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Health, Safety and Environment version 1.0 1 of 42 2009.01.30

Course: Health, Safety and Environment

This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


List of contentMODULE 1..........................................................................................................................................4

Activity Based Training...................................................................................................................4Additional litterature:.......................................................................................................................7

MODULE 2..........................................................................................................................................9Health and Safety in Welding.............................................................................................................11

The workshop environment...........................................................................................................11Electrical safety..............................................................................................................................11Fume..............................................................................................................................................12Noise..............................................................................................................................................12Optical radiation............................................................................................................................12Burns and Mechanical Hazards.....................................................................................................12Gas Bottles.....................................................................................................................................12Welding in difficult situations - outdoors, confined spaces etc.....................................................13

MODULE 3........................................................................................................................................14The working environment of the fabrication shop, general hazards, dust, heavy and hot material, cables ............................................................................................................................................14

Oxyacetylene cutting and heating......................................................................................................16Safe storage....................................................................................................................................16

Safe practice and accident avoidance........................................................................................16Handling compressed gases...........................................................................................................17

Safe practice and accident avoidance........................................................................................17Using compressed gases................................................................................................................17Suitable cutting processes for different types of steel to achieve a suitable cutting surface ........18Flame cutting, Principle and parameters, cutting blowpipes, cutting machines, quality of cut surface............................................................................................................................................18Other cutting processes as: plasma, laser, mechanical cutting......................................................18Safety precautions for cutting (PSS1)............................................................................................19Burns and fires, fire prevention, fire fighting ...............................................................................19

MODULE 4........................................................................................................................................21Noise hazards.................................................................................................................................24

MODULE 5.......................................................................................................................................26Specific rules and regulations .......................................................................................................26 Electric shock ...............................................................................................................................28Steps to Prevent Electrical Shock .................................................................................................30Emergency Procedures:.................................................................................................................30UV- and heat radiation ..................................................................................................................30Eye hazards....................................................................................................................................32Welding fumes...............................................................................................................................33Hazardous substances....................................................................................................................36Removal of hazardous welding dust..............................................................................................37

MODULE 6........................................................................................................................................41MODULE 7........................................................................................................................................45

What Is CPR?............................................................................................................................45When Is CPR Needed?..............................................................................................................46Three Parts of CPR...................................................................................................................46





MODULE 1

Objective:

Have an overview of the course structure and the course methodology for the education and training.

Scope:

Role and responsibilities of the welding personnel Know the most relevant standards for Quality Assurance Understand the fundamental ideas behind Activity Based Training (ABT)

Expected results:

Ensure that the health , environment and safety tasks related to the job are met Understand the relevance and fundamentals of health , environment and safety

Activity Based TrainingInstead of utilizing the traditional methodology whereby the student moves through a traditional education with theoretical content from A to Z, followed by hands on training, this course will use an Activity Based Training (ATB). With ATB it is understood that the training follow the production activities according the production path of a predefined structure or product. The course will also exploit a blended approach whereby different delivery technologies for the content itself will be used.

The course has been divided into 9 different modules and three of these are modules where the major part of the hours will be utilized for practical work. This means that the students have to participate together in a workshop or laboratory.This is an important aspect of the methodology itself. When working in an industrial environment the student has to work together with other personnel in order to meet the requirements in quality, time schedules and so forth. The team building effort, its importance for the final product and its importance for the total quality of the production environment must be stressed during the educational process. In a welding environment today the students will work together with other persons from different cultures, with different educational backgrounds and with different practical experience, which will require a profound focus on flexibility and open minded attitude towards other people. Few if any other educational routes will demand such flexibility to the student itself and to the students behaviour on a short and long term basis.



The course will consist of several job-elements. The figure shows how one work-package is built up of different elements, some are pure theory elements and other is a mixture of theory and hands-on training. The training will be carried out in the workshop, shop, or in a laboratory. Video streaming and/or videoconferencing will be used in Shop/Theory packages. The topics for health, environment and safety will be structured in the same way and will follow the production structure.

Work Package.

A work package might contain several job elements. A work package is a complete documentation package of specific activities that must be mastered in the welding industry in order to handle the whole production process. It contains at least the following information:

i. Drawing of the structure to be fabricatedii. Work description with which methods shall be used in the productioniii. Work description with process description of the work process for reaching the target and the

knowledge requirediv. Quality assurance requirements for the ingoing elementsv. Quality assurance description of the outgoing elementsvi. Work package description for the work to be donevii. Reference to available resources for the workviii. Reference to environmental resources or requirements or restrictionsix. Requirements for knowledge, prerequisite or knowledge that has to be obtainedx. Cooperation strategy with other in a defined group or to related groups

However, some basic prerequisite knowledge must be mastered by the production staff in order to follow the knowledge requirements. The knowledge and competence requirements include:

Ability to work in a multicultural environment with the colleagues due to exchange of mobile personnel across borders and among mechanical industry companies



Ability to understand and communicate the content in the job packages to the colleagues in a multilingual working environmentAbility to understand his/her responsibility in the production chain and to communicate the need for knowledge.Ability to search for relevant learning and training material when needed.To understand how a process plan might be visualized by utilizing a project plan.

A general design of a learning element. This element consists of both theoretical content as well as practical work. We can also see that the practical task, when completed shall be verified by the student as well as by a 3-part. This will both ensure that the student feel responsible for the part itself, but also be aware of the quality assurance aspect which is very important withing the welding activities. This is a simplified design where no loops are included in the process flow.

A central philosophy within fabrication is that the person who produce a product shall not be the one carry-ing out the quality control of the same product. To establish the same methodology in education one aims at introducing an alternative production flow whereby the product alternate between students or student groups.



A product is alternating between students during the fabrication process. When produced by student A at a certain stage then student B will carry out the quality control of the part. Student B will then use the part from A in his own production and then transfer it back to A for the following quality control.

This means that the students shall be familiar with and use the definitions and actions that are common in the industry. It will consequently be mandatory to switch the objects for this purpose in order to avoid that a per-son verifies himself. If defects or non-conformance is found then the necessary corrective actions have to be carried out by the student.

The use of objects should reflect the typical industry environment that is domination in the area where the course is held in order to create a more relevant training domain. But when this is done, then he other exam-ples and references in the material should be selected from a similar industrial background in order to make tis relevant fro the student .

For the course health, environment and safety the same structures will be used as described before. We will follow the production process and add and discuss the elements as we move along the production process as such.

Delivery.

The structure described here is a structure that can be used in different environments. The structure has not been designed for a special delivery method. However, when that has been said, it is possible to use a highly structured an d rigid structure whereby you may control an verify all steps of the student,If that is the correct way of carrying out the course is of course another question. The structure that follows is a an idea of which elements that a course should contain, if its running as a web course or if its running as a face-to face course without having access to the web itself.

Additional litterature:

Page Title Comment

Table with reference literature to be read in addition to the course documentation for the individual modules. This table to be compiled according to the national availability of reference literature. This table has to be created by the course organizer because the reference material may vary.This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.




MODULE 2

Objective:

Know how to perform welding activities in the fabrication shop in a safe manner.

Scope:lThe working environment of the fabrication shop; general hazards, dust, heavy and hot material, electrical cables lWelding in the fabrication shop; protection of other workers from welding hazards, lGeneral ventilation to minimise background pollution levels from welding hazards,

Expected results:

Know the general hazards in a fabrication shop. Know your duties and responsibilities related to health, environment and safety

General.Safety in welding starts before the welding itself. Some of the key elements in the company strategy for en-vironment and safety can be listed as follows as the managements tasks and responsibility:

1- The Safety Analysis during the welding activities/processes of the Company; 2- The Safety management programmes; 3- Structure and responsibility; 4- Training, awareness and competence of personnel; 5- The Health, Safety and Environment Handbook (HSE), documentation and document control; 6- The control of the elements implemented for Safety purpose; 7- Emergency situation control; 8-Nonconformities, preventive and corrective actions.

These objectives and tasks shall be clearly identified and cared for as procedures and actions that are clearly defined for all personel invoøved in the management and fabrication itself.

The company recognise that you have the necessary professional qualifications, competencies, skills and experience to fulfil your role within the company but in order to make sure you are aware of recognised HSE and security best practice you should also be provided with specific instructions and guidance on the particular features and activities of your new worksite. The worksite manager or supervisor is responsible for arranging your ‘safety induction’ as soon as possible after your arrival. Your introduction shall be in accordance with the company Introduction Policy and may include the following issues:

Organisation of the worksite – roles and responsibilities. The emergency plan and its location. Emergency alarms and responses. Overview of work areas, ‘no-go’ areas and general traffic areas. Muster points. Escape routes. Survival craft and equipment. Fire fighting equipment. First aid treatment and location of equipment. Safety signs and their meaning – first aid, warnings etc. Identification of safety representatives.



