Storz Couplings
DIN / EN standard · Aluminium forging, brass forging & SS316 · DN25–DN150 · 16–25 bar · Suction & delivery
Storz Couplings — DIN/EN Symmetrical Quick-Connect, DN25 to DN150
Storz couplings are the world's most widely used fire hose coupling for suction and delivery hose. The symmetrical hermaphrodite design means both halves of the coupling are identical — any Storz coupling connects to any other Storz coupling of the same DN size and lug-space (Ka dimension) without needing to check orientation. This makes hose-laying significantly faster under operational conditions compared with asymmetric male/female coupling systems.
CA-FIRE manufactures Storz couplings to DIN/EN standard across three materials — aluminium forging, brass forging and stainless steel 316 investment casting — in sizes DN25 through DN150. Every Storz coupling leaves our Fujian factory pressure-tested and supplied with an NBR gasket fitted. Custom anodising colours, private-label stamping and OEM packaging are available.
Storz couplings are manufactured on CA-FIRE's ten dedicated forging production lines, producing over 5 million industrial couplings per year. Forged aluminium Storz couplings are water-pressure tested to 8 MPA — compared with 3 MPA for die-cast equivalents — giving a substantially higher safety margin for fire pump outlet pressures.
Forging vs Casting — Why It Matters for Storz Couplings
- Grain structure aligned by forging process — superior tensile strength and fatigue resistance
- Water pressure tested to 8 MPA — no leakage
- No crack on forging surface when compressed by testing machine
- Tighter dimensional tolerances — consistent lug engagement across all sizes
- Thinner wall sections possible — lighter weight at equivalent strength
- Surface is suitable for anodising — custom colour available
- CA-FIRE standard for all suction and delivery hose Storz couplings
- Cast structure has random grain orientation — lower tensile strength
- Water pressure tested to 3 MPA — lower safety margin
- Surface porosity can cause leakage under sustained high pressure
- Wider dimensional tolerance — occasional inconsistent lug fit between brands
- Heavier at equivalent size due to thicker walls needed for strength
- Anodising adhesion inferior on cast surface
- Common in low-cost import couplings — not recommended for fire service use
Materials — Aluminium, Brass & Stainless Steel
Aluminium forging is the standard material for Storz fire hose couplings worldwide and CA-FIRE's highest-volume production. Forged from EN AW-6082 / 6061 aluminium alloy billet on ten dedicated forging lines, the couplings achieve a minimum tensile strength of 260 MPa. The forging process eliminates internal porosity, making the coupling water-tight at 8 MPA test pressure.
Aluminium Storz couplings can be anodised in any colour — red, yellow, green, blue, orange or custom RAL — for hose size identification or OEM branding. CA-FIRE offers anodised couplings with colour coding to DIN 14811 or custom specifications.
Weight advantage: an aluminium DN52 suction coupling weighs approximately 0.95 kg versus 1.15 kg for the brass equivalent — significant when 10+ couplings are carried by a single firefighter.
Brass forging Storz couplings are specified for seawater exposure, potable water systems, chemical plant fire protection and installations requiring maximum corrosion resistance without stainless steel pricing. CA-FIRE brass Storz couplings are forged from CW614N / CuZn39Pb3 brass and machined to DIN/EN lug geometry.
Brass Storz couplings are heavier than aluminium — a DN52 brass coupling weighs approximately 1.15 kg — but are preferred in coastal and marine environments where aluminium oxidation is a concern. Brass couplings are also common in Middle Eastern and some Asian fire service specifications.
Brass forged couplings are water pressure tested to 8 MPA and are dimensionally identical to the aluminium range — they connect and couple with aluminium Storz couplings of the same DN and Ka dimension without any incompatibility.
Stainless steel 316 investment casting Storz couplings are CA-FIRE's premium option for offshore, subsea, chemical plant, pharmaceutical and aggressive marine environments where neither aluminium nor brass provides adequate corrosion resistance. Investment casting (lost-wax process) allows the complex Storz lug geometry to be reproduced in SS316 with high dimensional accuracy.
SS316 Storz couplings are the heaviest and most expensive option but provide the longest service life in highly corrosive environments. They are specified on offshore platform fire systems, LNG terminal fire protection and chemical processing plant fire hose reels where the fire-fighting medium may contain corrosive agents.
SS316 Storz couplings are dimensionally compatible with aluminium and brass Storz couplings of the same DN and Ka — they can be used on the same hose network without adaption.
