Ducting

Ducting is a system of enclosed conduits used to convey air or other gases. In buildings, ductwork transports supply air, distributes return air, and exhausts stale air, forming the core of most heating, ventilation, and air conditioning (HVAC) systems. Ducting also appears in industrial settings for process ventilation, dust collection, fume extraction, and in vehicles for heating and cooling.

Ducts are made from rigid materials such as galvanized steel, stainless steel, aluminum, and PVC, or from flexible assemblies consisting of a plastic outer jacket with a fiberglass or foil core. Round ducts are common for airflow efficiency; rectangular ducts are easier to fit in tight spaces. Flexible ducts offer routing flexibility but generally have higher leakage and performance loss if overflexed.

Design and construction aim to balance airflow, pressure drop, energy use, noise, and space. Duct sizing uses required airflow, velocity limits, and friction losses; many designers use reference charts or software. Ducts should be insulated where temperature control or condensation is a concern, and joints should be sealed with approved mastic or foil tape to minimize leaks. Access doors, dampers, sensors, and vibration isolators may be included.

Installation and safety: proper supports and clearances prevent sagging and damage. Fire-rated ducts and fire dampers may be required in partitions and shafts. Cleanliness and hygiene are important in healthcare, laboratories, and food processing.

Maintenance and testing: regular inspection for leaks, corrosion, and mold, plus periodic cleaning where needed. Commissioning verifies airflow, balance, and control sequences.

Standards and codes: duct design and installation typically follow national or local codes and standards, such as those from IMC, ASHRAE, NFPA for leakage, filtration, and fire safety.