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How often does a pressure vessel need inspection?

In-service inspection intervals come from AS/NZS 3788 and depend on the equipment. Here are the typical periods — and how they can be extended on a justified risk assessment.

5 min read

How often your equipment needs inspecting is governed by AS/NZS 3788, the Australian/New Zealand standard for in-service inspection of pressure equipment. The standard sets intervals by equipment type and condition; the figures below are typical starting points, and the correct interval for your specific equipment should be confirmed against the current edition of the standard.

Typical intervals

  • Air receiver (in-scope) — external around every 2 years, internal around every 4 years
  • Boiler — external around yearly, internal around every 2 years
  • LP gas vessel — external around every 2 years, internal around every 10 years
  • Pressure relief valve — external checks around yearly, with periodic set-pressure testing and recertification through accredited partners

Risk-based inspection can extend intervals

AS/NZS 3788 allows inspection intervals to be extended where that's justified and supported by a risk assessment against the criteria in the standard. This is how many larger operators lengthen intervals safely — but it has to be evidenced, not assumed.

The practical upshot: at least an annual touchpoint

Even lower-touch equipment tends to generate at least a yearly relief-valve check, and boiler programs run on multiple frequencies. In practice most owners have at least an annual professional touchpoint per item — which is exactly what automatic due-date reminders are for, so nothing slips.

Not sure where your equipment stands?

Send a photo of the equipment and its nameplate and we'll tell you plainly under AS 4343 — free, no obligation.

Common questions

Can inspection intervals be extended?
Yes — AS/NZS 3788 permits extension where it's justified and supported by a risk assessment against the standard's criteria. It must be evidenced, not simply assumed.
What happens if an inspection is overdue?
Overdue inspection means the equipment may not meet your duty-holder obligations, and outdated records can undermine your position with regulators and insurers. A free assessment or a quote is the quickest way to get back on track.

This guide is general information, not legal or engineering advice. Inspection requirements depend on your specific equipment and jurisdiction; confirm against the current edition of the applicable standard. Speqo supplements but does not replace your own duty-holder obligations.

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