Stainless steel union, male/female 316L, PN 40, BSP threaded
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Shipping and Delivery
| Product Type | Delivery Method | Preparation Time | Transport Time | Delivery Time |
|---|---|---|---|---|
| All Parts | Pickup Point | 0 to 3 days | 3 to 6 days | 3 to 9 days |
| All Parts | Home Delivery | 0 to 3 days | 3 to 5 days | 3 to 8 days |
| Tubes > 90cm | Home Delivery | 0 to 3 days | 3 to 5 days | 3 to 8 days |
| Tubes < 200cm | Home Delivery | 0 to 3 days | 3 to 5 days | 3 to 8 days |
| Tubes > 200cm | Home Delivery | 0 to 6 days | 6 to 10 days | 6 to 16 days |
| Assembled Products | Home Delivery & Pickup Point | 0 to 5 days | (see methods) | 3 to 11 days |
* Tubes longer than 90cm cannot be delivered to a pickup point
For orders of more than 50 units of the same item or more than 100 kg, restocking may exceptionally extend the delivery time by up to 10 working days.
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Stainless steel union, male/female 316L, PN 40, BSP threaded
Stainless steel union, male/female 316L, PN 40, threaded BSP to ISO 7-1: R taper at one end, Rp tapped at the other, from 1/2" to 2" (DN15 to DN50). This machined conical (taper) seat union screws straight into a tapped port and provides a point of disconnection on the line. PN 40, drinking water compliant, for all fluids compatible with stainless steel.
Description of the machined stainless steel male/female union 316L
This 3-piece stainless steel union combines two ends in 316L stainless steel, the low-carbon version of 316, and a CF8M stainless steel nut. The seal is metal to metal, at the conical seat. Undoing the nut is enough to open the joint: the pipework stays screwed in.
One end is 6-sided. The other is cylindrical on the outside, with spanner flats. This union has no weld end: for a weld end on one side, see the PN 40 unions male/butt weld and female/butt weld.
Stainless steel male/female union 316L PN 40: technical specifications
| Material | 316L stainless steel ends, CF8M stainless steel nut |
| Manufacture | Machined conical (taper) seat union |
| Standard | ISO 4144 |
| Type | 3-piece: two ends and a nut |
| Seal at the seat | Metal to metal |
| Shape | One end 6-sided, the other cylindrical with spanner flats |
| Thread | Male end: R (taper), mates with an Rp female thread. Female end: Rp tapped (parallel), mates with an R male thread. To ISO 7-1 (BSP). Not compatible with NPT |
| Connection | Male/female |
| Nominal pressure | PN 40. Permissible pressure falls as temperature rises |
| Temperature | Stated range −20/+220 °C, with no high-temperature pressure values: consult us for hot applications |
| Fluids | All fluids compatible with stainless steel |
| Sizes | 6 sizes, from 1/2" to 2" |
| Compliance | 4MS; drinking water: French order of 25 June 2020 |
Pressure and temperature
This union is rated PN 40. The permissible pressure falls as temperature rises, and we have no high-temperature pressure curve for this part. The stated range of −20 to +220 °C therefore does not mean PN 40 across the whole range. For hot applications, contact us before choosing.
Certification and compliance
According to the technical data sheet for the series:
- 4MS: compliant with the 4MS requirements, the harmonized European rules for materials and products in contact with drinking water.
- Drinking water: compliant with the French order (arrêté) of 25 June 2020 on metallic materials and products in contact with water intended for human consumption.
Uses and installation advice
This union is used on drinking water systems and on circuits carrying fluids compatible with stainless steel, wherever a component must stay removable. Check the fluid’s compatibility with 316L and CF8M.
- Thread sealing: an Rp/R joint seals on the threads, using PTFE or jointing compound suited to the fluid and the temperature.
- Conical seat: keep it clean at every assembly.
- Galling: with stainless steel on stainless steel, the thread can gall. Screw in gradually, without forcing.
- Tightening: use an open-ended or adjustable spanner on the hexagon or spanner flats of the end and on the nut, not pipe grips or pliers, which mark stainless steel.
- Dissimilar metals: on a water system, stainless steel forms a galvanic couple with galvanized steel or cast iron.
Technical drawing
Dimensions (mm)
Dimensions in millimetres, PN in bar, weight in kilograms. M1: length of the nut. M3: length of the 6-sided section. L: overall length of the part. Ø: value from the technical data sheet, with no reference on the drawing.
| Rp/R size | French size | Ø | M1 | M3 | L | PN (bar) | Weight (kg) |
|---|---|---|---|---|---|---|---|
| 1/2" | 15x21 | 21.3 | 16 | 9 | 51 | 40 | 0.112 |
| 3/4" | 20x27 | 26.9 | 17 | 9 | 53 | 40 | 0.169 |
| 1" | 26x34 | 33.7 | 18 | 9 | 59 | 40 | 0.234 |
| 1"1/4 | 33x42 | 42.4 | 18 | 10 | 66.5 | 40 | 0.319 |
| 1"1/2 | 40x49 | 48.3 | 18 | 10 | 68.3 | 40 | 0.461 |
| 2" | 50x60 | 60.3 | 20 | 12 | 77 | 40 | 0.587 |
Size conversion
Conversion between the French size designation, inches, DN and the outside diameter stated in the designation (a rounded value, not a pipe dimension).
| French size | 15x21 | 20x27 | 26x34 | 33x42 | 40x49 | 50x60 |
|---|---|---|---|---|---|---|
| Inches | 1/2" | 3/4" | 1" | 1"1/4 | 1"1/2 | 2" |
| DN | DN15 | DN20 | DN25 | DN32 | DN40 | DN50 |
| OD (French size) | 21 mm | 27 mm | 34 mm | 42 mm | 49 mm | 60 mm |
Stainless steel male/female union 316L PN 40: frequently asked questions
Male/female, female/female or male/male?
This union has one R male end and one Rp female end. The female/female union PN 40 takes an R male thread at each end. The male/male union PN 40 screws into an Rp tapped port at each end.
PN 40 or PN 20?
The choice depends on the pressure at the working temperature. A PN 20 union is not suitable if your installation requires PN 40. The male/female union 316 PN 20 comes in sizes from 1/4" to 4", with published high-temperature values.
What is the pressure rating at high temperature?
We have no figure for this part. Contact us with the size, fluid, temperature and working pressure.
BSP or NPT thread?
BSP to ISO 7-1: R taper and Rp parallel. This union is not compatible with NPT.
The appearance of the part may vary depending on the batch in stock. Contact us for confirmation.
See also
Full range: all stainless steel BSP fittings
Other stainless steel fittings: male/female union PN 20, female/female union PN 40, male/male union PN 40.
Other materials: brass fittings, black malleable iron unions.
Useful guides:
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