Keep the heater at least 10 feet from canvas before it is lit
Before the temporary heater is lit, measure at least 10 feet to the nearest combustible tarpaulin, canvas, or similar covering.
Key takeaways
Before you light a temporary heater, three numbers and one phrase belong on the daily site record.
- The first is the distance to the nearest combustible covering.
- The second is the size of the insulating pad under the unit.
- The third is the fire extinguisher rating that must be nearby.
- The fourth is the exact wording used for the pad distance, which changes depending on which official page you are reading.
The canvas clearance line is consistent across the sources in this packet. Heaters used near combustible tarpaulins, canvas, or similar coverings must be at least 10 feet from those coverings, according to the California Department of Industrial Relations. The Washington State Legislature prints the same 10-foot requirement for heaters in the vicinity of such coverings. UpCodes, which reprints the federal temporary heating section, also states that heaters must be located at least 10 feet from combustible tarpaulins, canvas, or similar coverings, according to UpCodes. When you write this on the site record, use the digit "10" because all three pages print it as a number.
The California Code of Regulations, Title 8, Section 1693. Temporary Heating Devices requires that heaters used in the vicinity of combustible tarpaulins, canvas, or similar coverings be located at least 10 feet from the coverings, according to California Department of Industrial Relations. This 10-foot line is the minimum clearance that must be verified and written on the daily site record before ignition.
WAC 296-155-280 states that you must locate heaters used in the vicinity of combustible tarpaulins, canvas, or similar coverings at least 10 feet from the coverings, according to Washington State Legislature. The requirement applies to the same class of coverings and the same distance. Write the measured distance, not just a checkmark, so the record shows the specific gap maintained on that day.
Temporary Heating Devices | UpCodes reprints the federal wording, stating that heaters used in the vicinity of combustible tarpaulins, canvas, or similar coverings shall be located at least 10 feet from the coverings, according to UpCodes. This is a reprint of the federal section, not a separate state rule. The 10-foot figure is identical across these sources.
What each official page requires for this check
The floor pad requirement appears on both the California and federal pages, but the wording differs slightly in how the material is described. Temporary Heating Devices states that when such heaters are used, they shall rest on suitable heat insulating material or at least 1-inch concrete, or equivalent, according to California Department of Industrial Relations. This page names the specific material options: heat insulating material, 1-inch concrete, or an equivalent substitute. The federal rule, published as 29 CFR § 1926.154 - Temporary heating devices. | Electronic Code of Federal Regulations (e-CFR) | US Law | LII / Legal Information Institute, addresses the extent of the material. It states that the insulating material shall extend beyond the heater 2 feet or more in all directions, according to Legal Information Institute.
The California page also specifies the extension distance. It repeats the requirement that the insulating material shall extend beyond the heater 2 feet or more in all directions, according to California Department of Industrial Relations. This means the pad must cover the heater and extend at least 2 feet past its edges on every side. The federal page from the Legal Information Institute uses the same 2-foot measurement for the extension, stating the insulating material shall extend beyond the heater 2 feet or more in all directions, according to Legal Information Institute.
Where the pages use different words or numbers
The floor pad distance appears in the Washington State Legislature page as a spelled-out phrase rather than a digit. The insulating material must extend beyond the heater two feet or more in all directions, according to Washington State Legislature. This specific wording uses the words "two feet" instead of the number "2". When you write this on your daily site record, copy the exact phrase from the source to avoid misinterpretation during a review.
The covering fastening requirement shows a subtle shift in voice between the state and federal pages. The Washington State Legislature page states, "You must securely fasten the coverings to prevent ignition or upsetting of the heater due to wind action on the covering or other material," according to Washington State Legislature. The federal page, published by the Legal Information Institute, uses the phrasing, "The coverings shall be securely fastened to prevent ignition or upsetting of the heater due to wind action on the covering or other material," according to Legal Information Institute. One page uses the imperative "You must," while the other uses the passive "shall be securely fastened." Both address the same risk: wind action causing ignition or upsetting the heater.
The federal page also includes a requirement about the heater's physical orientation. Heaters, when in use, shall be set horizontally level, unless otherwise permitted by the manufacturer's markings, according to Legal Information Institute. This is a distinct check from the clearance and fastening rules. It focuses on the heater's base position relative to the ground. If your site record includes a field for heater orientation, this is the source that provides the rule.
