Cleanroom Energy Management
Cleanroom operators have typically put product safety and yields top of the agenda, giving energy efficiency a lower priority. The BSI’s 2010 Cleanroom Conference unveiled new standards that demand a greener ethos
All manufacturing sectors are facing major challenges in the current climate. Legislation is getting stricter, compliance increasingly expensive and international standards get ever more complex. Energy use is a further parameter for cleanroom operators to consider, with new regulation and standards coming into play as governments look to curb CO2 emissions and energy wastage.
The themes of the 3rd Annual Cleanrooms Conference organised by the BSI (British Standards Institution) Group in London this June were regulatory compliance and energy management.
Recent revisions to the cleanroom industry standard, ISO 14644, were discussed by Tony Harrison, Life Sciences manager, Pharmagraph, and the ISO standard for chemical contamination was reviewed by contamination expert and consultant Dick Gibbons; the validation of disinfectants was addressed by Karen Rossington, Shield Medicare (part of Ecolab), and the validation of cleanrooms was covered by Richard Swift, MS&T microbiologist, Eli Lilly. But the main new area of focus was on energy use and thus forms the focus of this report.
The cleanroom sector places a heavy requirement on HVAC, with air handling frequently run 24/7. The wide use of HEPA filters and the need to control humidity and temperature also notch up energy ratings. In the pharmaceutical and medical sectors, in particular, energy-expensive procedures have become in enshrined in the standards and are rigorously enforced by the regulatory authorities.
Tim Eaton, sterile manufacturing specialist, Astra Zeneca, travelled back in time to look at the development of clearooms over the past 50 years and revealed how many of the key pharma HVAC control parameters have their origins in the 1960s cleanroom technology developed for the electronics industry.
In particular, he looked at the evolution of cleanrooms as a result of NASA’s space travel programme in the 1950s and 1960s. He suggests it was from this period that the now familiar term “laminar flow” was introduced, as well as the specification of “0.46m/s velocity” and the requirement for “20 air changes per hour”. These concepts have since become “written in stone” in cleanroom guidelines, he said, regardless of their relevance or effectiveness in the different industry sectors.
Eaton believes there is a strong scientific rationale to challenge the current contamination control recommendations without affecting the effectiveness of the control. He maintains that with the required data to show there is no risk to product yield or safety, some of these parameters can be changed. For example, he said that AstraZeneca (AZ) had a number of locations using significantly less than the 0.46m/s velocity (typically around 30m/s) and that after two years of environmental monitoring, the drug company has found no notable cleanliness difference compared with the other working areas.
The situation is similar for the guideline suggestion of 20 air changes per hour. Eaton said that in his experience at AZ, two Grade B (10,000) cleanrooms performing the same manufacturing operation but with different volumes and significantly different rates of volume air supply, had both maintained similar levels of operational environmental cleanliness. Once inspectors were shown the monitoring data they were happy with the operations, he said.
He cited other research by Bill Whyte1 on unidirectional air flow (UDF) areas at the Orthopaedic Unit at Glasgow University, where measurements showed that after a certain point increasing velocities did not achieve lower contamination levels.
AZ and GSK are currently carrying out a combined study using smoke tests in a redundant parenteral development facility with UDF and non-UDF rooms and zones at AZ’s Macclesfield site. The aim is to study the effect of varying HVAC air velocity and air change rate on cleanroom cleanliness levels, under operational conditions.
What is clear from the studies so far, said Eaton, is that what is happening with the air in the cleanroom is fundamental to determining the optimum air velocities and that visualisation experiments involving smoke tests are key to understanding this.
In addition to considering a reduction in velocity from 0.46m/s to 0.3m/s, Eaton suggested other potential areas for energy savings are the use of fixed fan speed HVAC systems, which he believes can save energy in many applications compared with active fan systems; and the introduction of “out of hours set back” where the velocities and air changes are reduced in facilities not being used, i.e. overnight or at weekends – the proviso being that they air flow must remain high enough to maintain pressure differentials and that validated status needs to have been resumed before activities can be recommenced.
