A safety valve is one of the most critical safety components in industrial processes. Its purpose is to protect pressurized equipment in situations where pressure rises above the allowable limit. A properly functioning safety valve prevents equipment damage, production downtime and serious safety risks.
In industrial use, however, situations occur where problems arise in the operation of safety valves. What these situations typically have in common is that the root cause is not the valve structure itself, but the operating conditions, installation or use.
The most common safety valve failure situations
In industry, safety valve problems can usually be summarized into a few recurring phenomena:
- Continuous leakage
Occasional discharge of a safety valve when load or temperature increases is normal. Continuous leakage, hissing or dripping, however, often indicates that contaminants have entered between the sealing surfaces or that the sealing surfaces are damaged. Leakage weakens process control and may increase energy consumption or cause disturbances in system pressure.
- Valve sticking or blockage
Limescale, process residues or impurities left in the piping can prevent the free movement of the valve. In such cases, the safety valve may not open at the set pressure. This is one of the most serious failure modes, as uncontrolled pressure rise can lead to equipment damage or, in the worst case, structural failure.
- Incorrect installation or inadequate discharge piping
If the safety valve discharge line is not installed correctly or routed in a controlled manner, for example to a collection system, valve discharge may cause water damage or hazardous situations in the surrounding environment. In industry, this risk is particularly emphasized with hot media and steam.
- Incorrect sizing
An undersized safety valve cannot relieve pressure quickly enough. This is especially critical in steam boilers and other high-energy systems where pressure can rise rapidly. Incorrect sizing may make the safety valve appear to function, but in an actual upset condition it may be insufficient.
Why safety valve malfunctions are particularly critical?
A safety valve is primarily a protective device designed to safeguard process equipment from overpressure. If the safety valve does not operate as intended, the risks directly affect the entire pressurized system; boilers, pumps and other instruments may be exposed to damage.
In the most severe cases, safety valve failure can lead to process shutdown or significant safety hazards, such as explosion risk. For this reason, reliable safety valve performance is a key element of industrial risk management.
Problems are most often caused by external factors
Based on practical experience, most safety valve issues are caused by external factors. Piping impurities, incorrect design data and improper use repeatedly emerge as root causes. One common misconception is using a safety valve for continuous flow or pressure control. Repeated opening wears the sealing surfaces and significantly increases the risk of leakage.
When should the suitability of a safety valve be reassessed?
The sizing and performance of a safety valve should be reviewed whenever process conditions change. Changes in pressure, temperature, process medium or capacity can affect the valve’s ability to protect the system. Repeated activations and long operating periods without testing are also clear indicators that inspection is required.
How is reliable safety valve operation ensured in practice?
Reliable safety valve performance is based on correct design data, careful installation and preventive maintenance. The process operating pressure, temperature, flowing medium and required capacity determine valve sizing, and potential backpressure on the discharge side must be taken into account to ensure the valve operates as designed under all operating conditions.
In practice, one of the most significant individual factors affecting safety valve performance is piping cleanliness during installation. Impurities left in the piping can damage the valve sealing surfaces during the first opening and lead to permanent leakage problems. Careful installation creates the foundation for long service life and reliable operation.
In addition to proper installation, safety valve performance should be verified through regular testing. Testing ensures that the valve opens at the set pressure and recloses tightly after operation. Testing can be carried out either on a test bench or in situ in the piping, taking into account process requirements and the operating environment. Preventive testing helps detect deviations early and prevents malfunctions before they affect process safety or availability.
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The functionality of a safety valve is based on correct design inputs, careful installation and a thorough understanding of process conditions.
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This article is based on the practical experience of ECONOSTO Oy’s experts. Regional Manager Antti Kurvinen and Sales Manager Petri Hallikainen have extensive expertise in the operation, suitability and proactive management of safety valves in industrial processes.