The 4 Top Reasons Pressure Relief Valves Become Bad Actors -

09 Jan.,2023


Poorly performing pressure relief valves, aka bad actors, can cause unplanned downtime for your facility. And, as you know, that downtime can be very expensive — in the range of thousands of dollars per hour or more once you factor in product loss, maintenance labor costs, equipment, and so on.

Given the massive costs, it’s no surprise that for 72% of companies (across manufacturing, oil and gas, and similar industries), zero unplanned downtime is a top priority. A key step in achieving this goal is identifying poorly performing equipment before it fails so that repairs can be made before the whole line, or, worse, the whole facility, needs to be shut down.

Whether you’re in oil and gas, power generation, manufacturing, or another industrial sector, one of the most important types of equipment to keep tabs on is your pressure relief valves. 

Why are PRVs so important? First, because they’re the last line of defense and critical for safety — properly functioning PRVs prevent potentially devastating accidents. And, second, because you likely have a good number of them installed throughout your facility.

4 most common reasons PRVs become “bad actors”

  • The operating pressure is set too close to the stamped set pressure of the valve.

    Ideally, the operating pressure is 20% lower than the nameplate set pressure. This is the threshold where you can expect superior seat tightness. If 20% is not possible, a


    gap of 10% between the operating pressure and the set pressure should be maintained.

  • The system spikes above the allowable safe operating range of the valve.

    If a system experiences pressures above the maximum allowable working pressure (MAWP), the valve will not be able to function properly. 

  • The outlet piping is improperly supported.

    In our several decades in this industry, we’ve seen it all when it comes to piping. Too often, due to space constraints, the outlet piping is not fully supported, resulting in the valve bearing some of the weight of the piping. This can cause the valve to not seat properly, resulting in leakage.

  • The wrong valve is being used for the application.

    Sizing and selecting PRVs is a complex activity, requiring detailed knowledge of both the application and the equipment. Many, many times, when we’re called out to repair PRVs, the problem is that the wrong valve was spec’d to begin with. For more information, see our two-part article series on valve sizing and selection:

    Part 1


    Part 2


The best way to prevent valves from becoming bad actors and causing unplanned downtime is to know the condition of every valve in your system.

At Allied, we use the web-based software ValvKeep to collect valve data and maintenance records, which we can then use to anticipate future maintenance needs. For example, if a valve required excessive part replacement during the last repair job, that valve is at risk and may need more frequent servicing or to be replaced altogether with a different design valve.

If zero unplanned downtime is a priority for you, we can help you identify bad actors and repair or replace them before they cause larger problems for your facility. Contact us to learn more.