Essentials

Hazards on roofing jobs take many forms. A momentary lapse in attention, bad judgment or failure to properly set up a job site can result in an injury or, worse, a fatality.

As with all roof system applications, during spray polyurethane foam (SPF) roof system applications, workers should follow proper safety precautions, such as using appropriate fall-protection methods and guarding against burns and electric shocks. However, SPF chemicals present an array of unique safety challenges.

Chemicals

Diisocyanates and polyol resins are two essential chemicals found in SPF. Polyol resins can cause mild irritation to the skin and eyes. When inhaled in high concentrations, these chemicals also can induce labored breathing, light-headedness and headache.

Because of these potentially hazardous vapors, wearing appropriate personal protective equipment (PPE) is critical. Anyone who applies SPF must wear an air-supplied or air-purifying respirator. An air-supplied respirator uses oxygen from a tank and requires extensive training before use. An air-purifying respirator uses a cartridge or canister. A full-face mask provides additional protection because it has a larger face-to-respirator sealing than a half-face mask.

Proper PPE also includes chemical-resistant gloves; safety goggles; and a disposable, protective body suit with a hood. If a worker is handling application liquids, chemical-resistant boots are a good idea.

During SPF application, the eye protection, respirator and protective body suit a worker is required to wear by the Occupational Safety and Health Administration can hamper his peripheral vision and hearing. Limited vision and hearing can make him vulnerable to slips and trips. A good method for protecting a worker is to assign another worker to hold material and supply lines.

When working with SPF roof systems, a worker should wash his hands and face before eating. If chemicals contact a worker's skin, cleaning the area with soap and water will wash away chemicals. If chemicals get in a worker's eyes, he should flush his eyes with cool water for about 15 minutes. Medical assistance should be sought if irritation continues.

Setup

The old adage "an ounce of prevention is worth a pound of cure" especially is true of SPF applications. Proper job setup is imperative. Chemicals and coatings should be stored in proper containers away from heat sources. Excessive temperatures can cause pressure buildup inside containers, rupturing the containers or igniting the chemicals. Those working with SPF should read and understand the applicable material safety data sheets (MSDSs) regarding recommended work practices and procedures.

All equipment used during SPF application should be inspected to ensure it is in good operating condition. Before use, hoses and couplings should be checked for leaks and other signs of damage. If equipment is broken, it should be tagged, removed from the job site and repaired if possible.

Spills and sparks

If there is an SPF chemical spill, MSDSs should be reviewed for appropriate cleanup procedures. Typically, a spill can be absorbed and contained with sand or sawdust. These materials then should be placed in proper chemical containers and taken to a disposal facility. The spill area should be cleaned with water.

Another potential problem during SPF application is sparks that can ignite combustible fumes and cause an explosion or fire. When workers operate welding equipment, a welding curtain or other safety barrier can help protect ignitable chemicals from sparks.

Sparks also can be caused by static electricity sometimes generated from the pressurized flow of liquids and air through hoses and equipment. To help avoid static electricity, spray application equipment and flammable materials should be grounded.

Spray equipment should be kept away from electrical sources, such as transformers and power lines. Power cords should not be plugged in or unplugged in a spray area if there is a chance of igniting fumes. If a fan is used to dissipate fumes, it must be set up properly—fumes should be pushed away from a fan's electric motor. If fumes are drawn into the motor, they can ignite. Electric application equipment and power sources should be equipped with ground fault circuit interrupters.

Be prepared

Watching for potential hazards is critical during any roof system application. During an SPF job, a solid understanding of the unique hazards can minimize the risk of accidents and injuries.

Peter Greenbaum is NRCA's manager of education programs.