A filled reference table of the clearance rules
The table below lists the specific clearance and equipment requirements printed on each official page. Each row cites the publisher and the exact number or phrase used in that source.
| Publisher | What that page requires | Number printed on that page |
|---|---|---|
| California Department of Industrial Relations | Heaters near combustible tarpaulins, canvas, or similar coverings must be located at least 10 feet from the coverings. | 10 feet |
| California Department of Industrial Relations | Insulating material must extend beyond the heater 2 feet or more in all directions. | 2 feet |
| Washington State Legislature | Heaters near combustible tarpaulins, canvas, or similar coverings must be located at least 10 feet from the coverings. | 10 feet |
| Washington State Legislature | Insulating material must extend beyond the heater two feet or more in all directions. | two feet |
Write the distance to the nearest canvas and the pad status on your daily site record before the heater is lit.
How to make the check on today's site
Before the heater is lit, verify the extinguisher rating and the safety controls on the unit. The California Department of Industrial Relations requires that at least a 4A:40-B:C rated fire extinguisher shall be readily available for use when temporary heating devices are used, according to California Department of Industrial Relations. Write the specific rating on your daily site record. Do not assume a standard site extinguisher meets this requirement; the page specifies the 4A:40-B:C rating for this context. If the unit on the site is a different class, note the discrepancy before ignition.
Check the heater’s fuel system for the required safety control. UpCodes states that flammable liquid-fired heaters shall be equipped with a primary safety control to stop the flow of fuel in the event of flame failure, according to UpCodes. This applies specifically to heaters that burn flammable liquid. See flammable liquid storage limits for a flammable liquid heater. Confirm the control is present and functional before turning the key.
Review the clearance to combustible materials against the provided table. UpCodes requires that temporary heating devices shall be installed to provide clearance to combustible material not less than the amount shown in Table F-4, according to UpCodes. The table referenced in this section defines the minimum distances. Measure canvas, tarpaulins, and similar coverings against the 10-foot line, not against Table F-4. Record the measured distance and the table reference in your log.
Illustrative example
A crew places one temporary heater on a floor pad before anyone lights it. The nearest canvas covering is 10 feet from the heater. A second covering, a tarpaulin, is also 10 feet away. The pad is suitable heat insulating material and extends 2 feet beyond the heater on every side. A 4A:40-B:C extinguisher is readily available beside the work area. The coverings are fastened so wind cannot push them into the heater or upset it. The heater is set horizontally level. The crew writes 10 for the canvas distance and writes 2 for the pad extension on the daily site record. They also write the extinguisher rating. Only then does anyone light the heater. They copy two feet if that is the wording on the page they are using. Each line is written before ignition. The gap is measured on the ground before the heater is lit.
What to write on today's site record
Record the clearance check before the heater is lit. The insulating material shall extend beyond the heater 2 feet or more in all directions, according to California Department of Industrial Relations. Write the date, the measured distance to the nearest canvas, whether the floor pad is in place, and the extinguisher rating on the daily site record.
FAQ about temporary heater clearance
Does the 10-foot line apply to canvas and tarps?
Yes, the rule explicitly covers combustible tarpaulins, canvas, or similar coverings. The heater must be located at least 10 feet from these materials, according to California Department of Industrial Relations. This same 10-foot distance applies to the same list of coverings, according to UpCodes.
What floor pad does each page name?
The insulating material must extend beyond the heater 2 feet or more in all directions, according to California Department of Industrial Relations. Washington State requires the insulating material to extend beyond the heater two feet or more in all directions, according to Washington State Legislature.
Does every page print a 2-foot pad as a digit?
No, the pages use different formats for the same distance. The California page prints the number as "2 feet," according to California Department of Industrial Relations. The Washington page prints the distance in words as "two feet," according to Washington State Legislature.
Where does the extinguisher rating appear?
A 4A:40-B:C rated fire extinguisher must be readily available when temporary heating devices are used, according to California Department of Industrial Relations. This specific rating requirement is printed on the California temporary heating devices page.
What do I write on today's site record?
Write today's date, the measured distance to the nearest canvas, and whether the floor pad is in place. Record these details before the heater is lit. Keep the entry consistent with the Construction Daily Log Checklist for Supervisors.