A west coast construction company contacted ADL Insulflex looking for a solution to a recently introduced a new bylaw to their fire code (shown at the bottom of this article). This bylaw has made it mandatory that construction of buildings exceeding 80,000 sq. ft. have a fire protection barrier in place during construction to prevent the spread of fires to buildings that are less than 60’ apart.
The new fire code calls for the covering of exterior walls with 5/8” gypsum sheathing during the construction phase. Covering the exterior completely in gypsum sheathing makes it near impossible to finish the construction of buildings as access is needed to windows and outside doorways.
The construction company came to ADL Insulflex with hopes of finding an alternative to the gypsum sheathing to use on exterior doors and windows to use as a fire barrier to the outside.
ADL Insulflex worked with the company, a third party fire code consultant and the local fire marshal to offer a solution to the problem they were facing.
ADL Insulflex is pleased to announce that the Insulflex 17 oz Pyroblanket was approved by the city to be used as an alternative to gypsum sheathing on this project for the exterior doors and windows as a fire barrier. The light weight flexible design of the Pyroblanket made it ideal for the construction crew to be able to be raise the Pyrojacket in the day to allow for light and ventilation through the building and lowered at night for protection when the project was shut down.
17 oz Pyroblanket (shown below)
How does the 17 oz Pyroblanket compare to gypsum sheathing?
Gypsum drywall has a K value of 0.17 (K value is the co-efficient of thermal conductivity, so a lower number indicates better insulation performance).
In comparison, the K value for glass fiber in PB17 Pyroblanket is 0.04, which is multiple times better. When the additional silica refractory transformation effect due to flame exposure is taken into account, a thin wall Pyroblanket offers sufficient fire mitigation results to replace 5/8” gypsum drywall.
What is 17 oz Pyroblanket?
The 17 oz Pyroblanket is a glass fiber cloth coated with silicone rubber. When exposed to flame, the silicone rubber transforms to an expanded Silica refractory insulation crust, and this is an important part of the insulation and fire resistive technology. It is a unique heat ablative technology that is unique to certain grades of silicone rubber and it is this technology which significantly impacts the performance.
PB17 Pyroblanket has excellent insulative properties for such a thin blanket, it will block a continuous mass of flame/heat energy for extended periods. Once the flame propagation is blocked, gases such as air are the worst possible conductors of heat energy, this means that you could have a fire raging on one side of the blanket, and 3 feet away you could expect the ambient temperature to be less than 200°F.
The 17 oz Pyroblanket is ASTM E84 Certified which is the standard test method for surface burning characteristics of materials.
Please click here for more information on the 17 oz Pyroblanket or contact Insulflex to discuss your application.
23.11.3308 International Fire Code Section 3308
3308.8.3 Construction mitigations for wood frame buildings exceeding 80,000 s.f. when exposures exists within 60’ of a building under construction. The exterior wall of the building under construction shall be covered with 5/8-inch gypsum sheathing to include windows, doors or other openings until interior framing members have been covered with gypsum board or their finish materials.
For the purpose of measuring total square footage of wood framing, any adjacent on-going wood frame construction is considered to be within the project when adjacent structures are separated by less than sixty (60) feet of open air.
Exception: A mitigation plan developed by a Washington State Licensed Fire Protection Engineer. The mitigation plan may rely on temporary, permanent and/or active measures.
3308.8.4 Construction mitigations for wood frame buildings exceeding three hundred fifty thousand square feet; or two hundred thousand square feet when the building exceeds fifty feet in height:
Mitigating fire protection barriers consisting of at least one layer of 5/8-inch gypsum board or other equivalent fire resistive materials shall be installed such that the mitigating fire protection barrier(s) enclose area(s) of not more than fifty thousand square feet.
For the purpose of measuring total square footage of wood framing, any adjacent on-going wood frame construction is considered to be within the project when adjacent structures are separated by less than sixty (60) feet of open air.