Review of safety noticeboard. Documentation and procedures. Hazard identification and risk assessment system at the site. Hazardous areas and precautionary measures. Confined space working. Handling of dangerous substances. Protective clothing, equipment and what you must use in your job. Reporting of incidents, damage and injuries. Action in the event of incident, damage or injury. Reporting of safety observations. Worksite waste disposal policies. Worksite security procedures.

All incidents are preventable. You choose yourseself what type of risks you are encontering by deciding your work procedure, your attitude, your habits...

Do it safely or not at all There is always time to do it right When in doubt, find out

Your duties and responsibilities.

Your job description specifies your work duties and responsibilities, but you also have a duty to ensure the safety and welfare of you and your work colleagues as well as preventing damage to equipment and the environment.To make sure that all work to the same basic standardsthen the following tasks is also your responsibility:

Learn, understand and work to outline instructions set out in the HSE handbook. Read and understand the procedures listed in the handbook. Work safely in accordance with the security processes and specific project procedures; seek help from

your supervisor if you are unsure. Think about the hazards and risks you and others may be exposed to before you start any task and take

the necessary precautions to minimise these risks. Do not take short cuts or become complacent with regard to safety in carrying out your duties. Stop or shut down any activity or operation which is unsafe (including those of contractors). Report promptly all unsafe conditions and practices (including those of contractors) to your supervisor. Report all injuries, no matter how minor, to your supervisor or the medic promptly. Perform your tasks safely, with regard for your own personal safety, the safety of fellow workers, and

the protection of the environment and company property. Always use the proper safety equipment and keep to safe work practices and established safety

standards.

Safe Performance Self-Assessment. Before beginning any activity/task/job, after an incident or near miss, any unusual circumstances, then:

Assess the risk What could go wrong? What is the worst thing that could happen if something does go wrong? Analyze how to reduce the riskThis project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


Do I have all the necessary training and knowledge to do the job safely? Do I have all the proper tools and personal protective equipment? Take necessary action to make sure the job is done safely! Follow written procedures! Do not proceed unless everything is safe!

Health and Safety in WeldingIn most countries there is extensive legislation assigning responsibilities to employers to take reasonable care of the health and safety at work of their employees.

Welding is associated with several hazards to health and safety, and the employer needs to be able to ask informed questions:

The workshop environment

The employer needs to ensure that the lighting conditions are adequate for the work undertaken - giving extra lighting where necessary. Welders stand for long periods of time, since they must keep a very steady hand position, and this means that they can become quite cold if the workshop is not sufficiently well heated. Conversely in hot weather, the environment can become unbearably hot, and the welder has not got the option of removing clothing. Both overheating and underheating can cause fall in comfort, efficiency and productivity.

Housekeeping is extremely important to avoid slips, trips and falls, damage to equipment and fire.

Electrical safety

Clearly, the employer needs to establish the level of competence of the electrician who is given the task of wiring the installation, and the type of maintenance which the installation and the equipment will subsequently need. In the UK there is a requirement for periodic electrical checks to be done on power sources. The design of welding power sources themselves has gone through a number of changes, and for each, there are different standards of safety. The employer must ensure that his installation is correctly matched to the type he is using - for instance double insulated power sources should not be used with a separate earth lead to the workpiece.

Fume

Welding vaporises metals, and anything which is resting on the surface. This gives rise to fume, which is condensed fine particulate material. The fume is mostly oxides of the metals, including any alloying elements, but it also contains gases produced in the arc, such as ozone or oxides of nitrogen, and decomposition products from any paint or coating which was on the metal surface. The nature and quantity of this fume depends critically upon the welding process, the materials and the welding parameters. Some is harmful to health, for instance stainless steel fume contains chromium, and welding galvanised steel produces zinc fume.

Effects can vary from a bout of 'metal fume fever' to longer term, more serious problems if suitable fume removal is not carried out. There is guidance literature which may be consulted regarding the safe levels for each constituent, and the employer needs to be aware that for some fume constituents, there may be no safe level, and a statutory exposure limit may be imposed. Nickel, cobalt and stainless steel welding fume are the subject of statutory limits. Highly efficient exhaust apparatus is available. Some health surveillance may be necessary.



Noise

Welding environments are frequently noisy as other operations such as grinding, etc. may also be taking place. Some operations, such a de-slagging may take the noise up to such a level where it will damage workers hearing. In such cases this would mean that hearing protection is almost certainly required if the noise cannot be controlled by other means. Some health surveillance may also be necessary.

Optical radiation

The welding process produces a large quantity of visible light, ultraviolet and infra-red. Exposure to the radiation from an arc causes burns to the skin, and damage to the eyes. For this reason, welders need to wear clothing to protect their bodies and arms, regardless of the weather conditions. They also need efficient eye protection, which is usually supplied in the form of a protective shield. The precise choice of the shade of glass filter in these shields depends on the type of welding operation, since they vary in their light output.

Welders assistants also need protective clothing and eye protection. Passers-by should be protected by placing opaque or properly filtered screens around the work area.

Burns and Mechanical Hazards

Welders need good quality gloves, preferably leather gauntlets, safety boots or shoes and good quality cap and overalls. A leather apron may also be needed. Welding produces quantities of molten droplets of metal which are scattered in all directions. It is essential that the welder wears clothing which will not burn or melt, and which is stout enough to provide adequate protection.

In a workshop environment, suitable safety footwear is essential.

Gas Bottles

Gas bottles need to be stored to conform with the regulations, and the welders need to be aware of the safety rules - such as the use of the correct regulator, tethering the cylinder so that it does not fall, keeping the outlets free from contamination such as oil or grease.

Welding in difficult situations - outdoors, confined spaces etc.

There are many work situations which add to the hazards of welding. Each must be assessed carefully, since there may be added hazards such as falls or asphyxiation. This is particularly true of work in confined spaces, where there is a very real risk of death, and the employer should make a critical assessment of the work to be done, and how it may be carried out safely. There may be statutory requirements in these situations.



MODULE 3

Objective:

Know how to perform a cutting operation for cutting plates and the health environment and safety topics related to use of this processScope:

Handling gas cylinders Handling exhaust devices for cuttingHandling of material to and from the cutting table

Expected results:

Know safe handling of gas cylinders. Know the need for fume extractionKnow the risk of explosions

The working environment of the fabrication shop, general hazards, dust, heavy and hot material, cables .The welding processes are characterized by high temperatures, extensive fumes, light and heat radiation and risks from electric power. All these phenomena can endanger welder health, and potentially they are also dangerous for the environment.The basic task for health and safety is to eliminate these dangerous aspects of welding.

General HazardsThe general hazards in welding and cutting are:Fire from sparks and spatterExplosion and fires from reaction with welding gasesAsphyxiationElectric shockInhaling toxic fumes and gasesEye injuries from heat rays

There are many regulations regarding safety in welding, which are derived from more general safety regulations, like 'General rules for hygienic and technical safety measures at work' and 'Regulations for personal safety means'. Every welder has the right and obligation to be protected under these regulations.

The owner/operator is obliged to have a safety inspection performed on the welding equipments at least once every 12 months.A safety inspection, by a trained and certified electrician, is prescribed:- after any alterations- after any modifications or installations of additional components- following repairs, care and maintenance- at least every twelve months.

Measures - technical devices and equipmentWhen planning a workplace, the working height plays an important part in creating the correct working position. In this context, positioners and lifting tables can be very useful. The working position is partly determined by the welder’s need to have his/her eyes close to the workpiece to be able to see the molten pool This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


clearly while welding. If the working height is too low, the welder has to bend to see properly. A chair or stool might then be very useful. Working with the hands in a high position at or above shoulder level should be avoided whenever possible.In conjunction with heavier welding, the gun and hoses are also heavier and the load on the body is more static. A balanced load-reduction arm is very useful in this situation. Lifting the hoses off the floor also protects them from wear and tear, as well as facilitating wire feed.It is also a good thing if the workpiece is placed in a positioner and is positioned to ensure the best accessibility and height. A more comfortable working position can be created and, at the same time, welding can be facilitated as the joint is in the best welding position.Roller beds can be used for welding tubes or other cylindrical items. A hook or some other device on which the welding gun can be placed when it is not in use is another valuable piece of equipment.

