Under Pressure

A pressure-reducing device connected to a fire hydrant. (Photo by Z22.)
A pressure-reducing device connected to a fire hydrant. (Photo by Z22.)

By Anthony Rowett Jr.

Pressure-reducing devices are designed to reduce, restrict, or otherwise control the amount of pressure at a standpipe hose connection. From a design and even an installation perspective, these devices seem legitimate; however, from a firefighting perspective, these devices are nothing more than an additional obstacle and hazard during firefighting operations.

These devices are one of the most important aspects of operations at buildings that are equipped with standpipe systems. Pressure-reducing devices are installed on standpipe systems to do just as their name says-reduce pressure. This reduction in pressure should be of great concern to the fire service, as these devices have already caused line-of-duty deaths (LODDs). These devices are designed to be installed on standpipe systems in locations where the residual pressure at a hose connection exceeds 100 psi and the static pressure at a hose connection exceeds 175 psi. The concept behind pressure-reducing devices is to prevent high pressures on hoselines that can cause injuries to firefighters. So, as a firefighter, which scenario would you prefer: advancing a hoseline from a standpipe connection with no pressure-reducing device, resulting in an overpressurized hoseline that weighs more and is more difficult to advance as well as presents additional nozzle reaction, or advancing a hoseline from a standpipe connection with a pressure-reducing device in place that was possibly not installed or maintained properly, resulting in an inadequate flow once you reach the fire?

Pressure-reducing devices gained the attention of the American fire service on February 23, 1991, at the One Meridian Plaza Fire in Philadelphia, Pennsylvania, where three firefighters lost their lives. The post-fire investigation found the presence of pressure-reducing devices that had been incorrectly set to the wrong pressure and therefore identified pressure-reducing devices as a contributing factor in these three LODDs.

Pressure-reducing devices require additional activities to be performed before firefighting operations can begin. These include removing the pressure-reducing device, if possible. If the pressure-reducing device cannot be removed, you must determine if the flow from the outlet will be sufficient or even adjust the device.

Device Adjustment

While an inline pressure gauge should be installed on the standpipe hose connection during all standpipe operations, the inline pressure gauge is specifically important during standpipe operations in the presence of a pressure-reducing device. If the pressure-reducing device cannot be removed, the most effective way to determine if adequate pressure is present at the hose connection is the installation of an inline pressure gauge. Once the hoseline is charged, the reading on the inline pressure gauge should be communicated to the company officer. When reading the inline pressure gauge, whether the pressure-reducing device has been removed or remains in place, remember that the age of the standpipe system will dictate the correct pressure reading. National Fire Protection Association 14, Standard for the Installation of Standpipe and Hose Systems, has a distinction between standpipe systems installed prior to 1993 and standpipe systems installed after 1993. Standpipe systems installed prior to 1993 are required to be capable of a minimum of 65 psi of pressure at the topmost hose connection with 500 gpm flowing. Standpipe systems installed after 1993 are required to be capable of a minimum of 100 psi at the topmost hose connection with 500 gpm flowing. Therefore, when operating from a pre-1993 standpipe system, pressurization above 65 psi may not be possible, regardless of the presence of a pressure-reducing device on the hose connection.

While some pressure-reducing devices can be adjusted, others cannot. There are also some pressure-reducing devices that require special tools to adjust them. There are two types of pressure-reducing devices manufactured: nonadjustable and field adjustable. The nonadjustable pressure-reducing devices are designed to allow a specific pressure out of an outlet on a specific floor of a building. If installed on the wrong floor, removal of the device is the only way to obtain a sufficient flow. If the tools needed to remove the device are not available, the firefighters would have to stretch a supply line into the building to supply the handlines for the fire attack because there would be no way for them to obtain a sufficient fire flow from the improperly installed pressure-reducing device.

If firefighters encounter a field adjustable pressure-reducing device that was improperly installed, they can adjust the device to allow for a sufficient pressure and flow, but the tools needed to adjust the device may not be available. The tools that are required to adjust these devices vary; some devices can be adjusted by inserting a 3⁄8-inch steel rod into the adjustment hole and rotating the rod, while other devices require special tools that may not be present on scene.

