Connecting Hardware
The choice of snaphooks to link rope-grab components is a vital safety matter. Only instructions from the manufacturer of the rope grab should be followed to ensure the hardware is compatible. No other snaphooks should be used to avoide potential roll-out or burst-out. Other parts of this book address the problems of mixing and matching and misuse. All snaphooks should be of self-locking design, maintained in optimum operating condition, and discarded if they are jammed or damaged.
Anchorage Structures
Ladder rungs or steps, and guardrails or railings of any kind, should not be used for fall arrest anchorages unless they are designed and labeled specifically for that purpose. Steel members should be used for anchorage-point structures whenever possible. Masonry fittings can be suitable when used with through-bolts and plate washers. Expanded anchor bolts should be specified by a registered professional engineer.
Rescue Devices
It should be noted that a manually operated mechanical device could be utilized optimally at a lift rate of 10 to 20 feet per minute under demonstration conditions. Remember that the object of the retrieval process is to extricate the worker within 4 minutes, the rule-of-thumb limit for the onset of brain damage from oxygen deprivation. Therefore, when manually powered hoists are used to provide access from more than a 50-foot depth, a pneumatic operation should be the primary lifting force. Another factor in the 50-foot limit is the static, muscle work duration for upper-body cranking, set at approximately 30 pounds when non-stop for several minutes (5:1 ratio with 12-inch lever arm).
Residential Roofs
Because of difficulties in training residential roof workers, elimination of hazards seems to be the most feasible goal. A large enough crane capacity and boom length, plus pre-assembly at ground level, can go a long way toward the elmination of fall hazards.
Cable System Anchorages
Cable systems used for anchorages around buildings or structures on the roof should be made of stainless steel, with fittings attached according to the wire-rope manufacturer’s instructions or standard rigging handbooks. Cable systems used for anchorages should be designed, installed and tested by a licensed professional engineer experienced in such design, prior to being used for the attachment of suspension or fall arrest lines.
Ladder Types
Ladders comprise an almost infinite combination of steps and handholds for ascent and descent from one level to another. In general, there are 12 inches between each level, and the horizontal gripping element and foot placement are called “rungs”. Rungs can be supported by side rails at each end, typically 16-18 inches apart. If ladders can be moved by hand or crane, they are called portable. If they are bolted or welded to the structure, they are called fixed. Sidestep refers to rungs that continue up and the climber steps to a platform at the side. A walk-through is a series of rungs that stop, but the side rails continue up and the climber exits to a platform between the side rails.
Hazards – Lanyards used for Fall Protection
It is common practice for a worker to wrap a lanyard around a structural steel section for protection against falling. It was discovered during laboratory testing that 5/8-inch-wide (16 mm) 3-strand nylon lanyards lost up to 90% of their original strength when arresting a fall. The test was performed according to CSA Standard Z259.1-M1976. Similar tests on 7/8-inch-wide nylon web lanyards ended with no arrest at all. In both cases the lanyards’ loss of strength was caused by cutting action of the edges of the I-beam.
First Worker Up Fall Protection
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Harness Maintenance
Harnesses are a critical component of personal fall protection and offer comfort and confidence when working from heights. They come in numerous general varieties that are used in various applications, including:
Lifelines – Rope Weights
Rope Weights on Lifelines. Weighted lines are very important to keep lifeline slack from developing as the scaffold moves up from grade. However, in some windy conditions, rope weights could damage the building, especially windows. Physically securing the bottom of the line could be the answer in this case. In addition, proper termination of a rope can prevent unraveling of the strands.