The terms Department and Secretary are defined in 24 CFR part 5.

Acceptable separation distance (ASD)—means the distance beyond which the explosion or combustion of a hazard is not likely to cause structures or individuals to be subjected to blast overpressure or thermal radiation flux levels in excess of the safety standards in § 51.203. The ASD is determined by applying the safety standards established by this subpart C to the guidance set forth in HUD Guidebook, “Siting of HUD-Assisted Projects Near Hazardous Facilities.”

Blast overpressure—means the pressure, in pounds per square inch, in excess of normal atmospheric pressure on the surrounding medium caused by an explosion.

Danger zone—means the land area circumscribed by the radius which delineates the ASD of a given hazard.

Hazard—means any stationary container which stores, handles, or processes hazardous substances of an explosive or fire prone nature. The term “hazard” does not include:

(1) Pipelines for the transmission of hazardous substances, if such pipelines are located underground, or comply with applicable Federal, State and local safety standards;

(2) Containers with a capacity of 100 gallons or less when they contain common liquid industrial fuels, such as gasoline, fuel oil, kerosene, and crude oil, since they generally would pose no danger in terms of thermal radiation or blast overpressure to a project;

(3) Facilities that are shielded from a proposed HUD-assisted project by the topography, because these topographic features effectively provide a mitigating measure already in place;

(4) All underground containers; and

(5) Containers used to hold liquefied petroleum gas with a volumetric capacity not to exceed 1,000 gallons water capacity, if they comply with National Fire Protection Association (NFPA) 58. NFPA 58, Liquefied Petroleum Gas Code, 2017 Edition, copyright 2016 is incorporated by reference into this section with the approval of the Director of the Federal Register, under 5 U.S.C. 552(a) and 1 CFR part 51. All approved material is available for inspection at HUD's Office of Environment and Energy, 202-402-5226, and is available from National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169, telephone number 800-344-3555, fax number 800-593-6372, www.nfpa.org. It is also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email [email protected] or visit www.archives.gov/federal-register/cfr/ibr-locations.html. Persons with hearing or speech impairments may access the numbers above through TTY by calling the Federal Relay Service, toll-free, at 800-877-8339.

Hazardous substances—means petroleum products (petrochemicals) and chemicals that can produce blast overpressure or thermal radiation levels in excess of the standards set forth in § 51.203. A specific list of hazardous substance is found in appendix I to this subpart.

HUD-assisted project—the development, construction, rehabilitation, modernization or conversion with HUD subsidy, grant assistance, loan, loan guarantee, or mortgage insurance, of any project which is intended for residential, institutional, recreational, commercial or industrial use. For purposes of this subpart the terms “rehabilitation” and “modernization” refer only to such repairs and renovation of a building or buildings as will result in an increased number of people being exposed to hazardous operations by increasing residential densities, converting the type of use of a building to habitation, or making a vacant building habitable.

Thermal radiation level—means the emission and propagation of heat energy through space or a material medium, expressed in BTU per square foot per hour (BTU/ft. 2 hr.).