The Spirax Sarco M31S ISO is a DN50-DN200 full-bore ball valve intended solely for pipeline on/off isolation, not for control. It features EN 1092 PN16 flanges and an ISO 5211 actuator mounting interface. The maximum allowable pressure is 16 bar g, and the maximum allowable temperature is 260°C. It is suitable for isolation in steam mains and at equipment inlets, condensate recovery systems, and industrial oil transfer pipelines.
M31S ISO Full-Bore Ball Valve | Spirax Sarco
1 / 1
M31S ISO Full-Bore Ball Valve | Spirax Sarco
Full-bore ball valve for on/off isolation of steam, condensate, and industrial oil pipelines; suitable for pneumatic actuation.
Genuine product assurance
We can help verify product data and purchasing details.
Model confirmation
Confirm model, connection and key options before ordering.
After-sales support
After-sales communication support is provided according to the order agreement.
Specifications
- Valve type
- Full-bore ball valve (for isolation only; not for throttling)
- Flange standard
- EN 1092 PN16; face-to-face dimensions: DIN 3202 F1/F4/F5
- Mounting interface
- ISO 5211
- Nominal size
- DN50, DN65, DN80, DN100, DN150, DN200
- Maximum allowable pressure (PMA)
- 16 bar g at 50°C
- Maximum allowable temperature (TMA)
- 260°C at 0 bar g
- Minimum operating temperature
- -29°C
- Maximum operating pressure for saturated steam (PMO)
- 12.5 bar g
- Design cold hydraulic test pressure
- 24 bar g
- Flow characteristic
- Modified linear
- Leakage rate
- EN 12266-1 Class A / ISO 5208 Class A
- Antistatic feature
- Complies with ISO 7121
- Design standard
- BS 5351
- Body material
- M31S2: galvanized carbon steel ASTM A216 WCB; M31S3: stainless steel ASTM A351 CF8M
- Ball material
- Stainless steel AISI 316
- Stem material
- Stainless steel AISI 316 / AISI 420
- Seat material
- Carbon- and asbestos-reinforced R-PTFE PDR 0.8
- Flow coefficient Kv
- DN50:300, DN65:430, DN80:770, DN100:1030, DN150:2390, DN200:4530
- Operating torque
- DN50:40 Nm, DN65:50 Nm, DN80:70 Nm, DN100:200 Nm, DN150:600 Nm, DN200:750 Nm
- Certifications
- PED 97/23/EC; EN 10204 3.1
Application scenarios
Isolation of steam mains, branches, and equipment inlets
For on-off isolation on steam mains, distribution branches, and steam inlets to equipment. This full-bore ball valve is for isolation only and is suitable for steam lines operating within its allowable service limits.
Isolation in condensate recovery and transfer lines
For shut-off isolation in condensate return lines, collection headers, and piping associated with recovery equipment. It can be used when maintaining equipment or switching between pipe sections. The product literature explicitly lists condensate service, and the valve is for isolation only.
Isolation in industrial oil transfer lines
For on-off isolation in industrial oil transfer lines within the product's service limits. It can be installed in piping associated with storage tanks, pump sets, filters, or oil-consuming equipment. The product literature explicitly lists oil service and offers galvanized carbon steel or stainless steel body options.
Selection points
Full-bore isolation design
This full-bore ball valve is for isolation only. Nominal sizes range from DN50 to DN200, with Kv flow coefficients from 300 to 4530 depending on size, allowing the flow capacity of the piping system to be checked.
ISO 5211 mounting interface
The valve has a mounting interface compliant with ISO 5211. Check the mechanical interface dimensions when selecting an actuator.
Two body material options
M31S2 has a galvanized carbon steel ASTM A216 WCB body, while M31S3 has a stainless steel ASTM A351 CF8M body. Both configurations have a stainless steel AISI 316 ball.
Class A leakage rate
The valve leakage rate complies with EN 12266-1 Class A and ISO 5208 Class A, providing a basis for checking shut-off sealing acceptance requirements.
Steam pressure and temperature limits
The maximum operating pressure for saturated steam is 12.5 bar g. The maximum allowable temperature is 260°C, applicable only at 0 bar g. Check the actual pressure and temperature separately when selecting the valve.
Antistatic configuration compliant with ISO 7121
The valve has an antistatic configuration compliant with ISO 7121. Use this feature to verify project antistatic requirements during selection.
Installation & maintenance notes
For on-off isolation only
This full-bore ball valve is for isolation in fully open or fully closed service only. Do not use it for throttling or flow control.
FAQ
Can the M31S ISO full-bore ball valve be used to regulate flow?
No. The M31S ISO is a full-bore ball valve intended for isolation only. Do not use it as a control or regulating valve.
Which media and operating conditions is this ball valve suitable for?
It can be used with most industrial fluids. Typical applications include steam lines, condensate, oil, gas, and other media within its service limits. Confirm the specific configuration based on the model and application conditions.
What are the installation and connection features of the M31S ISO?
The series is available with an ISO mounting interface compliant with ISO 5211. The pipe connection is an EN 1092 PN16 flange, with face-to-face dimensions to DIN 3202 F1 and F4/F5.
What is the difference between the M31S2 ISO and M31S3 ISO?
The main difference is the body material: the M31S2 ISO has a galvanized carbon steel body, while the M31S3 ISO has a stainless steel body. Both models have an ISO-standard mounting interface.
Which parts should be considered for maintenance or replacement?
Available spare parts include seats, stem seals, and body gaskets. When ordering spare parts, specify the ball valve size and model to ensure the correct parts are supplied.