Pressure Relief Valves

A Pressure Relief Valve is a safety device or alarm used to limit or control the pressure level in a system, within a safe threshold to avoid an overpressure condition. Pressure Relief Valves are mainly used in liquid and gas systems to limit the pressure in the system to a predetermined preset level and if exceeded the relief valve will open and release any excess flow in order to prevent equipment failure. Other forms of relief valves are called Safety Valves; they are generally coded to a standard. Coded Safety Valves are commonly used on Steam Boilers and for other Steam systems and various pressure vessel requirements. Their level of opening pressure tolerance is far less than that of a relief valve. Safety Valves and Relief Valves are designed to operate in significantly different ways. The manufacture, use and operation of these devices is covered by a number of AU standards and International Standards all of which should be considered when sizing, selecting and setting any Pressure Relief Valve. The main purpose of any safety/relief valve is to protect life, property, and the environment in the event of overpressurization.

For a relief valve, the degree of opening is directly proportional to the increase in the pressure. The opening of the valve is gradual, allowing it to open only at a preset pressure and release fluids until the pressure drops to the desired set pressure. A safety valve, on the other hand, will fully open immediately when the system pressure reaches the set pressure level allowing the system to completely evacuate. It is a safety device capable of operating at all times and is the last line of defence to prevent a catastrophic failure during an overpressure event. In compliance with the manufacturer, all relevant local regulations and standards, a set point should be determined to maintain safe and continuous operation. All required procedures must be followed and can be quite complex. As a result setting a relief valve or safety valve should only be carried out by trained personell. After setting the valve should be tagged and sealed to avoid tampering. Once set the relief valve should be handled with care, packed and transported in a secure manner preferably in the vertical position to avoid disturbing the set point. It must also be noted that the sizing and selection of a relief/safety valve is also of the utmost importance. It is pointless installing an inappropriate type or undersized valve on any application, even if it is set correctly. It is recommended that you always obtain advice from the manufacturer.

This really depends upon the environment and the quality of the media that the valve operates with. A correctly selected, sized and set Pressure Relief Valve should perform for many years. It is highly recommended that regular inspection and function testing of the valve is carried out at least once a year or as required by the relevant local regulations and appropriate standards. This will give the valve the best opportunity to continually operate safely for many years.

Pressure Relief Valves should always be installed in accordance with the manufacturers recommendations, relevant local regulations and appropriate standards. In Particular always ensure; Correct direction of flow, Correct orientation, Clear access for general maintenance and repairs. Pressure Relief Valves can have various end connections such as flanged or threaded so installation will need to take this into account. Ensure there are no obstructions of the discharge port and ensure any seals or locking devices are still intact and not damaged.

There are many and varied reasons why a Pressure Relief Valve may be required for any particular application. In general they are installed to ensure plant and equipment pressure limitations are not exceeded. Examples can be found in; process equipment pressure limitations, piping, valves and ancillary pressure limitations, pressure vessel design limitations, system design pressure limitations etc

This depends upon where you are based and the freight method chosen. If the express freight option is selected it is usually next day delivery to metropolitan areas in Australia for under 5kg. If free freight has been selected it will go by road freight which can be anywhere from 1 to 10 days depending upon your location. It usually averages 3 days.

All of our products come standard with a 12 month warranty. The good news is we have very strict quality controls and all valves leave our warehouse tested (full material and testing certificates are available) and inspected so there are rarely any issues.