WAC 296-150C-0960
What requirements apply to commercial
coach roof trusses? (1) The construction of roof trusses must
be approved by a professional engineer. Roof trusses may be
produced by one of the following methods:
(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.
(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)(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.
(b) All test reports are to be stamped, signed, and dated
by the approved testing agency or engineer who performs the
test.
(c) These tests must not occur more than two times a year
per design unless there are problems with the roof trusses.
(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.