Glossary of Firefighting - H

H

• Hazard: a source of danger of personal injury or property damage; fire hazard refers to conditions that may result in fire or explosion, or may increase spread of an accidental fire, or prevent escape from fire. Under worker safety and health regulations, employers have a general duty to provide a workplace free of hazards. See also fire prevention, and HAZMAT.
• Hard Line: A smaller hose about one inch in diameter used by firefighters to clean apparatus.
• HAZMAT: Hazardous materials, including solids, liquids, or gases that may cause injury, death, or damage if released or triggered.
• Head pressure: How the pressure of a water stream is measured. By measuring the 'breakover' point, the point where the water stream breaks apart and begins to fall back to the ground, of a stream of water aimed vertically into the air. This is typically done with a 1-inch-diameter (25 mm) hose and a fixed nozzle. Therefore, if a water stream breaks over at 50 ft (15 m), then it is said the pump has 50 feet (15 m) of head pressure. Current measurements of pumping capacity are now in GPM, Gallons Per Minute.
• Helitack: A rotary winged (helicopter) fire-fighting aircraft, such as the Erickson Skycrane which can be modified to hold 2100 gallons (9500L) of water or retardant.
• High-pressure system: A supplemental pump system used to pressurize the water supply, sometimes used during a large fire, or whenever more than one hydrant is being used.
• High-rise building: Any building taller than three or four stories, depending upon local usage, requiring firefighters to climb stairs or aerial ladders for access to upper floors.
• High-rise pack: A shoulder load of hose with a nozzle and other tools necessary to connect the hose to a standpipe.
• Hose Pack: A hose pack is a backpack containing fire hose in a preconfigured arrangement, sometime completely made from fire hose without a bag.
• Fire Hose Vacuum: A small pneumatic device that removes residue air from the inside of a fire hose, thereby making it smaller and somewhat rigid
• Hotshot crew: An extensively trained group of approximately twenty people which specializes in wildfire suppression with little or no outside logistical support.
• Hot zone: contaminated area of HAZMAT incident that must be isolated; requires suitable protective equipment to enter and decontamination upon exit; minimum hot zone distance from unknown material with unknown release is 330 feet (United Nations Emergency Response Guidebook); surrounded by "warm zone" where decontamination takes place.