A feasibility study was carried out to investigate the potential to reduce the air change rates


  • €84,000

  • 6%

    Reduced Energy Consumption
  • €94,000

    Further Potential Savings

Decreasing the air change rate was not deemed a significant risk

Hollister ULC, Ballina, Co. Mayo was established in 1976 and currently employs around 800 people that develops, manufactures and markets healthcare products and services worldwide.

About the Project

The Facilities Department undertook a feasibility study to investigate the potential to reduce the air change rate in their cleanroom number three. A clean room is a sterile environment achieved by filtering the air. A clean room environment prevents any cross contamination that could reduce the quality and integrity of the product during production or storage. The results of the feasibility study showed that the room was operating well within its ISO 8 limits and in some cases close to ISO 6 limits.

Decreasing the air change rate was not deemed a significant risk. Therefore, in conjunction with the Quality Department, it was agreed to trial a reduced air change rate in the cleanroom from 20 air changes per hour to 16 air changes per hour.(ACH)

The room was re-validated at 16 ACH during the planned production shutdown in August 2017. It  was also independently validated by a third-party contractor to ensure that it was operating to 16 ACH.

Tests were also conducted on the temperature, humidity, pressure profiles, particle counts and laminar airflow to ensure that they remained within specification.


Reducing the air changes from 20 to 16, resulted in annual motor savings of €64,000 (710,000 kWh), This equates to a 60% reduction in the rooms operating cost and electrical energy consumption. There was an annual thermal energy savings of €20,000 (670,000 kWh) from reductions in dehumidification, rehumidifaction, cooling and heating.

This project has reduced the total energy consumption by 6%. From close to zero capital investment, the company was able to achieve savings of €84,000 per year, whilst maintaining the quality of the product. Non-energy benefits which include improvements in equipment and process reliability have also been achieved by reducing the demand on plant services such as boilers, chillers, motors, pumps and re-humidifiers.

Moving Forward

With the success of the air change reduction project, a similar project is being considered to reduce the ACH rates in cleanrooms one and two - as well as a review on the deduction of permanent objects from the total room volume.

This project has the potential to save a further €95,000 per annum. One of the lessons learnt through consistent monitoring and analysis was that the cleanrooms are operated to an ISO 7 limit in terms of particle count and in some cases close to ISO 6. This may be deemed excessive for the grade of medical device being manufactured.

The key to successfully implementing large energy savings projects such as cleanroom three is to take a step back, assess actual process requirements and apply common sense.  Often decisions can made based on precedent, thoughts and ‘feelings’ rather than facts! As this project required close to zero capital investment, the buy-in comes easier and the savings can in turn be significant  
Seb Doheny , Facilities Engineer