Appeal 25043

705.5

The required fire-resistance rating of exterior walls with a fire separation distance of less than or equal to 10 feet shall be rated for exposure to fire from both sides.

Allow the use of intumescent paint on exterior wood siding to provide equivalent 1-hour fire protection in lieu of type ‘X’ gypsum sheathing on the exterior side of the assembly.

The proposed alterations for this permit are for a 2nd story addition to the warehouse portion of the building. The building is located less than 10 feet from the south property line at this area. This portion of the exterior wall is required to be 1-hour fire-resistance rated per Tables 601 & 602 and rated from both sides.

The existing south exterior wall at the first story was constructed previously with wood panel siding (T1-11) over (2) layers fire-rated gypsum sheathing over (1) layer wood structural sheathing.

The new portion of the south exterior wall at the 2nd story had (1) layer of T-11 wood siding panels installed over 1/2" wood structural sheathing on the wood framing without fire-rated gypsum board. The T1-11 is intended to be the final exterior finish to match the rest of the building. The interior side of this wall will have (1) layer Type ‘X’ gypsum board installed.

The new portion of the south exterior wall at the 2nd story had (1) layer of T-11 wood siding panels installed over 1/2" wood structural sheathing on the wood framing without fire-rated gypsum board as was originally detailed in the approved permit plans. The T1-11 is intended to be the final exposed exterior finish.

Per OSSC Section 104.10, an alternative method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of the code, and that the material, method or work offered is, for the purposes intended, not less than equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.

The applicant proposes an alternative method of construction that provides equivalent fire resistance in lieu of the listed, tested assembly as originally detailed in the approved permit plans. The proposal is to use Shield Industries Inc. ForceField FireGuard E-84 intumescent paint for wood on the exterior wood siding. (1) layer 5/8” Type ‘X’ gypsum board will still be installed at the interior side of this assembly.

As outlined in Evaluation Report 442, section 4.2, ForceField FireGuard E-84 is permitted to be used as a component of a fire-resistance rated assembly in accordance with IBC(OSSC) section 703.2, based on testing in accordance with ASTM E119 or UL 263. The Shield Industries, Inc. product data sheet for the ForceField FireGuard E-84 Intumescent Paint states it is an intumescent coating designed for the fire protection of gypsum and wood.

A 2-hour fire test (Report No. GL 115511) provides evidence that a fire-resistance rating utilizing the FireGuard E-84 intumescent coating can achieve the required fire-protection when applied directly to a 1/2" (7/16”) wood substrate. The main differences between this fire test (Report No. GL 115511) and the assembly proposed in this application is that we’re trying to achieve a 1-hour fire-resistance rating, not 2-hours. The proposed assembly would have (1) layer 5/8” Type ‘X’ gypsum board installed to provide a 40 minute fire-resistance rating per Table 722.6.2(1) from the interior. The intumescent coating would be applied on the exterior wood siding with the required thickness to achieve a 1-hour fire-resistance overall assembly rating, as outlined in Evaluation Report 442.

The applicant requests that FireGuard E-84 intumescent coating installed on the exterior wood siding be allowed in lieu of the (1) layer of 5/8” Type ‘X’ gypsum board, meeting the requirements of the 1-hour exterior wall to be rated from both sides, meeting the requirements of Sections 104.10 & 705.5.