You’re asked to sign off a new compressed air installation, but the commissioning report contains only a compressor pressure reading and a signature. There’s no evidence from the production outlets, no explanation of the test conditions and no clear owner for unfinished work. Once the installer leaves, those gaps become your plant’s problem.
A compressed air commissioning checklist gives you a basis for accepting the installation. It connects the agreed specification to recorded results, safety documentation and the arrangements needed to operate the system.
At Design Air, Atlas Copco Premier Distributor in Scotland, we recommend reviewing the complete installation at handover, including the equipment and distribution network serving your production processes.
The Handover Records You Should Receive
A compressed air installation handover should include agreed acceptance criteria, recorded test results, safety documents, equipment records, operating instructions and outstanding actions.
Use the following as a document request list. Each record should identify the installation, its revision or test date, and the person responsible for it.
| Handover Item | Evidence to Receive |
|---|---|
| Agreed performance specification | Required pressure, flow and air quality, with operating conditions and measurement locations |
| Commissioning report | Recorded readings, test methods, instruments used and acceptance results |
| Equipment register | Manufacturer, model, serial number, asset reference and location |
| Installation drawings | Final pipework layout, isolation points, treatment equipment and electrical interfaces |
| Pressure-system documentation | Safe operating limits, applicable examination scheme and examination records |
| Operating information | Manuals, approved settings, alarm responses and isolation procedures |
| Maintenance and warranty arrangements | Service requirements, first service date, responsibilities and written warranty terms |
| Training and outstanding work | Attendance records, unresolved items, restrictions, owners and completion dates |
Ask for an indexed electronic pack your maintenance team can access. A folder of unidentified certificates is difficult to use when an engineer needs to match a document to a particular receiver or dryer.
Agreed Conditions Come Before Acceptance Readings
“Working correctly” needs a definition. Your acceptance specification should describe what the installation must deliver, where it must deliver it and under which operating conditions.
Establish the System Boundary
Identify everything included in the project: compressors, air receivers, dryers, filters, drains, controls and distribution pipework. Record connections to existing equipment and any retained components.
For pipework installation, the boundary matters particularly where a new main connects to older branches. A restriction downstream of the new work can affect an outlet reading, even when the installed equipment performs as specified. The report should distinguish the work being accepted from conditions elsewhere on the site.
Include any responsibilities split between the compressed air installer, electrical contractor and production-equipment supplier. Otherwise, an interface fault can remain unresolved while each party considers its own package complete.
Define a Representative Test
Agree which production equipment will operate during testing, whether simultaneous demand needs demonstrating, and which standby arrangements are included.
Record the actual conditions alongside the results. Relevant details include production loading, compressor configuration, pressure settings, dryer inlet conditions and compressor-room temperature.
If the site cannot reproduce its intended operating conditions, identify what remains unproven. A quiet-shift test may support initial checks, but it cannot establish performance during a production peak that never occurred. Agree a later verification date and the evidence required to close that gap.
Pressure and Flow Evidence Must Reach the Production Outlets
A pressure reading at the compressor tells you what is happening at that location. It does not establish the pressure available to a machine elsewhere in the factory.
Review Readings at Important Outlets
Ask the installer to record pressure at the agreed critical outlets while the relevant equipment operates. These may include a packaging line, an instrument-air connection or the furthest production branch.
Air encounters resistance as it moves through pipework, filters, valves and local connections. Under demand, this produces a difference between upstream pressure and the pressure available at the machine. An idle-system reading can conceal that difference.
The commissioning report should identify:
- The measurement point and instrument used.
- The production equipment operating during the test.
- The observed pressure range and any demand-related dips.
- The agreed acceptance criterion and result.
- Any adjustment made before the final reading.
We recommend retaining time-based records where short demand events matter. A single handwritten value provides little evidence about a brief pressure dip during a machine cycle.
Make Flow Results Comparable
Where delivered flow is part of the contract, receive the measured result, measurement location, method and reference conditions. Ask how the result relates to the supplier’s stated capacity.
A flow figure without its pressure and reference basis is difficult to interpret. Also clarify whether the figure describes compressor output or usable air after treatment and other system consumption.
