If you live in the southwest, then you have probably looked into different ways to keep your house or business cooler without raising you air conditioning bills.  One solution which has increased in popularity over the past couple of years is the installation of a reflective radiant barrier. Radiant barriers can be used in residential, commercial, and industrial buildings. Radiant barriers reduce summer heat gain and winter heat loss, which helps lower heating and cooling costs.  The potential benefit of attic radiant barriers is primarily in reducing air-conditioning cooling loads in warm or hot climates.

The two most common types of radiant barriers on the market today are radiant barrier coatings and radiant barrier foil coverings. Radiant barrier coatings (latex paint mixed with aluminum) are typically sprayed on the underside of the roof decking. Radiant barrier foil coverings usually consist of a thin sheet or coating of a highly reflective material, usually aluminum, applied to one or both sides of the substrate. Common substrates include kraft paper, plastic films (scrim), cardboard, plywood sheathing, and oriented strand board. Reflective radiant barrier foil products can be installed between the roof sheathing and attic floor insulation, in wall cavities, and around door openings, water heaters, and pipes.

While the potential benefits of radiant barrier foil coverings are well known and advertised, the potential risks are much less well know. It should come as no surprise that the aluminum laminate used in the reflective radiant barrier covering is an excellent conductor of electricity. When grounded, through incidental contact with the homes grounded electrical lines, plumbing lines, junction boxes or recessed light fixtures, it can effectively conduct electricity throughout the entire attic space. Because reflective radiant barriers are installed either on the attic floor or between the roof sheathing, the potential exists for them to become energized through contact with exposed or damaged residential wiring, as well as through a direct lightning strikes on the chimney cap, metallic roof penetrations, attic vents, and flashings. When a radiant barrier becomes energized and current begins to flow through it, intense heating can occur at the connection points. The intense heating at those connection points has the potential and often does ignite the various combustible substrate materials upon which the aluminum is mounted or laminated. The greater the amount of current flowing through the system (i.e. typical 120v residential wiring vs. lightning), the greater the risk of fire.

Over the past year, we have identified a number of radiant barrier fires with good recovery potential.  It should be noted that radiant barrier losses are not always easy to identify  because they can occur virtually anywhere along the energized radiant barrier foil, not just at the point where it becomes energized.  That being said, we continue to work closely with our experts to identify, understand and evaluate these losses.  If you believe that you have a loss potentially involving a radiant barrier, Cozen O’Connor stands ready to assist in evaluating all aspects of the loss for third-party opportunities.

About The Author

Leave a Reply