Hard suction hose

Last updated
5-inch (13 cm) flex suction hose with Storz fittings, mounted on an engine Hard suction large on engine.jpg
5-inch (13 cm) flex suction hose with Storz fittings, mounted on an engine

Flexible suction hose (Flex suction or suction hose), not to be confused with hard suction hose in U.S., is a specific type of fire hose used in drafting operations, when a fire engine uses a vacuum to draw water from a portable water tank, pool, or other static water source. It is built to withstand vacuum, rather than pressure, abrasion, and heat. Conversely, hard suction is capable of withstanding up to 200 PSIG, as well as vacuum. In the United States, it is standard equipment according to the National Fire Protection Association standards for fire engines. It is used in both structural and wildland firefighting throughout the world, and is made in various diameters and connection types.

Contents

Usage

Flexible suction hose, also known as a suction hose, is a specific type of rigid fire hose used in drafting operations. When using this technique, the fire engine draws water for fire fighting from an unpressurized supply, such as a portable water tank, pool, or other static water source, instead of drawing water from a pressurized water supply, such as a fire hydrant. Under complete vacuum conditions, a pump would lift water 33.9 feet (10.3 m), however pumps on fire apparatus are not capable of producing a perfect/ total vacuum. [1] : 388  Due to this limitation and friction loss, fire services do not recommend attempting to lift water more than 3 metres (9.8 ft). [2]

Hard suction hose may also be used to connect a fire engine to a hydrant, due to its ability to handle both vacuum and pressure. [2] [3] Using hard suction hose in this manner requires that the fire engine be positioned carefully for the limited flexibility of the hose, and may require multiple firefighters due to the weight and bulk of the hose section. [4] The use of flexible suction in this capacity is both ineffective and hazardous, as the hose and couplings may experience catastrophic failure. In certain circumstances, it may be possible to use hard suction hose to draft from a hydrant with adequate water supply but a low flow rate. [5]

Flexible suctions are built to withstand vacuum, rather than water pressure, abrasion, and heat. They are, therefore, constructed differently from the standard fire hose and have different end fittings. In the United States, they are standard equipment according to the National Fire Protection Association standards for fire engines. Since neither hard suction nor flexible suction hose can be folded, it is typically mounted on the side of a fire engine, often opposite ground ladders. [6] Such hose is used in both structural and wildland firefighting throughout the world. [7] [8]

Hard suction hose can also be used to extend the range of a water tender's dumping capability, if the fittings of the hard suction hose match those of the tender dumping water. This could be used to fill a portable dump tank not immediately adjacent to the water tender, from which another fire engine can draft. Since water movement during dumping relies on gravity, rather than mechanical pressurization, hard suction hose is useful for this task. [9]

Characteristics and construction

Suction hose differs from standard fire hose in both its construction and usage:

  1. Hard suction generally has a black opaque wrapped or laminated outer jacket surrounding a flat stock coil spring core. The inner and outer linings provide maximum rigidity, allowing it to be used up to 200 PSIG pressure as well as under vacuum. Flex suction is less rigid and generally corrugated in profile. Often, such hose is manufactured using molded clear or translucent synthetic material (such as PVC) shaped into a series of rings. [10] Construction methods include heat shrinking the material over round stock coil spring core. This shape allows the hose to be somewhat flexible, without allowing it to collapse on itself under suction, as a normal, woven-jacket fire hose would. [10]
  2. It uses suction gaskets. Gaskets in standard fire hose ("pressure gaskets") are designed to minimize the water leaking out between couplings. The gaskets connecting hard suction hose sections, pump, and strainer must instead prevent air from entering at the coupling, since that would spoil the vacuum and allow air into the pump intake. [11] Large diameter (4-inch (10 cm) or greater) hard suctions most often employ National Standard threaded brass connections while flex suction hose will typically use Storz fittings, which are genderless. 3-inch (7.6 cm) or smaller hard suction hose will typically use threaded fittings. In each case, the hard suction hose connection will match the fittings of the pump intake and supply hose, so that hard suction hose can be used in place of supply hose as appropriate.
  3. It is short. Typically, suction hose comes in 10 feet (3.0 m) lengths, while fire hose comes in 50 and 100 feet (15 and 30 m) lengths. [12] Since a fire engine's pump only produces a partial vacuum, it is only recommended for lifting water 3 metres (9.8 ft) or less. [2] For this reason, and because each junction is an opportunity for a crack or imperfect seal to spoil the vacuum, it is rare to see many sections of hard suction hose connected together.
  4. It is not designed for use in fire streams. [13] The airtight nature of hard suction hose, necessary for drafting, renders the hose unsuitable for the high pressure water flow needed to spray a pressurized stream of water on a fire. [14] Thus, suction hose is tested for the ability to "prevent collapse under vacuum conditions" rather than its ability to function as an attack hoseline. [12]

