compressed air receiver written scheme of examination requirements

Direct answer. A compressed-air receiver may fall under the Pressure Systems Safety Regulations 2000 (PSSR). For a qualifying system, the user or owner must know its safe operating limits, have a suitable written scheme of examination (WSE) prepared or certified by a competent person before operation, and ensure examination takes place in accordance with that scheme. The scheme identifies the parts and nature/frequency of examination; it is not a generic annual certificate. First establish the system boundary, operating pressure, vessel size and applicable exceptions, then ask a competent person to confirm the PSSR scope and scheme. HSE written-scheme guidance; HSE PSSR overview.

This Great Britain manufacturing guide addresses the air-receiver decision and evidence trail, not pressure-vessel engineering design. The existing compliance-management software page is the broad commercial owner. This article makes no claim that Complys creates a competent WSE, measures pressure, performs examinations or certifies a receiver.

Map the pressure system before applying a threshold

List the compressor, air receiver, connected pipework, safety valves, regulators, isolation points and equipment fed by the system. Record the manufacturer, serial number, design pressure, normal operating pressure, vessel volume, safe operating limits and site location. Draw or obtain a simple diagram showing how pressure is generated, stored and distributed. An equipment label alone may not identify the full system or where a failure could release stored energy.

HSE's PSSR overview identifies compressed or liquefied gas, including air, at pressure above 0.5 bar above atmospheric pressure as a relevant category, but specific exceptions and WSE scope depend on the system. Its updated written-scheme guidance notes that the compressor associated with an air receiver is not normally included in the WSE, while the receiver and relevant protective devices may be. Do not apply a single “all compressors need a scheme” rule. HSE PSSR overview; HSE written-scheme guidance.

The familiar 250 bar-litres pressure-volume trigger appears in HSE compressed-air guidance, but the legal classification can involve other factors, exemptions and connected-system details. Ask a competent person to classify the actual installation rather than calculating from a guessed gauge value. A small receiver that is exempt from a particular WSE duty can still present hazards and need suitable maintenance and inspection. Conversely, splitting a larger system into several labels does not remove the need to examine the pressure boundary as a whole.

Example. A factory buys a replacement receiver for an existing compressor. The maintenance team has a certificate for the new vessel but no drawing of the downstream pipework and no current WSE. The correct first step is to identify the installed system and ask a competent person whether the existing scheme covers the replacement and protective devices. The vendor's vessel certificate does not automatically define a site examination scheme.

What a written scheme does

The WSE is a forward-looking technical plan prepared or certified by a competent person. It specifies which parts of a qualifying pressure system must be examined, the type of examination and the intervals or circumstances requiring it. It should consider safety devices, pressure boundary and risks from deterioration or damage. The competent person can require preparation for examination, such as safe isolation, depressurisation and access. The user must ensure examinations actually occur as specified. HSE INDG178.

Do not confuse the WSE with the examiner's report after examination. A system can have a beautifully filed scheme but be overdue for examination, or an old report but no scheme covering the current configuration. Retain both, with clear dates and version references. The WSE is also different from routine maintenance: daily checks, draining condensate, testing safety devices and service work may be needed between thorough examinations under the system's instructions and risk assessment.

When asking for a scheme, give the competent person accurate vessel and protective-device details, previous reports, modifications, maintenance history and operating conditions. If the system runs in a corrosive or high-use environment, that context may affect examination needs. A competent person cannot reasonably certify a useful scheme from an incomplete asset list that omits a receiver or relief device.

Assign owner and user duties

PSSR differentiates duties of owners and users in different circumstances. For an installed system, the person using and controlling it may carry operational duties even where another party owns the equipment. HSE notes that Schedule 2 can allow a supplier of an installed system to assume specified responsibilities in writing. Make the allocation explicit in leases, maintenance agreements and operating procedures; do not assume that paying an inspection contractor transfers every legal duty. HSE PSSR overview.

For a hire arrangement, ask who supplies the WSE, who arranges the next examination, who receives the report, who maintains safety devices and who can stop use. A document stored by the equipment owner may be inaccessible to the site operator during an inspection or defect response. The site needs current information on safe operating limits and restrictions.

Nominate a person to maintain the inventory and alert the competent examiner when a receiver is replaced, relocated, repaired or operated outside its previous conditions. Confirm the user understands the limits; a report date alone cannot tell an operator whether the pressure setting has been increased beyond the accepted design.

Plan the examination safely

Schedule examination early enough to arrange a shutdown, drainage and access. The competent person determines scope and method under the scheme. Do not pressurise a vessel or bypass a protective device merely to make it available for testing. Coordinate with production so temporary compressed-air supplies and isolation do not create new hazards. Confirm the examiner will see the installed configuration, not merely the removed vessel in a workshop.

After examination, obtain the written report and read it. It should identify the system, date, scope, findings, defects, recommended actions and any revised examination timing or operating restriction. If a dangerous defect is found, take the action required by the competent person and PSSR process; the equipment should not return to routine service simply because a repair has been booked. Seek confirmation that the fix addresses the finding and that the competent person has any required re-examination or amended scheme.

Example. An examiner identifies corrosion at a receiver drain connection and limits use pending repair. The maintenance team replaces the fitting, but the cause may include trapped moisture and a failed drain routine. Close both the physical defect and the maintenance weakness; record how the receiver was verified before restart. A work-order “complete” box does not answer whether the pressure system is safe under its operating limits.

Keep the scheme current through change

Review the WSE after a change in receiver, pressure setting, pipework, relief device, location, operating duty or damage. Ask the competent person whether the existing scheme remains suitable and whether an additional examination is required before use. A replacement vessel can change the system's pressure-volume characteristics and protective-device assumptions. Updating the inventory and WSE at the same time prevents an examiner later discovering equipment that was never brought into scope.

Retain the current WSE, examination reports, defect actions, repair evidence, manufacturer documents and safe-operating-limit information together. A history of superseded versions is useful, but mark the live scheme unambiguously. Set reminders based on the competent person's scheme, not an assumed universal interval from a blog post.

Common mistakes

• Assuming every compressor automatically needs its own WSE, or that a vessel certificate is the WSE.
• Applying a pressure-volume calculation without establishing the whole system and exceptions.
• Treating a maintenance contract as proof a competent examination took place.
• Filing a WSE while the examination is overdue.
• Replacing a receiver or safety valve without asking if the scheme and operating limits still fit.
• Closing an examiner defect when a part is ordered rather than repaired and verified.
• Losing the report because the asset is hired or supplier-owned.

Where Complys fits

The compliance-management software page is the broad commercial owner for evaluating record and action workflows. This guide does not claim Complys determines PSSR applicability, writes or certifies a WSE, sets safe limits, performs pressure examinations or validates a repair. The next step is to choose one air receiver and trace its system boundary, competent WSE, latest report, open defects and next required examination.

Primary sources checked 4 October 2026

• HSE written schemes of examination, INDG178 — scheme purpose, scope and competent-person role.
• HSE PSSR overview — system and owner/user framework.
• HSE compressed-air safety guidance, HSG39 — air receiver context; some legacy regulatory references in this older publication require checking against current PSSR guidance.

Publication gate: A competent pressure-systems specialist should verify any system-specific inclusion, exception, pressure-volume calculation or interval. HSG39 has legacy references; current HSE PSSR and 2026 written-scheme guidance govern this draft's framing.

General information, not legal advice. Verify current requirements against the primary sources linked above.