b. lanyard
c. rope grab
d. lifeline
e. lifeline anchor.
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Compressed Gas Safety
Introduction Compressed gases used in a variety of industrial and laboratory situations. Since the gases are
contained in heavy, highly pressurized metal containers, the large amount of potential energy
resulting from compression of the gas makes the cylinder a potential rocket or fragmentation
bomb. The gases contained in these cylinders vary in chemical properties, ranging from inert
and harmless to toxic and explosive. Compressed gases are unique in that they represent both
a physical and potential chemical hazard (depending on the particular gas). The high pressure
of the gases constitutes a serious hazard in the event that the cylinders sustain physical
damage and/or are exposed to high temperatures. Careful procedures are necessary for
handling the various compressed gases, the cylinders containing the compressed gases,
regulators or valves used to control gas flow, and the piping used to confine gases during
flow.
Compressed gases present a unique hazard. Depending on the particular gas, there is a
potential for simultaneous exposure to both mechanical and chemical hazards
a. Gases can be:
b. Flammable or combustible
c. Explosive
d. Corrosive hazards
e. Poisonous/toxic
f. Inert
g. Cryogenic
h. Pyrophoric (burns on contact with air)
The main hazards from compressed gases are: a. Explosion of the cylinder due to mechanical damage, weakness or over-pressurisation
b. Exposure to released gas or fluid, which may have harmful properties [asphyxiant, toxic,
corrosive]. Oxygen is particularly dangerous as it can promote fires and explosion and
sustains combustion.
c. Fire due to escape of flammable gas/fluid.
d. Over-pressurisation in the event of fire
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e. Impact from falling cylinders
f. Manual handling injuries
Causes of Accidents a. Inadequate training and supervision
b. Poor installation
c. Poor maintenance
d. Faulty equipment and/or design(e.g badly fitting valves or regulators)
e. Poor handling
f. Poor storage
g. Inadequately ventilated working conditions
h.
Identification of gas cylinders
Identification
The contents of any compressed gas cylinder must be clearly identified. Gas cylinders are
often colour coded, but the codes are not standard across different workplaces, and
sometimes are not regulated. Never rely on the colour of the cylinder for identification.
Colour coding is not reliable because cylinder colours may vary with the supplier.
Additionally, labels on caps have little value because caps are interchangeable.
Cylinders have labels which identify the gas they contain and the label alone should be used
for positive identification. Such identification should be stencilled or stamped on the cylinder
or a label. No compressed gas cylinder should be accepted for use that does not legibly
identify its contents by name. If the labeling on a cylinder becomes unclear or an attached tag
is defaced to the point the contents cannot be identified, the cylinder should be marked
"contents unknown" and returned directly to the manufacturer.
Typical cylinder Label
Cylinder Label 1. Cylinder Specification:
2. Cylinder Serial Number
3. Date of Manufacture:
4. Neck Ring Identification:.
5. Retest Markings:
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6. Bar Code Label:
7. Cylinder Manufacturer’s Inspection Marking
8. Cylinder Tare (Empty) Weight:
The standard EN1089-3, ensure consistency of colours across Europe.
.
Application of Compressed Gases
Industrial Special uses
Medical
Acetylene
Air
Argon
Carbon Dioxide
Helium
Hydrogen
Nitrogen
Nitrous Oxide
Oxygen
MAPP Gas
HPG Fuel Gas
Propane
Air
Argon
Carbon Dioxide
Custom Gas Mixtures
Emission Gases
Helium
Hydrocarbons
Hydrogen
Nitrogen
Nitrous Oxide
Oxygen
Rare Gases
Refrigerant Gases
Sulfur Hexafluoride
Electronic Grade Gases
Air
Carbon Dioxide
Helium
Medical Device Gases
Nitrogen
Nitrous Oxide
Oxygen
Sterilants
Classes of Common Industrial Gases a. Oxidants support combustion e.g. air & oxygen
b. Inerts do not generally react with other materials, asphyxiants(leak displace air) e.g.
