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OSHA Hazard Information Bulletins
Poweray Infrared TR, CS, and Heat and Serve Heaters

March 28, 1991




  • Director
  • Office of Field Programs


  • Director
  • Directorate of Technical Support


  • Hazard Information Bulletin - Poweray Infrared TR, CS, and Heat and Serve Heaters

The Directorate of Technical Support issues Hazard Information Bulletin (HIB) in accordance with OSHA Instruction CPL 2.65 to provide relevant information regarding unrecognized or misunderstood health hazards, inadequacies of materials, devices, techniques, and engineering controls. HIBs are initiated based on information provided by the field staff, studies, reports and concerns expressed by safety and health professionals, employers, and the public. Information is compiled based on a thorough evaluation of available facts, literature and in coordination with appropriate parties. HIBs are used as vehicles for the dissemination of technical information to OSHA personnel.

The Hartford, Connecticut Area Office has brought to our attention a potential hazard associated with the use of the Poweray Infrared Heaters, TR and CS series and model Heat and Serve Heater. These heaters are normally used out doors in the process of repairing deteriorated asphalt streets.

The infrared heaters are trailer mounted, and consist of three major components: a heating chamber, a steel operating control box and propane cylinders. The control box houses 4-6 volt batteries, a trickle charger, solenoids and two stage pressure regulators (see attachment). Infrared is generated by delivering propane gas-air mixture to energy convertors using blowers for mixing proper amounts of gas and air.

In 1989, the National Fire Protection Agency issued a standard which prohibited the mounting of gas regulators in the battery boxes. In July of 1990, an employee sustained 1st and 2nd degree burns from a propane flash fire while operating an asphalt heater with a gas regulator located in the battery box. The employee reached into the attached control box to adjust the height of the heater when the fire occurred. Subsequent investigation into the accident revealed that a diaphragm within a regulator ruptured, discharging propane into the control box causing the propane flash fire to occur.

Prior to August 1986, the gas regulators of the heater units were mounted in the battery boxes and were vented inside the battery boxes. In October 1990, Poweray Infrared Corporation issued a warning regarding the existing venting procedure and provided a modification kit for this series heater. According to Poweray the kit will allow the regulator to vent outside the battery compartment. This is mandatory in order to meet the requirements of the 1989 National Fire Protection Agency standard. The company hopes to locate all of the subject heaters. The purpose of this Hazard Information Bulletin is to assist in identifying hazards associated with the subject heaters.

Please distribute this bulletin to all Area Offices, State Plan States and Consultation Project Officers.

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