Cleanroom Installations & HVAC Recommendations

Recently, Pharmacy Purchasing & Products (PP&P) posted an article in their State of Pharmacy Compounding issue about the installation of cleanrooms in the United States. As one might predict, The number of cleanroom installations continues to grow. The reason for this increase is directly influenced by the anticipated release of the final (USP) regulations.

HVAC systems continue to be the number one concern when renovating an existing cleanroom space. According to PP&P, only 65% of US hospitals have a dedicated HVAC system for their cleanroom. That means that a whopping 35% of hospital pharmacy cleanrooms still share their HVAC system with other spaces…this can be cause for concern. 

Like many Cleanroom Design Specialists, Guardian Medical strongly suggests that cleanrooms use a dedicated air handler system. Best practice would suggest the following:

• USP requires 30 ACH in a hospital cleanroom; however, many consulting firms and manufacturers alike suggest that you aim for 40-60 ACH to prevent microbial growth. Some states, such as New Jersey, are setting microbial growth standards that almost dictate 60 ACH to meet that standard.
  • This number of ACH is harder to achieve when using a non-dedicated HVAC system.
• A dedicated HVAC system provides for easier balancing of the cleanroom space and gives better control of the temperature and humidity.
  • Changes elsewhere in a non-dedicated system can affect the balance, humidity, volume, and/or temperature of the cleanroom space.

• In addition to a dedicated air handler for the cleanroom space, dedicated exhaust fans should always be considered for Type A-2 and B-2 hoods.
  • A B-2 hood should have its own dedicated exhaust fan on the roof, per the manufacturer’s recommendations.
  • It is also advisable to have an additional exhaust fan for the low wall return in a room with a B-2 hood. In case the hood’s exhaust fan fails, the negative pressure of the room can be maintained.