Classes of Standpipe Systems | NFPA-14

There are three classes of a standpipe system as per NFPA-14 (NFPA-14 is Standard for the Installation of Standpipe and Hose Systems) but before understanding the classes of the standpipe system, we should know-how about the standpipe and standpipe system. Let’s start to understand in an easy way…….

What is Standpipe?

The vertical portion of the system piping which is normally called riser pipe that delivers the water supply for hose connections and sprinklers on combined systems (standpipe is connected with sprinklers and hose connections is called combined system), vertically from floor to floor.

What is Standpipe System?

An arrangement of piping, valves, hose connections, and allied equipment is installed in a building or structure to protect the occupants. We can say in other words like a firefighting system that has standpipes with all required accessories and apparatus connected for supply water for the purpose of fire protection of properties in such a manner that water can be discharged in streams or spray patterns through attached hose and  nozzles.

Classes of Standpipe System

• Class-I System
• Class-II System
• Class-III System

Class-I System

A system that provides 2½ inch (65 mm) hose connections (Hose connections shall have external threads, for the valve size specified, in accordance with NFPA 1963) to supply water for use by fire departments and those trained in handling heavy fire streams because this connections have high flow and pressure therefore fire hose with jet nozzle can not handled by unskilled persons.

Class-I standpipe systems to be used automatic dry, automatic wet, semi-automatic dry, manual dry, or manual wet in buildings not classified as high-rise buildings. Class-I standpipe systems in buildings classified as high rise buildings shall be automatic or semiautomatic.

Class-II System

A system that provides 1½ inch (40 mm) hose stations (Closets and cabinets used to contain fire hose, nozzle and other accessories connected with standpipe system and they do not interfere with the prompt use of the hose connection and other equipment at the time of fire) to supply water for use primarily by trained personnel or by the fire department during initial response. This Class-II system has low flow and pressure therefore fire hose station with jet nozzle can be handled by unskilled persons or skilled fire department persons.

Moreover, a minimum 1 inch (25.4 mm) hose to be used for hose stations in light hazard occupancies where listed for this service and where approved by the authority.

Class-III System

It is joint venture of Class-I and Class-II. A system that provides 1½ inch (40 mm) hose stations to supply  water for use by trained personnel and 2½ inch (65 mm) hose connections to supply a larger volume of water for use by fire departments and those trained in handling heavy fire streams. This Class-III system can be handled by unskilled persons like Class-I and can be handled omly by skilled fire department personslike Class-II in case of fire.

Same like Class-II, a minimum 1 inch (25.4 mm) hose to be used for hose stations in light hazard occupancies where listed for this service and where approved by the authority.

Note:

1. Class-II and Class-III standpipe systems with 1½ inch (40 mm) hose stations shall be automatic wet systems unless located in a facility where piping is subject to freezing and where a fire brigade is trained to operate the system without fire department intervention, in which case an automatic dry or semi-automatic dry system shall be permitted.
2. In a non-high-rise building, the Class-I portion of a Class-III system shall to be manual. The Class-II portion of a Class-III system shall be automatic.

If you want to understand or learn through video in Urdu/Hindi language then watch this video:

References of this article:

• NFPA-14 (Edition 2019)