Heat Exchanger Revalidation (PSSR)

Photo of a Heat Exchanger


With heat exchangers categorised as pressure vessels under the Pressure Systems Safety Regulations (PSSR), they must be inspected on a regular basis to ensure that they continue to be safe to operate.

As part of a gas networks written scheme of examination (WSOE), heat exchangers are usually revalidated every 10 years.


Heat exchanger validation is one of our core services. We undertake revalidations for all the UK gas distribution network operators and pride ourselves on a nationwide, high-quality, good value service.

We inspect and revalidate heat exchangers of all sizes, from small units of 2″ to 3” diameter up to large units in excess of 40” diameter.

A service tailored to your needs

We offer a full or partial revalidation service, depending on your needs and inspection specification. Each revalidation includes a comprehensive report detailing our inspection findings within the statutory 28 days of completion. Our full service typically includes:

  • Removing the heat exchanger from your site
  • Transporting it to the AES workshop
  • Removing lagging and bolted reducers
  • Cleaning the heat exchanger
  • Inspection of small-bore tubing using the Dinsearch™ inspection method
  • Grit blasting weld areas
  • Magnetic particle or dye penetrant inspection of welds, identifying surface breaking flaws
  • Ultrasonic wall thickness measurement of the shell
  • Repainting the heat exchanger and reinstalling bolted reducers
  • Hydrostatic pressure testing of the shell and gas tubes
  • Reinstalling lagging
  • Transporting and reinstalling the heat exchanger

Our highly skilled and experienced team

All of our site and inspection technicians have a wealth of experience and have undertaken the required training courses to safely carry out these works including SHEA Gas passports, SCO Core (CP), VS02 and non destructive training courses including MPI, DPI and UT certified by BiNDT.

Get a quote!

Looking to get your heat exchanger inspected and revalidated? Please contact us on 01670 739999.