StacksVerified U.S. regulatory reference

24 CFR §51.203

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
The following standards shall be used in determining the acceptable separation distance of a proposed HUD-assisted project from a hazard:
  1. (a)Thermal Radiation Safety Standard. Projects shall be located so that:
    1. (1)The allowable thermal radiation flux level at the building shall not exceed 10,000 BTU/sq. ft. per hr.;
    2. (2)The allowable thermal radiation flux level for outdoor, unprotected facilities or areas of congregation shall not exceed 450 BTU/sq. ft. per hour.
  2. (b)Blast Overpressure Safety Standard. Projects shall be located so that the maximum allowable blast overpressure at both buildings and outdoor, unprotected facilities or areas shall not exceed 0.5 psi.
  3. (c)If a hazardous substance constitutes both a thermal radiation and blast overpressure hazard, the ASD for each hazard shall be calculated, and the larger of the two ASDs shall be used to determine compliance with this subpart.
  4. (d)Background information on the standards and the logarithmic thermal radiation and blast overpressure charts that provide assistance in determining acceptable separation distances are contained in appendix II to this subpart C.