#55 - Introduction to Standpipe Systems and Fire Hose Angle Valves
#55 - Introduction to Standpipe Systems and Fire Hose Angle Valves
The role of fire hose angle valves in standpipe systems – and how to choose one
Firefighters need reliable supplies of water to effectively extinguish fires. To do this, they have typically utilized some outside source of water, which is often supplied by a fire hydrant and pumped into the building through a fire department connection (FDC). What happens, however, when a building is so large that the distance between the fire and that outdoor source of water is simply too far? Enter the standpipe system and its main internal access valve, the angle hose valve.
By the end of this blog, you will know the many different standpipe systems and the roles that fire hose angle valves have in each one. Are you ready to browse for hose valves already? You can find the most popular models and sizes here.
Standpipes and internal hoses are needed in tall buildings
As buildings continued to increase in height and eventually earned the nickname skyscrapers, it was no longer feasible to effectively fight fires from the outside of a building using only hand hose lines. Code requirements were enacted, and the use of standpipe systems – a series of pipe designed to provide water for hose lines in strategic locations within a structure – and their outlets, the fire department angle hose valve, were mandated. Refer to NFPA 14: Standard for the Installation of Hose and Standpipe Systems for more information.
Fire hose angle valves (sometimes called angle hose valves) attach to standpipe systems and provide firefighters with a connection to water from inside the building. They eradicate the need for lengthy hose lays within tall buildings.
A quick introduction to standpipe systems
Several kinds of standpipe systems exist: automatic wet, automatic dry, semi-automatic dry, manual dry, and manual wet.
Automatic wet standpipe systems are the most popular choice. They are charged at all times and capable of supplying the correct amount of flow and pressure at a moment’s notice. They require little to no maintenance and operate under full autonomy.
Automatic dry systems are used in colder regions where pipes are more susceptible to freezing. Air pressure is contained inside the pipes at all times instead of water, and the angle hose valve governs water entering into the structure. When the stored air pressure drops below the pressure of the water supply, the dry-pipe valve opens, letting the stored emergency water supply rush in.
Despite already being charged, automatic standpipe systems are capable of receiving supplemental water through an FDC in the event that a fire grows to the size of a conflagration.
Semi-automatic dry standpipe systems are a little different in that they require someone to manually activate a remote control device to allow water into the system and remain ready at each angle hose valve. These devices are located at each one of these valves throughout the structure.
Manual wet standpipe systems actually retain water at all times using a smaller water supply pipe. This source, however, does not provide enough pressure and flow; fire departments must use tankers and pumpers to augment the supply from fire hydrants, channeling it through FDCs located on the outside of the building.
Last, but not least, are manual dry standpipe systems. Similar to automatic dry, these standpipe systems have air in the pipes. The difference is that there is no permanent water supply, so tankers or pumpers are required to charge the system using an outside fire hydrant and pumping it through an FDC.
For more information on FDCs, visit our blog – The Role and Components of Fire Department Connections.
Standpipes systems also fall under one of three different classes:
Class I Standpipe System [2 ½” hose connections]: Used by fire departments and those trained in handling heavy streams in high-rise buildings without sprinklers, Class I systems provide the primary source of water for fighting fires.
Class II Standpipe System [1 ½” hose lines]: Pin rack units – located in and near building stairwells – allow trained building occupants to effectively extinguish fires. These units connect to the building’s standpipe system and feature a hose to extend to the desired area.
Class III Standpipe System: These provide 1 ½” hose stations to supply water for use by trained building occupants, and 2 ½” hose connections to supply a larger volume of water for use by fire departments.
To read a more in-depth look at standpipes, read our series – the first installment of which can be found here.
Types of fire hose angle valves
Fire hose valves can either be a regular angle hose valve or a pressure restricting angle hose valve. The difference lies in the amount of pressure they can operate under. Ordinary hose valves can withstand pressures of up to 300 PSI. Pressure restricting valves have a stem and bonnet that features a specially designed mechanism to limit how far the valve itself can open. These valves are suitable where inlet pressures range from 70-175 PSI. Both types of hose valves come standard with female (NPT) inlets but are offered with either a male or a female outlet.
The size of the angle hose valve – either 1 ½” or 2 ½” – will tell you the type of standpipe system it operates on. Class I and III standpipe systems utilize 2 ½” angle hose valves (though Class III may utilize both) and class II systems utilize 1 ½” angle hose valves.
Angle hose valves are found within enclosed stairwells, exterior stairs, and corridors of larger buildings – including skyscrapers, hotels, and warehouses. Their convenient locations give firefighters or occupants useful connections to the standpipe system’s supply of water, which it carries from the ground level supply.
Installation of fire hose angle valves
The angle hose valve comes standard with taper pipe threads to conform to ANSI B2.1 (Basic Standard for Steel Pipe Threads). Installation of this hose valve can be accomplished with readily available field tools, including a wrench. Prior to installation, apply joint compound or thread seal tape to male threads. Next, tighten the hose valve until snug, and align as required.
Operation of hose angle valves
Connect the female end of the fire hose coupling. Next, slowly open the angle hose valve until the desired pressure is achieved. CAUTION: Do not bend fire hose. It may cause the connected female-end of a fire hose to detach from excess pressure.
Schedule consistent inspection of hose valves for tight shut off. If the valve leaks or requires excess torque to tighten, replace the disk or disk holder assembly as required.
What to look for when purchasing one:
Fire hose angle valves come in two sizes – 1 ½” and 2 ½”. If you’re dealing with a Class I system, pick the 2 ½” model. For Class II systems, a 1 ½” valve is the best choice. Class III systems may require both. Either type of hose valve comes standard with female (NPT) inlets but are offered with either a male or a female outlet in a variety of threads. The last thing to decide is the finish – polished brass, rough chrome-plated, or polished chrome-plated.
QRFS is proud to offer quality angle hose valves. Our selection of valves varies in design, but not in effectiveness. We carry every style previously mentioned in this blog.
This blog originally posted by Jason Hugo and Cameron Sharp at QRFS.com/blog on July 22, 2016, and updated on January 28, 2019. If you like what you’ve read, check us out at Facebook.com/QuickResponseFireSupply or at Twitter @QuickRsponseFS.