When a technology makes the transition from novelty to common-place, it’s normal for users and manufacturers to discover new wrinkles in its design or implementation. As photovoltaic (PV) roofing has come into wider use in the past decade, fire departments around the country have re-evaluated their procedures when responding to emergencies, and installers have tried to update the design installation of solar systems in order to minimize risk to firefighters.
Reason for Concern
There is a real risk in working around PV panels during a fire, both from the shock hazard and potential structural concerns. With their larger-scale operations, commercial installations especially can give responders enough pause that they hold back and let the building burn, focusing on preventing the flames from spreading to nearby buildings. One of the highest profile such incident was the Dietz & Watson warehouse fire in 2013.
Standard procedure for fire units is to kill all utility service from outside the building when arriving at a fire, an option traditionally not available for PV arrays. Firefighters normally cut one or more openings in the roofline to provide water access and to allow smoke to vent and clear the building. When PV panels are present on a large portion of the roof, opening vent holes becomes difficult at best and dangerous at worst. If the first responders have already applied water or foam to PV panels (panels which are likely already damaged by high heat or flames) the entire area may become a hazard.
The Push for Change
Just as California has been a leader in promoting the adoption of PV technology, the California Department of Forestry and Fire Prevention teamed with the solar industry to release one of the first guidelines to address the issue of firefighter safety in PV roofing installs. By 2011 Underwriters Laboratories released the 149 page Firefighter Safety and Photovoltaic Installations Research Project. All of this was a lead-up to the release of the 2014 NEC, which contains specs for the much-desired rapid shutdown of PV systems.
The 2014 NEC guidelines on rapid shutdown requires all building-mounted PV systems to be able to limit circuit charge to no more than 30 volts, within ten seconds of triggering the shutdown. Although a detailed examination of the 2014 NEC is beyond the scope of this article, its implementation serves as a step forward in combining safety and functionality for PV roofs.
Going Beyond the Guides
But the solar industry can and should be on the lookout for additional ways to work hand in hand with emergency services. As well as installing to code, technicians can take a critical look at the roof to be sure that there are no quirks that would cause problems in an emergency situation. Look to see if any peaks of valleys lead to walkway dead-ends or create situations where it is impossible to move without grabbing the array structure as a handhold.
As solar panels first started becoming more common a few years ago, the nation’s fire departments found themselves playing catch up, and the reality is that codes and regulations will always trail new technologies. The debut of solar shingles, for example, made it significantly more difficult to identify an array from the curbside. If you find yourself working with new equipment that might cause confusion for first responders, consider a courtesy call to the local fire department to let them know what they’re facing.
First responders assume a great deal of risk every time they walk into a building fire. By updating regulations and looking for ways to keep firefighters informed, installers can keep damage to a minimum and possibly even save lives.
With over a decade of construction experience, Dan Stout writes articles that help demystify the industry for both contractors and customers. Visit him at www.DanStout.com.