Falls - The Number One Cause of Construction Deaths
(Taken from Construction Safety Magazine, Construction Safety Association
of Ontario, Vol. 10, No. 3, Autumn 1999)
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Construction
Safety Association of Ontario
Despite variations
in fatality causes and frequency, falls remain the number one killer in
Ontario construction.
- Construction workers
have fallen off edges of every description. The most common are floors,
roofs, and openings in floors and roofs. When an unprotected edge makes
you worry about falling, take action. Set up guardrails, install opening
covers, or use a fall-arrest system securely tied off.
- A number of fatal
falls have occurred among small crews doing jobs of low cost and short
duration. Contractors evidently thought the jobs were small and quick
enough not to warrant fall protection. That was their fatal mistake.
- Construction workers
have been killed when they removed the plywood cover from a roof or
floor opening to use the material elsewhere and inadvertently stepped
into the opening. Covers should be clearly identified in bright paint:
OPENING COVER! DO NOT REMOVE!
- Your chances of
falling from a ladder are significantly reduced if you maintain three-point
contact when climbing up and down the ladder or working from it. Three-point
contact means one hand and two feet or two hands and one foot on the
ladder at all times.
- Construction workers
have been killed when they fell from ladders that slid or slipped because
the ladders weren't secured at top and bottom. In addition, use a mudsill
to support ladder feet on soft, uncompacted, or rough soil.
- On scaffolds and
other work platforms where personnel can fall 2.4 meters (8 feet) or
more, guardrails must be installed or a fall-arrest system must
be worn.
- Construction workers
have been killed by falls as low as two feet. Where practical, install
guardrails even on low work platforms. When working from any raised
surface, remember where you are. Don't step backward. Don't shift footing
without looking down first.
In Ontario
construction, falls have accounted for at least 30 deaths
since 1995.
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1995 |
1996 |
1997 |
1998 |
Fall
Fatalities |
6 |
8 |
8 |
4 |
Total
Fatalities |
13 |
23 |
15 |
24 |
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In 1999,
seven of the 12 construction fatalities so far have been from
falls.
Ministry
of Labour (MOL) inspectors have stepped up enforcement of
fall protection requirements. The most important initiative
is the move towards province-wide mandatory fall protection
training, expected to be included in revised regulations.
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Guardrails are the
first line of defense in fall prevention. They should be installed along
the open sides of any area where a worker may fall 2.4 meters (8 feet)
or more or into water, operating machinery, or hazardous substances. Areas
to be protected include
- floors and floor
openings
- balconies
- slab formwork
- stairways and
landings
- roof tops
- scaffolds and
other work platforms
- runways and ramps
- bridge surfaces.
Guardrails should
have a top rail, mid-rail, and toeboard secured to vertical posts or supports.
Available in wood,
wood-slat, wire rope, and manufactured wire mesh systems, guardrails must
meet the following minimum dimensions:
- top rail between
91 cm (3 feet) and 1.07 meters (3 feet, 6 inches) high
- toeboard at least
10.2 cm (4 inches) high and installed flush with the surface
- posts no more
than 2.4 meters (8 feet) apart.
These components
should be secured to the inside of the posts or jacks. Toeboards should
be installed on all open sides of a scaffold or work platform.
Guardrails should
be installed as close to the edge as possible and must be capable of resisting
any load likely to be applied. This may require extra reinforcement in
special situations, such as where forklifts or buggies are used.
For maximum resistance
to sideways force, the 2x4 top rail of wooden guardrails should be laid
flat, with the larger dimension horizontal. To further strengthen guardrails,
double the top rail and reduce the spacing of posts to between 1 and 2
meters (3 feet 4 inches and 6 feet 8 inches.)
Wood guardrails must
be supported by posts extending to the top rail and braced and solidly
fastened to the floor. Shoring jacks used as posts should be fitted with
plywood softener plates at top and bottom. Snug up and check the posts
regularly for tightness.
For slabs and the
end of flying slab forms, manufactured posts can be attached to the concrete
with either clamps or insert anchors.
If guardrails must
be removed, the opening edge should be roped off and marked with warning
signs. In addition, workers should use a fall-arrest system properly anchored
and tied off.
In construction,
eliminating the risk of falls may not be possible. It then becomes essential
to select proper fall protection.
Two basic types of
fall protection are
- fall arrest
- travel restraint.
Where guardrails
or other protection is not in place, you must use a fall-arrest or travel-restraint
system if you are in danger of falling
- more than 3 meters
- into operating
machinery
- into water or
another liquid
- into or onto a
hazardous substance or object.
Fall
Arrest
Fall arrest
is the most common system. It stops a fall within a few feet of
the worker's original position. A full body harness is required
with a fall-arrest system. A typical system consists of the following
parts connected together:
- full body
harness (CSA-certified)
- lanyard
(with locking snap hooks or D-clips)
- rope grab
- lifeline
- lifeline
anchor.
