Dirty and Moldy Ductwork
Air Handling Unit and Fan Coil Unit Problem 3
Mold Growth in duct
Damper inside AHU collecting condensation, leading to biological growth
Design
Conform to the design requirements for air duct systems, including fittings and accessories Fulfil the compliance requirements of thermal insulation for pipework. Comply with the ductwork seal requirements.
Ensure that rigid ducts are manufactured from steel, aluminum, glass-fiber or mineral wool, or other approved materials. Conform to the minimum duct insulation R-values for cooling supply / return ducts.
Construction
SS 652: F.6.3.1
Adopt the construction and installation requirements for air duct systems, their fittings and accessories.
Ensure duct or duct linings (places where glass fiber or mineral wool is exposed to the air stream) are suitably protected to prevent fiber erosion.
Ducts should be sturdily supported by using metal hangers and brackets for supporting ducts.
Guarantee that the inner surfaces of the ducts for supply and return air are smooth and resistant to abrasion in order to reduce dust accumulation.
All of the above has to be in accordance with SS 553, AS 1668.2 or equivalents.
Maintenance
SS 652: F.11.4.1.1
Carry out noise and air loss check when necessary.
SS 652: F.11.4.1.2
Perform testing and rating of performance of ducted air-conditioners (ventilation, exhaust, leakage air flow) in accordance with ISO 13253.
SS 652: F.11.4.1.3
Carry out yearly checks of ducting insulation.