D.C. Mun. Regs. tit. 24, r. 24-3210
When windows are cleaned from a sill, an approved safety belt of woven fabric or other approved material shall be provided, maintained, and used.
Fabric used in the manufacture of safety belts shall be made of first quality material, which shall be treated against mildew by a non-acid and non-corrosive anti-mildew agent.
Stitching of the material on safety belts shall be done with hot waxed, best quality linen thread, and shall be lock-stitched.
Fabric ends shall be bound or dipped in wax to prevent unraveling.
Belt terminals and other metal belt fittings (except rivets and thimbles) shall be of approved heavy forged bronze, monel metal or copper-nickel alloy equivalent to monel metal, stainless steel, or other approved durable corrosion-resistive metal of equal strength and toughness.
Non-corrosive metal thimbles shall be provided where straps are secured to eyes or rings.
The edges of thimbles shall be rounded and finished smooth, and shall run freely.
Each safety belt shall be designed and constructed so that it will be impossible for the safety terminals to pass through their fastenings on the body belt of the window cleaner, should one terminal become loosened from its window anchor.
The belt terminals shall have slots not less than four inches (4 in.) long; and the slots shall be one-half inch (1/2 in.) wide, with a tolerance plus or minus one-thirty second of a inch (1/32 in.).
That portion of the slot that passes over the anchor head shall be seven sixteenths of an inch (7/16 in.) deep by one inch (1 in.) wide, and shall have an approved catch to prevent the automatic or accidental release of the terminal.
Right-angle sections of forgings shall have one-eighth inch (1/8 in.) radius fillets in all inside corners.
Where the anchor head comes in contact with the belt terminal while in use, the terminal forging shall be not less than one-quarter of an inch (1/4 in.) thick.
Rope, if used, shall be not smaller than one-half inch (1/2 in.) Yacht Manila, or its equivalent.
Belt terminals and other metal belt fittings shall be capable of withstanding a tension pull of six thousand (6,000) pounds without fracture.
The complete assembly of the safety belt shall be capable of withstanding a drop test of three hundred fifty (350) pounds dead weight (no sand) falling a distance of four feet (4 ft.) without failure, with one (1) terminal only being attached. The connection between the weight and the belt shall be the waistband of the belt.
Once a safety belt or any of its parts have been used for testing purposes, the belt or any of its parts shall not be used by a window cleaner in the conduct of his or her work.
D.C. Mun. Regs. tit. 24, r. 24-3210