A fall-arrest
system must be worn when you are on a rolling scaffold that is
being moved or when you are getting on, working from, or getting
off suspended access equipment such as a swingstage or bosun's
chair.
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Travel-restraint
systems prevent falls by restraining a worker from getting too close to
an unprotected edge.
A travel restraint
system must be arranged to keep the worker back from the fall hazard area.
The system usually consists of
- safety belt of
full body harness (CSA-certified)
- lanyard
- rope grab
- lifeline
- lifeline anchor.
The basic problem
with travel-restraint systems is that the rope grab must be continually
adjusted to allow free movement and travel but still keep the worker away
from the edge. One technique is to use a self-retracting lifeline (see
article below).
In practice, travel-restraint
systems are not foolproof because the length of the lifeline is not always
adjusted properly. If the self-retracting lifeline, for instance, is longer
than the distance to the nearest edge, a worker moving in that direction
will not be restrained before falling.
But even if the system
doesn't prevent a fall, it still arrests the fall.
Self-retracting lifelines
(SRLs) are widely used in construction to provide fall protection, especially
where workers must move about to handle or install material. SRLs let
the user move the full length of the line but stop and lock at any sudden
pull. This action is designed for fall arrest -- not for travel restraint.
Users of SRLs most
know the manufacturers' recommendations for proper operation as well as
any safeguards required for specific applications.
SRLs have traditionally
been anchored above the worker's head with the line running near vertical
down to the worker's safety belt or harness. There's general agreement
that this is the best application of SRLs.
In construction,
however, different applications have appeared. In addition to the traditional
position, two other basic options are
- anchor and unit
at the ridge of a pitched roof above the worker's location
- anchor and unit
situated on a flat work surface so that the lifeline is drawn out by
the worker in a horizontal plane.
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Each manufacturer's
manual provides information and guidelines for SRLs anchored above
a worker's head.
Not all of
the manuals, however, cover the use of SRLs in horizontal applications.
In these cases the user must confirm that the particular model
is approved for horizontal use. The manufacturer will then outline
requirements for proper horizontal use.
Remember
-- SRLs are NOT travel restraints. Travel restraints are designed
to restrain the user's movement near open edges and prevent falling
altogether.
The only
time an SRL can act as a travel restraint is when the line is
completely drawn out yet still short enough to keep the user from
moving forward or laterally into a hazardous location.
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Fall-arrest systems
can only prevent fatal falls if they are used properly. Correct use includes
inspection. Your life depends on it.
- Always check the
tag for date of manufacture. Most web-type harnesses have a service
life of five years. If the harness doesn't have a tag, don't use it.
- Look for cuts,
fraying, broken stitching, and other damage to webbing. Check for chemical
or heat damage.
- Inspect metal
buckles for distortion, cracks, and sharp or rough edges. All buckles
should slide easily for adjustment.
- Check for worn,
cut, or frayed fibers where buckles attach to harness.
- Inspect D-ring
for distortion, cracks, sharp or rough edges, and chemical or heat damage.
- Ensure that the
plate holding the D-ring in position is free from cracks, heat damage,
and other defects. The plate must keep the D-ring from sliding out of
place.
Most lanyards have
a service life of five years. Check tag for date of manufacture. Inspect
lanyard for worn, broken, or cut fibers; signs of stretching; evidence
of chemical or heat damage; and cracked or distorted connecting hardware.
A shock absorber
should carry a tag indicating date of last inspection. If the tag is missing,
return the absorber to your supervisor for advice on its suitability.
If the absorber is made with tear-away stitching designed to absorb fall-arrest
load, make sure stitching is intact.
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Snaphook
- Check
for cracks and corroded or pitted surfaces.
- Ensure
that bill and eye sections are not twisted or bent.
- Check
that locking mechanism works properly. Push the keeper into
the open position with the
mechanism still engaged. If the keeper opens, discard the snaphook
immediately.
- Ensure
that spring has enough tension to close keeper securely.
- Open the
keeper and release. The keeper should sit into the bill without
binding.
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Rope
Grab
- Make
sure that grabs are installed rightside up. Most grabs feature
a directional arrow to indicate proper orientation.
- Ensure
that proper size lifeline is used. The required size is marked
on the rope grab.
- Mount
the grab on the lifeline. Pull the grab down sharply. The
grab should lock within 30 cm (12 inches).
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Lifeline
Lifelines
must be at least 16mm diameter polypropylene or material of
equal strength. Inspect lines from end to end before installation.
Look for cuts, burns, fraying, and chemical or heat damage.
Signs of decreased diameter may indicate that line has been
involved in a fall arrest and should be discarded.
Lifeline
Anchorage
- Ensure
that lifelines are securely attached to solid anchor points.
- Whenever
possible, attach only one lifeline to each anchor.
- Never
anchor to bundles of material that may be moved or depleted
through use. Do not anchor to exposed rebar unless embedment
length is adequate.
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