Keep acceptance tolerances tied to the agreed specification and supported test method. There is no useful universal pressure-drop allowance that can replace the requirements of your particular production equipment.
Air Quality Acceptance Needs Its Own Evidence
Pressure and flow can be satisfactory while the air remains unsuitable for the process. Treat air quality as a separate acceptance question.
Specify Particles, Water and Oil Separately
ISO 8573-1 is the compressed air purity classification standard. Its class designation addresses particles, water and oil separately. Atlas Copco’s air purity guidance (atlascopco.com) explains these distinctions.
Ask for the complete agreed designation, its application and the location where it must be achieved. “Food-grade air” or “clean air” alone is insufficient as an acceptance specification.
Where testing forms part of the project, receive reports identifying the sampling locations, methods, conditions and results. A dryer reading demonstrates a moisture condition at its measurement point. It does not establish particle or oil performance.
Likewise, equipment certification should be retained with its stated scope. Avoid treating a certificate for one component as evidence for every outlet in the installed network.
Interpret Pressure Dew Point Correctly
Pressure dew point, or PDP, is the temperature at which water vapour starts to condense at the stated compressed air pressure. It is different from an atmospheric dew point measurement.
According to Atlas Copco’s purity-class explanation (atlascopco.com), ISO 8573-1 Water Class 4 requires a PDP of +3°C or lower. Water Class 2 requires -40°C or lower, while Water Class 1 requires -70°C or lower.
Receive the achieved PDP with the operating pressure, measurement location and test conditions. Ask the installer to explain how the selected dryer’s rating covers the agreed flow, inlet temperature and ambient conditions.
For moisture-sensitive processes, the acceptance report should make clear whether the result came from an independent measurement or an installed indicator, and how the instrument’s suitability was established.
Account for Scottish Seasonal Conditions
An installation serving an unheated loading area in Fife presents a different moisture risk from one whose entire distribution network remains heated.
If compressed air cools below its pressure dew point downstream, water can condense in the pipework. Atlas Copco’s drying guidance (atlascopco.com) identifies the lowest temperature along the compressed air route as a dryer-selection consideration.
Your handover should record the environmental assumptions behind the selection. Our explanation of ambient temperature effects on compressed air systems provides further context for reviewing those assumptions.
A commissioning visit in mild weather leaves a seasonal question open. Where winter conditions cannot be demonstrated, retain the design basis and agree any follow-up verification.
Safety Documents Must Match the Installed System
Commercial acceptance and statutory pressure-system requirements need separate attention. A signed commissioning sheet cannot replace the documents and examinations applicable to your installation.
Confirm Pressure-System Responsibilities
The Pressure Systems Safety Regulations 2000 address the hazards associated with stored pressure energy. The Health and Safety Executive’s PSSR guidance (hse.gov.uk) states that qualifying pressure equipment requires a written scheme of examination and, where that scheme specifies it, an examination before first use.
At handover, establish who has confirmed applicability, the safe operating limits and the examination requirements. Where a scheme is required, obtain the scheme and relevant examination report, including any conditions affecting operation.
Exceptions exist. Avoid deciding applicability from compressor motor power or a general statement that the installation is “small”.
Match the Scheme to the Assets
Check that equipment references in the scheme can be matched to installed items. A receiver serial number, asset label and location should lead to the same vessel.
HSE’s written-scheme guidance (hse.gov.uk) describes identification of equipment, parts requiring examination, protective-device checks, examination intervals and preparation requirements.
If existing equipment has been retained or the system modified, ask the competent person to confirm that the documentation remains suitable. Include the next examination date and the site contact responsible for arranging it.
Receive the applicable equipment conformity documents and electrical installation records too. Ask the relevant contractors to identify which documents cover their work and any limitations on that coverage.
Drawings and Equipment Records Should Reflect the Finished Installation
During installation, routes and component positions can change. Your maintenance team needs drawings showing what was installed.
Request final drawings identifying pipe routes, sizes, materials, flow direction, isolation valves, receivers, treatment stages, drains and measurement points. Include electrical and control drawings for the supplied interfaces.
