The Challenge:

Medical Environmental Control

A design engineering firm came to us to design a Medical Environmental Control system (ECS) that could maintain <3% relative humidity (RH) and 75°F temperature ±2° for automated packaging of biotherapy reagents, some of which were highly sensitive to moisture and sensitive to heat. The desiccant humidity control and temperature regulation system would be located in an ISO 8 cleanroom space with ambient air from 65-77°F (18.3-25°C) and at 35-75% RH. In addition, some of the packaged items would include liquids that would introduce an evaporative load into the environment prior to the placement of heat seals. The heat sealing equipment would introduce 400W of heat to the environment. Finally, the machine would contain a stainless steel, pressurized dry-environment enclosure air-locked to minimize the introduction of ambient air.

The Solution:

In order to dehumidify the system to the required conditions, Air Innovations introduced a desiccant dryer with pre-filtered air into the design of this environmental control system. Re-circulated air is then returned to the acceptable ambient temperature and passed through HEPA filtration to maintain the cleanroom environment, while the hot exhaust is ducted away from the ECS. The system was designed to sit below floor level, though the end location was ultimately moved onto floor level. The air change rate was designed to ensure a recovery time of less than 30 minutes anytime after the doors opened.

Medical Environmental Control System Medical Environmental Control System with Desiccant Humidity Control and Temperature Control

Key Specifications:

  • Relative Humidity controlled to ±0.5%, and set to <3% RH with 0.011 µg/min. continuous evaporation latent load plus moisture leakage loads.
  • Temperature controlled to 75°F ±2°F
  • ISO 8 cleanroom level HEPA filtration (99.97% to 0.3µ)
  • Environmental Control System designed to fit in a 37.5” x 52” trench
  • PID loop controls for temperature and humidity
  • Stainless steel 304 exterior
  • Airflow designed for 90 CFM – Max. external static pressure of 1”
  • Hot-gas bypass refrigeration control
  • 1kW electric reheater

The Result:

The medical environmental control system controls humidity to desiccant levels and maintains a steady temperature in the ISO 8 cleanroom space. The system also employs HEPA filtration.

  1. Meets all key specifications
  2. Addresses humidity requirements through both creation of a vapor barrier and use of return air via a desiccant dryer to counteract internal evaporative loading.
  3. Meets UL standards
  4. Features stainless steel 304 exterior.

Additionally, we have whitepapers available covering the aerospace industry, the semiconductor industry, and our Micro Environments product line. The whitepaper page can be found here. If you would like to read case studies for other industries, view our general case studies page. If you are interested in viewing more case studies for the pharmaceutical industry, look at the items below.