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Cleanroom Air Conditioning Systems
for Hardwall Modular Cleanrooms

Terra hardwall modular cleanroom with split A/C system: heat generating compressor module roof mounted, with cool air ducted to cleanroom Fan/Filter Units.
Terra recommends three options for air conditioning in hardwall cleanrooms.
  • Use of Existing HVAC System
    An existing heating, ventilating and air conditioning (HVAC) system provides the most effective and economical means to cool your modular cleanroom.

    Because filter/fan units (FFUs) draw air from the surrounding room, they pass cooled air directly into the cleanroom without the need for ducting or special exhaust systems. The additional load on an existing HVAC system can be calculated by adding the heat dissipated by the specified number of FFUs (@ approximately 1,000 BTU/hour/unit) and by equipment and personnel inside the cleanroom.
  • Air Conditioning Modules
    The modules below provide economical cooling in facilities without adequate HVAC. Based on the cleanroom size, desired temperature, and heat dissipated inside the cleanroom, Terra will configure the appropriate number of units.

    Note: In these applications, heat removed from the cleanroom is vented into the room outside. In the case of large cleanrooms and/or significant heat-generating equipment, this vented heat will raise the ambient temperature and place greater load on the A/C modules as well as any existing HVAC system.

    For most efficient operation, exhaust ducts and ventilation fans should be installed to vent heat outside the facility.
  • Auxiliary Central Air System
    In large modular cleanrooms, a split A/C system, which moves the heat-generating compressor outside the facility is preferable to the A/C modules. In such applications, Terra will provide a ducting and recirculation system that routes exhaust air to the A/C system and delivers cooled feed air to the ceiling FFUs in ample volume to maintain the desired air velocity inside the enclosure. In addition, Terra will work with a local A/C contractor to connect this recirculation system to a central air unit that meets cooling requirements and local codes.

Call Terra Universal to discuss the most economical, efficient air conditioning solution for your application.

stainless steel air return
Stainless Steel BioSafe™ Cleanroom with HVAC Module No. 6704-32 and stainless steel Vertical Air Return.
Air conditioning airflow
Polypropylene Vertical Air Return
features removable side panels for easy cleaning of unit's interior; top baffle plate minimizes air turbulence.
Cleanroom Air Conditioning Module
  • Modular HVAC units ensure comfort and productivity of garbed cleanroom personnel
  • External air baffles allow quick, easy control over ratio of recirculated/make-up air
  • Models available with humidity control maintain stable sub-ambient RH levels
  • All units include Vertical Air Return that directs cooled air to ceiling FFUs via either a ceiling plenum or flexible ducts

These modular units remove heat to keep working conditions inside a modular cleanroom cool and dry.

Each HVAC unit is mounted to a Vertical Air Return (VAR), which includes a plenum chamber mounted to the side of the cleanroom. This structure (polypropylene or steel, depending on room design) draws air from the cleanroom into the HVAC module and then directs cooled air upward to the cleanroom ceiling, where it enters either a ceiling plenum or duct manifold (see illustrations below). On BioSafe® Cleanrooms, return air is directed to the HVAC unit via ducts inside the BioSafe® panels. An adjustable baffle mounted outside the cleanroom lets you adjust the percentage of fresh make-up air.

A Terra application engineer will help select the HVAC module(s) appropriate to your cleanroom, based on room size, number of FFUs, and heat load. Typically, supplemental Vertical Air Returns are required to recirculate a portion of the cooled cleanroom air through ceiling FFUs. Select FFU Connect Packs to connect return ducts to individual FFUs.

Vertical Air Return (each services up to 3 FFUs)
  Cat. # Price
For Cleanrooms with up to 7' (2134 mm) ceilings 6601-10-HC/HE Price
For Cleanrooms with ceilings over 7' (2134 mm) 6601-11-HC/HE Price
A/C Modules: Includes air distribution Plenum.
All models operate on 230/208VAC, 60Hz, i Phase
KW AC Control Only AC and RH Control
Cat. # Price Cat. # Price
18,000 1.5 8 6704-27 Price
48,000 4 10 6704-28 Price 6704-31 Price
57,000 5 10 6704-29 Price 6704-32 Price

HVAC Air Return Configurations
Air Conditioning with a Ceiling Plenum
Cleanroom with ceiling plenum,
HVAC module and Vertical Air Return
Ductless Applications:
Air Conditioning with a Ceiling Plenum

In very large modular facilities, Terra recommends an insulated ceiling plenum, which provides cooled return air to the fan/filter units.

Air conditioning modules are mounted to air returns, which direct cooled air upward to the plenum. Depending on the number of fan/filter units (FFUs) being serviced, additional Vertical Air Return modules may be required to ensure ample recirculated air supply to the FFUs. Adjustable baffles on the A/C modules allow some fresh make-up air to enter the system.

Ducted Applications
Cleanroom with HVAC module, Vertical Air Returns and FFU Connect packs
Vertical Air Return connection to ductwork
Connect Pack
FFU connection using No. 6601-00 kit
Ducted Applications:
Air Conditioning without a Ceiling Plenum

In these structures, cooled air is directed from the HVAC module upward through an air return module (included with the A/C unit). This air return attaches to ductwork that feeds the Fan/Filter Units (FFUs) positioned on the cleanroom ceiling. A single A/C module can typically feed up to three FFUs.

Additional FFUs are typically fed air recirculated from the cleanroom through Vertical Air Returns, as shown in the illustration above. Depending on the number of fan/filter units (FFUs) being serviced, additional A/C or Vertical Air Return modules may be required. Adjustable baffles on the A/C modules allow some fresh make-up air to enter the system.
Each FFU requires an FFU Connect pack, which includes flexible ducting and all hardware required to connect and seal the duct.

FFU Connect Packs
Includes needed ducting, duct splitters,
mounting hardware
Cat. # Price
For Cleanrooms with up to 9' (2743 mm) ceilings 6601-00 Price
For Cleanrooms with ceilings over 9' (2743 mm) 6601-01 Price


UV Duckwork Sanitizers
UV Ductwork Sanitizers
Ideal for installation in HVAC returns, these UV modules decrease germ loads on ceiling HEPA filters, minimizing contamination of bio-cleanrooms and contributing to an aseptic processing environment.


File Type File Name Publication Date
White Paper (PDF) Cutting Cleanroom Costs
A few simple modifications to your cleanroom can increase efficiency, boost performance and slash operating expenses. Read about the steps you can take to optimize your controlled-environment facility.
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