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An Introduction to Ladder Safety Awareness
Ladder Safety
Ladder SafetyAn Introduction to Ladder Safety
Awareness
Ladder Safety
In the United States, one person almost every day of the year is killed by falling from a ladder; approximately 300 deaths and 130,000 serious injuries.
Probably hadn’t thought much about it, huh? After all, ladders are one of those tools we use every day and take for granted.Yet, if a falling accident occurs from a ladder, the chances are excellent the accident will result in injury or death.
Fortunately, almost all falls are preventable – if the fundamentals of ladder construction, use and safety are understood.
Ladder Safety
How long does it take you to fall? Many workers believe that they have time to regain their balance before they fall. However, this belief is usually untrue.
The following table shows how far you can fall in different time spans:
Time (Seconds) Distance (feet)0.5 41.0 161.5 362.0 642.5 1003.0 1444.0 256
Two snaps of the fingers, and a 150# person has fallen 64 feet and if stopped
there, crashes with an estimated impact force of 4800# - more than enough to break a lot of otherwise healthy bones! Makes you appreciate the seriousness of the “sudden stop at the bottom”!
Ladder Safety
For all their apparent simplicity, two primary hazards are associated with the use of ladders. The hazards are…
– Falls (and the sudden stop at the bottom!)– Electrical hazards
• Electrocution• Shocks (often with resulting falls with sudden stops at
the bottom!)
In this course, you will learn how ladders are designed and constructed, how to use portable ladders safety. You will also learn about the safety equipment necessary to safely climb fixed ladders at industrial facilities.
As in any knowledge-based course, the development of hands-on skills in the deployment, use and maintenance of fall arrest equipment is essential before climbing industrial fixed ladders.
Portable ladders and electricity
Right up front, the student should understand that portable ladders (of any type) and electricity truly do not mix!
Portable ladders are difficult to handle and can easily accidentally break lighting and other power fixtures.
Worse, portable ladders used outdoors can contact elevated high tension supply lines by accident resulting in electrocution. In many cases, conductive ladders do not have to contact the line – they can merely come sufficiently close to it to cause a short circuit through the ladder to ground.Do not use metal (or wet) ladders when working near power-lines or fixtures. Keep all ladders at least ten feet away from residential power-lines and much further away from larger power-lines.
Ladder Safety
Portable ladder constructionPortable ladders come in many lengths and essentially one of three different construction materials…
– Wood– Aluminum or steel– Fiberglass
Ladder Safety
They range from small “step-stool” models to truck mounting extension ladders. Portable ladders are manufactured in essentially three configurations…
– Straight ladders– Extension ladders– Step-ladders
– Type 1A Industrial – heavy duty – 300# (OSHA requires safety factor of 3.3X @75.5 deg.)
– Type I Industrial – heavy duty to 250# (OSHA requires 4X safety factor @ 75.5 deg.)
– Type II Commercial – Medium-duty to 225# (OSHA requires 4X safety factor @ 75.5 deg.)
– Type III Household – light duty to 200# (OSHA requires 4X safety factor @ 75.5 deg.)
Ladder Safety
There are also three different weight-bearing standards for portable ladders.
Straight ladders
Straight ladders are used for repetitive climbing to a relatively fixed height.
Straight ladders may be of wood, metal or fiberglass construction. Most are wood or metal. Straight ladders are usually constructed of solid wood or metal rails joined with rungs.
The rungs in a wood ladder are usually hickory, oak, ash or other hardwood to provide the maximum strength for the weight. Rails are usually fir, hemlock or similar softer woods that are much lighter.
Metal ladder rungs are either welded to the rails or attached with expansion plugs.
Ladder Safety
Extension ladders
Extension ladders essentially combine straight ladder sections with an interlocking rail system, and mechanisms to extend the ladder
from the ground to its working height and lock it in position. The extension section is called the “fly” section, the lower section is the “base”.
Extension ladders can be built of wood, aluminum, steel or fiberglass. Almost all are made of wood, aluminum or fiberglass, with aluminum and fiberglass the most common materials in recent years. Both aluminum and fiberglass offer significant advantages over wood.
Fly sections usually extend using a system of pulleys and a rope. The pulleys run on ball bearings to make them easy to use, and the rope may be either natural manila or a synthetic rope. Manila is preferred in fire service applications because it doesn’t burn easily and doesn’t melt or elongate when exposed to heat as synthetics do. However, it must be replaced regularly.
Ladder Safety
Extension ladder locking mechanisms are usually either gravity activated automatic “catches” that rest on a base section rung and are locked in place when weight is placed on the ladder, or spring loaded catches.
Most extension ladders are made of aluminum. Aluminum is relatively light and very strong for its weight. Aluminum also bends before it breaks and that provides an additional safety margin.
