Safety & Relief Valves
A safety relief valve (SRV) is the last line of defence against overpressure in a pressure vessel or piping system. When system pressure exceeds the set point, the valve opens automatically and discharges fluid until pressure returns to a safe level, then reseats. Without a correctly sized and maintained SRV, an overpressure event can cause catastrophic vessel failure.
Why Overpressure Protection Is Non-Negotiable
Pressure vessels — separators, storage tanks, heat exchangers, and process piping — are designed for a maximum allowable working pressure (MAWP). If the pressure source (compressor, pump, or blocked-in well) exceeds the MAWP, the vessel fails. An SRV set at or below the MAWP opens before the vessel reaches its design limit, venting the excess pressure safely.
Regulatory requirements in Azerbaijan and across the Caspian region mandate ASME-coded safety valves on all pressure vessels. The ASME UV stamp and National Board (NB) certification confirm that the valve has been designed, manufactured, and tested to the required standard.
Product Range
2500 Series Safety Relief Valve (SRV)
The WNS Lowery 2500 Series SRV is an ASME-coded, spring-loaded safety relief valve for general-purpose gas and liquid service. It is manufactured and tested in accordance with ASME Boiler and Pressure Vessel Code Section VIII, with flow capacities independently certified by the National Board.
Key features:
- ASME UV stamp and NB certification — meets regulatory requirements
- Suitable for gas and liquid service
- Set pressure range: available for a range of operating pressures
- Carbon steel body standard; stainless steel on request
- Full-lift design for maximum relieving capacity
1500 Series Vapor Relief Valve (VRV)
The WNS Lowery 1500 Series VRV is designed specifically for controlling vapor emissions from storage tanks and low-pressure vessels. It is a non-code relief valve — not ASME Section VIII rated — designed for low-pressure vapor applications.
Key features:
- Set pressure range: 3 oz/in² to 12 PSI
- Controls vapor emissions from atmospheric and low-pressure tanks
- Suitable for crude oil storage tanks and produced water tanks
- Carbon steel construction standard
Key Specifications
| Parameter | 2500 Series SRV | 1500 Series VRV |
|---|---|---|
| — | — | — |
| Code | ASME Section VIII (UV stamp, NB certified) | Non-code |
| Service | Gas and liquid | Vapor / low-pressure gas |
| Set pressure | Contact Proxima for range | 3 oz/in² – 12 PSI |
| Body material | Carbon steel (SS on request) | Carbon steel |
| Application | Pressure vessels, separators | Storage tanks, low-pressure vessels |
Certifications and Standards
The WNS Lowery 2500 Series SRV carries:
- ASME UV stamp — manufactured in accordance with ASME Boiler and Pressure Vessel Code Section VIII
- National Board (NB) certification — flow capacity independently certified
- Material test certificates provided with each valve
These certifications are required for regulatory compliance with pressure vessel codes in Azerbaijan (AZS standards), Kazakhstan (KST), and across the Caspian region.
Why Source Through Proxima
Proxima supplies WNS Lowery safety relief valves with full ASME documentation packages — UV data report, NB certification, and material certificates — required for regulatory acceptance in Azerbaijan and regional markets. We stock standard set pressures for fast delivery.
Frequently Asked Questions
Q: How is a safety relief valve set pressure determined?
Set pressure must be at or below the MAWP of the protected vessel. For pressure vessels designed to ASME Section VIII, the SRV set pressure must not exceed the MAWP stamped on the vessel nameplate. Proxima confirms the correct set pressure from your vessel data sheet.
Q: What is the difference between a safety valve and a relief valve?
A safety valve is designed for gas or vapour service — it opens rapidly (pop action) on reaching set pressure. A relief valve is designed for liquid service — it opens gradually in proportion to overpressure. A safety relief valve (SRV) is designed for both gas and liquid service. The WNS Lowery 2500 Series is an SRV suitable for both.
Q: Does the SRV need to be recertified after operation?
Yes. After a relief event, the SRV should be inspected and recertified before returning to service. The valve seat may be damaged by the relief event. Proxima can advise on inspection and recertification requirements.
Q: Is the ASME UV stamp accepted by Azerbaijani and Kazakhstani regulators?
ASME certification is widely recognised across the Caspian region and Central Asia. Local regulatory acceptance should be confirmed with your HSE team for each specific project. Proxima provides the full documentation package to support regulatory submission.
