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Cleanroom Servicing

A Cleanroom, or other such controlled environment, is designed and constructed to control the concentration of airborne particulates. At Crowthorne Group we test, service and classify your Cleanroom.

We understand the importance of your Cleanroom conforming to regulatory standards including: ISO 14644:2015 and to the guidelines of agencies such as the Medicines and Healthcare Products Regulatory Agency (MHRA) and the Food and Drug Administration (FDA).

At Crowthorne Group we want to ensure that any performance testing or maintenance within your Cleanroom creates minimal disruption to your processes, production, and lab activities. All of our engineers are Cleanroom Testing and Certification Board (CTCB-I) qualified and have a wealth of experience working within critical environments, so are well practised in working efficiently and reliably.

We are independent from any designer, builder or equipment manufacturer, so you’re guaranteed that our testing, results and subsequent reports are completely unbiased.

Classifying your Cleanroom

We understand Cleanroom classifications and can advise on yours:

  • Facilities designed for pharmaceutical development or manufacturing, need to conform to either CGMP and/or ISO 14664:2015
  • All Cleanrooms have a classification which is determined by the concentration of airborne particles, ranging from 0.1μm to 5μm. Nanoparticles which are smaller than 0.1μm and macroparticles which are larger than 5μm are not covered within this range, however more information on these particle sizes is available upon request


Cleanroom Validation Tests

Measuring the performance of your Cleanroom or controlled environment is crucial when you need to regulate the level of airborne particulate contamination. Depending on your specific requirements, some or all of the following performance tests would form part of the annual or routine validation testing.

Frequency of Services

It’s essential that all Cleanrooms are routinely tested, monitored and certified to ensure that they continually perform efficiently and stay within their designed classification parameters.

Additional performance tests such as airflow visualisation, particle deposition rates, recovery rate and containment leak should be undertaken during commissioning and every 4 years thereafter, unless significant changes have been made to the airflow system or facility. Temperature and humidity are measured as required, subject to the requirements of the Cleanroom user.

Containment Laboratories

It is the recommendation of the Advisory Committee on Dangerous Pathogens (ACDP) that containment measures are in place to provide protection to laboratory staff from working with biological agents, which can potentially cause severe disease and pose a serious risk to health. The primary aim of any containment laboratory should be to control the exposure to biological agents at source, using procedural and engineering control measures.

Containment laboratories are classified depending upon the types of biological agents being used. For a detailed explanation on the various classifications available contact us. If you know the containment level of your laboratory, see below for the differences in control measures for Containment Level 2 (CL2) and Containment Level 3 (CL3).


Differences in Control Measures Required for CL2 and CL3



CL3 Documentation Required

  • Documented ,strong>facility design and operational procedures, including a routine and emergency fumigation protocol
  • Operational verificationprior to use and following any remedial or modification works
  • Annualre-verification, including integrity testing to ensure sealability for fumigation.


Routine Inspection

We recommend annual testing of CL3 facilities (minimum) to ensure the laboratory provides adequate protection to lab workers.

Testing to include:

  • Room integrity and sealability
  • In-situ HEPA filter integrity testing (DOP testing)
  • Measuring air volumes and calculating air change rates
  • Inspection to ensure functionality of controls, interlocks and anti-blowback devices.


Sealability of CL3 and CL4 Facilities

All laboratories which require fumigation will need to provide evidence to the Heath and Safety Executive (HSE) that sealability tests using smoke pencils have been undertaken and any identified leak paths adequately rectified.

Click Here for Details of Emergency CL3 Fumigation Scheme

Operating Theatres

Post-operative infection is strongly influenced by the suitability and quality of air within an operating theatre. HTM 03-01 provides guidance on the design and management of heating and specialised ventilation systems in health sector buildings, it states that if specialised ventilation systems in healthcare premises do not achieve and maintain the required standards, there is an increased risk to patients’ health.

All specialised ventilation systems serving critical areas should be inspected quarterly, with a verification of performance measured annually to ensure the system is fit for purpose.

Operating Theatre Service

For your annual verification we recommend the following performance and preventative maintenance programmes:

Ultra-Clean Ventilated Canopy (UCV) Theatres

  • Visual theatre and Air Handling nit (AHU) inspection
  • Measure supply and extract airflow rates
  • Measure dimensions and calculate air change rates
  • Particle counting for air quality checks
  • In situ HEPA filter integrity testing
  • Measure airflow velocities under UCV canopy
  • Measure room pressure differentials
  • Record room temperature and humidity
  • Measure room noise and light levels
  • Check mechanical, electrical and control functions
  • Microbiological air sampling (optional)
  • Re-entrainment test (optional)


Conventional Theatres

  • Visual theatre and AHU inspection
  • Measure supply and extract airflow rates
  • Measure dimensions and calculate air change rates
  • Particle counting for air quality checks
  • Measure room pressure differentials
  • Record room temperature and humidity
  • Measure room noise and light levels
  • Check control functions
  • Microbiological air sampling (optional)


For UCV theatres we recommend a bi-annual service to ensure the canopy is operating efficiently, including the following performance tests:

  • Visual theatre and AHU inspection
  • Check mechanical, electrical and control functions
  • Record room temperature and humidity
  • Measure room noise and light levels
  • Replace pre-filters
  • Measure airflow velocities under UCV canopy (grid velocity profiles at 1m & 2m from FFL)


In addition to operating theatres, Crowthorne can provide an annual verification for other critical areas, such as:

  • Mortuaries
  • Pharmacies
  • Sterile services
  • Isolation rooms


All inspection and performance testing of operating theatres should be undertaken by trained, experienced and qualified engineers. Crowthorne have been working in operating theatres and cleanroom environments for many years and understand the importance of accuracy and consistency when providing these services within such critical environments.