But aluminum conducts heat and electricity very readily making aluminum dangerous to use around electrical and heat hazards. In addition, aluminum used in ladder construction is heated to about 6000 F. to increase the strength of the aluminum. If aluminum ladders are exposed to heat in excess of 6000 F. (as in a fire scenario) they may be unable to bear even the weight of a man.
Ladder Safety
Many extension ladders are made of fiberglass. Fiberglass is very strong and heat tolerant. It does not conduct heat quickly, nor does it conduct electricity when dry. Fiberglass ladders made of self-extinguishing polymers do not burn except when directly exposed to flame. They lose strength comparatively slowly.
Fiberglass is much heavier than aluminum and breaks suddenly when over-stressed. Also, fiberglass ladders need to be protected with a lacquer coating to prevent oxidation damage.
This combination of properties, however, makes fiberglass ladders the ladders of choice for electrical work.
Wooden extension ladders are rarely used these days. They used to be the ladders of choice for electrical and fire work because wood is non-conductive and for ladder purposes, fire-resistant. However, the maintenance requirements for wood ladders have made them obsolete for most applications.
Ladder Safety
Extension ladders must be rigorously maintained. Extension pulleys and locking mechanisms must be oiled occasionally. Extension ropes must be replaced when worn, frayed or deteriorated. Locking mechanisms must be inspected and their ability to lock and secure properly must be ascertained.Candle wax is the lubricant used to lubricate the rails where they slide against each other.
In all cases, the locking mechanisms for both rails must be properly and securely locked before climbing the ladder.
Many extension ladders, and some fixed ladders have “spurs” attached to the rail bottoms to help stabilize the ladder in soil. However, the spurs do not work on hard surfaces such as concrete and must be replaced with non-slip rubber pads. Many ladders have swiveling feet allowing rubber pads or spurs to be selected based on the type of support surface.
Ladder Safety
Straight and extension ladders are constructed to resist the force of gravity directed downward. Theoretically, a ladder is strongest when it is in the vertical (900) position relative to the surface it is on. However, vertical ladders are not safe to climb, unless they are secured in some manner, so a stable angle is used to weight-rate ladders…75-760 relative to the support surface…a slope of 4/1.
Therefore the most stable angle for a portable ladder is approximately 750 or a 4/1 slope. In setting up a portable ladder the base should be one foot from the wall or other vertical support for every four feet of vertical height.
The reference height used to calculate the angle to set up a ladder is the height of the vertical support surface…not the length of the ladder.
Ladder Safety
Note in figure 2 that “A” represents the distance from the base of the ladder to the top support surface for the ladder, and that the distance from a vertical line between the base support surface (the ground in this case) to the top support surface is ¼ of “A”.
For example, if a wall is 12’ high, A= approximately 12’6” and the base of the ladder should be approximately 3’ 6” from the base of the wall.
Also note the extra three feet of ladder beyond the support surface. If a climber is leaving the ladder for the support surface, ie, a roof, OSHA requires the ladder to be a minimum of A+3’ in length.
Figure 2
Ladder Safety
Some safety pointers for using straight and extension ladders
– Keep your belt buckle between the rails!Keeping your belt buckle between the rails means that you have not extended your weight far over one rail causing the ladder to over-balance, slip and fall.
– Never hand carry loads up a ladder!If tools or supplies are required, carry them in your pocket, in a tool belt, or lift them from the ground in a line.
– Always use a three-point stance!One hand and both feet on the ladder; both hands and one foot on the ladder. If you must work with both hands, hook one leg over a rung to hold and support you.
Ladder Safety
– Never stand on the ladder’s top three rungs!Its easy to overbalance and fall off.
– Never use a ladder that is damaged or weakened!
– Never “walk” a ladder into position while you are on it! Climb down and re-position the ladder from the ground.
– Use care around electrical fixtures!You can get an electrical shock on any ladder, but dry
fiberglass and wood ladders do not normally conduct electricity.
Using aluminum ladders around electrical fixtures can result in electrocution.
Ladder Safety
– Never use a ladder in front of a door unless it is locked, blocked or guarded!
– Never use a ladder in a strong wind!
– Never have more than one person on a ladder at one time!
– Never carry a ladder in the vertical position. Carry a ladder in the horizontal only.
– Never jump from a ladder!
– Be certain you are in good enough physical condition to climb!
Includes not being under the influence of alcohol or drugs that make you dizzy, drowsy or subject you to fainting.
Ladder Safety
– Make sure ladders are kept free of oils, greases or other contaminants that may cause slipping!
– Use ladders only for their intended purpose!Ladders are not bridges. If you need to bridge a gap with a ladder, a whole different load bearing analysis must be done to ensure safety.
– Secure ladders subject to displacement by other inadvertent workplace activities!
– Keep areas around tops and bottoms or ladders clear!