Hard suction hose predates steam or gas powered fire engines and has been available since at least 1888, sometimes referred to as "spiral suction hose". [15] Modern apparatus are commonly equipped with flexible suction as opposed to hard suction, due to the relative ease of use associated with flexibility, as well as the increasing rarity of employing suction hoses to pressurized water sources.

Diameter

Suction hose comes in multiple sizes, from 2 to 6 inches (5.1 to 15.2 cm) in diameter. [10] 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 suction hose that matches the engine's pump rating. [12] 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, [1] : 181  while a wildland fire engine will typically carry 2-to-2.5-inch (5.1 to 6.4 cm) hard suction hose. [16]

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 twinned to provide adequate flow rates. [17] 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. [17] 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. [17]

Strainers

Strainer with 5-inch (13 cm) Storz fitting Strainer Storz.jpg
Strainer with 5-inch (13 cm) Storz fitting
Strainer on a 2.5-inch (6.4 cm) diameter hard suction hose Hard suction end med strainer.jpg
Strainer on a 2.5-inch (6.4 cm) diameter hard suction hose

When being used in a drafting operation from a pool, portable water tank, or other uncovered water source, the length of suction hose farthest from the pump is usually attached to a strainer, to keep foreign objects in the water from being pulled into and damaging the pump. [12] If used in a pond, stream, or other body of water, an appropriate flotation device must be used to keep the strainer below the surface and above the bottom, so that neither mud nor air are sucked into the fire engine's pump. [12] Industry accepted standard is to maintain two feet of distance from the water's surface, bottom, or any other obstruction.

The United Kingdom official guidance is to: [18]

Related Research Articles

<span class="mw-page-title-main">Fire engine</span> Emergency vehicle intended to put out fires

A fire engine is a road vehicle that functions as a firefighting apparatus. The primary purposes of a fire engine include transporting firefighters and water to an incident as well as carrying equipment for firefighting operations. Some fire engines have specialized functions, such as wildfire suppression and aircraft rescue and firefighting, and may also carry equipment for technical rescue.

<span class="mw-page-title-main">Fire hose</span> Flexible tube used for delivering water or foam at high pressure, to fight fires

A fire hose is a high-pressure hose that carries water or other fire retardant to a fire to extinguish it. Outdoors, it attaches either to a fire engine, fire hydrant, or a portable fire pump. Indoors, it can permanently attach to a building's standpipe or plumbing system.

<span class="mw-page-title-main">Fire hydrant</span> Connection point by which firefighters can tap into a water supply

A fire hydrant, fireplug, or firecock (archaic) is a connection point by which firefighters can tap into a water supply. It is a component of active fire protection. Underground fire hydrants have been used in Europe and Asia since at least the 18th century. Above-ground pillar-type hydrants are a 19th-century invention.

A vacuum ejector, or simply ejector is a type of vacuum pump, which produces vacuum by means of the Venturi effect.

<span class="mw-page-title-main">Storz</span> Hose coupling

Storz is a type of hose coupling invented by Carl August Guido Storz in 1882 and patented in Switzerland in 1890, and patented in the U.S. in 1893 that connects using interlocking hooks and flanges. It was first specified in standard FEN 301-316, and has been used by German fire brigades since 1933. Amongst other uses, it has been widely employed on fire hoses in firefighting applications. It is the standard coupling on fire hoses in Portugal, Denmark, Slovenia, Germany, Austria, Switzerland, Sweden, the Netherlands, Poland, Israel, Croatia, Serbia, Bosnia & Herzegovina, Macedonia, Montenegro and Greece. It is also one of the standard couplings on fire hoses in Australia and the United States.