Hot work exposes workers to: - Molten metal - Toxic gases - Fumes and vapors - Harmful radiation - Excessive noise - Electrical shock - Fire hazards. Appropriate personal protective equipment (PPE) must be selected to protect the worker from these hazards. Fire watches in the area are required.

Hot work operations include: - Gas Welding and Cutting - Electric Arc Welding - Carbon Arcing or Plasma Arc Cutting Each of these operations may present unique hazards.

Electro- magnetic effectsCurrent gives rise to a magnetic field around the conductor. The magnetic field is stronger closer to the conductor and rapidly subsides as the distance increases. A magnetic field is created around the welding cable and earth cable when welding is in process.Studies have indicated that one should not be exposed to strong magnetic fields. However, there is no evidence of any injuries. No limits have been yet set.

Recommendations: You should make sure that as little as possible of the welding cable is directly adjacent to your body when welding. If you are right-handed, the welding machine should be placed on your right-hand side to avoid laying the welding cable on your lap or around your body. It is not a good idea to rest the welding cable around your body while erection welding (with the welding machine on the ground).Do not forget that MAGNETIC FIELDS can affect pacemakers and hearing aids.

Recommendations:- Pacemaker wearers keep away.- Wearers should consult their doctor before going near arc welding, gouging, or spot welding operations.

Ancillary measures for preventing EMC problems:a) Mains supply- If electromagnetic interference still occurs, despite the fact that the mains connection is in accordance with the regulations, take additional measures (e.g. use a suitable mains filter).

b) Welding cablesThis project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


- Keep these as short as possible- Arrange them so that they run close together (to prevent EMI problems as well) Lay them well away from other leads.

c) Workpiece grounding (earthing)- where necessary, run the connection to ground (earth) via suitable capacitors.d) Shielding, where necessary- Shield other equipment in the vicinity Shield the entire welding installation.

Oxyacetylene cutting and heating

The oxyacetylene process produces a high temperature flame, over 3000 degrees C, by the combustion of pure oxygen and acetylene. It is the only gas mixture hot enough to melt steel; other gases (propane, LPG or hydrogen) can be used for lower melting point non-ferrous metals, for brazing and silver soldering and as a preheating/piercing gas for cutting.

Safe storage

Gases are normally supplied under high pressure in steel cylinders. The cylinder should also have a label marked with the type of gas. To prevent the interchange of fittings between cylinders containing combustible and non-combustible gases, oxygen cylinders have a right-hand and acetylene have a left-hand thread. All cylinders are opened by turning the key or knob anticlockwise and closed by turning them clockwise.

Oxygen will cause a fire to burn more fiercely and a mixture of oxygen and a fuel gas can cause an explosion. It is, therefore, essential that the oxygen cylinders are separated from the fuel gas cylinders and stored in an area free from combustible material.

Safe practice and accident avoidance

Store the cylinders in a well-ventilated area, preferably in the open air The storage area should be well away from sources of heat, sparks and fire risk Cylinders should be stored upright and well secured Oxygen cylinders should be stored at least 3m from fuel gas cylinders or separated by a 30 minute

fire resisting barrier The store area should be designated 'No Smoking'.

Handling compressed gases

Cylinders are fitted with regulators to reduce the gas pressure in the cylinder to the working pressure of the torch. The regulator has two gauges, a high pressure gauge for the gas in the cylinder and a low pressure gauge for the gas being fed to the torch. The gas flow rate is controlled by a pressure adjusting screw which sets the outlet gas pressure.

Factors to be considered are that the gas system is suitable for the pressure rating and the hoses are connected without any leaks. Valve threads should be cleaned before screwing in the regulator. The valve of an acetylene cylinders can be opened slightly to blow out the threads but the threads in oxygen cylinders are best cleaned using clean compressed air (the threads on hydrogen cylinders must always be blown out using compressed air).



As oxygen can react violently with oils and grease, lubricating oils or sealant for the threads must not be used.

Safe practice and accident avoidance

Cylinders are very heavy and must be securely fastened at all times Cylinder valves or valve guards should never be loosened Check the regulator is rated for the pressure in the cylinder When attaching the regulator to the cylinder the joints must be clean and sealant must not be used Before attaching a regulator, the pressure adjustment screw must be screwed out to prevent

unregulated flow of gas into the system when the cylinder valve is opened

Using compressed gases

Gases are mixed in the hand-held torch or blowpipe in the correct proportions. Hoses between regulator and torch should be colour coded red for acetylene and blue for oxygen. Hoses should be kept as short as possible and users should check periodically that they are not near hot or sharp objects which could damage the hose wall. Acetylene cylinders must always be used upright.

When connecting the system, and at least at the start of each shift, hoses and torch must be purged to remove any inflammable gas mixtures. It is essential the oxygen stream does not come into contact with oil which can ignite spontaneously. Purging should also not be carried out in confined spaces.

The torch should be lit with a friction lighter or stationary pilot flame to avoid burning the hands; matches should not be used and the flame should not be reignited from hot metal, especially when working in a confined space.

The cylinders should not become heated, for example by allowing the torch flame to heat locally the cylinder wall. Similarly, arc welding too close to the cylinder could result in an arc forming between the cylinder and workpiece/electrode.

Suitable cutting processes for different types of steel to achieve a suitable cutting surface The three thermal cutting methods: flame cutting, plasma cutting and laser cutting are widespread and well known to most people.'Flame cutting, Principle and parameters, cutting blowpipes, cutting machines, quality of cut surfaceFlame cutting is the traditional and clearly predominant method, but its use is slightly declining because of the increase in laser cutting and plasma cutting. Flame cutting remains a very useful cutting method, partly owing to its versatility. It covers the entire thicknesses range from 3 to 300 mm for unalloyed steels. By using special torches the field of application can be extended to thicknesses of up to 1000 mm or even more. The quality of cut is excellent when the cutting parameters are correctly set. In economic terms, flame cutting is clearly an alternative where numerically-controlled machines are used in conjunction with several torches in order to increase the productivity per employee.

Other cutting processes as: plasma, laser, mechanical cuttingLaser cutting give a high-quality cut, narrow kerfs and low heat transfer to the workpiece. The economic thickness for unalloyed steel is 2 to 3 mm. The use of laser cutting will increase, mainly due to increased laser power output, which will enable thicker material thicknesses to be cut.The economic material thickness range for plasma cutting is 3 to about 20 mm. In this range plasma is faster then laser, but the quality of cut is not comparable. In an effort to compete with laser cutting, recent developments in plasma cutting have aimed to produce a system which is capable of producing cuts with completely square edges and narrow kerf width to enable higher cutting accuracy to be achieved.



The resulting systems are commonly known as high tolerance plasma cutting and are characterized by torches having high current density cutting arcs.Smaller sets intended for manual cutting are usually air plasma, whilst larger mechanized installation use oxygen, nitrogen or argon mixtures as the plasma gas. Plasma power sources above 300 amps never use air.In connection with subsequent welding of air-plasma cut edges, weldability problems like pore formation and lack of fusion have been noticed. Investigations have shown that high concentrations of nitrogen in the cut edges are responsible for the problems. There are different ways to avoid the problems. One is to grind off the thin layer of the cut surface that has a high nitrogen concentration. This is an expensive method and it will reduce the productivity. Another way is to cut with oxygen plasma.

An alternative to the thermal cutting methods is water jet cutting. The method emerged during the 1970s, when it was used to cut composites. Since then it has been developed to cut metals. This was made possible by adding abrasives to the jet, a technique known as abrasive water jet cutting. Using water jet cutting without abrasives it is possible to cut, in addition to composites, materials such as leather, rubber, textiles, wood, mineral wool and frozen foodstuffs. Abrasive water jet cutting can be used to cut sheet metal in gouges up to 50 mm, concrete up to 200 mm, stone and ceramics.Abrasive water jet cutting competes to some extent with the thermal methods, but as figure 1 shows, the cutting speed is very low, so the method is only competitive where some particular technical advantage can be exploited. Examples of such advantages are that the quality of cut is very good and that no heat is transferred into the workpiece the latter feature means that there are no deformation of the workpiece. Abrasive water jet cutting is also a suitable method for cutting surface treated materials like Zn, AlZn or polymer coated sheet metal, since this cutting method will minimize destruction of surface treatment.



Safety precautions for cutting (PSS1)In the table 1 are presented the representative cutting speed for different cutting methods.

