Standpipe (firefighting)

External access point for fire sprinkler and dry standpipe at a building in San Francisco, US

Antique wet standpipe preserved at Edison and Ford Winter Estates

A standpipe or riser is a type of rigid water piping which is built into multi-story buildings in a vertical position, or into bridges in a horizontal position, to which fire hoses can be connected, allowing manual application of water to the fire. Within the context of a building or bridge, a standpipe serves the same purpose as a fire hydrant. NFPA 14 - Standard for the Installation of Standpipe and Hose Systems regulates the design of standpipe system in the United States. Some standpipe systems are combined with fire sprinkler systems, using common pipes to supply both the sprinklers and hose connections.

Types of standpipe systems

Fire standpipes have two broad types: "Wet" and "Dry". The terms describe their state during normal, non-firefighting situations.

Dry standpipe

Labeled dry standpipe outlet in a university building

Dry standpipe systems do not contain water in the piping during normal, non-firefighting situations. Water is only introduced when needed for firefighting purposes.

Manual Dry Standpipe System - A standpipe system that is not connected to a water supply and requires water to be pumped into the system via a fire department connection (FDC), often by a fire truck.

Semiautomatic Dry Standpipe System - A standpipe system that is connected to a water supply and capable of supplying the water at any time, but requires the manual activation of a valve or other control to introduce the water into the system.

Automatic Dry Standpipe System - A standpipe system that is connected to a water supply and capable of supplying the water at any time, that is kept under air pressure, so that upon the opening of a hose supply connection valve, water is drawn into the system via a dry pipe valve.

Wet standpipe

Wet standpipe systems contain water at all times.

Manual Wet Standpipe System - A standpipe system that contains water, but requires additional water to be pumped into the system via a fire department connection (FDC), often by a fire truck.

Automatic Wet Standpipe System - A standpipe system that is connected to a water supply and capable of supplying the water without any action except opening a hose supply connection valve.

Wet standpipe systems are often more complex and expensive to both install and maintain due to the presence of water always being in the system, and the need to supply water a specific pressures which may require the use of pumps.

Standpipe classes

Under NFPA 14, standpipes designs are classified as Class I, II, or III based on intended user, size of hose connections and design pressure.

Class I

Class I standpipe systems are intended for use by firefighters, and consists of 2.5 inches (64 mm) hose connections to accommodate the fire hoses used by fire departments. Class I systems must be constructed with 4 inches (100 mm) pipe, and at least 6 inches (150 mm) in buildings with fire sprinkler systems to ensure adequate water supply during usage, and water pressure at the hose connection must be between 100–175 psi (6.9–12.1 bar).

Class II

Class II systems are intended for use by building occupants, such as employees, residents or members of the public, and include a hose station containing a 1.5 inches (38 mm) fire hose and nozzle pre-connected to the standpipe. Class II systems have become less common in recent years, but are still found in buildings. 1.5 inches (38 mm) hose no longer than 100 feet (30 m) must be installed and ready for firefighting usage in Class II systems.

Class II systems are required to be 'wet', except in regions subject to freezing temperatures and on-site personnel, such as an industrial fire brigade, are trained how to activate the system without assistance from the local fire department. Pipes supplying hose stations on Class II systems do not have a specified size, and must be calculated based on the needs of the specific system. Water pressure at hose connections must be between 65–100 psi (4.5–6.9 bar).

Class III

Class III systems are designed to include both Class I and Class II: An occupant operated 1.5 inches (38 mm) fire hose and 2.5 inches (64 mm) hose connections for firefighters. The system must be able to operate both the occupant hose and a firefighter's hose simultaneously, and comply with the design standards for both systems.

Location of standpipes

Standpipe equipped with pressure gauge in the stairwell of a Texas hotel

NFPA 14 requires that Class I and III standpipe hose connections be found at the main floor landing of exit stairways, along exit routes, both sides of fire doors. Hose connections on standpipes also cannot be blocked by stairway doors, when open or closed positions.

Class II systems must be located on each floor, with hose stations distributed so an occupant is always within 120–130 feet (37–40 m) of a hose station.

Standpipe systems are required by the International Building Code (IBC) in the following situations:

• Structures that are 4 or more floors above ground level, or over 30 feet (9.1 m) above or below ground level.
• Structures allowed to contain more than 1,000 people.
• Shopping malls, both open and enclosed.
• Structures with stages larger than 1,000 square feet (93 m²)
• Underground structures
• Structures with rooftop heliports
• Marinas and boatyards
• Structures with landscaped roofs

Advantages

Laying a firehose up a stairwell takes time, and this time is saved by having fixed hose outlets already in place. There is also a tendency for heavy wet hoses to slide downward when placed on an incline (such as the incline seen in a stairwell), whereas standpipes do not move. The use of standpipes keeps stairwells clear and is safer for exiting occupants.

Standpipes go in a direct up and down direction rather than looping around the stairwell, greatly reducing the length and thus the loss of water pressure due to friction loss. Additionally, standpipes are rigid and do not kink, which can occur when a firehose is improperly laid on a stairwell.

Standpipe systems also provide a level of redundancy, should the main water distribution system within a building fail or be otherwise compromised by a fire or explosion.

Disadvantages

Standpipes are not fail-safe systems and there have been many instances where fire operations have been compromised by standpipe systems which were damaged or otherwise not working properly. Firefighters must take precautions to flush the standpipe before use to clear out debris and ensure that water is available.

See also

• Fire sprinkler

References

1. Essentials of Fire Fighting, Fourth Edition, copyright 1998 by the Board of Regents, Oklahoma State University