You must make sure the overhead supporting members are designed, based upon impact loads, with a safety factor of:
(1) Nine if wood;
(2) Five if steel.
[Statutory Authority: RCW
49.17.010,
49.17.040,
49.17.050,
49.17.060. WSR 15-24-102, § 296-56-60205, filed 12/1/15, effective 1/5/16. Statutory Authority: RCW
49.17.040 and
49.17.050. WSR 86-03-064 (Order 86-02), § 296-56-60205, filed 1/17/86; WSR 85-01-022 (Order 84-24), § 296-56-60205, filed 12/11/84.]