The Avalon at Edgewater apartment fire in late January caught our attention, largely because of the initial reaction from Scott Rumana, a New Jersey legislator who proposed a two-year moratorium on light-weight wood framing for multifamily housing. The suggestion of freezing all wood-framed multifamily projects until the state could review the safety of the current building codes seemed premature at best, given the fire investigation report has still not surfaced. Or was it some kind of a diversion? Video coverage of the fire showing how quickly the fire spread through the apartment attics suggests that the code-required fire separation between units did not extend through the attic to the underside of the roof sheathing. Such an assertion is only conjecture, but it's hard to imagine the fire met any kind of barrier given its rapid spread through the attic.
The rate of fire spread through the attic of the AvalonBay apartments makes one wonder if the prescribed fire walls actually extended through the attic, as required by code.
It seems strange to call for strengthening the existing building code when there is not yet clear evidence that the existing codes were actually followed. Where is the evidence that the existing codes are deficient? And why would a NJ Republican be calling for more government regulation of multi-family construction?
There may be legitimate reasons to go beyond code. New Jersey fires codes currently require sprinklers in multifamily dwellings and allow for a number of fire barrier assemblies constructed with wood framing, gypsum, fire-rated insulation and, of course, masonry. Like most state codes that have adopted the IBC, no one type of assembly is required between units in a multi-family structure, as long as the assemblies meet at least a 2-hour fire-resistance rating. Following the Edgewater fire, AvalonBay developers sought beyond-code solutions for apartment complexes in Princeton and in Maplewood, NJ, which included more sprinklers than required by code and masonry fire-separation walls.
Masonry fire barriers can perform better, but they need to be fully grouted (each block core filled with concrete). A fully-grouted, 8-inch CMU wall has a 4-hour fire rating, whereas most double-wall wood-framed separation walls, or wood-framed barrier assemblies with two layers of Type-X drywall on both sides - the kind of separation walls conjectured to be missing from the attics at the Edgewater complex - only have a 2-hour fire-resistance rating. (See "Building Accepted Fire Barriers for Multifamily Homes," Aug/12). A partially-grouted (every other core filled), 8-inch CMU wall has only a 1-hour fire rating, similar to an insulated 2x4 wall with one layer of Type-X drywall installed on resilient channel on both sides.
The drawback, of course, to masonry fire barriers is the labor required to build them, especially when every core must be filled. Obviously, this added cost should not be a concern when life and safety is on the line. But before raising the bar, someone still has to prove that all fire barriers currently allowed by code were actually in place and built correctly at the Avalon at Edgewater apartments. A signed set of plans or an inspection certificate is not enough to establish the buildings met the existing codes.
Regardless, Rumana continues to garner attention for his hard-line stance against engineered lumber. Speaking recently after a meeting with a task force formed by the N.J.-chapter of the AIA in response to the fire, Rumana said he was open to the idea that some types of light-frame construction are safe. But he added "As long as we move away from engineered wood products like those used in the Avalon complex." Naturally the Portland Cement Association has applauded Rumana's efforts, while the engineered wood industry has stepped up efforts to demonstrate the fire safety of wood-frame construction.
In March, the APA-The Engineered Wood Association issued a technical bulletin "Designing to Meet IRC Fire Protection Provisions for I-Joist Floor Systems" and broadcast a webinar on the same topic. The APA recommendations include:
• sheathing the webs or the whole depth of exposed I-joists with drywall (details for this application are available in this PDF from Boise-Cascade);
• installing a mineral wool insulation, such as Roxul, above the bottom flange of wood I-joists;
• installing a ceramic fire blanket, such as Boise-Cascade's Fire Break, which was introduced at IBS 2015;
• installing I-joists treated with a fire-resistive coating. One example is Trus Joist's Flak Jacket, I-joists with an intumescent coating applied to the web and bottom flange. (Intumescent means the coating puffs up to create a protective insulation that will prolong the structural integrity of the I-joist during a fire. The coating reportedly won't abrade when handling I-joists, is not effected by water, and the dust is non-toxic.)