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Fire Performance of Cross-Laminated Timber Fire Protection of Penetrations CLT has been at the forefront of the mass timber revolution It is often necessary to penetrate a fire resistance-rated floor, �dwide, including in North America. It is a dimensionally roof or wall assembly to accommodate mechanical, electrical le solid timber panel that performs well structurally and or plumbing(MEP)service members.These members can under fire conditions. CLT was first recognized in the 2015 range from combustible pipe or tubing,to noncombustible IBC,Section 2303.1.4,when manufactured in accordance wiring with combustible coverings,to noncombustible with ANSI/APA PRG 320-Standard for Performance-Rated members such as pipe,conduit and ductwork.To maintain Cross-Laminated Timber the continuity and integrity of rated assemblies, penetrations 2015 and newer versions of the NDS give char depth must be properly sealed and protected in accordance with calculations for exposed CLT members. These provisions IBC Section 714. Note that Sections 708.7, 707.7, 713.8, differ from those of solid sawn,glulam and SCL members and 7121.4,which cover penetrations in fire partitions, in that the lamination thicknesses in combination with the fire barriers, shaft enclosures and horizontal assemblies required fire-endurance rating determine the effective char (respectively),all point to section 714 for their protection. depth.The effective char depth for CLT panels is given in Section 714.4.1 addresses penetrations in wall assemblies, NDS Table 16.2.1B. and gives the following options for demonstrating acceptable The calculated fire-resistance method for CLT presented protection measures'. in the 2015 NDS was developed based on full scale ASTM E119 fire tests.Additional discussion on these fire tests and 1.Penetrations shall he installed as tested in an approved the resistance-rated assembly i.e.,( incorporated during how the CLT fire-resistance calculations presented in NDS the conduct of an ASTM E119 test of the wall assembly, Chapter 16 were derived is available in TR 10. per Section 714.4.1 1)or, more commonly, 2.Protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479,with a minimum positive pressure differential of 0.01 inch of water and shall have an F(flame) rating of not less than the required fire-resistance rating of the wall penetrated(per Section 714.4.1 2). 10 The requirements for penetration protection in floor/roof assemblies are given in IBC Section 714.5.1 and are similar to those for walls.The main difference is that,when using a tested and approved firestop system, a T(temperature)rating is requited for floors, in addition to an F(flame)rating. This requirement is noted in IBC Section 714.5.1.2. The purpose and construction of common firestop systems are described in the commentary to Section 714.4.1.2: A through-penetration firestop system consists of specific materials or an assembly of materials that are designed to restrict the passage of fire and hot gases for a prescribed period of time through openings made in fire resistance- rated v ' walls or horizontal assemblies. In certain instances, the through-penetration firestop system is also required to limit the transfer of heat from the fire side to the unexposed Fnoro:Alexander Schreyer side. In order to determine the effectiveness of a through TABLE 8: Effective Char Depths for CLT(for en= 1.5 inches/hour) a t�'i Y)1 t, ;Lammadonffikkdiim r fitefi6sl , :tam 1� 4 2.2 2.2 2.1 2.0 2.0 1.9 1.8 1.8 1.8 3.4 3.2 31 3.0 2.9 2.8 2.8 2.8 2.6 4.4 4.3 4.1 4.0 3.9 3.8 3.6 3.6 3.6 Source AIDS Table 16.21E I$