AHU Servicing & Maintenance: Supporting COSHH Compliance and Laboratory Ventilation Performance
Overview & The Challenge
This project demonstrates the importance of AHU servicing for COSHH compliance within laboratory and controlled environments.
The Fume Cupboard Company carried out a scheduled annual service of air handling units (AHUs) at a multi-use facility supporting laboratories, offices, and welfare areas, following earlier maintenance in 2025.
While AHUs are not subject to fixed COSHH testing intervals, they are critical in maintaining compliant environments. Poor performance can lead to:
- Reduced airflow and ventilation rates
- Imbalanced room pressurisation
- Increased contamination risks
- Reduced effectiveness of fume cupboards and LEV systems
Maintaining air handling system performance is therefore essential to support safe and compliant laboratory operations.
Our Approach
As part of a planned preventative maintenance programme, our engineer returned in May 2026 to deliver AHU servicing for COSHH compliance.
Key Works Completed
- Full AHU inspection and annual service
- Replacement of all filters, including heavily soiled pre-filters
- Internal cleaning of AHU units
- Clearing of inlet louvres obstructed by debris
- Cleaning of bird guards to maintain airflow
- Service and refrigerant leak checks on all on-site air conditioning systems
System Checks
- Start-up and operational checks completed
- Visual inspection of ductwork and insulation
- Airflow restrictions identified and resolved
This structured approach ensured the system was operating efficiently and safely.
Key Findings & Outcomes
Filter and Airflow Issues
The pre-filter was found to be severely contaminated, restricting airflow and reducing system performance.
- Replacing filters restored airflow and improved efficiency.
Blocked Air Intake
The inlet louvre was partially blocked with leaves and cobwebs.
- Cleared on-site, restoring proper air intake and reducing system strain.
Ductwork Integrity Concern
During AHU start-up, slight ballooning of the PIB insulation on the supply duct was observed, indicating a potential positive pressure condition within the ductwork. Subsequent inspection confirmed no significant leakage or structural concern, with the system operating within normal design tolerances.
This potentially could of impacted:
- Airflow control
- System efficiency
- Air quality within laboratory spaces
Outcome
This AHU servicing for COSHH compliance delivered:
- Improved airflow and ventilation performance
- Reduced energy and mechanical strain
- Removal of airflow restrictions
- Early identification of a potential ductwork issue
- Continued support of safe laboratory environments
COSHH Compliance & Next Steps
Although COSHH specifically mandates testing for LEV systems, it also requires that all engineering controls are maintained in efficient working order.
AHUs play a key supporting role by providing:
- Background ventilation
- Stable airflow and air change rates
- Support for safe fume cupboard operation
In simple terms:
- AHU = whole-environment airflow control
- Fume cupboard = localised hazard extraction
If AHU performance drops, COSHH compliance can be compromised.
Are your systems meeting AHU servicing requirements for COSHH compliance?
At The Fume Cupboard Company, we specialise in maintaining air handling and ventilation systems that underpin safe laboratory environments.
Get in touch today to arrange your AHU service or discuss a tailored maintenance plan.
