Walk the plank

Scaffolds can get you closer to your work, but they can also put you closer to danger.

Each year, more than 60 workers are killed by falls from scaffolds, and about one in five of the fatal falls involves a construction worker, reports the Center for Protection of Workers’ Rights (CPWR), which has developed this information as a hazard alert for construction work crews.

Besides problems with planks and guard rails, the main causes of injuries and deaths on scaffolds are poor planning for assembly and disassembly, missing tie-ins or bracing, loads that are too heavy, and being too close to power lines. Also, falling objects can hurt people below scaffolds.

Protect yourself
Scaffolds are supported (usually by posts/beams and legs) or suspended (by ropes). OSHA says a scaffold must be designed by a qualified person. Supported scaffold must be able to support its own weight and at least four times the maximum intended load.

Further, OSHA says a competent person must inspect a scaffold before each work shift and after anything happens that could affect the structure. The competent person should be trained in scaffold safety, and is defined by OSHA as a person who is capable of identifying existing and predictable hazards and has authorization to take prompt measures to eliminate them. A competent person must supervise if a scaffold is assembled, changed, moved or taken apart.

Scaffold dangers
Power lines present electrocution dangers and scaffolds should be placed no closer than 10' from power lines or within 3' if lines are less than 300 volts, unless you are sure the power lines are de-energized.

Weather can also play havoc with scaffolds. Don’t work on a scaffold in high winds or a storm unless a competent person says it is safe and you use personal fall-arrest or a wind screen. If you use a screen, the scaffold must be secured against the expected wind force. OSHA says you must not work on a scaffold that has ice or snow on it — except to get ice or snow off of the scaffold.

Guidelines for checking a scaffold
If a scaffold is more than 2' above or below a level, there must be a way to get on or off it, such as a ladder, ramp or personnel hoist. The access must not be more than 14" from the scaffold.

Put a standing scaffold on a firm foundation with base plates attached to feet, for instance, with one piece of wood under each pair of legs across the shortest distance and extending at least 12" past each leg.

Uprights must be vertical and braced to prevent swaying; all platforms must be level.

A scaffold that is more than four times higher than its base is wide must be tied to supports.

Most scaffold platforms and walkways must be 18" wide or more. If a work area is less than 18" wide, guard rails and/or personal fall-arrest must be used.

With 10' planks, they must extend at least 6" past the end supports, but not more than 12"; there should be no more than 1" between planks or between planks and uprights.

>> Wood planks must be unpainted so any
     cracks in the wood shows.

>> For supported scaffolds, check at least
     these points:
       1. Completely planked platforms
       2. Proper access
       3. Complete guard rails
       4. Proper ties to buildings, where required

Suspended scaffolds
>> Supporting outrigger beams must be able to support at least four times the intended load. To keep a scaffold from falling to the ground, it must be attached to the roof, tied to a secure anchorage or secured with counterweights. The suspension ropes and rigging must support at least six times the intended load.

>> Counterweights must be attached to secured, strong places on a building so they won’t move.  Do not use bags of sand or gravel, masonry blocks or any roofing materials that can flow or move.

>> Do not use gas-powered equipment or hoists. Hoists must have automatic brakes for emergencies.

>> A one-point or two-point suspended scaffold must be tied or secured to prevent swaying.

Fall protection
OSHA says if a scaffold is more than 10' above a level, workers must have fall protection.

A competent person must decide if fall protection is feasible when you assemble a scaffold or take it apart.

On most scaffolds, guard rails must be on all open sides and ends. On supported scaffolds and some other scaffolds, guard rails or personal fall protection is enough. On most suspension scaffolds, both are needed. Use a harness, not a body belt, for personal fall protection.

You do not need a guard rail on the working side when the platform is less than 14" from the work (18" for plastering and lathing). The open side of an outrigger must never be more than 3" from the face of the building.

In most cases, with supported scaffolds, the top rail must be 38" to 45" above the platform. A top rail must be strong enough to hold 200 lbs. (or 100 lbs. on single-point and two-point suspension scaffolds). A mid-rail must be about halfway between the platform and the top rail; most mid-rails must be able to hold 150 lbs. If mesh, screens or panels are used, a top rail is needed unless the mesh was designed and installed to meet guard rail requirements.

The scaffold walkways must have no more than a 9 1/2" gap between planks and a guard rail.

Don’t let junk collect on the scaffold. You can trip and fall.

Protect people below a scaffold
There must be a 3 1/2"-high toe board to prevent tools and supplies from falling off a scaffold.

If items on the scaffold are taller than 3 1/2" above the toe board, other systems. like debris nets, can be used to catch falling tools or materials.

If there is a chance that items can fall off a scaffold, people must be prevented from walking under or near the scaffold.

Training
>> The employer must have a qualified person provide safety training for each worker using the scaffold. A competent person must train any worker who assembles, takes apart, moves, operates, repairs, maintains or inspects scaffolds.

>> If the jobsite changes or the type of scaffold or safety equipment changes, workers using scaffolds must be retrained.

Published in the September/October 2007 issue of Contractor Tools and Supplies magazine.

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