Let’s Talk Safety—Working at Altitude: Don’t Fall Into Danger

This column addresses safety issues of interest to water and wastewater personnel, and will appear monthly in the magazine. The Journal is also interested in receiving any articles on the subject of safety that it can share with readers in the “Spotlight on Safety” column.

Working at Altitude: Don’t Fall Into Danger

S A 39-year-old worker died after falling 40 feet when a scaffolding suspension rope broke. He was a member of a three-man crew engaged in the abrasive blasting and painting of the interior of a 48-foot-high, 30-foot-diameter steel water tank. At the time of the accident, the victim was standing on an outer end of the scaffold platform and was pulling on the suspension rope to raise that end of the scaffold. He fell when the rope broke and his end of the platform dropped to a vertical position.

The victim was not using personal fallprotection equipment, although it was available and was being used by a second painter. An investigation revealed that the hoist rope broke at a point where it had been burned some time before the incident. S A worker was killed, another was injured, and a third coworker was left hanging when a scaffold rope broke while they were painting the side of a building in

San Francisco. They were on a twopoint suspension scaffold that did not have guardrails, the ropes suspending the scaffold were old and had not been inspected, and the employees were not wearing safety belts. When the left scaffold rope broke and the scaffold collapsed, one painter was killed, while another fell to a nearby roof and broke both arms. The third coworker was left hanging on to the remaining scaffold rope.

These case reports from Occupational Safety and Health Administration (OSHA) files demonstrate the dangers of a failure to have a good fall-protection, fall-arrest, and fallrestraint system in place for employees. Anyone working at elevation needs to be aware of the dangers and have the proper protection in place to prevent such accidents.

Falls can occur from floor and roof edges, elevated platforms, ledges, elevated tanks, machine rooms, and attached ladders and stairways. Falls can also occur from temporary structures used for construction and maintenance, such as scaffolds or ladders.

The OSHA standards state that a guardrail system, safety net system, or personal fall-arrest system must be in place to protect workers who are exposed to an unprotected side or edge from which they could fall 6 feet or more.

Built-in Safety

The safest strategy for workers who must work at elevation is to have built-in fall restraints, such as: S Permanent guardrails that meet OSHA height and strength requirements. S Built-in anchor points with appropriate personal fall-arrest systems and lifelines. S Other forms of fall protection, such as safety netting.

On-the-Job Safety

Workers at elevations with vertical drops of 6 feet or more should also be provided a personal fall-restraint system that secures the worker via an anchor point, connector, lanyard, and body harness. This system is designed to prevent a fall.

A personal fall-arrest system also uses an anchor point, connectors, lanyards, and body harnesses, but allows exposure to the fall and is then designed to stop the fall after it has begun.

Key points about a personal fall-arrest system include: S Connectors should be made of drop-forged, pressed, or formed steel, or of equivalent materials, and covered with a corrosionresistant finish, with smooth surfaces and edges to prevent damage to interfacing parts of the system. S D-rings and snaphooks should have a minimum tensile strength of 5,000 pounds and proof-tested to a minimum tensile load of 3,600 pounds without cracking, breaking, or becoming deformed. S Locking snaphooks must prevent disengagement of the snaphook if the connected member contacts the snaphook keeper.

S Unless designed for it, locking snaphooks must not be attached in any of the following ways: • Directly to webbing, rope, or wire rope. • To each other. • To a D-ring to which another snaphook or other connector is attached. • To a horizontal lifeline. • To any object that is incompatible with the snaphook such that unintentional disengagement could occur. S Horizontal lifelines should be designed, installed, and used (under the supervision of a qualified person) as part of a complete personal fall-arrest system that maintains a safety factor of at least two. S Lanyards and vertical lifelines should have a minimum breaking strength of 5,000 pounds. S When vertical lifelines are used, each person must be attached to a separate lifeline. S Lifelines must protect against being cut or abraded. S Self-retracting lifelines and lanyards that automatically limit freefall distance to 2 feet or less must sustain a tensile load of at least 3,000 pounds.

When stopping a fall, personal fall-arrest systems should: S Limit the maximum arresting force on a person with a body harness up to 1,800 pounds. S Prevent a freefall of more than 6 feet or contact with any lower level. S Bring a person to a complete stop and limit maximum deceleration distance to 3 and a half feet. S Withstand twice the potential impact energy of a person freefalling a distance of 6 feet, or the freefall distance permitted by the system (whichever is less).

Use body harnesses and components only for personal protection, and never use harnesses to hoist materials. Inspect personal systems before use for wear and damage. Any fall-arrest systems and components that are subjected to impact loading must immediately be removed from service and not used again for protection until inspected by a competent person and determined to be undamaged and suitable for reuse.

For more information, see the OSHA Fall Prevention Campaign at www.osha.gov/ stopfalls/. S