Safety valves: is your pressure system really protected?

BY Adegilns Longang, SOLUTION MANAGER – PRESSURE MANAGEMENT

Although safety valve technology has been around for over 100 years, their misuse is still the cause of many industrial accidents. 
 

Safety valves are the last line of defense in protecting process equipment against overpressure. So many unforeseen events can occur in an industrial process: a failure in the cooling system leading to a condenser, for example, or even a power outage affecting a component of the steam system would have serious consequences if a valve did not protect the system from overpressure.

However, in order to perform this role properly, the valve must be designed, selected, installed and maintained according to specific criteria.

It is therefore essential that the engineer, technician, operator and/or industrial inspector be adequately trained to ensure the proper selection and operation of these valves. Among others, at the regulatory level:
 

• The construction code of the valve must be known and respected: ASME Section I, IV, VIII/XIII, CSA B.51, Quebec's RISP (RBQ), etc.
• Consequently, the valve must also be installed according to the regulations in force. 

When selecting the valve, the sizing criteria must be based on the worst case scenario of overpressure. This scenario must be adequately identified.

The pipe and installation conditions must be known when sizing to take into account concepts such as:
 

• Pressure drop at the inlet
• Dynamic or static back pressure

Then, the right type of valve must be chosen: it is important to remember that the typical spring-loaded valve is not suitable for all applications. The operating and performance limits must be known, as well as the sealing limitations that must be respected. Also, it is important to remember that a valve is not a process valve. It should be designed and used only for overpressure protection and should open only in case of emergency.
 

Finally, maintenance is a crucial aspect of overpressure prevention. It is this aspect that will ensure that the valve will protect your system, your equipment and your employees beyond its installation date. It is therefore necessary to plan its periodic maintenance, but also to consider monitoring its condition in order to know when to perform maintenance to ensure its proper operation during an emergency.

Fortunately, technology has evolved and there are now remote monitoring solutions for safety valves. It is important to know about them and to choose the right one to ensure that your system's last line of defense is operational at all times.

Want to learn more? We periodically offer group courses that touch on the topics listed in this article.  Click here to view the course syllabus and registration page.