MaterialsPlate

thicknesses (mm)

Cutting speed (mm/min)

Flame cutting

Plasma cutting

Laser cutting

Abrasive water jet cutting

SteelSteelStainless steelStainless steelAluminumAluminum

520

3

40240

850660

-

---

4500A2000A

5000B

500B>6000B1200B

2200 C-

6500

-1000 C

-

20050

200

10-2080080

A - Nitrogen plasma with water injected, 500 AB - Gas plasma (Ar/H2), 240 AC - Carbon dioxide laser 1000W, with oxygen as cutting gas

Table 2 shows the cutting methods for different materials.

Table 2

Cutting method MaterialMild steels Stainless steels Aluminum Titanium

FlamePlasmaLaserMechanicalWater jet

++++++++++++

+

+++++++++

+

+++++

+++++

++++

++++++

++++ well suited++ suited+ possible

Burns and fires, fire prevention, fire fighting The basic precautions for fire prevention in welding or cutting work are:Cutting or welding must be permitted only in areas that are or have been made fire safe.When work cannot be moved practically, as in most construction work, the area must be made safe by removing combustibles or protecting combustibles from ignition sources.If the object to be welded or cut cannot readily be moved, all movable fire hazards in the vicinity must be taken to a safe place.If the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed, then guards must be used to confine the heat, sparks, and slag, and to protect the immovable fire hazards.If these requirements cannot be followed then welding and cutting must not be performed.Suitable fire extinguishing equipment must be maintained in a state of readiness for instant use.Such equipment may consist of pails of water, buckets of sand, hose or portable extinguishers depending This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


upon the nature and quantity of the combustible material exposed.Fire watchers must have fire-extinguishing equipment readily available and be trained in its use.They must be familiar with facilities for sounding an alarm in the event of a fire. They must watch for fires in all exposed areas, try to extinguish them only when obviously within the capacity of the equipment available, or otherwise sound the alarm.

Before cutting or welding is permitted, the area must be inspected by the individual responsible for authorizing cutting and welding operations. He must designate precautions to be followed in granting authorization to proceed preferably in the form of a written permit.

Cutting or welding must not be permitted in the following situations:- in areas not authorized by management- in sprinklered buildings while such protection is impaired- in the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts

with air), or explosive atmospheres that may develop inside uncleaned or improperly prepared tanks or equipment which have previously contained such materials, or that may develop in areas with an accumulation of combustible dusts.

- in areas near the storage of large quantities of exposed, readily ignitable materials such as bulk sulfur, baled paper, or cotton.

Where practicable, all combustibles must be relocated at least 10 m from the work site. Where relocation is impracticable, combustibles must be protected with flameproofed covers or otherwise shielded with metal or asbestos guards or curtains.



MODULE 4

Objective:

Know and understand hazards and basic safety requirements when welding.

Scope:

Welding fumes Respiratory hazards Personal protective equipment and clothing Noise hazards

Expected results:

Know the health risks of welding fumesKnow the personal protective equipmentKnow the respiratory hazards

Personal protective equipment and clothing Personal protective equipment especially designed for the task at hand must always be used when arc welding. Protective clothing must not be heavily soiled or torn.

1. Head ProtectionThis provides protectiona) against falls (e.g. crash helmets, cycle helmets, climbing helmets)b) against falling objects or against striking fixed objectsc) against striking fixed objects (e.g. objects in confined spaces).

2. Eye ProtectionWelding helmetA welding helmet must always be worn when welding to protect the eyes and face from radiation and welding spatter.The welding helmet can be lowered in front of the face. The lens should be lowered using one hand instead of the "chin-up" method as repeated nodding can cause neck injuries.Welding lensesWelding helmets and welding lenses both have dark glass, so-called welding lenses. The welding lens is used to filter out UV and IR radiation. Only visible light is allowed to pass the lens.Lens protectorLens protectors are used in welding helmets and shields to protect the welding lens from spatter.Automatic welding lensesAutomatic anti-dazzle welding lenses are also available. This type of welding lens darkens automatically the moment the arc is ignited and becomes lighter again when the arc is extinguished. Automatic welding lens can be set to different densities.Welding helmet with fresh-air supplyEquipment is available for supplying fresh and cool air to the welding helmet. The positive pressure created inside the welding helmet prevents weld smoke from mixing with the air the welder inhales. Comfort is also enhanced and mist is prevented from forming on the welding lens.

Relevant standards:This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


a) EN169 welding filtersb) EN175 welding eye protectorsAlways choose eye protection appropriate to the hazard and ensure that fits properly and is comfortable.Dirty lenses impair vision, causing eye fatigue and leading to accidents. The plastic lenses of eye protectors should be wet cleaned to avoid scratching; scratched lenses should be replaced, as should face shields if they become crazed or brittle with age.Safety spectacles and goggles should be issued on a personal basis and should be thoroughly cleaned before issue to someone else.

3. Foot ProtectionSafety footwear should comply with EN 345 (with toe protection of 200 or 100 joules). Footwear with anti-static or slip resistant properties should conform to EN 347.The choice of safety footwear should first be made on the basis of the protection required, but comfort is a significant issue and should not be ignored. Care should be taken in the choice of anti-static and conductive footwear. Both give protection against the hazard of static electricity and anti-static footwear also gives some protection against electric shock. However conductive footwear provides no protection against electric shock and must not be used where this is a risk.Footwear should be checked for wear or damage and replaced if necessary.

4. GlovesGloves may be used to give protection against toxic or corrosive chemicals, microbiological or radiological contamination, cuts and abrasions, impact, vibration or extremes of heat and cold.Standards for protective gloves are complex and basic standards are listed below. Gloves may additionally be described as of simple, intermediate, or complex design (a measure of their suitability for risks ranging from minimal to high); a performance level (usually on a scale from 0 to 4) may also be quoted.a) EN 407 for protection against heat and/or fireb) EN 421 for protection against ionizing radiation/radiation contaminationc) EN 659 for protection against heat and flamesChoose gloves appropriate for the job and consider whether long cuffs, gauntlets, or sleeve protectors may be required. Ensure that they offer good fit, comfort, and dexterity.Gloves rarely provide complete protection against hazards and this protection is much diminished by wear, damage, and chemical contamination. They should be checked before wear for cuts or pinholes and replaced if necessary.

5. Protective ClothingProtective clothing should be maintained as specified by the manufacturer.





Welder equipped with personal protection equipment.

In addition to the general protective clothing for welding and cutting operations, arc welding requires the fol-lowing extra clothing:Wear clothes made of materials heavy enough to protect against ultraviolet rays.Wear dry welder’s gloves to protect against shock and electrocution.

Noise hazards.Noise is usually defined as undesirable sound and is a health hazard. Noise can cause hearing damage. Disturbing noise levels in combination with requisite ear defenders can make it difficult to communicate, which may lower the level of enjoyment in the workplace. Psychological well-being is also affected by noise.Noise abatementSources of noise in a welding workshop are grinding, slagging and beating. This kind of work must be minimized. When grinding or hammering must be performed the use of equipment and aids that give the lowest possible noise levels is requested.Clang dampersIt is the workpiece that generates most noise during grinding, slagging and beating. Using clang dampers will reduce the noise level considerably. Clang dampers are elastic dampers with a magnetic layer for fastening on the workpiece.Silenced machinesQuieter hand-held machines have been developed during the last few years. Pneumatic slag picks and grinding machines are now fitted with silencers. Quieter grinding discs have been developed. Using modern equipment will reduce the noise level considerably.Noise absorbing screensScreens made of porous material such as mineral wool erected between the welding areas can limit the noise in many cases. The screen must be high and wide and located as close as possible to the source of the noise. By erecting absorbers above and beside the screen, noise can be reduced at longer distances.Ear defendersIn many welding shops the noise level is so high that ear defenders must always be used. Wearing ear defenders of down or earplugs will provide basic protection against background noise and unexpected sound. The noise level when slagging and beating is so high that ear cups are required. It is essential to wear ear defenders all the time in extremely noisy environments. Even short periods without protection can risk damaging your hearing. A hearing impairment cannot be cured.

Resume: Noise of 85 db (A) or higher might lead to hearing damage



Safety measures:- noisy techniques to be substituted by quieter ones- protection from sound waves - isolation- spatial division- marking noisy areas- personal safety equipment (ear phones)- medical prevention and ambulanceIf the 85 db (A) level is reached - one must posses personal hearing protection equipmentAbove the level >90 db (A), standard noise protection is required for all employees.



