Posted on October 26th, 2010 by Lynn Sheils
We are getting into the time of year where northern locations need to start thinking about issues associated with Ice and Snow. Below are some ideas and tips related to the protection of commercial property:
The weight of ice, snow, and accumulated water on a building’s roof can be tremendous. A contributing factor to roof collapse is the rapid freeze and thaw cycles that often occur throughout the winter. Ice can quickly accumulate in roof drains preventing water from properly draining. The following loss control guidelines will help prevent a roof collapse.
Verify that drains are clear to allow melting, or heavy rains, to run-off. If the roof is pitched and without drains, open paths to the eaves to ensure drainage and prevent “ponding”.
If a roof is susceptible to large snow drifts, is in an area with heavy snowfall, or is difficult or hazardous to access, initiate a formal snow removal program with a local contractor qualified for roof snow removal with trained staff and proper equipment (shovels, snow blowers) and the appropriate safety planning for those workers/contractors. Equipment that can damage a roof, e.g., ice chopper, blowtorch (a fire hazard!), should never be used. Keep an updated winter emergency response plan in effect, especially for snow removal. Include emergency contact numbers for qualified contractors and the building landlord (if leasing the building).
If snow loads are already at a dangerous level, and qualified contractors are not available, remove snow from the roof in increments – if you deem it safe to do so. This is critical in areas where snowdrift potential exists, including:
1) Roof elevation changes;
2) Moderate- or low- sloped, peaked, or curved roofs where winds cause drifting;
3) Valleys formed by multiple-gable or multiple peak roofs;
4) Roofs with multiple projections (parapets, etc.);
5) For standing seam metal roofs, remove snow in strips starting at the peak and ending at the eaves, alternating side to side to assure the roof load is maintained in balance; and
6) Identify loads added to the building since it was constructed; such as equipment hung from the roof, or roof mounted equipment. Additional bracing may be needed. Ensure that any additional internal bracing does not interfere with the effectiveness or operation of automatic sprinkler systems.
Regularly inspect drains and remove any debris, which could prevent flow. Make sure exterior down spouts are clear of snow or ice at outlets.
Be alert for the beginning of ponding-deflection cycles. As snow compresses and absorbs rainwater, the increased weight on the roof will result in areas of depressions that will not drain. Once this condition begins it only gets worse and eventually the roof could collapse.
For new construction, ensure that the roof is properly designed to meet snow load calculations and the adequate number and size of roof drains is provided.
Ensure that wet type sprinkler systems are adequately heated so that system does not freeze.
Large amounts of water, ice and snow can accumulate in containment dikes and protective berms. Facilities should be aware of this exposure and take steps to reduce the volume of such accumulations, as appropriate, so that the dikes/berms have enough available volume to contain spills. Care should be taken to avoid pollution when removing ice, snow or water.
Cleared drives and parking areas allow easier site access for emergency response vehicles and personnel.
