What are the two types of couplings on a fire hose?

In firefighting operations, the reliability and performance of fire hoses are critical to saving lives and property. One key component that determines how efficiently fire hoses are deployed, connected, and disconnected is the hose coupling. These fittings, attached to the ends of fire hoses, allow hoses to be joined together, connected to nozzles, hydrants, or pump outlets.

While there are many variations in design and regional standards, fire hose couplings are generally categorized into two main types: Threaded Couplings and Storz Couplings (also called sexless or nonthreaded couplings). Each type has unique characteristics, advantages, and ideal use cases in the fire service.

In this article, we will explore these two primary types of fire hose couplings in detail, including their design, applications, pros and cons, and why understanding their differences is essential for any firefighting team or fire safety professional.

1. Threaded Couplings (Also Known as ScrewType or Conventional Couplings)

Threaded fire hose couplings are perhaps the most traditional and widely used in many parts of the world, especially in North America. These couplings feature a male and female end that are screwed together to form a secure connection.

The male end has external threads, while the female end has internal threads. When connected properly, they create a strong, leakresistant seal capable of withstanding the high water pressure common in firefighting operations.

Design Characteristics:

Threaded connections rely on matched threading patterns—usually national or regional standards like NH (National Hose), NPT (National Pipe Thread), or BSP (British Standard Pipe).
Some couplings may be made of brass, aluminum, or other durable metals.
Often used on supply lines, attack hoses, and pump outlets.

Applications:

Threaded couplings are used in a variety of fire services where tradition, existing infrastructure, and standardization are dominant. These are typically seen in:

Fire hydrants and standpipes
Hose reels
Fire engines and tankers
Municipal firefighting systems in the United States and Canada

Threaded couplings are preferred in situations where compatibility and secure sealing are critical, especially when connecting to hydrants or pressurized systems.

Advantages:

Provide a tight, secure connection that prevents water leakage.
Widely standardized in specific regions, ensuring compatibility across equipment.
Durable and timetested; many legacy systems are designed for threaded couplings.

Disadvantages:

Slower to connect and disconnect than sexless couplings—threads must be aligned carefully and tightened, which can be challenging in lowvisibility or highstress situations.
Incompatibility between regions—different fire departments may use different thread standards, leading to connection problems during mutual aid or crossborder operations.
Threaded parts can wear or become damaged, causing difficulty in connecting, especially in the field.

2. Storz Couplings (Also Known as Sexless or NonThreaded Couplings)

Storz couplings are a type of nonthreaded or "sexless" coupling. Unlike threaded couplings, Storz fittings do not have male or female ends. Instead, both ends are identical, and they connect by interlocking lugs and a quarterturn twist to lock into place.

This design makes Storz couplings extremely quick and efficient to use, especially in emergency situations where speed is crucial.

Design Characteristics:

Storz couplings use interlocking hooks and flanges that snap together with a twist.
Often made of highstrength aluminum or composite materials.
Available in various diameters, ranging from smalldiameter hose lines to largediameter supply lines.

Applications:

Storz couplings are commonly found in:

European firefighting systems (widely used in Germany, Austria, and Scandinavia)
Airport firefighting vehicles and rapidresponse teams
Largediameter hoses for water supply or relay operations
Mutual aid scenarios where fast hose deployment is essential

In recent years, many North American departments have adopted Storz couplings—particularly for LDH (Large Diameter Hose)—to enhance speed and interoperability.

Advantages:

Fast and easy to connect/disconnect, even with gloves or in the dark.
No need to align threads, which reduces setup time.
Ideal for highvolume water supply operations due to wide diameters and quick connections.
Reduced training burden—no male/female identification required.

Disadvantages:

Requires special tools to disconnect under high pressure if the coupling becomes stuck.
Storz fittings may be less familiar to firefighters trained on threaded systems.
Higher initial cost, especially for retrofitting departments using traditional threaded hoses.
Not as widely compatible with existing infrastructure in some regions.

Comparison and Use in the Field

Understanding the difference between these two coupling types is vital for firefighting personnel, procurement teams, and maintenance technicians. The choice of coupling often depends on department standards, regional regulations, and operational requirements.

Speed vs Security: Storz couplings offer faster hose connections, which is a major advantage in emergency scenarios. However, threaded couplings tend to be more secure for connections that remain in place for long periods, such as hydrant attachments.

Compatibility: Fire departments operating in mutual aid zones often need adapter kits to connect threaded hoses with Storz fittings, or vice versa. These adapters are crucial during largescale emergencies involving multiple jurisdictions.

ApplicationBased Decisions: In highpressure environments like interior attack lines or booster lines, threaded couplings may still be preferred. For rapiddeployment water supply lines, Storz couplings are often the better option.

Why It Matters in Firefighting

Choosing the right fire hose coupling is not just a matter of preference—it can have a real impact on lifesaving efficiency, team coordination, and fireground safety.

For example, when multiple crews from different departments respond to a structure fire, mismatched couplings can delay water flow, leading to dangerous setbacks. If the departments use different thread types, they may be unable to connect hoses without proper adapters.

Similarly, in highrise firefighting or wildland operations where speed and agility are crucial, being able to deploy and break down hoses quickly can improve outcomes and reduce firefighter fatigue.

Evolving Standards and Trends

As firefighting practices evolve, many regions are gradually shifting toward standardizing on Storz couplings, especially for largediameter hose applications. This trend is driven by:

The need for faster response times
Increased interagency cooperation
Advances in material engineering that make Storz couplings more durable and reliable

However, legacy systems and the cost of replacement mean threaded couplings will continue to coexist with newer connection methods for years to come.

Conclusion

So, what are the two types of couplings on a fire hose? They are:

1. Threaded Couplings – traditional screwtype connections requiring a male and female end.
2. Storz Couplings – modern, sexless twistlock fittings that allow fast, universal connections.

Both types play critical roles in different firefighting scenarios, each offering unique advantages depending on the situation. Understanding their differences is essential for ensuring compatibility, operational efficiency, and safety during firefighting operations.

As technology and fire tactics evolve, so too will the tools used by firefighters. But regardless of changes in materials or hose types, the importance of a secure, fast, and reliable hose connection will always remain at the heart of effective firefighting.