MODULE 5

Objective:

Know and understand hazards and basic safety requirements when welding.

Scope:

Electric shock UV- and heat radiation Eye hazards Burns and fires, fire prevention, fire fighting Welding fumes Respiratory hazards Personal protective equipment and clothing Noise hazards Specific rules and regulations

Expected results:Know dangerous situations in relation to electricity, humidity, DC and AC. Know the health risks of welding fumes. Know the signals for escape routes. Name adequate means of personal protection. Know measures to be taken to prohibit fire. Know measures to prevent noise hazards. Know the specific rules and regulations.

Specific rules and regulations

Welding Safety (resume)

Hazard Factorsto Consider Precaution Summary

Electric shock can kill Wetness

Welder in or on workpieceConfined spaceElectrode holder and cable insulation

Use dry insulation. Rubber mat or dry woodWear dry, hole-free gloves.Do not touch electrically "hot" parts or electrode with bare skin or wet clothing.If wet area and welder cannot be insulated from workpiece with dry insulation, use a semiautomatic, constant-voltage welder or stick welder with voltage reducing device.Keep electrode holder and cable insulation in good condition. Do not use if insulation is damaged or missing.

Fumes and gases can be dangerous

Confined areaPositioning of welder's headLack of general ventilationElectrode types, i.e., manganese, chromium, etc.Base metal coatings,

Use ventilation or exhaust to keep air breathing zone clear, comfortable.Use helmet and positioning of head to minimize fume in breathing zone.Read warnings on electrode container and material safety data sheet for electrode.Provide additional ventilation/exhaust where special ventilation requirements exist.Use special care when welding in confined area.



galvanize, paint Do not weld unless ventilation is adequate.

Welding sparks can cause fire or explosion Containers which

have held combustiblesFlammable materials

Do not weld on containers, which have held combustible materials unless procedures are followed. Check before welding.Remove flammable materials from welding area or shield from sparks, heat.Keep a fire watch in area during and after welding.Keep a fire extinguisher in the welding area.Wear fire retardant clothing and hat. Use earplugs when welding overhead.

Arc rays can burn eyes and skin Process: gas-shielded

arc most severe

Select a filter lens, which is comfortable for you while welding.Always use helmet when welding.Provide non-flammable shielding to protect others.Wear clothing, which protects skin while welding.

Confined space Metal enclosure WetnessRestricted entryHeavier than air gasWelder inside or on workpiece

Evaluate adequacy of ventilation especially where electrode requires special ventilation or where gas may displace breathing air.If basic electric shock precautions cannot be followed to insulate welder from work and electrode, use semiautomatic, constant-voltage equipment with cold electrode or stick welder with voltage reducing device.Provide welder helper and method of welder retrieval from outside enclosure.

General work area hazards

Cluttered area Keep cables, materials, tools neatly organized.

Indirect work (welding ground) connection

Connect work cable as close as possible to area where welding is being performed. Do not allow alternate circuits through scaffold cables, hoist chains, or ground leads.

Electrical equipmentUse only double insulated or properly grounded equipment.Always disconnect power to equipment before servicing.

Engine-driven equipment

Only use in open, well ventilated areas.Keep enclosure complete and guards in placeTurn off engine before refueling.

Gas cylindersNever touch cylinder with the electrode.Never lift a machine with cylinder attached.Keep cylinder upright and chained to support.

Electric shock



The physiological effects of electric currentIf electric current passes through the body, it can cause various injuries such as:- Burns- Cramp- Auricular fibrillation- Damage to the central nervous system.

The effects of electrical current on the human body depend on:- Circuit characteristics (amount of current, resistance, frequency, and voltage). - The current’s pathway through the body. - How long the contact lasts. - Condition of the person’s skin (breaks in the skin or wet skin will lower the bodies resistance to the flow of electricity).

In some cases low currents passing through the body can cause contraction of the muscles of the heart and lungs followed by failure of the heart and an inability to breathe.

In normal circumstances gloves and shoes will serve to reduce the risk of shock from the ‘low voltage’ welding output (that is, 48 to 113 volts). The risk is increased if the contact resistance is lowered (for example, in wet conditions).Electricity can strike the human body and, depending on the current type, magnitude, duration, and path, produce injuries (damage). The effects of alternating current are presented in table.

Amount of current in Milliamps (mA) Response

0.5-3 Start to feel the energy, tingling sensation3-10 Experience pain, muscle contractions10-40 Grip paralysis threshold (can't let go to source)30-75 Respiratory failure100-200 Heart fibrillation200-500 Heart clamps tightOver 1,500 Tissue and organs burn

Particular danger exists at open circuit source voltage since this is the highest voltage of the welding circuit.Power sources should have protection for solid foreign objects and water penetration provided by the enclosure (IEC 60529). The degree of protection is indicated by the IP-code (International Protection) on the rating plate. Power sources for outdoor use shall have a minimum degree of protection of IP23.

In order to minimize the chance of electric shocks, the highest open-circuit voltage value for the power source has to be defined. Some cases are distinguished:- normal workshop conditions, with good insulation for welder and welded parts, - conditions with "higher electric shock danger".Higher shock danger appears: in forced contact of electricity conducting parts with unprotected human body (e.g. when kneeling, sitting or leaning) if the free movement distance between the electric conducting components is less than 2 m when working sites are wet, damp or hot, as well as for working outside.The allowed open circuit voltage for the welding power source are shown in a simple table:



Workshop Higher danger of shock

Transformer net entrance 220 V

net entrance380 V S

55 V 80 V 48 V

Transducer 113 V S113 V

Commutation 113 Vwith collector

113 V

without collector

S 113 V

Inverter 113 V S113 V

The symbol S replaces the former symbols 42V and K.

Power sources for use in spaces with increased electrical danger (e.g. boilers) must be identified by the (for “safety”) mark. However, the power source should not be in such rooms.

Steps to Prevent Electrical Shock There are few steps that can be taken to prevent electrical shock. To prevent electrical shock: - Use well insulated electrode holders and cables. - Make sure welding cables are dry and free of grease and oil. - Keep welding cables away from power supply cables. - Wear dry hole-free gloves. - Clothing should also be dry. - Insulate the welder from the ground by using dry insulation, such as a rubber mat or dry wood. - Ground frames of welding units. - Never change electrodes with bare hands or wet gloves.

Emergency Procedures:If someone is being shocked, follow these procedures:1. Shut off the power immediately. The longer the person is in contact with the electricity, the more damage will be done.2. Do not try to touch or approach the person until the power has been shut off, or you too will become a part of the circuit. Use a dry wood broom, leather belt, plastic rope, or something similar that is non-conductive such as wood or plastic to free the person from the energy source.3. An electrical shock victim must go to the hospital even if they claim they are not hurt. Internal damage This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


cannot be seen; only a physician can determine if the victim has been injured or not.4. If the victim is unconscious, check to see that they have a pulse and are breathing. Initiate CPR or mouth-to-mouth resuscitation if necessary and if you are trained to do so.5. Keep the person lying down and keep them warm to prevent shock.6. Do not move the victim unless they are in immediate danger. Moving the victim could aggravate internal injuries or paralyze them since severe muscle contractions caused by electricity have been known to break bones in the victim.

UV- and heat radiation Radiation arises from arc welding that the welder must be protected from this radiation, by wearing proper clothing and protective glasses (with filter). Radiation can be classified in three groups: - ultraviolet radiation (UV) (causes eyesight blurring, skin burns).- visible radiation (visible light) (blindness at long exposure).- infrared radiation (IR, heat radiation) (leads to eye lid inflammation, and eyesight nerve damage in extreme cases (cataracts), as well as skin burns).

UV radiation is the predominant danger. Eyes and skin can both be damaged if not protected with a welding shield, gloves and suitable clothing. The UV radiation from an arc is so strong that even reflections can cause eyesight blurring and skin burns. Short wave length UV radiation (130–175 nanometers) causes also the breakdown of oxygen to form ozoneThe cornea in the eyes is affected by UV radiation. The eyes start to chafe a few hours after being exposed to UV radiation. Usually this happens during the night. In this case, they are weld flash burns. Normally, weld flash burns will disappear after a couple of days without leaving any permanent damage. Repeated weld flash burns can cause permanent eye damage.The skin can react to UV radiation in the same way as sunburn, that is to say the skin becomes red and sore and will eventually start to peel. Therefore, it is essential you use gloves and button up your clothing around your neck so that no bare skin is exposed to radiation.

