Name: Pressure Systems Pty Ltd
Address: 35 Sir Laurence Drive, Seaford, VIC, 3198, AU
Telephone: +61 3 9776 9477

Question 1

What's the difference between a safety valve and a pressure relief valve?

Accepted Answer

Although the terms are often used interchangeably, they describe devices designed for different service conditions: Safety valves are typically used for gas, vapour, or steam service. They open with a sudden "pop" action when set pressure is reached, releasing media rapidly to protect the system. Pressure relief valves are used for liquid service. They open gradually in proportion to the overpressure, providing modulated relief. Many modern devices — referred to as PSVs (Pressure Safety Valves) — combine both behaviours and can be specified for either fluid type. The terminology used on a datasheet depends on the manufacturer and the regional standard. If you're unsure which type your application needs, contact our sales engineers with your operating conditions and we'll recommend the right valve.

Question 2

How often should my safety valves be tested?

Accepted Answer

We certify safety valves on a 12-month interval. To keep your certificates current, book a retest each year before the previous one expires. The maximum interval between tests depends on the pressure equipment the valve protects. AS3788 sets these limits: Steam boilers: annual (required) Compressed air and process vessels: every 2 to 4 years (recommended) LPG and static storage tanks: every 2 to 10 years (recommended) Pressure piping: every 5 years (external) (recommended) Transportable vessels (LPG, ammonia, chlorine): every 1 to 2 years (recommended) Most customers stick with annual testing. It keeps certifications valid for insurers and inspectors, and catches problems early. Shorter cycles apply for corrosive, dirty, or high-cycling service, harsh environments, or where your insurer requires it. Not sure when your valves are due? Send us your asset list and we'll work out a schedule.

Question 3

How do I get a quote?

Accepted Answer

Three ways to ask: Click Request Quote on any product page. The form pre-fills with the product details. Use the contact form for general questions or non-product enquiries. Email or phone us directly: sales@pressuresystems.com.au or +61 3 9776 9477. To help us turn around an accurate quote, include: Application (set pressure, application medium, required relief capacity, operating/releiving temperature, required material) Quantity required Required-by date Any preferred brand or model Compliance requirements (ISO, API, AS standards etc.) Quote lead times are subject to enquiry complexity. We strive to give an answer back within 24-48 hours. For urgent enquiries, we recommend calling us.

Question 4

Do you supply test certificates with new valves?

Accepted Answer

We offer two certificate options on new valves, supplied as a quoted item at the time of order: AS 1271 certificate — pressure test only AS 1271 + API 527 combined certificate — pressure test plus seat tightness test Certificates are not included by default. If your application requires documentation, specify which certificate type you need when requesting a quote and we'll include it in the pricing. The absence of a certificate is not an absence of testing. Every valve we dispatch is verified during workshop processing. The certificate is the formal documentation of that testing — we only distribute it when you've requested it at quotation. Certificates are issued digitally under our ISO 9001:2015 quality management system, with results traceable to NATA-calibrated test equipment. Need certification for a new valve? Include the certificate type with your enquiry and we'll quote the appropriate package.

Question 5

What information do you need to size and select a safety valve?

Accepted Answer

To size a safety valve accurately, our sales engineers work through your application's operating and design conditions against API 520 Part I. Send us the following with your enquiry: Process conditions Vessel Maximum allowable working pressure (MAWP) Fluid type (gas, vapour, liquid, two-phase, steam, etc.) Composition or specific service (e.g. natural gas, water, hydraulic oil, ammonia) Operating temperature and pressure Design temperature and pressure Required relieving capacity (mass or volumetric flow rate) Allowable overpressure (% above set pressure) Back pressure conditions (constant/variable superimposed, built-up) Mechanical and installation Set pressure required Inlet and outlet connection type and size (flanged, threaded, welded; ANSI/AS/DIN rating) Orientation (vertical, horizontal) Mounting and access constraints Compliance and material Applicable code (AS 1210, ASME Section VIII, PED, etc.) Material specification (body, trim, spring, gasket) Special service requirements (NACE MR0175, oxygen-clean, food-grade, low-temperature) Required certifications (e.g. CE/PED, ASME UV stamp) Application context Industry and service description Brief description of the protected equipment Any preferred brand or model Once we have this, we'll work through the sizing calculation, recommend a suitable valve from our manufacturer range, and confirm availability and lead time. The end user (process or plant designer) remains responsible for confirming the final selection against the application's design basis per AS 1210. Submit a Request Quote with these details or email sales@pressuresystems.com.au.

Inlet Sizes	1/4" – 3/4" BSPT
Pressure Ratings	To 450 psig
Materials	Series 140: B16 brass body, 440 SS disc, 302/17-7 SS spring. Series 141: 316 SS body, brass internals, 440 SS disc. Series 143: full 316 SS construction
Approvals	ASME Section VIII (UV stamp) for air and gas service, Non-code versions available for steam and low-pressure service
Connection	Threaded

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Mon–Thurs	8.30am–4.30pm
Fri	8.00am–4.00pm
Sat–Sun	Closed