Oregon Revised Statutes Protection from Fire § 476.170

(1) Except as provided in subsection (2) of this section, in executing an inspection warrant, the person authorized to execute the warrant, before entry, shall make a reasonable effort to present the person's credentials, authority and purpose to an occupant or person in possession of the building or premises and present the warrant or a copy thereof.

(2) An inspection warrant must be executed and returned to the court by whom it was issued within 10 days from its date, unless such court before the expiration of such time, by indorsement thereon, extends the time for five days. After the expiration of the time prescribed by this subsection, the warrant unless executed is void.