FIREFIGHTERNATION.COM SEPTEMBER 2017 FIRERESCUE MAGAZINE 51
ith cold weather approaching, I thought it was time to start
preparing ourselves to deal with snow and all the challenges that come with it. With the multiple snowstorm incidents experienced here in the Northeast during our last cold season, the fire service needs to take a look up before we commit to an interior or exterior operation. The type of structural material, roof design, and structural condition all play a major role in whether that snow load is going to be a problem for our companies.
Last winter, I took a few minutes to travel around my response district and took an assess- ment of many potential hazards to my company. I was surprised to find that more than three- fourths of the dwellings in my district were still heavily loaded with heavy wet snow. When we arrive at a reported building fire, the dwelling’s snow load should be directly consid- ered when the incident commander determines a strategic plan. The potential of a roof collapse before the fire is put out should be a consider- ation as well. The structural support system hold- ing all that snow may be directly or indirectly under attack by the fire, and that can add to the potential early onset building collapse. Another consideration should focus on newer dwellings constructed with a lightweight “truss- roof” system. As seen in many past fire tests, a lightweight truss roof system, once assaulted by fire, fails at an alarming rate. None of those fire tests were ever conducted with a potential snow load as seen from our recent storm of the week. Heat loss from a building may result in some snow loss through melting between storm events. Roofs that allow heat loss to melt snow are called “warm” roofs; this may be by design or lack of proper insulation. Other roof systems remove lost heat before it has a chance to melt the snow. These roofs that prevent heat from reaching the snow are known as “cold” roofs. Sometimes buildings are either unheated during winter months or are intentionally kept at or below freezing so there is no heat loss that results in snow melt or ice buildup.
One factor that needs to be considered by inci- dent command is how the department can safely commit to an interior firefight while considering the level of danger. What are the dangers to be
Snow-loaded roof considerations
BY WILLIAM GREENWOOD