On most roofing jobs, potential risks are easy to spot. However, spray polyurethane foam (SPF) application hazards often are invisible. Roofing workers who install SPF roof systems must contend with vapors, airborne particles, electric sparks and potential falls—all of which can be prevented by using proper safety equipment and taking certain precautions.
SPF contains two basic chemical ingredients: diisocyanates and polyol resins. Inhaling high concentrations of these chemicals can cause light-headedness, difficulty breathing, headaches, vomiting and unconsciousness and may lead to death by asphyxiation. In addition, polyol resins may be slightly irritating to the skin, and some types of catalysts present in polyol resins can be highly irritating if they contact eyes.
Because of potentially dangerous vapors, a roofing worker must wear an air-purifying or air-supplied respirator while installing an SPF roof system. Air-purifying respirators consist of cartridges or canisters connected to respirators. Air-supplied respirators use external air supplies, such as oxygen tanks. Respirators with full-face pieces provide better protection than those with half-face pieces because they have larger face-to-respirator sealing areas and protect eyes.