The pressure-reducing devices that are adjusted using a 3⁄8-inch steel rod also contain a plastic cover over the adjustment cylinder to prevent people from adjusting the device. To adjust this type of adjustable pressure-reducing device, the plastic cover, which is held in place by a tamper-resistant screw, must be removed, and then a 3⁄8-inch steel rod is inserted into the adjustment hole and rotated to adjust the amount of pressure that exits the device.

Standpipe Connection

While all standpipe operations should be conducted with 2½-inch hoselines and solid bore nozzles with 11⁄8-inch or 1¼-inch tips, it is even more important when pressure-reducing devices are encountered that this setup is used, as it is less pressure sensitive than a 1¾-inch hoseline equipped with a fog nozzle. It is imperative that automatic nozzles are not used on standpipe systems in general, especially when pressure-reducing devices are present, because these nozzles will provide a good-looking fire stream regardless of insufficient nozzle pressure and gpm flow.

The responsibilities of the firefighter who is making the standpipe connection when a pressure-reducing device is found will vary depending on the equipment carried in the company’s high-rise pack. If possible, the pressure-reducing device should be removed and then the hoseline should be connected directly to the standpipe connection. If the firefighter cannot remove the device, he should attempt to determine if the device will provide an adequate flow. This can be accomplished by attaching an inline pressure gauge to the standpipe connection outlet and then attaching the hoseline to the outlet of the inline pressure gauge. This setup will inform the firefighter if there is adequate water flow or not.

If the firefighter does not possess the ability to remove the pressure-reducing device or measure the pressure on the outlet side of the pressure-reducing device, he should, at a minimum, open the standpipe outlet valve all the way and observe the flow exiting the outlet. This will at least provide the firefighter with an idea of the amount of water that is flowing through the device. Any time a pressure-reducing device is found, regardless of the ability to remove the device or measure its output, the firefighter making the connection should notify the company officer of the presence of the pressure-reducing device and the company officer should notify the incident commander.

Absent or Present?

What if you are not sure if there is a pressure-reducing device present? There are a couple of ways in which you can identify the presence of a pressure-reducing device, including the following:

  1. The pressure-reducing device will be a separate device attached to the standpipe outlet connection.
  2. The device housing will be larger than a standard standpipe outlet connection.
  3. If you are still unable to determine if a pressure-reducing device is present, remove the outlet cap and look inside the hose connection outlet.
    1. If the stem inside the outlet contains threads, there is no pressure-reducing device present.
    2. If the stem is smooth, there is a pressure-reducing device present.

Preplanning is extremely important regarding pressure-reducing devices. It is during preplanning when most of the information about these devices will be obtained. During preplanning, you should do the following:

  • Determine if pressure-reducing devices are present.
  • If they are present, determine if they are located at all the standpipe hose connections or only on certain floors.
  • Determine if the pressure-reducing devices are adjustable and, if they are, what tools are required.

Know the Hazards

Pressure-reducing devices are present in all areas of the country, especially in newer buildings and buildings that have been recently renovated. These devices are seen as safety features in the eyes of designers and code writers, but firefighters must be aware of the hazards that are presented by these devices, principally the lack of adequate pressurization of hoselines. These devices have already resulted in firefighter LODDs, and without continuous training these devices will continue to pose a threat to firefighters.

All firefighters should be able to identify the presence of pressure-reducing devices as well as operate effectively when these devices are encountered. Any time these devices are encountered, they should be removed, if possible. If the pressure-reducing device cannot be removed, an inline pressure gauge should be attached to the outlet side of the pressure-reducing device and the presence of the device as well as the pressure reading should be announced.

Anthony Rowett Jr. is an 11-year veteran of the fire service and a captain with the Mobile (AL) Fire Rescue Department. He was previously a firefighter with the Ogdensburg (NJ) Fire Department. Rowett has an associate’s degree in fire science technology from County College of Morris (NJ), a bachelor’s degree in fire science, and a master’s degree in emergency services management from Columbia Southern University in Alabama. He has been published in Fire Engineering and FireRescue magazines.

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Volume 12, Issue 4