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NFPA 1963: Standard for Fire Hose Connections,The Guide of Fire Hose Adapters and Fittings

NFPA 1963: Standard for Fire Hose Connections

NFPA 1963 provides manufacturers with the latest industry guidelines for standardized couplings and adapters for fire hose connections.When it comes to manufacturing fire hoses, connections, coupling and nozzles, every detail counts. Failure of a component can have serious consequences for those at a fire scene.

NFPA 1963: Standard for Fire Hose Connections details performance requirements for new fire hose couplings and adapters with nominal sizes from 3/4 in. (19 mm) through 8 in. (200 mm) along with the specifications for the mating surfaces. Requirements apply to:

    Coupling assemblies and adapters
    Screw-thread connections
    Non-threaded connections
    Fire hose nozzle gaskets and gasket seats

Fire hose adapters are small but essential components that reduce fire truck weight and enhance readiness

Fire trucks are often very, very big. Like giant toolboxes with wheels, these vehicles carry thousands of pounds of hose, tools, people, and water. Fire hose adapters and fittings are likely some of the smallest products on those engines, but they play an important role in reducing loads—and keeping firefighters ready for anything.

Thread types dictate which hoses and equipment connect

First, just what are hose couplings? Well, a hose coupling is simply a connector located on the end of a hose. It couples, or connects, with a hose, tap or water source and is typically made of brass, stainless steel or aluminum.

The key characteristics to understand with regard to proper thread attachment are size (3/4” to 6”), thread standard and gender. Male coupling has threads on the outside,while the female coupling has threads on the inside. Some couplings are “sexless.” Storz, for example, is a quarter-turn quick connection.

The easiest way to identify what type of thread you need is by looking at the couplings on the hose you want to replace. There should be a stamp with the initials of the thread type. A water source fitting/adapter may also have the stamp. If you need to know what to use on a fire hydrant, call the local fire department.

Most fire hose fittings and adapters have threaded ends. Male ends couple only to female ends of the same size (and vice-versa). And for the most part, different styles of thread aren’t interchangeable. Their angle (pitch), spacing, and diameter vary. Mixing these thread types may cause fittings to leak or fly off under pressure, creating hazards to firefighters and the people they protect.

While thread standards vary from place to place, adapters designed for fire hose typically feature one of the following:

  • Most often: National Standard Thread/National Hose (NST or NH)
  • Second-most-often: National Pipe Straight Hose/Iron Pipe Thread (NPSH or IPT)
  • In wildland firefighting and special uses: Garden Hose Thread (GHT)
  • For connection to fixed piping systems or pressure gauges: National Pipe Thread (NPT)

Fittings with National Pipe Thread (NPT) are among the most confusing in the fire service. Here’s why: when two NPT threads screw together, they do so permanently. However, some NPT-threaded fittings and NPSH-threaded fittings can connect temporarily.

But there’s a big caveat: only male NPT threads can attach to NPSH fittings temporarily. Connecting a male NPSH fitting with a female NPT fitting will result in a permanent connection.

So, in short, follow these rules with NPT-threaded adapters:

  • Male NPT ends – to NPSH fire hoses or female NPT-threaded pipes
  • Female NPT ends – to male NPT ends only, for permanent installation to fire pumps or piping systems

Different types of fire equipment have different thread genders

Male or female threads on fire hose fittings and adapters connect to corresponding inlets or outlets on firefighting equipment. In most cases, equipment that discharges water has a male-threaded outlet—much like a garden hose—and orifices that receive water have fixed female threads or female swivels.

While it’s up to fire departments and local governments to decide which components use which threads, most follow a few simple conventions. Here’s a short list of fire equipment and the gendered connections they typically feature:

  • Fire hoses have a male coupling at one end and a female coupling at the other, allowing firefighters to chain hoses together as needed.
  • Fire department connections (FDCs) utilize female swivels. FDCs connect to male-ended fire hoses to supply fire sprinkler and standpipe systems with water.
  • Fire hose nozzles have female inlets that connect to male-ended fire hoses.
  • Fire hydrants have male-threaded outlets or nozzles.
  • Dry hydrants are pipes connected to unpressurized water sources, like lakes or ponds. The choice of male or female threads varies from place to place.
  • Hose angle valves, often used with permanent indoor hose installations, feature either male or female-threaded outlets. Swinging hose racks typically use hose valves with female-threaded inlets, which allows for the attachment of a double-male nipple. Stationary hose angle valves, such as those found with rack and reel hose, may use male-threaded outlets.

Some fire hoses and equipment connect with no threads at all

While threaded fire hose adapters and fittings are common, many hoses, valves, and pumps use threadless couplings called Storz connections.  

  • Fire hose couplings
  • Fire department connection inlets
  • Inlets and outlets on tankers/engines
  • Large-diameter “pumper nozzles” on fire hydrants

Fire adapters connect perfectly good (but differently threaded) pieces of fire equipment


Storz x 2 1/2″ MNST

Common uses: Connecting standard 2 1/2″ FDC inlets to large-diameter Storz hose—or joining Storz hydrants to NST hoses.

Hex Adapters – FNST x MNPT (1 1/2″ &2 1/2″)

Common uses: Like swivel adapters, these hex adapters connect the male end of an NST hose to the female end of an NPSH hose or fitting. They join NST hoses with NPSH nozzles, NST and NPSH hoses, and NPSH hoses with NST pumps.





Swivel Adapters – 1 1/2″ or 2 1/2″ Female NST to Male NPT 

Common uses: Joining the swivel end of NPSH hose to NST-threaded hose (male). They’re also useful when connecting NST hoses to NPSH nozzles, or connecting an NPSH-threaded hose to an NST-threaded port on a fire pump.





2 1/2″ Double Female NST

Common uses: Joining mislaid hoses to each other or to hydrants. Many double-female adapters have swivels designed to make connecting quicker.

2 1/2″ Double-Male NST

Common uses: Connecting mislaid NST hoses to fire department connections, nozzles, engines, or other hoses.

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