Standpipe & Sprinkller Systems Refresher
Standpipe Systems Review
by Brian Brush
Jun 24, 2014
Standpipe systems are designed to supply water to a remote area (high-rise/low rise commercial and residential, malls, parking garages, stadiums, warehouses). Standpipe systems are either wet or dry and systems may or may not be supported (pumps, domestic water). When we discuss standpipe systems we should also discuss our attack systems; hose, nozzles and appliances because these tools we will be using are also going to be remote from our apparatus.
There are three classes of standpipe systems per NFPA 14, Standard for Installation of Standpipe and Hose Systems. Class I: 2 ½” Outlets for firefighter use. Class II: 1 ½” outlets with 1 ½” hose for occupant use. Class III: 2 ½” outlets with removable 1 ½” reducer for occupant and firefighter use.
There are two pressure standards for Standpipe Systems. From 1918 until 1993 the NFPA standard was 65 PSI at the most remote outlet of a standpipe system. This was pressure was designed to support 100 feet of 2 ½” hose flowing 266 GPM from a 1 1/8” solid bore nozzle. (15 PSI friction loss for the 100’ of hose and 50 PSI for the nozzle.)
The One Meridian Plaza Fire in 1991 claimed the lives of 3 firefighters and completely consumed 9 floors of a 35 story high-rise. This fire and the resultant pressure from the American fire service led NFPA to change the standard to increase outlet pressures. In 1993 the standard changed to 100 PSI at the most remote outlet, while a significant increase it is still far below most target pressures to support fog nozzles and 1 ¾” hose attack line packages. Additionally NFPA included this disclaimer in the new standard.
“It is very important that fire departments choose an appropriate nozzle type for their standpipe firefighting operations. Combination fog, constant pressure and automatic type nozzles should not be used for standpipe operations because many of this type require a minimum of 100 PSI of pressures at the nozzle inlet to produce a reasonably effective fire stream. In standpipe operations, hose friction loss might prevent delivery of 100 PSI to the nozzle inlet. In high-rise standpipe systems with pressure reducing hose valves, the fire department has little or no control over hose valve pressures.” (NFPA 14 A-5-7.)
Standpipe systems may be poorly maintained, vandalized, improperly designed and incorrectly installed. Lack of attention to these systems not only during initial construction but also over the years they sit in these structures leads to decreased reliability. NFPA estimates that roughly 20% of America’s standpipe systems are not suitable for use.
Pressure Reducing Valves and Devices. PRVs and PRDs are designed to limit the outlet’s pressure. For example: a system that is designed to supply 100 PSI outlet pressure to the 12th floor requires at least 155 PSI from the ground level just to overcome head pressure. Pressure reducing valves or devices may be found on outlets of lower floors including basements to reduce that higher pressure to the standard 100 PSI outlet pressure. Pressure reducing valves are typically more complex and built in to the outlet valve which may or may not be field adjustable. Pressure reducing devices are typically a simple add on to the valve stem as pictured or outlet orifice like a butterfly or restrictor, to limit the amount that the valve can be opened or flow. Due to the simplicity of pressure reducing devices they can often be removed or defeated in the field easily as long as they are recognized.
Longer “Reflex Time” (the duration of time from arrival and recognition of fire to the time crews are applying fire streams). Standpipes supply water to areas beyond the reach of conventional operations so right away we loose time to travel. Due to the type of areas standpipes serve (ex: high-rise offices) actual recognition and location of a fire causes delay. Equipment must not only be carried to the fire area but it also must be set-up, which only provides the fire more time to grow.
Considerations and Operations:
Ensure that the system is supported appropriately. In addition to the exterior FDC, standpipe systems may also be alternatively supported through a lower floor outlet with the appropriate adapters and removal of any PRDs or PRVs.
As mentioned above the plumbing of standpipes is only one part of the standpipe system. Our attack system is the other. Low pressure and high volume are the most desirable properties of attack systems for standpipe operations.
Andy Fredericks gave us the ADULTS acronym in his 1996 Fire Engineering 2 1/2" handline article.
Advanced fire upon arrival
Unknown location or extent of fire
Large uncompartmentalized spaces
Tons of water
As you can see standpipe operations finishes out the acronym. In a 1999 two part article by Chief Dave McGrail of the Denver Fire Department he outlines the importance and details the components of a standpipe hose pack. The article uses the Denver Fold system.
At my department we utilize the Denver Fold which was developed by Chief McGrail for both our standpipe operations and our extended reach stretches so you can see the versatility of these attack systems is not limited to high rise or standpipe applications. Below is a video of the system we utilize but I recommend you reference Chief McGrail's article (linked above) first for the original design and a more detailed presentation as well as consider your department's area and operations before applying modifications.
Take time prepare and consider extra equipment to prevent further delay due to malfunction. (Spanners, adapters, pipe wrench, vise grips, door chocks, bottles, hose, ect)
Check outlets that you pass
Remove or adjust pressure-reducing devices if present.
Flush system to pass debris
Make the connection and advance either dry or charged line.
A blog post on this topic is less than adequate coverage, but it is not intended to be comprehensive, it is set as a review. The embedded links should start to take you further in preparation and planning. The biggest take away for discussion is that standpipe systems are more common than high rises.
If your department is not evaluating the use of standpipe packs because you district lacks high rises you may not have done a very good job of evaluating risks and you may be limiting your operational versatility.
Hit the streets and find some buildings with standpipes, try building the Denver Fold and compare it to the FDNY Bundle in your apparatus bay. Go online and search pressure reducing valves compared to pressure reducing devices and explain the differences in construction and operation. Do something today to help improve your odds of success at a fire in a standpipe building tomorrow.