Eye protection from electric arc radiation is accomplished by EN 169 filter with protection factor of 8 (low energy processes), up to 15 (high energy processes).

Protection factor Application3 brazing and resistance welding4 & 5 auxiliary welding operation6 to 8 arc welding I=30-75 A9 & 10 arc welding I=30-200 A11 & 12 arc welding I=200-400 A13 & 14 arc welding I over 400 A15 arc welding with extremely high I

What measures can you use for skin protection from welding radiation? - wear tightly woven work-weight fabrics to keep UV radiation from reaching your skin. - button up your shirt to protect the skin on the throat and neck. - wear long sleeves and pant legs. - cover your head with a fabric cap to protect the scalp from UV radiation. - protect the back of your head by using a hood. - protect your face from UV radiation by wearing a tight-fitting, opaque welder's helmet. - make sure that all fabric garments are resistant to spark, heat and flame. Keep the fabrics clean and free of combustible materials that could be ignited by a spark.



- what are some tips to know when using protective clothing?

You should:- wear clothing made from heavyweight, tightly woven, 100% wool or cotton to protect from UV radiation, hot metal, sparks and open flames. Flame retardant treatments become less effective with repeated laundering. - keep clothing clean and free of oils, greases and combustible contaminants. - wear long-sleeved shirts with buttoned cuffs and a collar to protect the neck. Dark colors prevent light reflection. - tape shirt pockets closed to avoid collecting sparks or hot metal or keep them covered with flaps. - pant legs must not have cuffs and must cover the tops of the boots. Cuffs can collect sparks. - wear high top boots fully laced to prevent sparks from entering into the boots. - use fire-resistant boot protectors or spats strapped around the pant legs and boot tops, to prevent sparks from bouncing in the top of the boots. - remove all ignition sources such as matches and butane lighters from pockets. Hot welding sparks may light the matches or ignite leaking lighter fuel. - wear gauntlet-type cuff leather gloves or protective sleeves of similar material, to protect wrists and forearms. Leather is a good electrical insulator if kept dry. - direct any spark spray away from your clothing. - wear leather aprons to protect your chest and lap from sparks when standing or sitting. - wear layers of clothing. To prevent sweating, avoid overdressing in cold weather. Sweaty clothes cause rapid heat loss. Leather welding jackets are not very breathable and can make you sweat if you are overdressed. - wear a fire-resistant skull cap or balaclava hood under your helmet to protect your head from burns and UV radiation. - wear a welder's face shield to protect your face from UV radiation and flying particles.

You should not:- wear rings or other jewelery. wear clothing made from synthetic or synthetic blends.Eye hazardsWhy is eye protection important? - Eye injury can occur from the intense light and radiation from a welding arc and from hot slag that can fly off from the weld during cooling, chipping or grinding. - Protect your eyes from welding light by wearing a welder's helmet fitted with a filter shade that is suitable for the type of welding you are doing. - ALWAYS wear safety glasses with side shields or goggles when chipping or grinding a work piece if you are not wearing a welding helmet.

What are the various components of eye protection for welders? - eye protection is provided in an assembly of components:- helmet shell - must be opaque to light and resistant to impact, heat and electricity. - outer cover plate made of polycarbonate plastic which protects from UV radiation, impact and scratches. - filter lens made of glass containing a filler, which reduces the amount of light passing through to the eyes. Filters are available in different shade numbers ranging from 2 to 14. The higher the number, the darker the filter and the less light passes through the lens. - clear retainer lens made of plastic prevents any broken pieces of the filter lens from reaching the eye. - gasket made of heat insulating material between the cover lens and the filter lens protects the lens from sudden heat changes, which could cause it to break. In some models the heat insulation is provided by the frame mount instead of a separate gasket.- choose a tight fitting helmet to help reduce light reflection into the helmet through the space between the This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


shell and the head. - wear the helmet correctly. Do not use it as a hand shield. - protect the shade lens from impact and sudden temperature changes that could cause it to crack. - use a cover lens to protect the filter shade lens. Replace the cover lens if it gets scratched or hazy. - make sure to replace the gasket periodically if your helmet uses one. - replace the clear retaining lens to protect your eyes from broken pieces. - clean lenses periodically. - discard pitted or damaged lenses.

For Arc welding, the correct filter shade is selected according to the welding process, wire diameter, and operating current.ALWAYS use suggested shade numbers instead of minimum shades. For gas cutting, welding and brazing, the intensity of the light is much less than from arc welding. Lighter shade filter lenses are used with goggles in place of a helmet.

Dust particles or chemicals that can irritate the eyes may be present in many welding areas. Wearing contact lenses is not being advisable in such workplaces.

Welding fumesDefinitionHazardous substances in welding and allied processes are repairable air polluting substances generated by welding, cutting and allied processes, which at an intolerable concentration may be injurious to health.

ClassificationHazardous substances generated by welding and allied processes operations can be classified with respect to their occurrence and effects.

OccurrenceHazardous substances are generated by welding and allied processes in the form of gases and/or particles. Particulate substances are dispersed as minute solid particles in the air.

Inhalable fraction – The fraction of particles, which is inhaled through the mouth and nose into the body: it comprises particle sizes up to and exceeding 100 μm. In the past this fraction was called "total dust".

Respirable fraction – The fraction of particles capable of penetrating into the alveoli (air sacs); it comprises particle sizes up to 10µ . In the past this fraction was called "fine dust".

Airborne particles generated by welding are very small. In general, they have a diameter of less that 1µ m (in most cases less that 0.1 µm), are therefore respirable and called "welding fume".During thermal cutting and some allied processes the airborne particles generated are only partially respirable.

EffectsGaseous and particulate substances generated by welding, cutting and allied processes can be classified This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


according to their effects on different organs of the human body as follows:

Lung-stressing (inert) substances – long-term intake of high concentrations leads to a restricted lung function which is due to a decrease in the exchange of oxygen, due to dust deposited in the lungs.

These dust deposits are generally not pathogenic, they are reversible. Iron oxides and aluminum oxides are part of this group, for example:

Toxic (poisonous) substances – have a toxic effect on the body, if a certain dose (=amount per unit weight of the body) is exceeded. This is a dose-effect-relationship. Slight poisoning leads to mild health disorders; high concentrations of these substances in the inhaled air may cause very serious poisoning which results in death.

Toxic substances are, for example, gases such as carbon monoxide, nitrogen oxide and dioxide, ozone, as well as oxides of metals such as copper, lead, zinc in the form of fume and dust.

Carcinogenic (cancer-causing) substances – are substances that are known to cause malignant tumors.

Welding and cutting operations create hazardous fumes and gases. In order to minimize inhalation of haz-ardous substances:- ventilation.- portable fans to create air currents that take fumes away from your face. - don’t get too close to an arc welder’s arc.- leave the area immediately and get medical help if you feel sick.

GenerationHazardous substances generated by welding and allied processes may arise from: - filler materials- parent materials- shielding gases- coatings- contamination- ambient airAt high temperature (due of arc or flame) by physical and/or chemical processes such as:- evaporation- condensation- oxidation- decomposition- pyrolysis- combustion

Influencing factorsThe amount and kind of hazardous substances are also influenced - apart from the processes and materials used - by surface coatings and contamination as well as by the following factors:Current, voltageHigher welding current and welding voltage lead - for identical processes and materials to higher emission rates of hazardous substances.Type of currentHigher emission rates are observed with a.c. current than with d.c. current.Diameter of the electrodeEmission of hazardous substances increases with the electrode diameter.Type of coatingThis project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


Rutile coated electrodes have the lowest emission rates of hazardous substances while cellulose covered electrodes have the highest.Type of weldingOverlaying produces higher emission rates of hazardous substances than joint welding.

Allowed values and recommended valuesIn order to reduce the exposure of the welder to dangerous material, the allowed values are named:- OEL - values, or- MAC - defined values.OEL: these limit values specifies the average concentration, which does not normally represent a health risk during eight hours of work a day (level limit value).MAC is the highest allowed concentration of material that develops cancer, but does not lead to disease. MAC is the maximum permissible concentration of a chemical compound present in the air within a working are a which generally does not impair the health of the employee. That are scientifically backed criteria of health protection are definitive here, not the technical and economical feasibility of realizing them in practice. In general, the MAC-value applies only to single substances (pure substances) and is a long-term value, e.g. a time-weighted average concentration for an 8 hour exposure and a 40 hour working week (in four-shift operations for an 40 hours per week average over four successive weeks). Due to the fact that the concentration of different substances in the workplace atmosphere may fluctuate, short-term limit values have been laid down to allow evaluation when the time-weighted average' concentration (peak exposures) is exceeded over a short period. They are limited according to dose, duration, frequency and time intervals.The OEL value is also a medium value that refer to 8-hour daily working cycles, or 40-hours/ week.Short exposures can in some limited time have higher values. This is determined by the character of dangerous material, and duration and frequency of work in shafts.

