WAC 296-307-061   What requirements apply to working around bins, bunkers, hoppers, tanks, pits, and trenches?  (1) Employees must be prohibited from entering any bin, bunker, hopper, or similar area when loose materials (such as chips, sand, grain, gravel, sawdust, etc.) may collapse, unless the employee wears a safety belt with a lifeline attached and is attended by a helper.


Note: Silage pits are exempt from this section.
Reference: For requirements relating to confined spaces, see WAC 296-307-642 through 296-307-656.


     (2) When employees are required to work in a trench or a pit 4 feet deep or more, the trench or the pit must be shored or sloped according to the following table:




SOIL OR ROCK TYPE

MAXIMUM ALLOWABLE




SLOPES (H:V) (1) FOR

EXCAVATIONS LESS

THAN 20 FEET DEEP

     (2)

STABLE ROCK
VERTICAL (90°)
TYPE A 3/4:1 (53°)
TYPE B 1:1 (45°)
TYPE C 1 1/2:1 (34°)


1 Numbers in parentheses next to maximum allowable slopes are angles in degrees from the horizontal. Angles have been rounded off.
2 Sloping or benching for excavations greater than 20 feet deep must be designed by a registered professional engineer.


     (3) Each soil and rock deposit must be classified by a competent person as Stable Rock, Type A, B, or C according to the definitions in WAC 296-155-66401. "Competent person" means someone who is able to identify working conditions that are hazardous to employees, and has authority to take prompt action to eliminate the hazards.

     (4) Classification of the deposits must be based on the results of at least one visual and at least one manual analysis. The analyses must be conducted by a competent person using tests in recognized methods of soil classification and testing such as those adopted by the American Society for Testing Materials, or the U.S. Department of Agriculture textural classification system.



[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060. 05-01-166, § 296-307-061, filed 12/21/04, effective 4/2/05. 97-09-013, recodified as § 296-307-061, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. 96-22-048, § 296-306A-061, filed 10/31/96, effective 12/1/96.]