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Request for assistance in preventing hazards in the use of water spray (fog) streams to prevent or control ignition of flammable atmospheres.

Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 85-112, 1985 Jul; :1-6
Water in the form of a spray or fog pattern has been used by fire departments and other first response teams in efforts to prevent or control fires when dealing with flammable materials. In a review of several cases, the use of water sprays or fog actually increased the risk of danger to fire fighters and others. Water sprays have been used in the past to ventilate or otherwise reduce the concentration of the fuel to a level below that which is flammable, to raise the required ignition beyond that available, to render the flammable atmosphere inert, or to quench or prevent propagation of an incipient or developed flame front. In some experimental cases, however, the flame traveled through the water spray resulting in a more severe fire or explosion than would otherwise have occurred. Additional tests demonstrated that handlines using standard fire department water spray nozzles could not prevent ignition and that they could not produce water with small enough droplet size and uniformly high concentrations to render inert a flammable atmosphere. Fire departments and other responders are cautioned that the use of a water spray or fog does not eliminate the need for other recognized control methods to dilute the flammable atmosphere and prevent ignition due to sparks, arcs, or open flames.
Fire-safety; Fire-prevention; Fire-fighting; Fire-fighting-equipment; Fire-extinguishing-systems; Safety-research; Emergency-equipment
Publication Date
Document Type
Numbered Publication; Alert
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
DHHS (NIOSH) Publication No. 85-112
NIOSH Division
Source Name
National Institute for Occupational Safety and Health
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division