Appeal 34761

2022 OSSC 703.2.1 Tested Assemblies

A fire-resistance rating of building elements, components or assemblies shall be determined by the test procedures set forth in ASTM E119 or UL 263.

The City of Portland has raised a question regarding the proposed use of UL X790 to specify a given Spray Applied Fire-Resistive Material (SFRM) thickness to achieve a fire-resistance rating for a horizontal HSS beam element, given that UL X790 has been tested for vertical HSS column elements.

Appeal to apply SFRM to HSS beams for a 1-hr fire resistance rating in accordance with UL X790 for HSS columns.

The Health Technology (HT) Building is an existing Type II-A Building located at the PCC Sylvania Campus in SW Portland. Built in 1964, it is a fully sprinklered four-story building, including the basement, and contains partially separated Group A-3, B, and S-1 mixed occupancies. The building is located on a sloped site with exits directly to the exterior on all floors of the building.

In accordance with the 2022 OSSC Table 601 and 704.3 for Type II-A Buildings, a 1-hr fire-resistance rating (FRR) is required for primary structural framing elements.

Two HSS 12x4x1/4 beams are utilized to support the existing precast concrete channel roof structure at the new elevator overrun. The proposed design includes the application of applied fire protection thicknesses for primary HSS columns in accordance with UL X790, to primary HSS beam elements, for the full length of the beam.

Listed assemblies for applied fire protection to HSS elements are limited to columns and unavailable for HSS beam elements.

As permitted by OSSC Section 703.2.2, an engineering analysis has been conducted. Please see the attached Engineering Judgment.

As demonstrated in the Engineering Judgement, the proposed SFRM thickness for a 1-hr FRR in accordance for UL X790 for HSS columns is considered to satisfy the FRR requirements for HSS beams and provide the level of safety intended by the code.