There are a range of factors that influence cleanroom particle management. Making some small but vital considerations about SOPs upfront can make a big difference. Not just to your cleanroom, but to the planet. Written by Sue Springett
Optimal cleanroom design has been, and always will be, primarily about microbe management and controlling particle levels. But as we all work towards collectively meeting COP26 energy reduction targets, how do we retain our focus on achieving unwavering, stringent hygiene standards to minimise risk whilst, at the same time, reducing our energy consumption?
There has never been a more appropriate time to consider how best to optimise cleanroom design and drive down energy consumption, without risking hygiene standards. And there are varying approaches to this.
What part does intelligent layout design and smart specification of furniture play
Ventilation systems for clean air are absolutely critical in ensuring that cleanroom operators adhere to ISO 14644; guaranteeing that the concentration of airborne particles is at a safe level at designated sampling locations. But, while these systems remain crucial, there are steps to ensure HVAC systems are running more efficiently.
Ventilation systems in cleanrooms are constantly pumping to change air, to deliver a regular, fresh flow and, as a consequence, consume a huge amount of energy. Energy, that in a post COP26 world, every person, sector and corner of the UK has to curtail. Ventilation has been put firmly under the sustainability spotlight.
There are many questions to ask. How can we design better, more energy-efficient cleanrooms, where air flow is utilised efficiently, while minimising risk and always maintaining the highest hygiene standards? What part does intelligent, upfront layout design and smart specification of furniture play, when it comes to optimising clean down SOP? Where ventilation systems are concerned, how can a thorough, well-considered design process ensure air flows efficiently, energy consumption is reduced, and stringent hygiene standards are never once compromised?
Historically, ACR (air change rates) have been used as a measure of performance, where the efficiency and quality of cleanroom ventilation systems was measured by the number of complete air changes which took place each hour. However, these are no longer a reliable indicator of cleanroom performance. Over-reliance on HVAC systems results in running very energy-intensive spaces with anything up to 80% of a cleanroom’s energy consumption.
As Tom Nutley of EECO2 explains, “Between 40-80% of a cleanroom site’s total energy expenditure comes from ventilation systems. And it’s an issue that has been thrown under the spotlight thanks to COP26. We all recognise the importance of reducing energy usage to meet these crucial, planet-saving targets. Ventilation specialists should be applauded for finding ways to reduce the number of air changes required, whilst still ensuring effective and compliant particle management.”
There are other ways to achieve ISO 14644 cleanroom standards, while reducing the CO2 emissions in line with ISO 140001 targets.
The direction of air travel influences particle count management so, at design stage, it is vital to consider where vents are placed in relation to usage and the furniture. How does the layout and positioning of furniture hinder airflow and increase your risk?
Clever furniture design can and will enable the airflow to effectively dispel particles
Getting it right from the start is so important. It may be obvious to state, but ventilation systems, once installed, are often prohibitively expensive to change. Understand from the beginning where the risk points for vents are located. Not just with larger pieces of furniture, but smaller items too. Consider where your people are going to be working and their activity. Where could blockages be created or still air points occur? Assess your layout at design stage, seek specialist advice on where best to place your furniture in relation to vents and airflow to avoid a build-up of risk, and take steps to ensure that when HVAC is applied, it is as energy efficient as it can possibly be.
There are a multitude of factors to consider when designing a cleanroom, to manage microbes and assist with successful particle management. As we have talked about with the layout, the design of individual pieces of furniture will also make a difference.
Clever furniture design can and will enable the airflow to effectively dispel particles from the cleanroom, and even a small decrease in consumption can have a positive impact. For example, a 10% improvement can lead to a 28% reduction in the fan power consumed. Air change rate reduction is such an effective energy reduction strategy for cleanrooms, without ever compromising on hygiene.
Furniture design and positioning will either hinder or assist the flow of air in your cleanroom. For example, a unit with a solid back panel immediately creates a barrier for ventilation, preventing airflow and causing still points where particles will settle and microbes can amass. However, by considering that unit’s function and purpose, and incorporating the right design, dirt particles can be safely dispersed, mitigating risk.
A workbench is most frequently a solid surface. By ensuring it has open sides you again have a positive impact on air flow and reduce risk. A second shelf below should ideally not be solid. Instead, opting for a series of bars as a shelf allows maximum air flow and enables particles to move freely. Even chairs with solid backs can create blockages or still areas if poorly sited in relation to vents. When planning how your cleanroom will be used, take time to accurately predict where the windbreaks will be and how they can be mitigated. By taking time to consider what will stop and block air flow and prevent air particles from being effectively removed by your ventilation system, risk can be managed.
Without these upfront considerations, poorly designed or poorly purchased furniture can create dangerous harbourage points in which microbes thrive; quickly becoming super-bugs. Gravity-defying bacteria will take over an unassuming ledge in no time at all: growing, flourishing and spreading at an incredible rate, with the monitoring systems then creating extra demand on the HVAC system. Specifying the right furniture at outset can reduce your HVAC energy consumption.
Whilst in a perfect world we would avoid harbourage points altogether, efficient cleaning is, of course, GMP critical. Just as engineers are vigilant when specifying cleanroom furniture, ensuring the design supports the SOP for GMP standard cleaning, the same specification also supports self-cleaning using air flow.
As well as selecting furniture pieces that allow air flow and avoid particle build-up, clever cleanroom layouts also allow sufficient space between pieces. This is entirely critical too, as the space around the equipment can help prevent air stagnation.
Focus on where people will be working from
Mobile and modular furniture which can be easily moved around to free up space, make the clean down process for walls and floors much quicker, reducing lost time as well as providing flexibility in terms of working environment and project management.
Humans remain the main source of contamination in cleanrooms. The single biggest risk is the human factor, and the 10 grams of skin we each shed every day. While effective gowning reduces the risk of skin fragments escaping, ventilation and air flow need to disperse these potentially bacteria breeding particles. Focus on where people will be working from, and how air flow will be managed around your team to ensure ventilation can work most effectively to maintain stringent hygiene.
Just as you consider the position of vents and pieces of furniture; considering the placement and movement of your people too helps identify the contamination risks.
Consider reviewing the purpose of the smoke test, as there may be many more ways to use the insight these tests offer, beyond providing visual evidence that your ventilation system is directing air flow correctly. What about when you add furniture or people to the scenario? Each person, chair or desk will create a potential windbreak to halt the flow of air and reduce effective particle management and create additional energy demand. For smoke tests to provide a realistic picture, you need to factor in ‘real life’ to your test situation.
Where are your people going to be standing, working and where could blockages occur? Where are they moving to and from, with the potential to create an aftermath of particles behind them?
By understanding these hazards from the very start, the HVAC system can be specified and built to help manage risk and exceed compliance from the project outset. Effective risk management hygiene can never be compromised, but by thinking smart, and planning ahead, your business can successfully deliver ISO 140001 energy savings whilst also maintaining ISO 14644 hygienic standards. It’s a win-win for your business and the planet.