Temporary heating systems create an elevated risk of fire and expose building owners to property loss and business interruption. Whenever possible, consider installing a permanent heating appliance instead of a temporary heater.
If a temporary heat system must be used, diligent management of this hazard should include:
- Selecting appropriate heating equipment
- Maintaining adequate clearance to combustibles
- Installing fuel supplies in accordance with applicable codes or standards
- Using a fire watch program
Selecting heating equipment
To reduce the risk of fire, use the appropriate type of heating appliance — sized accordingly for the task. Have the system custom-designed and installed by a heating contractor with expertise in temporary heat systems. The contractor should furnish equipment that’s in good repair, regularly maintained and clean. Additionally, heating appliances should be listed by a recognized testing laboratory. Solid fuel and open flame salamander-type heaters are highly discouraged, as they may jeopardize insurance coverage in the event of a loss.
Heating appliances that use pressurization methods are preferred because they minimize cold spots and, in turn, reduce the need to relocate heating equipment after initial set up. Pressurization type heaters source combustion air from the exterior of the building and push the heated air to the interior space. Pressurization methods also offer the benefits of improved indoor air quality — which include less employee exposure to the products of combustion — and reduced water vapor production (which can adversely affect building materials).
Often, the heating contractor and fuel supplier are separate business entities. Because the scope of their services may sometimes overlap or have gaps, it’s important for them to have a non-adversarial relationship and show a willingness to work together.
Clearance to combustibles
To ensure heating appliances have adequate clearance to combustible materials, reference the heating equipment manufacturer’s recommended clearances, as well as the clearances prescribed in Table F-4 of section 1926.154(b)(3) of OSHA CFR Part 1926, Safety and Health Regulations for Construction. (A reproduction of Table F-4 appears below for your convenience.)
||Minimum Clearance (inches)
|Room heater, circulating type
|Room heater, radiant type
Always consider the material immediately below a heating appliance. Heating appliances not specifically rated to be placed directly over combustible material must have suitable heat-insulating material installed below the heating appliance. Heat-insulating material must extend a minimum of 2 feet beyond the heating appliance in all directions.
Following initial system setup, it’s imperative to ensure an adequate clearance to combustibles is maintained. Make sure a legible safety data plate is affixed to each heating appliance, indicating required clearances. Do not allow modifications or movement of the heating appliances after initial setup, unless it’s done under the guidance of the heating contractor. This precaution also helps prevent accidental loosening of fuel supply fittings.
Fuel supplies for temporary heating appliances should be installed exactly as prescribed in NFPA 58: Liquefied Petroleum Gas Code or NFPA 54: National Fuel Gas Code . All piping, tubing or hoses must be checked for leaks following installation. Also, a deliberate effort should be made during system design to minimize the amount of gas piping, tubing or hoses that must be installed inside the building. Equipment selections that eliminate the need for refueling operations inside the building are strongly recommended.
If flexible hoses are used to supply fuel, they must pass a 25-pound, 12-hour pressure test, be installed at least 3 ½ feet off the ground and be supported and out of the way of traffic. Hose fittings should be factory applied and specifically rated for gas service.
Institute a program of routine visual inspection of heating appliances to ensure proper operation and to verify adequate clearance to combustible materials is being maintained. Inspections should occur during the first hour of operation and every 2 hours thereafter. Continue to monitor the heating appliances for 3 hours after the equipment has been shut down. The inspecting individual should be knowledgeable in the operation of the heating appliances and trained to safely de-energize the appliance and shut off fuel supplies.
Consider using a management control, such as an hourly inspection log, to ensure the visual inspection is being carried out by employees. Place an inspection log in close proximity to each heating appliance, but not so close that the inspection log itself compromises the required clearance to combustible materials. Also make sure a 20-pound ABC fire extinguisher is placed in close proximity to each heating appliance and train employees on proper usage.
For more information about preventing fires when using temporary heating systems, we encourage you to seek the assistance of your fire protection engineer or contractor, or contact Nationwide’s Property Engineering Group.