Fenestration Forum: February 2016
Putting out fires
February 9, 2016 By Brian Burton
Many readers have indicated their interest in fire protective fenestration components and this forum will provide some general explanations of available options. The reader should keep in mind that every glazing application or building is unique and will require special attention. Unfortunately there is no simple formula where one size fits all.
As a rule, obtaining a design review quote from a life safety consultant can be very useful. In my experience it also helps keep your knowledge regarding definitions, product labeling and product limitations up to date. However, manufacturers are generally your best source of information about fire protection.
You should carefully study all applicable codes, standards and occupancy requirements that may apply to a specific building or occupancy type. One reader asked me who is responsible for errors or omissions with regard to installation of fire-rated products. While no single professional is ultimately responsible, because of the number of parties involved in specifying, designing and installing fire rated products, theoretically the owner and designer and his representatives are ultimately responsible for ensuring compliance. Designers may view glaziers as glass experts and solicit their input, but glaziers are not usually solely responsible for the performance of fire-rated fenestration. Regardless of who may be responsible, when it comes to life safety, it’s essential to avoid mistakes. After narrowing the options, review the product literature in detail noting any and all special requirements, limitations or exclusions.
There are important differences between fire-protective and fire-resistive glazing systems. “Fire-protective” means the glazing defends against the spread of flames and smoke. Examples include wired glass, glass ceramics and specially tempered glass. Fire-protective glazing is typically suitable where building codes allow “opening protective” assemblies. Such glazing is available with fire ratings ranging from 20 to 180 minutes. It’s use is subject to area and size limitations under the applicable building code.
Fire-resistive glass provides the same protection against flames and smoke as fire-protective glazing, however it adds further protection by limiting the transfer of radiant and conductive heat. Fire-resistive glass products generally incorporate several layers of glass with fire-resistive interlayers, suitable where building codes require an assembly designated “fire resistant” to enclose a space.
The glass product most often associated with fire rating for the last 100 years is polished wired glass. The product is relatively inexpensive, however, because of its low impact resistance, the International Building Code has prohibited its use in hazardous locations in some facility types.
Another option is glass ceramic, which provides greater design flexibility and can withstand the thermal shock of water from sprinklers or fire hoses. Glass ceramics are also available in insulated glass units.
Fire-rated glass wall panels are another option. These multi-layer assemblies effectively block the transfer of radiant and conductive heat.
Read the literature on fire-rated products carefully. Architects and designers should always be wary of product listings that carry what appear to be unusual limitations. Limitations should raise red flags.
Some architects question whether fire-rated glass really necessary if the building has sprinklers. While sprinklers do save lives, they are not a substitute for the use of passive fire-rated glazing materials. If sprinklers do not activate due to faulty manufacturing, poor maintenance, a loss of water pressure or other reasons, fire-rated glass will still perform its critical function of compartmentalization.
Brian is involved with an innovative multi-disciplinary firm specializing in website design and development; Award Bid Management Services http://award-bid-management-services.com. The firm also assists companies interested in selling goods and services to governments and institutions. He can be reached at; firstname.lastname@example.org
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