PDFWAC 296-54-54740
Rigging—Straps.
Straps must be used according to the following requirements:
(1) Straps or chokers used to hang corner or tail blocks and straps used to anchor skylines/slacklines must be the size required by Table 1: Strap/Choker Size in Inches.
Table 1: Strap/Choker Size in Inches | ||
Running Line Size in Inches | Block or Skyline / Slackline Hung in Both Eyes | Block Hung in Single Eye |
5/16 | 1/4 | 1/2 |
3/8 | 3/8 | 9/16 |
7/16 | 7/16 | 5/8 |
1/2 | 1/2 | 3/4 |
9/16 | 9/16 | 7/8 |
5/8 | 5/8 | 1 |
3/4 | 3/4 | 1 1/8 |
7/8 | 7/8 | 1 1/4 |
1 | 1 | 1 3/8 |
1 1/8 | 1 | |
1 1/4 | 1 | |
1 3/8 | 1 | |
1 1/2 | 1 1/8 | |
1 5/8 | 1 1/4 | |
1 3/4 | 1 1/4 | |
1 7/8 | 1 3/8 | |
2 | 1 3/8 | |
Note: | Both strap ends must be under equal tension. |
(2) Straps/chokers must be equivalently sized for the line they support, e.g., extra improved plow steel (EIPS) line requires EIPS straps or equivalent strength material, and swaged lines require swaged straps or equivalent strength material.
(3) When a single choker or single part strap is used to support lift blocks, jacks and tree shoes they must be adequately sized to support the applied loads.
(4) When a two part strap or two chokers are used to hang a block, jack, tree shoe, or rigging, both eyes or ends must be under equal tension.
(5) Where two equal length chokers are used instead of one choker to gain extra breaking strength, they must be arranged in a swede connection.
(6) Straps or chokers used to hang or support blocks, jacks, tree shoes, or rigging must be replaced when there is evidence of damaged or broken wires. They must:
(a) Be made of new wire rope; or
(b) Meet the pull test strength of new wire rope.
(7) Threading wire rope straps eye through eye is prohibited.
(8) Synthetic straps must be used as recommended by the manufacturer and only at a flat or downward angle unless wrapped one full turn around the tree support to prevent the strap from riding up on the support.
(9) Synthetic straps must be removed from service when wear reaches the limits prescribed by the manufacturer or when deterioration is evident.