In the event neither manufacturer's data nor design data on safe working loads (including any applicable limitations) are obtainable, the safe working load ratings assigned must be based on the owner's information and warranty that those so assigned are correct. Unit test certificates must state the basis for any such safe working load assignment.
Wash. Admin. Code § 296-304-20011
Order 74-25, § 296-304-20011, filed 5/7/74.