The equipment register should connect each asset to its manual, service requirements and supporting documents. Capture installed model and serial numbers rather than relying on a quotation that may describe the original selection.
We recommend reviewing a drawing against the physical installation with the installer. A labelled valve that isolates a different branch from the one shown on the drawing creates a practical problem during maintenance.
Record any temporary arrangement explicitly, including its intended removal date. Otherwise, temporary bypasses and connections can become undocumented permanent features.
Drainage and Condensate Arrangements Need a Named Owner
A functioning dryer does not complete the moisture-control checks. Ask for evidence that installed drains operate as intended and that their discharge reaches the agreed collection or treatment arrangement.
The handover should identify drain locations, discharge routes, condensate treatment equipment and maintenance responsibilities. Where discharge permissions or other environmental requirements apply, record who has confirmed them and retain the relevant evidence.
Do not infer that treated condensate is suitable for any available drain. The disposal route needs checking for the particular site.
Our guide to compressed air moisture issues explains why water management extends beyond the dryer. At handover, the practical question is whether someone owns each part of that arrangement.
Controls and Alarms Require Demonstrated Results
Ask the installer to provide the approved controller settings and records of the agreed functional tests. Include compressor sequencing, standby changeover and remote interfaces where these form part of the project.
For a system connected to site monitoring, receive evidence that the agreed signals reach the intended destination. A working local alarm does not demonstrate that the facilities team receives a remote notification.
Record emergency-stop and interlock test results where applicable, including their scope and any outstanding interface work. These checks belong with the responsible engineers under the approved test arrangements.
Also establish who may change settings after handover. Retaining the accepted settings gives future engineers a reference when investigating altered system behaviour.
Operators Need Training and a Working Maintenance Plan
A manual supports operation, but the handover should also demonstrate that the responsible people understand their tasks.
Record Practical Training
Request a training record identifying attendees, equipment covered and subjects demonstrated. Include normal operation, alarm response, approved isolation arrangements and escalation contacts.
Separate routine operator observations from work reserved for trained maintenance personnel. Your shift team should know what to report and when operation must stop under the site’s procedures.
If the installation serves several shifts, record how absent staff will receive equivalent instruction. Training one supervisor leaves a gap if nobody on the night shift can locate the operating information.
Confirm Maintenance and Warranty Terms
Receive the manufacturer’s maintenance requirements, the planned service schedule and the first service due date. Clarify responsibility for compressors, dryers, filters, drains and condensate treatment.
Keep statutory examinations and routine maintenance identified separately in the maintenance system. Each has its own purpose, scope and scheduling requirements.
Warranty paperwork should state the covered equipment, start date, registration requirements, exclusions and service conditions. Avoid relying on a verbal description of an extended warranty. The written terms determine what evidence you need to retain.
Retain a Baseline for Later Performance Reviews
Keep the accepted pressure settings, production conditions and available operating records together. Include measured electrical input, flow or running patterns where these were within the agreed scope.
This baseline helps distinguish an installation issue from later changes in demand, settings or maintenance condition. A comparison is useful only when the operating conditions are understood.
Where demand remains uncertain, Design Air provides an energy audit to assess compressed air requirements and system performance. For a useful assessment, have the equipment schedule, shift patterns, critical outlet requirements and existing readings available.
The resulting evidence can support a decision about further investigation or optimisation. It should remain distinct from any acceptance testing still owed under the installation contract.
Outstanding Work Must Stay Visible After Sign-Off
Give each unresolved item a description, named owner, target date and closure requirement. Identify whether it affects safety, required performance, documentation or an agreed finishing detail.
An acceptance record should distinguish completed work from conditional acceptance and deferred verification. Missing evidence should remain visible until the agreed test or document has been received.
Safety-related restrictions need explicit resolution through the responsible people before the affected equipment is used. A general promise to return later is insufficient as a handover record.
Before closing the meeting, agree who will review the outstanding-item register and when. Put that review in the maintenance calendar alongside the first service and any deferred production-load test. The next shift should be able to see exactly what has been accepted and what still needs proving.