Meeting Fire Protection Requirements—Without Breaking the Bank

Designing to meet code requirements is not always an easy process- but building codes, and particularly those addressing fire, are designed to protect the lives of building occupants and first responders and therefore will continue to be a key component to the design and construction of buildings.

Fortunately, there are often multiple ways to meet code requirement with fire-rated wall assemblies and LP FlameBlock^® Fire-Rated^® OSB Sheathing offers architects and designers an opportunity to meet code requirements while saving money and time compared to alternative assembly options.

Featuring an ignition-resistant Pyrotite^® coating, LP FlameBlockOSB is a listed component in fire-rated interior wall assemblies, exterior wall assemblies, and roof deck applications. The fire-rated structural sheathing provides 15-minute thermal barrier protection, a 30-minute Class A flame spread rating, and a combination of flame spread resistance and burn-through resistance. What’s more, it provides additional value in the form of strength, savings, and greater design flexibility and is versatile enough for use in Type II, III, and V construction.

Because structural design values for LP FlameBlock sheathing are not reduced by the fire-retardant treatment, the panel carries load/span and shear design values equivalent to an untreated wood structural panel in the same panel thickness category. Using LP FlameBlock sheathing in fire-rated wall assemblies can provide more flexibility in design of wall openings as well as more options in framing and bracing to meet structural requirements. Finally, each panel carries an Exposure 1 classification, meaning it can withstand exposure to moisture during normal construction delays.

Cost & Labor Savings

With these characteristics, LP FlameBlock sheathing can be used to create assemblies that are more efficient than those using double layers of gypsum or gypsum combined with FRT plywood, helping to improve construction timelines and reduce labor costs.

As an alternative to assemblies using FRT plywood and gypsum, LP FlameBlock OSB allows a reduction of layers which results in a thinner panel and increased design flexibility. Installation of exterior facing is simplified by fastening into and through LP FlameBlock OSB rather than a combined layer of FRT plywood and gypsum.

For example, in a two-hour rated, load-bearing partition wall, fire-rated on both sides, commonly used for multifamily projects and townhomes, the assembly consists of Type X gypsum, LP FlameBlock OSB, and fiberglass insulation on each side of a double 2x4 stud assembly. The use of LP FlameBlock OSB saves labor and reduces dead load by eliminating the use of Shaft Wall Liner. It also brings an STC rating of 62.

Such savings can be achieved on the exterior, as well. For example, Grimm+Parker Architects used LP FlameBlock OSB for a wood-over-concrete-podium mixed-use university housing project building in Maryland. The two sided LP FlameBlock Sheathing was used in place of one layer of FRT Plywood and gypsum board. Not only did this save the expense of gypsum board, but the contractor was able to use the same crews already working on site since the same tools and techniques are used to work with LP FlameBlock sheathing as with standard OSB sheathing.

Certainly, meeting codes requirements could mean increasing expenses, but advancing product technologies are offering builders and designers more options that reduce installation time and materials—helping to ease the burden on tight budgets.