nitrogen, argon, helium
c. Flammables when mixed with oxidant and ignition source will burn e.g. acetylene,
hydrogen, propane
d. Toxics toxic in small concentrations e.g. ammonia, chlorine, carbon dioxide
e. Corrosives react with materials causing reactions e.g. chlorine, sulfur dioxide
f. Pyrophorics ignite spontaneously in air e.g. silane, phosphine
Description of Common Industrial Gases
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a. Acetylene Gas (C2H2) – a colourless, flammable gas with a garlic-like odour. Acetylene
has the highest flame temperature of any common hydrocarbon because of its triple-bond
structure H-C=C-H.
b. Argon (Ar) A colourless, odourless, nontoxic, non flammable, inert gas. Argon gas is
used primarily for applications such as arc welding, steel making, heat-treating and
electronics manufacturing.
c. Carbon Dioxide (CO2) – a non flammable, colourless, odourless gas. Airgas is a
supplier of carbon dioxide gas in high pressure compressed gas cylinders, liquid
cylinders, and bulk
d. Ethylene Oxide - Ethylene oxide is widely used in hospitals as a sterilizing agent for
instruments and equipment.
e. Helium (He) – a colourless, odourless, tasteless inert gas at room temperature and
atmospheric pressure. Helium gas is available in compressed gas cylinders, liquid
cylinders, and bulk.
f. Hydrogen (H) is a flammable, colourless, odourless, compressed gas at high pressure.
Hydrogen is used in chemical synthesis to produce ammonia, methanol and other
products. It is used in hydrogenation of edible oils and petroleum products. It is mixed
with air to form the fuel gas for FID gas chromatography (usually Zero Grade) and is
sometimes a carrier gas. Other uses are annealing and heat treating of metals.
g. MAPP (C3H4) – MAPP® is a stabilized mixture of Methylacetylene and Propadiene.
MAPP gas is a very versatile fuel gas with a flame temperature (5301° F) second only to
acetylene. The BTU value of mapp gas also makes it an excellent fuel gas for pre-heating
and stress relieving metals.
h. Neon - Neon is a colorless, odorless, and tasteless gas used for glow lamps, electron
tubes, signs, plasma studies, fluorescent starter tubes, cryogenic refrigeration and gas
lasers
i. Nitrogen Gas (N2) – makes up 78.03% of air. Nitrogen is often used as an inert gas
because of its nonreactive nature with many materials.
j. Oxygen - Widely distributed in hospitals, Oxygen is also stored and used on airplanes
and in electronics manufacturing processes.
k. Propane (C3H8) – a colourless, flammable, liquefied gas. Pure propane is odourless so
like natural gas it has Ethyl Mercaptan added which gives it its distinctive “smell”.
Propane is primarily used in heating applications and as fork truck fuel. Propane is also
used in heavy steel fabrication for heating and cutting.
i.
Safe Working with Gas Cylinders:
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Safe Working with Gas Cylinders
Work Practices
Handling & Use a. Cylinders must never be used to support loads.
b. Never repaint, change markings or identification, or interfere with valve threads.
c. If a cylinder is involved in an incident, withdraw it from service and set it aside
clearly marked. Contact the supplier.
d. Never lift a cylinder with a magnets, or chains or slings.
e. Always leave cylinder keys in the valves when working so that they may be quickly
turned off in any emergency.
f. Securely restrain cylinders to prevent them falling over
g. Close the cylinder valve and replace dust caps when cylinder not in use
h. Before connecting a gas cylinder to equipment or pipework make sure regulator and
pipework are suitable for the gas and pressure being used
i. Never drop a gas cylinder
j. Never tamper with cylinders or subject them to abnormal mechanical shocks which
could damage the valve or safety device
k. Never re-paint, change markings or identification or interfere with threads
l. Never disguise damage to a cylinder or valve. Label as faulty and contact the supplier
m. Never attempt to repair a cylinder
n. Never scrap a cylinder
o. Never subject cylinders to abnormally high or low temperatures
p. Never mix gases in a cylinder
q. Never try refill a cylinder
r. Never transport by rolling them on the ground or use them as rollers or supports
s. Never subject to abnormal mechanical shocks which could damage the valve or safety
device
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Safe Working with Gas Cylinders
Daily Inspection a. Cylinders should be inspected daily and prior to each use for corrosion, leaks, cracks, etc.
b. Inspection should include the cylinder, piping, safety relief devices, valves, protection
caps and stems.
c. Leaking regulators, cylinder valves or other equipment should be taken out of service.
