Precast lifting factors: 1926.704
29 CFR 1926.704 sets three safety factors, each a multiple of the maximum intended load:
- (b) lifting inserts in tilt-up members: at least 2 times
- (c) lifting inserts in other precast members: at least 4 times
- (d) lifting hardware: at least 5 times
The common error is mixing up the three. Sort the question first: is it an insert or the hardware, and if an insert, is the member tilt-up or other precast? There is no 1.5 or 3 times factor in the rule.
Worked example
A precast (not tilt-up) wall panel has a maximum intended load of 6,000 lb. The question asks about the lifting hardware, so the factor is 5: 6,000 × 5 = 30,000 lb. Using 4 gives 24,000 lb, but 4 times is for the embedded inserts in other precast members. Using 2 gives 12,000 lb, the tilt-up insert factor.
Limited access zone: 1926.706(a)
Before a masonry wall goes up, a limited access zone is set up:
- Width: wall height plus 4 ft.
- Location: on the unscaffolded side.
- Length: the entire length of the wall.
- Entry: only employees actively building the wall.
For a 10 ft wall: 10 + 4 = 14 ft on the unscaffolded side, full length. Traps: 10 ft forgets the extra 4 ft, 18 ft adds 8 ft, and putting the zone on the scaffolded side is the listed common error.
Bracing: 1926.706(b)
All masonry walls over 8 ft high must be braced against overturning and collapse unless otherwise adequately supported, and the bracing stays until permanent supporting elements are in place. A wall exactly 8 ft is not over 8 ft, so it does not trigger bracing; an 8 ft 6 in wall does. Triggering at exactly 8 ft is the listed common error. For walls over 8 ft the limited access zone stays until the wall is braced; removing the zone does not trigger bracing.