Cleanroom HVAC and Air Handling Equipment

Makeup Air Unit

A dedicated outdoor-air unit that replaces exhausted process air and maintains the intended cleanroom pressure relationship.

Exhaust Air Replacement
Pressure Cascade Support
Tempered Outdoor Supply
Airflow Tracking Control

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Product Introduction

The makeup air unit delivers conditioned outside air in proportion to fume-hood, process, canopy or room exhaust. Unlike a general fresh-air unit, its primary control duty is mass-balance: supply airflow must respond predictably as exhaust devices start, stop or modulate. Filters, coils and optional humidity treatment bring the outdoor air to a condition that the room or recirculation system can accept without upsetting temperature and moisture control. A low-leakage casing and fast fan response help prevent door forces and unwanted infiltration.

Key Features

Supply airflow can track a combined exhaust-air signal rather than operate at one fixed ventilation rate.

Tempering coils prevent replacement air from imposing abrupt heating, cooling or moisture loads on the cleanroom.

Fast variable-speed fan control supports stable room pressure during process exhaust transitions.

Separate intake filtration prevents outdoor particles from entering through uncontrolled building leakage paths.

Customer Product Concerns

A facility can have sufficient cooling capacity yet still lose pressure control when exhaust and replacement air do not change together.

Starting a process exhaust fan pulls adjacent cleanrooms below their pressure setpoint.The makeup fan follows the combined exhaust airflow signal with a configured offset for pressure cascade.

Untempered winter replacement air causes cold drafts and local condensation.Preheat and final heating stages deliver supply air at a controlled temperature.

Outdoor humidity overwhelms the room AHU during high exhaust operation.Cooling and dehumidification are sized for the full makeup-air latent load.

Unfiltered infiltration enters around doors when replacement air is insufficient.Measured makeup volume enters through staged filters and a defined supply path.

Typical Applications

Pharmaceutical process exhaust replacementLaboratory fume-hood makeup airClean manufacturing canopy exhaustChemical handling roomsHospital isolation support areas

Technical Parameters

Representative makeup-air unit casing and connection ranges are provided below.

Core Material	Closed-cell polyurethane or mineral-wool insulation within double-wall casing
Panel Thickness	50–60 mm insulated panel
Effective Width	800–3000 mm nominal casing width
Maximum Length	Up to 9000 mm with staged filtration and thermal treatment
Steel Facing Thickness	0.6–1.0 mm sheet steel casing skins
Core Density	40–43 kg/m³ polyurethane or 80–96 kg/m³ mineral wool
Thermal Conductivity	0.022–0.040 W/(m·K) according to insulation selection
Surface Finish	Powder-coated galvanized exterior with galvanized or stainless wet-section interior
Joint Type	Thermal-break frame and gasketed block joints with flexible supply-duct connector
Customization	Available based on the intended application and operating environment.

Available Options

Exhaust-airflow or room-pressure trackingGas, steam, hot-water or electric heatingChilled-water, DX or desiccant dehumidificationOutdoor roof, floor or plant-room arrangement

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