This Web Exclusive article comes from Jeff Razwick, vice president of business development for Technical Glass Products (TGP).
Do life jackets really need labels? All life jackets offer users some degree of flotation, but improperly fitted vests can fail to keep people afloat in times of need. Labels help prevent improper use by quickly pointing users to the jacket’s size, weight and type.
In the same way, building industry professionals rely on fire-rated building material labels to help select and inspect appropriate products—which is critical for protecting building occupants and valuables from the spread of flames and smoke. Of the various fire-rated building materials available, fire-rated glazing is one product class whose label is essential to understand for effective use. Such labels are mandatory, and are required to be compliant with current codes.
A Look At The Basics
Fire-rated glass labels include basic product information, such as product name, characteristics (e.g., tempered, laminated), and whether it is listed by an independent testing agency like Underwriters Laboratories (UL). Labels compliant with the 2006 International Building Code (IBC) also include four easy to decipher marking categories (example label at right):
- suitability per testing requirements for use in doors, openings or walls;
- conformance with the hose stream test;
- conformance with any temperature rise door criteria; and
- fire-rating in minutes.
Suitability per testing requirements
The label includes one or more specific designations that describe where the system may be appropriate for use based on applicable testing standards:
- “D” indicates Doors (doors, sidelites, and transoms meeting NFPA 252)
- “O” indicates Openings (window openings meeting NFPA 257)
- “W” indicates Walls (fire-resistant glazing meeting ASTM E119)
Products marked with a “D” or “O” are designed to remain intact during a fire as a door or opening for the specified number of minutes in the fire rating. A “W” marking is for products tested as wall assemblies that are intended to block the spread of smoke and flames, as well as provide a barrier to radiant heat. Such fire-rated walls may be suitable for areas where people can be trapped for extended periods of time, such as exit corridors and stairwells.
The hose stream test
Performance on a required hose stream test is indicated on the label by:
- “H” indicates glazing meets the NFPA HOSE STREAM test standards (required for all windows and door assemblies with ratings of 45 minutes or more)
- “NH” indicates glazing does NOT meet HOSE STREAM test standards (an NH marking is only appropriate for some 20-minute fire-rated door assemblies)
The hose stream test is an essential part of fire-rated glass testing. It addresses the “cooling, impact, and erosion effects” of a stream of water and is designed to eliminate “inadequate materials or constructions.” Products that fail the test may be at risk for breaking or shattering if heated in a fire and cooled by water from fire hoses or sprinklers.
Temperature rise door criteria
Similarly, conformance with temperature rise criteria is shown on the label with:
- “T” indicates glazing meets TEMPERATURE RISE door criteria per codes
- “NT” indicates glazing does NOT meet TEMPERATURE RISE criteria
Fire rating in minutes
The final marking is a two- or three-digit number showing the fire rating in minutes. Fire-rated glass can earn anywhere from a 20-minute to a 3-hour rating, depending on how long it can be expected to perform in a fire.
Safety Is Key
Correctly installed fire-rated glazing materials can buy individuals more time to escape burning buildings before firefighters arrive, as well as help reduce building damage. By taking the time to understand labeling systems, building industry professionals can decipher which materials are suited for use in various applications.
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