Safe Working with Gas Cylinders
a. Maintenance of cylinders and their valves or relief devices shall be performed only by
trained personnel.
b. An emergency response plan shall be developed and implemented wherever compressed
gas cylinders are used, handled or stored.
c. Never smoke around compressed gas cylinders.
d. Valve protection caps must remain in place at all times except when cylinders are secured
and connected to dispensing equipment
e. Only wrenches or tools provided by the cylinder supplier should be used to open or close
a valve. At no time should pliers be used to open a cylinder valve.
f. Never apply tape, jointing compounds or any other sealing material to the valve in an
attempt to achieve a tight seal, if a gas tight seal cannot be achieved metal to metal,
replace the regulator or change the cylinder
Gas Cylinder Use
Gas Cylinder Regulators
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A regulator is a device that receives gas at a high pressure and reduces it to a much lower
working pressure. It is precision instruments and MUST be handled with care to avoid
damage to their sensitive springs, diaphragms, valve seals etc.
After the regulator is attached, the cylinder valve should be opened just enough to indicate
pressure on the regulator gauge (no more than one full turn) and all the connections checked
with a soap solution for leaks. Before a regulator is removed from a cylinder, the cylinder
valve shall be closed and the regulator relieved of gas pressure. The valve cap shall be
replaced, the cylinder clearly marked as "empty,” and returned to a storage area for pickup by
the supplier
a. Regulators, gauges, hoses and other apparatus shall not be used on gas cylinders having
different chemical properties
b. Valve outlet thread size is different for different products but the same products from
different gas suppliers will have the same thread
c. Never use oil or grease on the regulator of a cylinder valve or fitting.
a. Leave the pressure adjustment knob/screw fully out when the regulator is not in use (this
ensures a minimum of tension on the springs and diaphragms)
b. Cylinders should be placed with the valve accessible at all times. The main cylinder valve
should be closed as soon as it is no longer necessary that it be open, it should never be left
open when the equipment is unattended or not operating
c. This is necessary not only for safety when the cylinder is under pressure, but also to
prevent the corrosion and contamination resulting from diffusion of air and moisture into
the cylinder after it has been emptied.
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Test for leaks at connections with soap and
water solution. The solution is applied by
brush.
Regulators and Fittings a. Cylinder valves and all other gas connections should be kept from oil and grease.
b. Cylinder valves should be firmly closed when they are left unattended for a long time,
e.g., at the end of the day or a work shift.
c. Valves of empty cylinders should also be closed.
d. Only the type of regulator designed for the gas being used should be fitted to the cylinder.
e. Blow out the valve socket before connecting regulator. ‘Cracking open’ the cylinder
valve momentarily. The adjusting screw of the regulators must always be released before
the cylinder valve is opened, which should be done slowly.
f. A flashback arrestor should be fitted to the regulator outlet in the acetylene line to avoid
accidental flashback. A second flashback arrestor in the oxygen line will give additional
security.
g. Cylinder valves should be operated by using standard keys. Long leverage spanners or
keys fitted with extension pieces should not be used. Excessive force should be avoided
in closing valves. Copper or copper-rich alloys should not be used for making fittings for
acetylene supply. Copper with acetylene is liable to form a dangerous explosive-
substance.
h. The oxygen pressure for welding should be the same as acetylene to prevent mixing of
gases inside the hoses.
i. Do not attempt to repair regulators.
j. If gauge pointers do not return to zero when the pressure is released, the mechanism is
faulty and the regulator should be replaced.
k. Always treat a pressure regulator as a precision instrument. Do not expose it to knocks,
jars or sudden pressure surges caused by the rapid opening of the cylinder valve. Always
open the cylinder valve slowly and smoothly using the special spindle key.
