Cleanroom refurbishment:
what should happen before work starts?

A cleanroom refurbishment can extend the useful life of a facility, correct performance problems or adapt it for a new process. It can also expose undocumented services, ageing seals and design assumptions that no longer match how the room is used. The project needs a verified baseline, a controlled change plan and agreed acceptance criteria—not a quotation based only on floor area.

First decide whether refurbishment is the right intervention

Start with the problem to be solved. The driver might be damaged finishes, poor pressure stability, inadequate cooling, obsolete controls, a revised room layout or a process that now needs a different cleanliness level. Each points to a different scope. Replacing wall panels will not correct an undersized air-handling system, while a controls upgrade will not resolve inaccessible or deteriorating fabric.

Record the intended use of every affected room, the required classification or grade, environmental limits, pressure relationships, equipment loads and operating pattern. Compare these with the current approved requirements. If the new process is materially different, the work may be closer to a redesign than a repair.

ISO 14644-4:2022 applies to new, refurbished and modified cleanroom installations. It sets out a process from requirements through design, construction, start-up and verification, with life-cycle and maintenance considerations. That makes it a useful framework for treating refurbishment as an engineered change rather than a finishes exercise.

Survey the existing cleanroom before finalising the design

Drawings are the starting point, not proof of what is on site. Check room dimensions, ceiling voids, panel construction, doors, glazing, floor build-up and every visible penetration. Trace supply, return and extract routes. Confirm filter positions, fan duties, controls architecture, sensors, utilities and the access needed to maintain them.

The survey should also capture condition. Look for failed sealant, damaged coatings, corroded components, loose coving, floor defects and evidence of air leakage or condensation. Review maintenance records, alarm history, balancing data and previous qualification reports. A recurring failure may reveal the real priority more clearly than the room's appearance.

Where intrusive investigation is needed, plan how openings will be made, contained and reinstated. The project team may need to consider asbestos information, structural capacity, fire stopping and other building risks before work starts. Assumptions that cannot be verified should be visible in the design and commercial documents, with a process for dealing with discoveries.

Plan how the work will coexist with operations

Many refurbishments take place inside an occupied factory, laboratory or healthcare building. Define the boundary between the work zone and live operations. Temporary partitions, pressure control, protected access routes, cleaning arrangements and waste removal may all be needed to stop dust and debris migrating into controlled areas.

Map the people and material routes for contractors as carefully as the permanent cleanroom flows. Decide where materials can be stored, cut and unpacked; how tools are cleaned; which lifts or corridors can be used; and whether noisy or disruptive activities are restricted to shutdown periods. Utilities and alarms must not be isolated without an agreed permit and communication process.

The Construction (Design and Management) Regulations 2015 set duties for commercial clients, designers, principal designers, principal contractors and contractors. Cleanroom controls do not replace those construction duties. The project arrangements must cover both contamination risk and conventional health and safety.

Treat HVAC, controls and interfaces as one coordinated change

Layout changes alter airflow paths, room volumes and pressure relationships. New equipment adds heat and may obstruct returns or unidirectional airflow. Moving a wall can also affect fire compartments, sprinkler coverage, lighting, detection, utilities and maintenance access. Each interface needs an identified designer and acceptance requirement.

Use current operating data to test the proposed HVAC duty. Air volume, filter pressure, fan capacity, heating and cooling loads, extract demands and control ranges all matter. If the existing system is close to its limit, adding another terminal filter or increasing air changes may create instability elsewhere.

Controls deserve their own scope. Define new alarm limits, delays, trends, user access, sensor locations and links to the building management system. Agree how existing data and settings will be backed up before modification. Our guide to cleanroom environmental control covers the monitoring points that should be settled with the design.

Fabric details should be coordinated before manufacture. Door swings, glazing, coving, service penetrations and wall-mounted loads need to match the revised layout. The cleanroom construction details guide explains what coordinated drawings should show at these junctions.

Set the change-control and requalification strategy early

Acceptance cannot be reduced to “the room looks finished”. Define inspections, commissioning tests and qualification activities against the intended outcome. The scope may include installation checks, airflow balancing, filter leakage testing, room pressure verification, recovery testing, particle classification, environmental checks and airflow visualisation. Not every project needs every test; selection should follow the change, sector and risk assessment.

For medicinal-product facilities, EU GMP Annex 15 states that planned changes which may affect product quality should be documented and their impact on the validated state or control strategy assessed. It also links qualification and validation to the facility life cycle. EU GMP Annex 1 adds specific expectations for sterile medicinal manufacture. Other sectors need their own applicable framework rather than automatic use of pharmaceutical requirements.

Agree who approves the protocol, witnesses testing, reviews deviations and authorises release back to operations. Preserve the original baseline and document what changed. Updated drawings, asset registers, operating instructions, calibration records, maintenance plans and training should form part of handover.

What should a cleanroom refurbishment brief contain?

• The business and compliance reason for the change
• Current and intended room uses, classifications and occupancy states
• Verified drawings, surveys and known condition issues
• Room data, equipment loads, utilities and environmental limits
• Operational constraints, shutdown windows and temporary controls
• Demolition, protection, cleaning and waste responsibilities
• HVAC, controls, fire, electrical and building-service interfaces
• Inspection, commissioning, qualification and release criteria
• Required records, training, warranties and maintenance information

Issue the same information to every bidder and ask each to list assumptions, exclusions and provisional items. This makes proposals easier to compare and reduces the chance that a low initial figure simply reflects missing survey work or incomplete requalification.

For a project involving substantial reconfiguration, use the brief alongside the wider cleanroom design and build process. Where the testing scope needs separate specialist input, the guide to comparing cleanroom validation services helps define the evidence and commercial boundaries.