Few manufacturing units need to be as militant about maintaining indoor air quality as those of pharma. A slight rise in humidity and the manufacturing process is stalled; air filters are not functional and airborne impurities are incorporated in the product. Balancing intensive requirements with energy costs is akin to walking a tightrope. With a specialisation in HVAC systems for pharma, B Gautham Baliga, Director, Opal HVAC Engineers Pvt Ltd maps out a system for this industry.
What unique challenges do your pharma clients face related to their HVAC systems?
Some of the challenges that are unique to pharma clients are:
- Huge energy consumption made worse by overdesigning the systems
- High filtration requirements and filter cleaning or disposal
- Stiff validation requirements and documentation
- Service providers are inadequate in terms of capability to execute the requirements.
We help the pharma industry keep up to date with the latest standards and codes, and explain to customers the need for optimal design.
In general, what parameters should a pharma manufacturing unit adhere to when it comes to indoor air quality?
Pharma manufacturing units need to comply with relevant ISO & cGMP standards for HVAC which call for a high degree of filtration, inducting makeup fresh air, maintaining temperature and relative humidity, and using room pressure gradients for containment of contaminants. This brings about good indoor air quality if the standards are adhered to.
It must be pointed out that it is quite common for some of the manufacturing units to fudge data for audit. When this happens, pharma units can have very poor indoor air quality as these units may generate substantial quantities of airborne particulate or gaseous contaminants.
Is the HVAC system calibrated differently for production areas of different types of products (tablets, ointments, injectables, etc)?
Each of the production areas has a different set of environmental requirements. To start with, we have different cleanliness classes for various departments. This could be ISO Grade 5 for critical departments like aseptic filling areas to ISO8 for compression and granulation areas. There are in between cleanliness classes and CNC [controlled but non-classified] for other areas.
The cleanest areas are maintained at the highest pressures. Processes requiring containment may require negative pressures.
Though the most common relative humidity requirement is 40%~60%, there are processes that require relative humidity as low as 8~10%.
Depending on the drugs that are being processed, the filters can go right up to HEPA & ULPA filters.
What is the role of air filters in this industry?
Filters are at the heart of HVAC systems for the pharmaceutical industry. Huge air quantities are involved to churn the air many times through the system to achieve the desired air cleanliness. As a result, a large number of filters get used up. These filters need to be cleaned periodically or are to be used and thrown. In both cases, the costs involved are considerable.
Filter cleaning is a specialised task that needs to ensure that the filters are cleaned thoroughly without damage. The technicians ought to wear suitable PPE kits and the water consumed is safely disposed of.
An additional precaution is required to ensure that filters of one air handling unit are not mixed with another during the cleaning process as this will lead to cross-contamination.
How are energy efficiency, low humidity, and in some cases, also low temperatures/ balanced with each other in a pharma setup?
Energy required for HVAC systems is a significant portion of the total production cost of pharmaceutical products. To obtain high energy efficiency, it is not adequate to only concentrate on high-efficiency chillers, cooling towers, pumps, air handling unit fans, etc. One has to also look at the quality of filters that are responsible for consuming energy on account of what resistance they pose to the air that they handle.
Filters offer resistance to the air path and are thus responsible for guzzling power. Good air filters pose less air resistance for the same duty requirements compared to inferior quality filters. A life cycle analysis of filters is important whenever filters are to be procured.
Temperature in pharmaceutical departments is mostly decided by the comfort that needs to be provided. Very clean areas require heavy gowning of personnel and they will be comfortable in low temperatures (20°C~21°C). Less clean areas will require less stringent gowning of personnel and they will find comfort at higher temperatures (22°C~24°C).
Low humidity is mostly a process requirement. Otherwise, it is common to use 40%~60% humidity. In this range, the growth of pathogens is considered the least.
How can the pharma industry do better?
Specialized training for the design, installation, testing, and commissioning of HVAC systems and the associated validation and documentation is the need of the hour.
Inferior designs rely on empirical numbers and lead to overdesign most of the time. This leads to inefficient plant design apart from involving higher capital costs.
A well thought URS [User Requirement Specification] by the customer is a critical starting point for HVAC design. Gathering accurate data on heat dissipations and exhausts by the designer will result in correctly sized plants.