1. (1) The construction of roof trusses must be approved by a professional engineer. Roof trusses may be produced by one of the following methods:

   1. (a) Use of graded materials when an approved testing agency certifies truss construction and load requirements are met; the testing agency must prepare an approved quality control program which allows them to test the trusses with appropriate testing procedures.
   2. (b) Use of nongraded materials, if each truss is tested in an approved testing jig at the manufacturer's site with a load equivalent to full design load (1.75 times the full design load sustained for twelve hours). See WAC 296-150C-0930.
2. (2) (a) Representative trusses must be tested from the production line, when we request. The approved testing agency or engineer must submit the testing report to us.
3. (b) All test reports are to be stamped, signed, and dated by the approved testing agency or engineer who performs the test.
4. (c) These tests must not occur more than two times a year per design unless there are problems with the roof trusses.

5. (d) The manufacturer is required to maintain an acceptable quality level not exceeding one percent using acceptable sampling procedures.

   Note:

   The acceptable quality level is defined as the maximum allowable percentage of defective units.

[Statutory Authority: RCW 43.22.340 and 43.22.480. WSR 99-13-010, § 296-150C-0960, filed 6/4/99, effective 7/5/99. Statutory Authority: Chapter 43.22 RCW. WSR 98-14-078, § 296-150C-0960, filed 6/30/98, effective 7/31/98. Statutory Authority: RCW 43.22.340, [43.22.]355, [43.22.]360, [43.22.]432, [43.22.]440 and [43.22.]480. WSR 96-21-146, § 296-150C-0960, filed 10/23/96, effective 11/25/96.]