Hard Suction Hose - Diameter

Diameter

Hard suction hose comes in multiple sizes, from 2 to 6 inches (5.1 to 15 cm) in diameter. Large diameter hose are carried on full-size fire engines, but smaller diameters of hard suction hose can be carried on apparatus with smaller fire pump ratings, such as wildland fire engines. In the United States, NFPA 1901 requires engines to have hard suction hose that matches the engine's pump rating. For example, an engine with a 1,000-US-gallon (3,800 l) per minute pump is required to carry 5-inch (13 cm) or larger hose, while a wildland fire engine will typically carry 2-to-2.5-inch (5.1 to 6.4 cm) hard suction hose.

The United Kingdom, has a standardised range of metric hose diameters: 7, 9, 12.5 and 15 cm (2.8, 3.5, 4.9 and 5.9 in), with the two smallest diameters sometimes used twined to provide adequate flow rates. Within this range, the 7 centimetres (2.8 in) hoses are fitted with "Instantaneous Couplings"; the 12.5 and 15 centimetres (4.9 and 5.9 in) hoses have Storz couplings; and the 9 centimetres (3.5 in) hose comes in two types, one with "Instantaneous Couplings" and one with Storz fittings. Fire Service Manuals provide tables of maximum volumetric flow rates for a given pump pressure, hose diameter and total hose length. The use of these tables, is to facilitate the selection of suitable hoses, taking into account the frictional losses caused by transporting water through the strainer, hoses, pump and fire fighting nozzles, to draft water from source to the fireground.