Hazardous substancesGaseous hazardous substances Argon (Ar) Non-toxic. Used as a shielding gas, alone or mixed with other gases. Heavier than air and can accumulate at the base of any closed vessel being welded and can form layers at the bottom of the welding operation in a badly ventilated welding shop. Essential to have extraction and circulation of the atmosphere



around the welding point.Helium (He) Non-toxic. Used generally mixed with other gases (e.g. 50% helium 50% argon). Helium is not produced in this country but is imported from the United States and is therefore much more expensive than argon.Oxygen (O2) Non-toxic but it promotes rapid oxidation especially in the pure state. Atmosphere roughly 4 parts nitrogen to I part oxygen (the proportions required by the human body to enable it to function). Used in small quantities (1 % to 2%) mixed with argon for stainless steel welding.

Carbon monoxide (CO) is generated in critical concentrations during 132 MAG welding with carbon dioxide or during metal-active-gas welding with mixed gases (with a high concentration of carbon dioxide) by thermal decomposition of carbon dioxide (CO2). Furthermore carbon monoxide is generated during any form of combustion with an inadequate oxygen supply.Nitrogen oxides (NOx = NO, NO2) are generated by oxidation of the atmospheric nitrogen (from the oxygen (O2) and the nitrogen (N2) of the air) at the edge of the flame or the arc. Nitrogen monoxide is generated at temperatures exceeding 1000 0C. Nitrogen monoxide oxidizes to nitrogen dioxide in the air at room temperature.Phosgene (COCl2) is generated, in addition to hydrogen chloride (HCl), by heating or by UV-radiation of degreasing agents containing chlorinated hydrocarbons.Gases from coating materials are generated by welding of workpieces with shop primers (surface coatings preventing corrosion) or with other coatings (paints, lacquers). Depending on the chemical composition of these coatings, not only metal oxides are generated, which are particulate, but also gases, e.g. carbon monoxide (CO), formaldehyde (HCHO), toluylene disocyanate, hydrogen cyanide (HCN), hydrogen chloride (HCl).

Particulate hazardous substancesChromium-VI-compounds Hexavalent chromium compounds are generated in critical concentrations when using high-alloy covered electrodes for manual metal arc welding and also when welding with high-alloy flux- cored wires containing chromium.Chromium-VI-compounds may also occur in repair welding of materials coated with shop primers containing zinc chromates, a practice followed in the past. It can cause cancer and asthma-like problems.

Nickel oxides (NiO, NiO2, Ni2O3) are mainly generated by:- welding with pure nickel and nickel-base alloys (from the filler material)- plasma cutting of high-alloy steel containing nickel (from the parent material)- thermal spraying with nickel-base spraying materials (from the spraying material).Can cause cancer and asthma.

Toxic gaseous (hazardous) substancesCarbon monoxide (CO)Very poisonous, odorless gas. In higher concentrations the oxygen-carrying capacity of the blood is impeded by the great affinity of carbon monoxide to hemoglobin (hemoglobin is necessary for transporting oxygen in the body). The result is a lack of oxygen in the tissues.Dizziness, lassitude and headache occur at a concentration of 150 ml/ m3 in the breathing zone. A level of 700 ml/ m3 causes fainting, increased pulse and breathing rates, ending in unconsciousness, respiratory paralysis, cardiac arrest and death.MAC value = 33 mg/ m3, 30 ml/m3.

Nitrogen oxides (also called nitric oxides or nitrous gases)Nitrogen monoxide (NO) is a colorless, poisonous gas. Nitrogen dioxide (N02) is a brown-red, poisonous gas causing oxidation. Nitrogen dioxide is much more toxic than nitrogen monoxide and acts even in relatively low concentrations as an insidious irritant gas. At the beginning there is an irritation of the air passages and This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


dyspepsia, followed for several hours (in general 4 to 12 hours) by an asymptomatic state, which in severe cases, ends in fatal pulmonary edema (accumulation of fluid in the lungs).MAC value for N02 = 9 mg/ m3; 5 ml/ m3 MAC value for NO = 30 mg/ m3; 25 ml/ m3

Ozone (O3)Ozone is a colorless gas having a penetrating smell and being strongly toxic that is formed during arc welding when oxygen in the air is exerted to ultraviolet radiation. O 2 molecules (oxygen) are converted into O3, which is the chemical formula for ozone. Ozone is a strong corrosive and can damage mucous membranes. Characteristic effects of ozone are a pungent or burning feeling in the throat, chest pains and difficulty in breathing. The risk of troublesome ozone levels is greatest when 141 - TIG and 13| MIG welding aluminum.Ozone (O3) is formed when oxygen is exposed to ultra violet (UV) radiation in the wavelength range from 130 to 175 nanometers. The oxygen required may be part of the gas mixture used, may be entrained from the atmosphere or the UV irradiation may reach the area just outside the shielding gas envelope. Ozone is an extremely active, oxidizing gas and will react with many other materials in the immediate area of the arc. Whilst its activity makes it particularly damaging to the respiratory system, its concentration in the breathing zone is usually reduced by its reactions with other materials. Since its generation depends on the intensity of UV radiation, the amount generated increases with current but may decrease with increasing amounts of particulate fume. High levels of ozone can be found however in high current gas metal arc welding of aluminum and high current gas tungsten arc welding.Ozone levels in the arc area may also be controlled by nitric oxide (NO) gas additions. It acts as an irritant gas on the respiratory organs and eyes. It causes an irritation of the throat, dyspepsia and possibly a pulmonary edema.MAC value = 0,2 mg/ m3; 0,1 ml/ m3

Phosgene (COCl2) (Carbonyl chloride or carbon dichloride oxide) Is an odorless, extremely poisonous gas with a musty smell. Initially (3 to 8 hours) there are slight symptoms, which may be followed by heavy irritations of the respiratory tract ending in pulmonary edema (accumulation of fluid in the lungs).MAC value = 0,4 mg/ m3; 0,1 ml/ m3

Removal of hazardous welding dustProtection from dangerous material (Ventilation)Ventilation is mostly the only way to dispose dangerous material, and these procedures are common:- natural ventilation (welding shop should be as large, airy and high as possible)- forced ventilation- vacuuming in the area of origination- wearing gas masks.The type of ventilation depends on the:- procedure- material- duration of operation with electric arc and/or flame torch- size of working surface.Certain procedures can diminish the concentration level of dangerous material as:- alteration of the process - so that less dangerous material is emitted- good positioning of the working object- or the proper position of the human body relative to welding- proper choice of parameters for welding and cutting- optimal working conditions, for example, use of special cleaning equipment, devices that save gas, water resistance.

A method of eliminating fumes consists of a suction unit fitted with a filter, from the suction side of which a large diameter, fixed, rigid tube is fitted (spot extractor). This tube passes down the shop (well above head This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


height) and over every welding position or bench. Flexible tubes of a similar large diameter are fitted, which reach down to the welding position or bench. At the lower end of the flexible tube a collecting head is fitted (see Figs. l and 2).

Spot extractorAn efficient method of ventilating weld smoke is to use a spot extractor to collect the smoke as close to the arc as possible. There are a number of types of spot extractor- spot extractor arms- portable suction vents- welding guns with integrated extractor- fixed extractors (in welding table and fixtures).The spot extractor can be either a central ventilation unit or portable weld smoke filters.Portable weld smoke filters usually only take away solid particles while gas is allowed to pass through. Therefore, it is important that the weld smoke filter is located outdoors when welding in confined spaces so that the gas is transported out.Permanent welding positions (welding tents, etc.) are best equipped with an extractor arm that is connected to a central ventilation unit and can be set to the desired position anywhere in the working zone. Remember to place the vent so that the weld smoke does not pass the breathing zone.When erection welding on large structures, a suction hose with vent can be used that the welder is able to place above the weld joint. It is essential that the vent is placed as close to the weld joint as possible as the suction capacity decreases considerably as the distance increases.

Electrostatic precipitation can be utilized where it is inconvenient to install a fixed collector. Upon entering the precipitator, fume particles are charged electrostatically and then pass through an insulated sleeved tube to plates of opposite polarity to that of the particles. They are deposited on the plates, which are part of the filtering elements, and the air issuing from the unit is fume less and is returned to the atmosphere. Figure 17 This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


shows a sectional view of a filter.

