HVAC Plenum Installation

A plenum is an enclosed space used for heating, ventilation or air-conditioning (HVAC) air flow. Correct plenum installation requires certain materials and sealants, as identified by the system manufacturer.

Materials

Plenums should be constructed out of galvanized material, duct board or flexible duct. Building cavities may not be used as a plenum unless a sealed duct board or metal liner is also used.

Sealing

All joints and seams, including plenums, must be sealed with mastic, mastic and embedded mesh, or pressure-sensitive tape. Also check with the manufacturer to ensure the type of sealant used is appropriate.

Testing

Once installed, plenum must display the correct static pressure. Static pressure drop across the fan may be tested using a small probe in the return plenum and the supply plenum.

References

• The California Energy Commission: Procedures For HVAC System Design and Installation