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Flashback Arrestors a. Flashback is the result of mixture of fuel gas and oxygen burning within the hose, flame
travels and burns its way towards the gas source at great speed, can result in force of
explosion in either cylinder
b. Flashback arrestors must be fitted on both oxygen and fuel gas regulators
c. If flashback arrestor is dropped/damaged replace immediately
d. Flashback arrestors should only be used with the gas they are labelled for and the pressure
they are designed for
e. Common reasons for flashback: incorrect purging of hose/torch prior to use, incorrect gas
pressure, incorrect nozzle, damaged torch valves, gas passages blocked within the torch,
kinked or trapped hose
Hoses
Correct hose bore size, pressure rating, length and colour coding are essential for safety BS
EN 559
Colour code for Hose
Blue Oxygen
Red Acetylene and other fuel gases(except LPG)
Black Inert and non combustible gases
Orange Liquefied Petroleum Gas
a. Never use hoses that are longer than necessary
b. Never use equipment while hoses are wrapped around the cylinders or trolley
c. Length of hose should be suitable for the task
d. Keep hoses in good condition
e. Examine the hose for cracks, deterioration, damage and test the hose for leaks before use
f. Do not repair hoses unless you have the skill and means to test them in accordance with
BS En 1256
g. Purge hose thoroughly before lighting torch
h. Do not put wrapping tape around hosing as this contains combustible hydrocarbons
i. Do not use copper piping with acetylene hoses as it is potentially explosive
j. Protect hosing from heat, oil, grease or mechanical damage
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Piping
a. Distribution lines and their outlets should be clearly labeled as to the type of gas
contained
b. Piping systems should be inspected for leaks on a regular basis
c. Special attention should be given to fittings as well as possible cracks that may have
developed
Blow Pipes and Torches a. Leaks are a serious hazard as they are closest to the operator
b. Always check condition before use, ensure tip is free of obstruction
c. Signs of heat damage around the blow pipe or torch may indicate the equipment has
suffered internal damage and is leaking and should be replaced immediately
d. Always fit the correct size nozzle for the job (hole size and pressure set at regulator
determine gas flow and gas velocity exiting the nozzle, manufacturer gives a pressure
rating for the nozzle being use, if the gas exit velocity is slower than the combustion
velocity backfire and flashback may occur
e. Replace blow pipe or torch if
i. Broken bent or loose gas control valve
ii. Bent mixer, misshapen cutter head
iii. Bent cutter tube
iv. Broken of bent cutting oxygen lever
f. Leak test all connections and valves prior to use
g. If replacing O ring seals always use the correct materials
Handling Gas Cylinders
a. Wear PPE: gloves, protective footwear, eye protection
b. Correct way to move cylinders is to: keep upright, secure and with valves uppermost
c. Use mechanical aids such as a trolley where reasonably practicable( do a risk assessment)
d. For short distances on even ground the practice of ‘milk-churning’ (manually moving
cylinders) can be used only by trained personnel and never for longer distances, in uneven
ground, wet or icy conditions, poor lighting, or at speed a trolley should be used
e. All personnel involved should have completed manual handling training
f. Never attempt to catch a falling cylinder just get out of the way
Transporting Cylinders Transporting gas cylinders requires careful consideration and appropriate precautions. These
considerations and precautions include:
a. Motor vehicle transport of cylinders
b. Flammable gas and oxidizer cylinders transport
c. Hand truck (dolly) transport of cylinders
d. Cylinder transport precautions
Motor vehicle transport of cylinders shall only be done with vehicles equipped with racks
or other means of securing the cylinders. Cylinders containing liquefied hydrogen or toxic
gases shall be transported in open body vehicles.
Flammable gas cylinders and cylinders containing an oxidizer must not be transported
together, or with poisons or corrosives. However, the transportation of oxygen and acetylene
cylinders together is allowed if:
a. The cylinders are transported in the rear truck bed below the cab level
b. A roll bar is installed over the rear truck bed to prevent the cylinders; from falling out
of the truck bed in the event of the vehicle overturning.
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Poison label materials are not to be transported with food or other items intended for human
consumption.
Hand truck (dolly) transport of cylinders shall be used for the transfer of compressed gas
cylinders from loading area to shop and other areas within the workplace.