Efficient extraction of fumes is essential to the long-term health of the welder, as it may be many years until the effects of fumes inhaled over a long period are apparent. Almost all the toxic substances in the table above have a long-term effect on the respiratory tract and lungs, and in time seriously affect the health of the operator. Ventilation is considered to be sufficient if: - the ceiling height is not less than 5 m. - cross ventilation is not blocked by partitions, equipment, or other structural barriers. welding is not done in a confined space.



MODULE 6

Objective:

Know and understand the hazards by chemical components

Scope:

Understand how chemical elements behave and their symbols

Expected results:

Know the different symbols for chemical elements

General.Injury can be caused by chemicals only if they reach sensitive parts of a person or other living organism at a sufficiently high concentration and for a sufficient length of time.

Thus, injury depends upon the physicochemical properties of the potentially toxic substances, the exact nature of the exposure circumstances, and the health and developmental state of the person or organism at risk.

Major routes of exposure are through the skin (topical), through the lungs (inhalation), or through the gastrointestinal tract (ingestion). In general, for exposure to any given concentration of a substance for a given time, inhalation is likely to cause more harm than ingestion which, in turn, will be more harmful than topical exposure.

Skin absorption

Many people do not realise that chemicals can penetrate healthy intact skin and so this fact should be emphasized.

Amongst the chemicals that are absorbed through the skin are aniline, hydrogen cyanide, some steroid hormones, organic mercury compounds, nitrobenzene, organophosphate compounds and phenol.

Some chemicals, such as phenol, can be lethal if absorbed for a sufficient time from a fairly small area (a few square centimetres) of skin. If protective clothing is being worn, it must be remembered that absorption through the skin of any chemical which gets inside the clothing will be even faster.

Inhalation

Gases and vapours are easily inhaled but inhalation of particles depends upon their size and shape. The smaller the particle, the further into the respiratory tract it can go.

Dusts with an effective aerodynamic diameter of between 0.5 and 10 micrometres (the respirable fraction, the PM10 fraction) can persist in the alveoli and respiratory bronchioles after deposition there.

Peak retention depends upon aerodynamic shape but seems to be mainly of those particles with an effective aerodynamic diameter of between 1 and 2 micrometers. Particles of effective aerodynamic diameter less than 1 micrometre tend to be breathed out again and do not persist either in the alveoli or enter the gut (see below).

Remember: The effective aerodynamic diameter is defined as the diameter in micrometers of a spherical particle of unit density which falls at the same speed as the particle under consideration.

Dusts of larger diameter either do not penetrate the lungs or lodge further up in the bronchioles and bronchi where cilia (the mucociliary clearance mechanism) can return them to the pharynx and from there to the This project has been funded with support from the European Commission. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use, which may be made of the information contained therein.


oesophagus.

From the oesophagus dusts are excreted through the gut in the normal way: it is possible that particles entering the gut in this way may cause poisoning as though they had been ingested in the food.

A large proportion of dust breathed in will enter the gut directly and may affect the gut directly by reacting with it chemically or indirectly from contamination with micro-organisms. As already mentioned, some constituents of dust may be absorbed from the gut and cause systemic effects.

Physical irritation by dust particles or fibres can cause very serious adverse health effects but most effects depend upon the solids being dissolved. Special consideration should be given to asbestos fibres which may lodge in the lung and cause fibrosis and cancer even though they are insoluble and therefore not classical toxicants: similar care should also be taken with manmade mineral fibres.

Identification of chemical and hazardous material.

The Supplier must decide whether or not chemicals are hazardous and, if they are, they must be allocated a category of danger and one or more risk phrases or risk combinations.

Explosive, E

(Chemicals that explode)

Oxidising, O

(Chemicals that react exothermally with other chemicals)

Extremely Flammable, F+, or Highly Flammable, F, or Flammable

(Chemicals that have an extremely low flash point and boiling point, and gases that catch fire in contact with air OR chemicals that may catch fire in contact with air, only need brief contact with an ignition source, have a very low flash point or evolve highly flammable gases in contact with water.)

Very Toxic ,T+, or Toxic, T.

(Chemicals that at very low levels cause damage to health OR Chemicals that at low levels cause damage to health)

Harmful

(Chemicals that may cause damage to health)

Corrosive , C

(Chemicals that may destroy living tissue on contact)

Irritant, Xi

(Chemicals that may cause inflammation to the skin or other mucous membranes)



Sensitising, Xn or Xi

Carcinogenic, Categories 1 and 2, T

Carcinogenic, Category 3, Xn

(Chemicals that may cause cancer or increase its incidence)

Mutagenic, Categories 1 and 2, T

Mutagenic, Category3, Xn

(Chemicals that induce heritable genetic defects or increase their incidence)

Toxic for Reproduction, Categories 1 and 2, T

Toxic for Reproduction, Category 3, Xn

(Chemicals that produce or increase the incidence of non-heritable effects in progeny and/or an impairment in reproductive functions or capacity)

Dangerous for the Environment, N

(Chemicals that may present an immediate or delayed danger to one or more components of the environment)



MODULE 7

Objective:

Know the basic actions to be taken when an accident has occurred

Scope:

Have basic knowledge about CPR

Expected results:

Know the basic CPR principles and are able to start CPR

When something happens.

The basic rules when something happens are as follows and if it is personnel involved in the accident:

What has happened ? Does the person breath ? Call for help Organize if you have more people present Start CPR if needed Continue until professional assistance are available

If more people are available then: Keep other people away from the area Plan for access by rescue team

Everybody should know about and and when to administer CPR. When performed correctly, CPR can save a persons life by restoring breathing and circulation until advanced life support can be given by health care providers.

What Is CPR?

The letters in CPR stand for cardiopulmonary resuscitation, a combination of rescue breathing (mouth-to-mouth resuscitation) and chest compressions. Without oxygen, permanent brain damage or death can occur in less than 8 minutes.

Reading about CPR and learning when it's needed will give you a basic understanding of the concept and procedure, but it's strongly recommended that you learn the details of how to perform CPR by taking a course.

When Is CPR Needed?

CPR is most successful when administered as quickly as possible, but you must first determine if it's necessary. It should only be performed when a person isn't breathing or circulating blood adequately.

First, determine that it's safe to approach the person in trouble.. If someone touched an exposed wire and was electrocuted, you'd have to be certain that he or she is no longer in contact with electricity before offering assistance, to prevent becoming electrocuted yourself.



Once you know that you can safely approach someone who needs help, quickly evaluate whether the person is responsive. Look for things like eye opening, sounds from the mouth, or other signs of life like movement of the arms and legs.

The next step is to check if the victim is breathing. You can determine this by watching the person's chest for the rise and fall of breaths and listening for the sound of air going in and out of the lungs. In a CPR or basic life support (BLS) course, participants practice techniques for determining if breathing or circulation is adequate. If you can't determine whether someone is breathing, you should begin CPR and continue until help arrives.

Three Parts of CPR

The three basic parts of CPR are easily remembered as "ABC": A for airway, B for breathing, and C for circulation.

A is for airway. The victim's airway must be open for breathing to be restored. The airway may be blocked when a person loses consciousness or may be obstructed by food or some other foreign object.

B is for breathing. Rescue breathing is begun when the person is not breathing. Someone performing rescue breathing essentially breathes for the victim by forcing air into the lungs. This procedure includes breathing into the victim's mouth at correct intervals and checking for signs of life.

C is for circulation. Chest compressions can sometimes restore circulation. Two rescue breaths should be provided and followed immediately by cycles of 15 chest compressions and 2 rescue breaths. It is not necessary to check for signs of circulation to perform this technique. This procedure involves pushing on the chest to help circulate blood and maintain blood flow to major organs.

1. CALL

Check the victim for responsiveness. If there is no response, Call ambulance urgently and return to the victim. In most locations the emergency dispatcher can assist you with CPR instructions.

2. BLOW

Tilt the head back and listen for breathing. If not breathing normally, pinch nose and cover the mouth with yours and blow until you see the chest rise. Give 2 breaths.

3. PUMP

If the victim is still not breathing normally, coughing or moving, begin chest compressions. Push down on the chest 15 times right between the nipples. Pump at the rate of 100/minute, faster than once per second.

CONTINUE WITH 2 BREATHS AND 15 PUMPS UNTIL HELP ARRIVES


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