A Guide To Storz Couplings
Figure 1: Storz coupling
Storz couplings are non-shut-off symmetrical fittings often used and designated as Storz fire hose couplings. To connect Storz couplings, align the lugs on the two fittings, press them together, and then twist them clockwise until they lock securely in place. These couplings are ideal for working with water and other fluids. Often used with fire hoses, these fittings can also be used as connecting couplings for connecting other hose types.
Table of contents
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Advantages
- Storz couplings are easy to connect quickly to fire hydrants, so they are used for Storz fire department connections and Storz couplings for fire hoses.
- Aluminum Storz couplings are forged instead of cast, making them stronger and minimizing the risk of breaking.
- Available in aluminum, brass, and stainless steel.
- Replacement seals are available in NBR, EPDM, Silicone, and FKM.
- Storz couplings are easy to assemble and disassemble manually. If the coupling does get jammed after being pressurized, use a Storz wrench/key to disassemble it.
- All Storz couplings of the same size have the same lug distance, making them compatible.
Learn about the advantages of other fittings by reading our couplings overview article.
Figure 2: Storz couplings connected to firefighting hoses
Storz hose coupling connection types
Storz couplings are available in a wide variety of connections and types. As seen in Table 1, the most common are:
Table 1: Storz connection types
| Connection type | Description | Image |
| Male or female thread | As the name implies, the coupling's hose connection point can have either male or female threads to screw into a component. |  |
| Hose pillar | Storz couplings with hose pillars are often used in static firefighting situations. Other applications include agricultural, military, and maritime use. |  |
| Elbow rotatable hose pillar | This Storz coupling has a rotatable hose connection. The rotation prevents a hose from becoming entangled and, as such, is particularly popular for use in firefighting and agriculture. |  |
| Flange connection | Flange connections are one of the most common connections. The flange allows for easy attachment to flanged pipes and fittings, ensuring a tight and reliable connection. |  |
| Storz reducer | Storz reducers are vital equipment to connect hoses, pipes, and couplings of different sizes. |  |
Storz accessories
Besides couplings, there is a wide array of Storz accessories. See Table 2.
Table 2: Storz accessories
| Accessory | Description | Image |
| DIN 14365 jet pipes | Storz jet pipes come with a handle for 3-way operation: shut off, full jet, and spray jet. |  |
| Storz distributors and collectors | Storz distributors and collectors offer various solutions for collecting and distributing hoses and are available with shut-off valves. |  |
| Standpipe hydrants | There are aboveground and underground standpipes. Aboveground standpipes are mainly used for buildings and bridges in the United States. Underground standpipes are used mainly in countries with underground fire hydrant Storz connections. The fire department can connect the standpipe to the hydrant. |  |
| Storz coupling caps | Storz coupling caps are largely used to close fire department connections and hydrants, but they can be used anywhere Storz-coupled hoses are used. |  |
| Keys | While Storz couplings may be connected and disconnected manually, a coupling can become jammed and a Storz key will be useful in this case. |  |
| Safety clamps | The steel safety clamp is suitable for all Storz couplings. It has a lug mechanism that strongly grips both halves of the coupling mechanism. |  |
| Protective cages | Used in combination with pumps, the protective cages for Storz couplings are designed to prevent large debris, leaves, twigs, and other materials from entering the system. |  |
Dimensions
Storz couplings are easily identifiable by their lug distance. To determine the lug distance of a coupling, measure the inside distance between the lugs with a pair of calipers. There are other sizes but the following are the most common Storz couplings and their lug distances, commonly identified with letter designation:
- Storz D-couplings dimensions (lug distance 31 mm)
- Storz C-couplings dimensions (lug distance 66 mm)
- Storz B-couplings dimensions (lug distance 89 mm)
- Storz A-couplings dimensions (lug distance 133 mm)
Storz coupling size chart
Table 3 is a Storz coupling size chart with male and female threads. It includes the standard D, C, B, A sizes as well as the sizes in between. For the other Storz connection types, refer to a manufacturer's data sheets to confirm their sizes.
Table 3: Storz coupling size chart: male and female threads
Male threads
| Storz size | Lug distance (mm) | Connection size (inch) |
| 25-D | 44 | G 3/4 |
| 25-D | 31 | G 1 |
| 32 | 44 | G 1 |
| 32 | 44 | G 1-1/4 |
| 65 | 51 | G 1-1/4 |
| 65 | 51 | G 1-1/2 |
| 52-C | 66 | G 1 |
| 52-C | 66 | G 1-1/4 |
| 52-C | 66 | G 1-1/2 |
| 52-C | 66 | G 2 |
| 65 | 81 | G 2 |
| 65 | 81 | G 2-1/2 |
| 65 | 81 | G 3 |
| 75-B | 89 | G 2-1/2 |
| 75-B | 89 | G 3 |
| 90 | 105 | G 3 |
| 100 | 115 | G 4 |
| 110-A | 133 | G 4 |
Female threads
| Storz size | Lug distance (mm) | Connection size (inch) |
| 25-D | 31 | G 1/2 |
| 25-D | 31 | G 3/4 |
| 25-D | 31 | G 1 |
| 32 | 44 | G 1 |
| 32 | 44 | G 1-1/4 |
| 65 | 51 | G 1-1/4 |
| 65 | 51 | G 1-1/2 |
| 52-C | 66 | G 1 |
| 52-C | 66 | G 1-1/4 |
| 52-C | 66 | G 1-1/2 |
| 52-C | 66 | G 2 |
| 52-C | 66 | G 2-1/2 |
| 65 | 81 | G 2 |
| 65 | 81 | G 2-1/2 |
| 65 | 81 | G 3 |
| 75-B | 89 | G 2 |
| 75-B | 89 | G 2-1/2 |
| 75-B | 89 | G 3 |
| 90 | 105 | G 3 |
| 100 | 115 | G 4 |
| 110-A | 133 | G 4 |
| 110-A | 133 | G 4-1/2 |
FAQs
What are Storz couplings?
Storz couplings, also known as fire hydrant Storz couplings, are non-shut-off symmetrical couplings. They resist corrosion, acids, and water, making them ideal for various industries.
What are the dimensions of a Storz C coupling?
Storz C coupling dimensions typically include a 66 mm lug distance and are used for hoses with diameters of 52 mm. They are common in firefighting applications.
What is the pressure rating for Storz couplings?
Storz couplings generally have a pressure rating of up to 16 bar (232 psi), making them suitable for high-pressure applications like firefighting and industrial use.
How do you connect Storz couplings?
To connect Storz couplings, align the lugs, plug them into each other, and twist until they lock. This quick connection method is efficient for emergency and industrial use.