<span class="mw-page-title-main">Water tender</span> Type of firefighting apparatus that specialises in the transport of water

A water tender, sometimes known as a water tanker, is a type of firefighting apparatus that specializes in the transport of water from a water source to a fire scene. Water tenders are capable of drafting water from a stream, lake or hydrant.

<span class="mw-page-title-main">Draft (water)</span>

A draft is the use of suction to move a liquid such as water from a vessel or body of water below the intake of a suction pump. A rural fire department or farmer might draft water from a pond as the first step in moving the water elsewhere. A suction pump creates a partial vacuum and the atmospheric pressure on the water's surface forces the water into the pump, usually via a rigid pipe or a semi-rigid hard suction hose.

Firefighting jargon includes a diverse lexicon of both common and idiosyncratic terms. One problem that exists in trying to create a list such as this is that much of the terminology used by a particular department is specifically defined in their particular standing operating procedures, such that two departments may have completely different terms for the same thing. For example, depending on whom one asks, a safety team may be referred to as a standby, a RIT or RIG or RIC, or a FAST. Furthermore, a department may change a definition within its SOP, such that one year it may be RIT, and the next RIG or RIC.

This glossary of wildfire terms is a list of definitions of terms and concepts relevant to wildfires and wildland firefighting. Except where noted, terms have largely been sourced from a 1998 Fireline Handbook transcribed for a Conflict 21 counter-terrorism studies website by the Air National Guard.

This is a glossary of firefighting equipment.

<span class="mw-page-title-main">Garden hose</span> Flexible tube used to convey water

A garden hose, hosepipe, or simply hose is a flexible tube used to convey water. There are a number of common attachments available for the end of the hose, such as sprayers and sprinklers. Hoses are usually attached to a hose spigot or tap.

A hydrant wrench is a tool used to remove fire hydrant caps and open the valve of the hydrant. They are usually adjustable so as to fit different sized hydrant nuts.

<span class="mw-page-title-main">Hose coupling</span> Connector on the end of a hose

A hose coupling is a connector on the end of a hose to connect it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel, brass, stainless steel, aluminium or plastic.

<span class="mw-page-title-main">Wildland fire engine</span> Fire engine designed for fighting wildfires

A wildland fire engine or brush truck is a fire engine specifically designed to assist in fighting wildfires by transporting firefighters to the scene and providing them with access to the fire, along with water or other equipment. There are multiple types of wildfire apparatus which are used in different scenarios. According to the U.S. National Fire Protection Association, if the apparatus will be used primarily for outdoor and wildland responses, then it is to be considered a wildland fire apparatus and must conform to NFPA 1906.

<span class="mw-page-title-main">Wildland water tender</span>

A wildland water tender is a specialized vehicle capable of bringing water, foam, or dry chemicals to fire trucks in the field that are engaged on the fireline. Water tenders have a large truck mounted tank that carries a minimum 1,000 gallons and up to 4,000 gallons of water. These vehicles are specifically designed for fire fighting often with four-wheel drive, rugged suspension and high wheel clearance for mountainous dirt road conditions. According to the National Fire Protection Association, if the apparatus will be used primarily for outdoor and wildland responses, then it is to be considered a wildland fire apparatus and must conform to NFPA 1906.

<span class="mw-page-title-main">Compressed air foam system</span>

A compressed air foam system is used in firefighting to deliver fire retardant foam for the purpose of extinguishing a fire or protecting unburned areas.

<span class="mw-page-title-main">Piping and plumbing fitting</span> Connecting pieces in pipe systems

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.

Firefighting is the act of extinguishing destructive fires. A firefighter fights these fires with the intent to prevent destruction of life, property and the environment. Firefighting is a highly technical profession, which requires years of training and education in order to become proficient. A fire can rapidly spread and endanger many lives; however, with modern firefighting techniques, catastrophe can usually be avoided. To help prevent fires from starting, a firefighter's duties include public education and conducting fire inspections. Because firefighters are often the first responders to victims in critical conditions, firefighters often also provide basic life support as emergency medical technicians or advanced life support as licensed paramedics. Firefighters make up one of the major emergency services, along with the emergency medical service, the police, and many others.

