In "Performance Characteristics of Roof Insulation" (1979) Donald Brother, Small Homes Council at the University of Illinois, wrote:
To qualify as a satisfactory roof insulation, a material requires more than low thermal conductivity. Here are the other requirements:
- Surface Smoothness
- Light Weight
- Dimensional Stability
- Shear Strength
- Heat Resistance
- Moisture Resistance
- Compatibility with Other Components
- Impact Resistance
- Wind Resistance
- Fire Resistance
- Chemical Stability
After looking at dimensional stability in the last article, this article will focus on fire resistance, another of the characteristics Donald Brother highlighted in 1979.
Why is Fire Resistance Important on the Roof?
In the case of a fire event, having non-combustible or fire-resistant materials in the building can reduce the acceleration and severity of the fire, allowing for additional time for occupants to leave the building and get to a safe location, and for the local fire service to arrive on the scene and be able to address the fire before it spreads to other areas of the building or to nearby areas.
Fire resistance in the building provides passive fire protection, unlike active measures (such as sprinklers, which are only activated in the case of the fire). Roof insulation specifically helps to limit the spread of fire inwards from the exterior and helps limit the spread of fire from the interior of the building.
Using fire-resistant materials can help reduce the risk of fire events occurring as well as help limit the potential for increased costs after a fire event occurs. These potential costs could include:
- Loss of Business
- Increased Insurance Premiums
- Delays in Production
- Public Relations Management
When is Fire Resistance Important on the Roof?
Every building should be resistant to fires, but certain buildings and construction types require extra care in order to reduce the risk of a fire, or the effects of a fire. When utilizing combustible materials in the roof system, additional measures may be required to meet the building code such as mineral wool or gypsum products to increase the fire rating. For critical facilities, where extra time is required to evacuate the building or to prevent the damage of valuable materials, providing a fire-resistant roof system can be key in reducing the risk and allowing for additional time.
With wood frame construction taking on larger and taller buildings, extra thought should be given to the risk during the construction stage of the project, when active fire measures are not installed or operational. Utilizing fire-resistant insulation or cover boards can help reduce the risk of a fire occurring.
Owners and facility managers may also have a decreased tolerance for risk on a particular project due to operations or to the significance of the building to their company. Understanding your client's or your own tolerance for risk can be important in recommending going beyond the code requirements in your local jurisdiction.
Andrew Lindley - Segment Manager, Roofing