Aluminium casting Storz couplings are CA-FIRE's economy option, produced by gravity die casting. Casting allows more complex geometries and larger sizes to be produced economically. Cast aluminium Storz couplings are pressure tested to 3 MPA and are suitable for low-pressure suction hose applications and civil defence / forestry hose systems where budget is a primary consideration.
CA-FIRE AL casting Storz couplings cover standard suction hose sizes and are used in applications where the lower 3 MPA test rating is acceptable. For all standard fire service delivery hose applications, CA-FIRE recommends forged aluminium couplings.
Storz Coupling Range — Key Sizes (Selection)
| Name | Ka (mm) | Hose Ø D (mm) | Height H (mm) | Weight (kg) | Material | Code |
|---|---|---|---|---|---|---|
| SZT25/25 | 31 | 24.5 | 53 | 0.26 | AL Forging | L0803299 |
| SZT38/38 | 51 | 38 | 90 | — | AL Forging | L0803047 |
| SZT52/52 | 66 | 52 | 90 | — | AL Forging | L0803277 |
| SZT65/65 | 81 | 65 | 95 | — | AL Forging | L0803274 |
| SZT75/75 | 89 | 75 | 125 | — | AL Forging | L0803360 |
| SZT110/110 | 133 | 110 | 170 | — | AL Forging | L0803289 |
| SZT150/150 | 160 | 150 | 180 | — | AL Forging | L0803155 |
| SZT25/25 | 31 | 24.5 | 53 | 0.26 | BR Forging | L0803075 |
| SZT38/38 | 51 | 38 | 90 | 0.59 | BR Forging | L0803082 |
| SZT52/52 | 66 | 52 | 90 | 1.15 | BR Forging | L0803094 |
| SZT65/65 | 81 | 65 | 95 | 1.50 | BR Forging | L0803104 |
| SZT75/75 | 89 | 75 | 125 | 2.08 | BR Forging | L0803107 |
| SZT110/110 | 133 | 110 | 170 | 4.88 | BR Forging | L0803114 |
| SZT150/150 | 160 | 150 | 180 | 9.05 | BR Forging | L0803150 |
| SZT25/25 | 31 | 24.5 | 53 | 0.26 | SS316 | L0803002 |
| SZT52/52 | 66 | 52 | 90 | 0.95 | SS316 | L0803378 |
| SZT75/75 | 89 | 75 | 125 | 1.95 | SS316 | L0803010 |
| SZT110/110 | 133 | 110 | 170 | 4.25 | SS316 | L0803012 |
| SZT150/150 | 160 | 150 | 180 | 8.43 | SS316 | L0803149 |
* Weights shown for suction hose couplings (SZT series). Female thread (SZF), male thread (SZM), reducers (SZW), blind caps (SZC) and smooth-bore (SZDT) variants available — contact CA-FIRE for full data sheets.
All CA-FIRE Storz couplings are supplied with an NBR gasket fitted as standard. Viton and silicone gaskets are available as replacements or for special service conditions. View full gasket range →
Frequently Asked Questions about Storz Fire Hose Couplings
A Storz coupling is a symmetrical, hermaphrodite quick-connect fitting used to connect fire hoses, nozzles, hydrants and pump outlets. The key feature of the Storz design is that both halves of the coupling are identical — there is no male or female end — so any Storz coupling of the same size and lug-space (Ka dimension) will connect to any other, regardless of orientation. This allows hose-laying to proceed faster under operational conditions because firefighters do not need to check which end is which.
Storz couplings were invented by Carl August Guido Storz in Stuttgart in 1882 and have since become the dominant fire hose coupling standard in Germany, Austria, Switzerland and much of central and eastern Europe. They are specified to DIN 14307 and European standard EN 1775. CA-FIRE manufactures Storz couplings to the full DIN/EN range from DN25 to DN150 — full details are available on our firefighting couplings overview page.
CA-FIRE Storz couplings are available from DN25 to DN150. The correct coupling size is determined by the internal bore of the fire hose being fitted. Common size matches are:
DN25 / DN32 — small-bore forestry and reel hose, Ka 31 mm (Storz D)
DN38 — 38 mm reel hose and small attack hose, Ka 52 mm (Storz 38)
DN52 — standard 52 mm attack hose (most common), Ka 66 mm (Storz C)
DN65 — 65 mm delivery hose, Ka 81 mm (Storz 65)
DN75 — 75 mm supply hose, Ka 89 mm (Storz B)
DN110 / DN125 — large suction hose, Ka 133 mm (Storz A)
DN150 — large-diameter supply and suction, Ka 160 mm
Where different-size hoses need to be connected, a Storz reducer is used — for example a DN75/DN52 reducer to connect a supply line to an attack line at a branch divider.
