For your fire hose to work properly, you need the right fire hose couplings and fittings. A coupling is a connector that joins one length of hose to another. It can also be used to connect hose to a tap or other water source.
If your fire hose coupling parts are mismatched, it can lead to loss of money and time, not to mention frustration. Get exactly what you need for your hose connection by following this handy checklist. We help explain different coupling types and more. Below, we explain the different fire hose coupling types, thread standards, genders, compatibility requirements, and sizes to consider.
1. Determine the Fire Hose Coupling Thread type
To begin the process of identifying the right fire hose coupling, begin with the thread type or thread standard. Each fitting uses a specific type, and each type has a different pitch and spacing to the threads, also known as threads per inch, or TPI.
National Standard Thread (NST) or National Hose (NH)
This is the most common thread type for fire hose. It may even be referred to simply as “fire hose thread,” because fire departments use this type the most. You’ll find this type of thread on many fire hydrants and accessories.
National Pipe Straight Hose (NPSH) or Iron Pipe Thread (IPT)
This is the second-most common type of thread for fire hose. You’ll often find this straight thread on low-pressure water suction or discharge hose couplings.
National Pipe Tapered (NPT)
This is commonly used to connect hose to fixed piping systems, such as in plumbing and industrial use. We recommend using plumber’s tape when using connectors with this type of thread.
Other fire hose thread types
For fighting wildfires and other special uses, you may encounter Garden Hose Thread (GHT). You will also find specific fire hose threads for certain cities. The Fire Department of New York uses its own thread type, which is different from the Chicago Fire Department or even Chicago Hose Thread.
Where to find the thread type
To know which type of thread is used on an existing hose or coupling, check the fire hose coupling for a stamp with the initials of the thread type.
Once you’ve learned what type of thread you need, it’s time to decide which gender you require.
2. Determine the Fire Hose Coupling Gender
There are three basic genders for fire hose couplings: male, female and ungendered.
Male couplings
Male couplings, hoses and fittings have threads on the outside. You will typically find male couplings on equipment such as fire hoses, which discharge water.
Female couplings
Female couplings have threads on the inside that allow them to receive a male coupling. You’ll often find female couplings on equipment that receives water.
Ungendered or ‘sexless’ couplings
There is a third gender for couplings that are neither male nor female. These fittings instead use what’s called a Storz connection, which lets firefighters connect two parts using no threads at all. Storz uses a quarter-turn quick connection instead of threads.
3. Check Fire Hose Coupling Compatibility
Note that you may be able to combine different thread types and genders.
| Thread type/gender | Compatible with: |
| NH/NST male | NH/NST female |
| NH/NST female | NH/NST male |
| NPT male | NPT female, NPTF female, NPTSH female |
| NPT female | NPT male, NPTF |
| NPSH male | NPSH female, NPSM female |
| NPSH female | NPSH male, NPT, NPTF, NPSM |
Checking compatibility before purchasing your fire hose coupling can help prevent connection problems and ensure the components fit together properly.
4. Determine the Correct Fire Hose Coupling size
Finally, once you’ve determined which thread type you need and what gender, you must make sure you have the proper fire hose coupling size. Generally, sizes range from 3/4” to 6” in diameter.
How to determine your hose fitting size
You can find the size on the female coupling, or it may be printed on the fire hose itself.
If necessary, you can measure the diameter of the inside of the male coupling to determine the coupling dimensions.
Find the Right Fire Hose Couplings for Your Needs
Now that you know how to identify the fire hose couplings you need, it’s time to give Rawhide Firehose a call. Contact us for all of your firehose and hose fitting needs, including answers to any questions you may have about how to measure hose diameter or quick connect fittings.
We’re happy to help you make sure you have the right fire hose coupling type, size, and connection for your specific application.
