If you are installing solar panels in the northern half of the United States, there are a few winter safety precautions you need to take to prevent potentially dangerous situations.
Traditional residential asphalt shingle roofs have a high coefficient of friction that helps to hold rooftop snow accumulations in place until the snow gradually melts and is gone. However, solar panels have a smooth surface that can result in a very sudden slide of snow in quantities large enough to cause severe damage to anything or anyone below. One of the most economical ways to prevent a snow avalanche is to install a snow retention system or snow guards.
Snow guards aren’t new. Used frequently to stop snow from suddenly falling off the slick surfaces of metal roofs, snow guards are now offered in a variety of styles and types and are available for almost every kind of roofing material. The most effective snow guards consist of brackets that attach to the roof near the eave and support a bar or multiple bars running parallel to the eave across the length of the roof. Snow guards can also be installed over a walkway, doors or delicate shrubs and are available in both bar or rail types. Regardless of the style selected, the layout and specifications should be designed to meet your local snow load requirements.
Having a snow retention plan created along with the PV panel plan will help maximize rooftop space and also determine the height necessary for the snow retention system to hold back the snow sliding off the array. A trained designer will take into account the local building code snow loads, roof pitch and roofing surface materials to best plan and design the solar array placement along with the snow retention system. They’ll also consider whether your PV panels need to be installed with a railed racking system or as a rail-less system, and what the distance from the top of the PV panels to the rooftop will need to be.
Local fire code requirements for positioning the solar array on the roof should be reviewed, and you will need to allow space for emergency personnel to access the rooftop in case of a fire or other disaster. Some jurisdictions mandate a specific, clear distance between the array and the eave and valleys of adjacent roof sections, often 3 ft or more. Discuss the impacts of installing a snow rail within that distance to your customer.
Questions to consider
- As the solar installer, do you have a recommended snow retention system?
- Will it be adequate for all your homes or buildings?
- Will you need more than a single row installed at the eaves to hold back the snow or should the array be designed to allow an intermediate row part way up the roof?
- There are a number of manufacturers of snow guards. Has the snow guard manufacturer you have chosen had experience with solar arrays in high snow?
A customer’s decision to invest in a quality solar array should also determine whether a snow retention system should be part of the installation. If chosen wisely, the solar and snow retention systems will serve together for many years.
Caroll Marston is a sales engineer for AceClamp.
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— Solar Builder magazine