Yes — provided both couplings conform to the same DIN/EN standard, the same DN size and the same Ka (lug-space) dimension, they will be fully interchangeable regardless of manufacturer. The DIN 14307 standard defines the lug geometry, Ka dimension, gasket seat and thread form precisely enough that couplings from any compliant manufacturer will connect and seal correctly.
CA-FIRE Storz couplings are dimensionally verified against the DIN/EN reference gauge for every production batch. A CA-FIRE DN52 aluminium forging Storz coupling will connect with a DN52 Storz coupling from any other DIN-compliant manufacturer.
The letter codes A, B, C, D and the numeric codes 65 and 38 refer to the Ka dimension — the lug-space or "bayonet circle" diameter of the Storz coupling. Couplings with the same Ka dimension will connect; couplings with different Ka dimensions will not engage even if the hose bore is similar:
Storz D — Ka 31 mm: smallest coupling, for DN25/DN32 small-bore hose
Storz 38 — Ka 52 mm: for DN38 hose
Storz C — Ka 66 mm: most common delivery coupling, for DN52 hose
Storz 65 — Ka 81 mm: for DN65 hose
Storz B — Ka 89 mm: for DN75 hose
Storz A — Ka 133 mm: large suction coupling, for DN110/DN125 hose
Yes — CA-FIRE manufactures a complete range of Storz thread adaptors that allow Storz couplings to connect to BSP (BSPP/BSPT) and NPT threaded fittings. These are available as Storz female thread (SZF), Storz male thread (SZM), Storz swivel female / swivel male thread, and Storz long male thread (SLM).
All thread adaptors are available in aluminium forging, brass forging and stainless steel, from G½" to G4½". See the BSP Thread Couplings page for the full range.
A Storz reducer is a double-ended Storz fitting that connects two Storz couplings of different Ka dimensions (and therefore different hose sizes) to each other. Common applications include:
• DN110/DN75 reducer (Ka 133/89): connects a large suction hose to a pump outlet or to a 75 mm supply line
• DN75/DN52 reducer (Ka 89/66): connects a 75 mm supply hose to a 52 mm attack line at a branch divider
• DN52/DN25 reducer (Ka 66/31): reduces a standard attack line to a small-bore forestry hose
CA-FIRE Storz reducers are available in aluminium forging, aluminium casting and AL forging with carbon steel body from DN45/DN25 up to DN150/DN125. The full reducer range is listed on the Coupling Accessories page.
CA-FIRE aluminium Storz couplings can be anodised in any colour. Standard colours include red, yellow, green, blue, orange, black and natural silver. Custom RAL or Pantone colours are available for OEM orders.
Colour coding of Storz couplings is used in several systems: DIN 14811 (Germany) specifies colour coding by hose diameter. CA-FIRE can anodise to any published colour coding standard or to a customer's own specification. Anodising does not affect the dimensional compliance of the coupling — anodised couplings remain fully interchangeable with bare aluminium Storz couplings of the same size and Ka.
For AFFF and FFFP foam applications, Viton (FKM) gaskets are recommended. FKM provides temperature resistance up to 200°C and chemical resistance to fluorosurfactants and petroleum-based foam agents superior to standard NBR gaskets. NBR is acceptable for short-contact use with synthetic AFFF when the hose is flushed after use.
CA-FIRE supplies Viton gaskets in all Storz Ka sizes as replacements or pre-fitted on request. See the full gasket range for codes and sizing data. For further guidance on foam compatibility, refer to the foam manufacturer's technical data sheet and NFPA 11.
To get an accurate quotation, please provide: 1. Coupling type — SZT (suction), SZDT (smooth-bore), SZF (female thread), SZM (male thread), SZW (reducer), SZC (blind cap). 2. DN size — e.g. DN52, DN75. 3. Hose tail bore (D) — internal diameter in mm. 4. Thread specification (if applicable) — BSPP/BSPT/NPT and size. 5. Material — AL / BR / SS. 6. Gasket material — NBR / Viton / Silicone. 7. Quantity. 8. Special requirements — anodising colour, private-label marking, test certificates.
Contact CA-FIRE by email at sales@ca-fire.com, via WhatsApp, or through the contact page. We respond within 24 hours with pricing and lead time.