Despite fire hose and hydrant coupler standardization efforts that are at least 144 years old, there remain significant areas in Canada, the United States, and Mexico that use fire hose and hydrant threads and other couplings that are incompatible with those used by neighboring fire departments. This is notable because the first fire hydrant was invented by Manhattan fire fighter George Smith in 1817, making these devices 200 years old.

References

  1. 1 2 Mahoney, Gene (1986). Introduction to Fire Apparatus and Equipment. PennWell Books. ISBN   0-912212-12-8 . Retrieved 2008-08-10.
  2. 1 2 3 Fire & Emergency Services Authority of Western Australia (2008). "GL 08 Hard Suction (Storz) connections" (PDF). Retrieved 2009-08-19.
  3. ↑ Fornell, Dave (2013-01-14). "Fornell: Hydrant Hook-ups, Chicago Style". Firehouse. Retrieved 2023-05-20.
  4. ↑ International Association of Fire Chiefs (2007). Industrial Fire Brigade: Principles and Practice. Jones & Bartlett. p. 492. ISBN   978-0-7637-3502-9 . Retrieved 2009-08-19.
  5. ↑ Lamm, Willis (2001). "Drafting From Low Pressure Hydrants". firehydrant.org. Retrieved 2009-08-19.
  6. ↑ Shapiro, Larry (1999). Pumpers: Workhorse Fire Engines. MBI Publishing. p. 25. ISBN   0-7603-0672-9 . Retrieved 2009-08-30.
  7. ↑ "Vehicle Mounted Pump - Godiva World Series WT2010 and WT4010". Hampshire Fire and Rescue Service. Archived from the original on 2011-07-20. Retrieved 2009-08-19.
  8. ↑ "Draft Number: DZ 4509, New Zealand Fire Service Firefighting Water Supplies Code of Practice" (PDF). 2008-02-05. Archived from the original (PDF) on May 26, 2010. Retrieved 2009-08-19.
  9. ↑ Eckman, William F. (1994). The Fire Department Water Supply Handbook. PennWell Books. p. 285. ISBN   0-912212-35-7 . Retrieved 2008-08-10.
  10. 1 2 3 The Firefighter's Handbook: Essentials of Firefighting and Emergency Response . Delmar Publishers. 2000. p.  209. ISBN   0-7668-0581-6 . Retrieved 2008-08-10. hard suction hose.
  11. ↑ "FAQ's". Jerome Fire Equipment Co., Inc. Archived from the original on 2008-05-13. Retrieved 2008-08-06. "Suction gaskets have a flap on the outer rim, facing the outside. The coupling torque to assemble mating suction couplings is higher so that these flaps on mating couplings are pressed together initially, sealing out the outside air, so that the draft can be started."
  12. 1 2 3 4 5 Sturtevant, Thomas B. (2004). Introduction to Fire Pump Operations. Thomas Delmar Learning. ISBN   0-7668-5452-3 . Retrieved 2008-08-10.
  13. ↑ "Manual: LDH Hard Suction Hose" (PDF). Task Force Tips. 2007-03-21. Retrieved 2008-08-06.
  14. ↑ Stacey, John W. (2001). "Report of the Committee on Fire Hose" (PDF). National Fire Protection Association. Archived from the original (PDF) on 2011-06-09. Retrieved 2009-08-19. "Positive pressure requirements for hard suction hose were deleted as using hard suction hose for positive pressures is not a practical application."
  15. ↑ The Goulds M'f'g. Co's. illustrated ...: catalogue and price list, of pumps, engines ... The Goulds Mfg. Co. 1888. p. 177. Retrieved 2009-08-30.
  16. ↑ National Wildfire Coordinating Group (NWCG). "Glossary of Wildland Fire Terminology" . Retrieved 2009-08-19.
  17. 1 2 3 HM Fire Service Inspectorate (2001). Chapter 7: "Pre-Planning" in: Fire Service Manual, Volume 1, Fire Service Technology, Equipment and Media: Hydraulics, Pump and Water Supplies. London: the Stationery Office. ISBN   0-11-341216-9.
  18. ↑ HM Fire Service Inspectorate (2001). Chapter 6: "Pump Operation and the Distribution of Water on the Fireground" in: Fire Service Manual, Volume 1, Fire Service Technology, Equipment and Media: Hydraulics, Pump and Water Supplies. London: the Stationery Office. ISBN   0-11-341216-9.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.