As with many energy saving options, these actions are much easier to achieve when considered at the design stage of a new building, rather than retrospectively.
Brendon McManus, md of Clean Air Technologies, reminded delegates that the UK’s mandatory Carbon Reduction Commitment (CRC) Scheme started in April and online registration ends on 30 September.
McManus said the qualification criteria for the scheme are any facilities in a group that have at least one half hourly meter (HHM). In the UK, HHMs are mandatory for all electricity customers with a maximum power demand (peak load) greater than 100kW. McManus suggested that a rule of thumb for qualification is if the company electricity bill is more than £30,000 p.a. and if, in 2008, the collective annual electricity supply through all HHMs was at least 6,000 MWh (£500,000).
The penalty for non-registration is £5,000 plus £500 per day until registered. Once registered, organisations then have to monitor their emissions through energy bills and purchase allowances to emit carbon dioxide (CO2).
Not only is the scheme designed to penalise those companies that do not show a reduction in CO2 emissions year-on-year, but companies will also appear in a league table so that brand image could also be affected by poor performance.
To improve their performance, McManus suggested that existing facilities should look first at quick wins within their existing air management systems. This involves giving the system a health check, getting rid of leaks and revalidating air commissioning data. On air handling units, he suggested: fitting efficient pre-filtration devices, as well as synchronous drive belts to fans, ensuring all heating and cooling coils are clean, monitoring and trending fan motors, correctly sizing humidifier bottles and cleaning strainers.
Air distribution systems should also be properly balanced to minimise fan resistance, he suggested. Any slippage of measured room air change rates from standard operating procedures (SOPs) should be removed. Companies should ensure terminal filter selection reflects current available technology and measure room air leakage rates of cleanroom envelope against the industry norm.
McManus also suggested that where rooms have changed use, it is worth considering whether the SOPs and environmental criterion reflect the current use. It is also worthwhile to do a site survey to identify system wastage.
Meanwhile, to help companies take a more structured and systematic approach to energy management, a new European Energy Management standard BS EN 16001 has been introduced.
Energy and environmental consultant at Tenby Consultancy Group, Trevor Floyd has been involved at committee level with the development of the standard on behalf of the Energy Institute. He suggested that BS EN 16001 fits neatly with the ISO 14001 Environmental Management standard, ISO 9001 Quality Management and other management systems.
The standard for Energy Management Systems, he said, can be used separately but had been designed to complement ISO 14001 and it applies to all types and sizes of businesses.
Energy monitoring is one of its main tenets and a key clause states: “The organisation shall… establish the relationship between energy consumption and its associated energy factors and shall at defined intervals, assess actual versus expected energy consumption.”
Thus, it requires companies to calculate how much energy they expect to consume and then to monitor how much they actually consume alongside associated energy factors, such as weather. In this way, companies can identify anomalies or exceptions.
While it will require some technical manpower to implement it – ie, someone who can calculate energy units – the standard is designed to ensure that systems are in place for continuous improvement in energy management and it enables companies to check their energy management performance against benchmarks from within their own company.
Already adopted by some European countries, BS EN 16001 is being updated to become ISO50001. Although the ISO version won’t be that different, said Floyd, it is not expected to be out for about another year.
It was clear from the conference discussion session, chaired by Tim Triggs, director, Dop Solutions, that while safety and product yield have been considered paramount, quality personnel have held sway over cleanroom operation and energy efficiency considerations have taken a back seat. But QA personnel are now conceding that through real-time monitoring records and particle data, inspectors can be persuaded that the previous “belt and braces” approach can be tailored to meet today’s energy management needs.
The conference also reinforced the need for companies to start, if they are not already doing so, monitoring energy use and to think about suitable ways of benchmarking performance from year to year.