– Do not move shift or extend ladders while in use!
Ladder Safety
– Ensure the ladder is in good condition!
– Ensure the ladder can handle the weight!
– Raise a straight or extension ladder by placing the base of the ladder against a wall or other resistance, then, beginning with the top rung walk the ladder up to vertical. Rest it on the upper support, then move the base out to the proper location.
Ladder Safety
1. Transport ladder horizontally.
2. Place base of ladder against base of wall or block.
3. Raise ladder starting at the top rung.
4. Raise ladder to vertical position. Hold with one hand and grasp lower rung with other hand.
5. Pull the base of the ladder back until the ladder is 750 relative to the base’s support surface.
750
Figure 3
Ladder Safety
Step-ladders may be made of wood, aluminum or fiberglass. Aluminum Step-ladders have the advantages of high strength to weight and the malleable properties of aluminum that allow it to bend before it breaks.
Aluminum step-ladders have the same disadvantages of being highly conductive for electricity and heat, and have the same strength reduction if exposed to heat over 6000 F.
Aluminum step-ladders usually do not exceed 20’ in height.
Figure 4 – Step-ladder
Ladder Safety
Fiberglass step-ladders are strong, durable and non-conductive of heat and electricity. They should be chosen for use where there are heat or
electrical hazards. However, they are heavier and may be more difficult to use than aluminum ladders.
Use step-ladders on level surfaces!While straight ladders must be placed on level footing, the area of level footing required for safe use of a step ladder is much larger. All four feet must be on a firm level surface to use a step-ladder safely. How much level surface is required varies in direct proportion to the length of the ladder. Long step-ladders – 16-20 feet - require large flat level areas.
Using a step-ladder with one or more feet improperly supported may result in a fall. If it does not result in a fall, and it used regularly in that manner, it will result in twisting of the ladder frame and eventual loosening of the rungs and braces potentially reducing the service life of the ladder.
Ladder Safety
The general safety rules for step-ladders are similar for the safety rule for straight and extension ladders.
– Keep your belt buckle between the rails!Keeping your belt buckle between the rails means that you have not extended your weight far over one rail causing the ladder to over-balance, slip and fall.
– Never hand carry loads up a ladder!If tools or supplies are required, carry them in your pocket,
in a tool belt, or lift them from the ground in a line.
– Always use a three-point stance!One hand and both feet on the ladder; both hands and one foot on the ladder. If you must work with both hands, hook one leg over a rung to hold and support you.
Ladder Safety
– Never stand on the ladder’s top rung or top platform!Its easy to overbalance and fall off.
– Never stand on the braces on the back of the ladder, on the tool/paint shelf, or on the rail tie-bar/ side-braces!
These structures are not designed to hold your weight.
– Never use a ladder that is damaged or weakened!
– Never use a ladder in front of a door unless it is locked, blocked or guarded!
– Never have more than one person on a ladder at one time!
– Never use a step-ladder when all four feet are not firmly and equally supported!
Ladder Safety
– Make sure ladders are kept free of oils, greases or other contaminants that may cause slipping!
– Never jump from a ladder!
– Ensure the ladder can handle the weight!
– Never use a wet ladder for jobs with electrical hazards!
Used properly and safely, step-ladders are safe and useful tools.
Ladder Safety
• Portable ladders are normally one of three types… Straight Extension Step-ladders
• Portable ladders are normally constructed on one of three materials… Wood Aluminum Fiberglass
• Wood ladders are difficult to maintain and have a limited service life. They are used less than they used to be.
• Aluminum ladders are light-weight, maintenance-free, strong for their weight and bend before they break. Aluminum ladders are good general service ladders unless exposure to heat or electricity is expected.
• Fiberglass ladders are strong, durable and relatively stable to heat and electricity. They are good general service ladders but are somewhat heavy.
Key Point Review
• Straight and extension ladders may have “spurs” on the feet to prevent slippage in soils, or rubber pads to prevent slippage on smooth surfaces. Newer ladders may have the two types of feet combined and interchangeable through a pivot arrangement.
• Step-ladders require firm level surfaces for safe use.• The most stable angle for a ladder is approximately 750 from
horizontal.• “Keeping the belt buckle between the rails” effectively keeps
the climber’s weight centered on the ladder and prevents over-balancing.
• All ladders must be kept in good condition,and must not be used if they are not in good condition.
• All ladders must be kept dry and free of oils and greases that may cause slips and falls.
• Straight or extension ladders used to access a roof or elevated deck must extend at least three feet above the roof or deck in order to provide the necessary hand grip surface to enter and exit the ladder safely.
• Ladders must be inspected regularly for loose rungs or defective rails or braces. All mechanical hardware must be maintained in good operating condition. Threaded rods on wood step-ladders must be kept tight.
Key Point Review