Cylinder transport precautions include: a. Cylinders have the valve protection cover in place while being transported (inter- and
intra-building transport)
b. Cylinders are not to be rolled or lifted by the valve or valve cap for moving
c. Cylinder valve shut off and valve caps must be in place during transit from location to
location
d. Cylinders that are dropped during transit will be taken out of service and returned to the
supplier for inspection
e. Cylinders will be securely supported at all times during transport
f. Smoking is prohibited during loading, unloading, and hand transportation of flammable
gas cylinders
g. If possible carry in open vehicles or trailers
h. If they must be carried in closed vans/cars ensure good ventilation at all times
i. If the load compartment is not separated from the driver do not carry toxic gas cylinders
(those with a toxic gas label and having yellow as a colour on the cylinder)
j. Secure cylinders properly so they cannot move or fall in transit or do not project beyond
the edges of the vehicle, normally in the upright position unless instructions for transport
state otherwise
k. Carry propane cylinders upright and do not carry flammable gas cylinders in the same
compartment as toxic gas cylinders
l. Unload the cylinders as soon as possible and move to a well ventilated storage area
m. If you suspect it is leaking, park the vehicle, investigate the fault and contact the supplier
n. If you are involved in an accident advise, any emergency services involved what gas
cylinders are being carried
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Safe Storage
Each Storage area should be subject to unique risk assessment
a. It is best to store gas cylinders in the open and on concrete in a fenced compound with
some weather protection
b. In storage areas oxygen cylinders must be stored at least 3 metres away/separated by a
fire wall from fuel gases such as acetylene, propane, methane etc.
c. Full cylinders should be stored separately from empties and empty oxygen cylinders
should be segregated from empty fuel gas cylinders
d. Other products should not be stored in the gas storage areas especially not oil or corrosive
liquids, sources of ignition or flammable materials
e. LPG cylinders have special requirements including storage 3m away from other gases
f. Pyrophoric and toxic gases should be stored seperately in locked, suitable ventilated
storage areas with restricted access
g. Cylinders should be clearly labelled to show contents and associated hazards
h. Store all cylinders upright and secure on a level surface to prevent them from falling
i. Acetylene and propane must never be stacked horizontally either in storage or in use
j. Cylinders should be located away from any heat/source of ignition and if possible away
from the fire exits, elevators, walkways, building egresses, unprotected platform edges, or
in locations where heavy moving objects may strike or fall on them
k. Storage arrangements should be clearly described in the emergency plan
l. Storage area must have good housekeeping and adequate warning signs with fire fighting
equipment as necessary
Out door storage areas
Emergencies
1. In the event of a leak or suspected leak of gas, evacuate the building or area. Activate the
fire alarm by pulling the nearest fire alarm box.
2. Use soapy water to detect leaks.
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3. An emergency plan must be prepared and updated wherever compressed gases are
produced, handled, stored or used. The plan must include the following information:
a. The type of emergency equipment available and its location (e.g. emergency eyewash
& shower, fire extinguisher).
b. An indication that hazard identification labelling is provided for each storage area.
c. The location of posted emergency procedures.
d. A material safety data sheet (MSDS) for each compressed gas or list with name of gas,
hazard class, and quantity, stored or used in the area.
e. A list of personnel who are designated and trained to be liaison personnel for the fire
department/emergency responders and who are responsible for the following:
i. Aiding the emergency responders in pre-emergency planning
ii. Identifying the location of the compressed gases and cryogenic fluids stored or used
iii. Accessing material safety data sheets
iv. Knowing the site emergency procedures.
Where a cylinder has been damaged
a. If it has been dropped or physically damaged check it for leakage and deal with as for a
leaking cylinder
b. For handling acetylene cylinders should not be moved unless it is clearly established that
there is no thermal disassociation
c. Clearly mark any cylinder that has been exposed to excessive heat or physical impact and
contact the supplier
If a flashback has occurred:
a. Close both blowpipe valves oxygen first
b. Close both cylinder valves
c. Check the temperature of the acetylene cylinder for thermal decomposition
d. Check the blowpipe has not overheated
e. Check the nozzle is not damaged
f. Open both blowpipe valves oxygen first to vent the system
g. Unwind the pressure adjustment screw on each pressure regulator
h. Before starting up again, check the integrity of the whole system