Industry-Specific Cleanroom Equipment

Laboratory Negative Pressure Control System

A room-level laboratory pressure-control package combining direct differential-pressure sensing, independent supply and exhaust VAV valve actuation, closed-loop flow tracking, a local HMI with alarm indication, and configurable BAS communications on one serviceable control assembly.

Closed-Loop Room Pressure Control
Supply and Exhaust Flow Tracking
Dual VAV Valve Actuation
Local HMI, Alarms and BAS Connectivity

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Product Introduction

The Laboratory Negative Pressure Control System is a fixed room-HVAC control package for laboratories that must maintain inward directional airflow relative to an adjacent space. A low-pressure transmitter measures the room-to-reference differential through two dedicated pressure tubes, while separate airflow pickups report the condition of the supply and exhaust terminals. The programmable controller compares the measured differential and airflow balance with the configured operating state, then commands the two VAV actuators to maintain the intended exhaust-over-supply offset without treating a fixed damper position as proof of room pressure. The illustrated purchasable assembly includes one powder-coated control cabinet, a local HMI, three status indicators, an alarm acknowledge control, a 24 V power supply, programmable controller and I/O, a network gateway, one room-pressure transmitter, one supply VAV valve and one exhaust VAV valve on an aluminum service frame. It is a control and demonstration package rather than a portable fan or filtration unit; room leakage, terminal airflow range, fan capacity, door behavior and the project risk assessment determine the final pressure setpoint and sequence.

Key Features

Direct room-to-reference differential-pressure measurement closes the control loop and supports alarm limits based on the actual room boundary rather than valve position alone.

Independent supply and exhaust VAV channels support airflow-offset control, minimum ventilation limits and coordinated recovery when a hood, door or room operating mode changes the air balance.

The door-mounted HMI, green-amber-red status indication and acknowledge control give operators a local view of normal, warning and alarm states before the signals are forwarded to the building system.

A segregated 24 V supply, programmable controller, I/O terminals and selectable network gateway keep sensor, actuator, alarm-relay and BAS connections organized for commissioning and service.

Customer Product Concerns

Stable laboratory containment depends on the measured relationship between room pressure, supply flow, exhaust flow and changing operating conditions rather than on a single fixed damper command.

A door opening, hood sash movement or building static-pressure change can upset the intended inward airflow even though the original damper command has not changed.The differential-pressure transmitter continuously feeds the room controller, which trims the supply and exhaust VAV outputs around the configured airflow offset and alarm limits.

Using one uncontrolled exhaust damper makes it difficult to preserve both minimum room ventilation and the negative pressure relationship across changing loads.Separate supply and exhaust valve channels provide measured-flow coordination, minimum-airflow constraints and a selectable lead-follow control sequence for the room.

Personnel may enter without knowing that the room differential has drifted outside its normal band or that an actuator has failed to reach command.The local HMI and three-state indication present room and valve status at the assembly, while configurable alarm relay and network points send the deviation to remote supervision.

A proprietary stand-alone controller can leave pressure, airflow and alarm data isolated from the facility automation strategy.The cabinet accepts selectable BACnet or Modbus communication hardware and organized I/O terminals for room-state contacts, alarm outputs and project-specific BAS integration.

Typical Applications

Chemical laboratories maintained negative to corridors or other non-laboratory circulation areasMicrobiology and biocontainment rooms requiring monitored inward directional airflow under a facility risk assessmentAnimal-research procedure or support rooms using cascaded pressure relationships between adjacent zonesVariable-air-volume laboratories where fume-hood exhaust and general exhaust must be coordinated with room supply airflow

Technical Parameters

Representative construction values for the illustrated freestanding twin-valve control assembly are listed below; pressure range, valve diameter and airflow capacity are selected for the actual room and duct design.

Core Material	EN AW-6063-T6 aluminum extrusion frame and mounting plate, galvanized-steel VAV bodies, a RAL 7035 powder-coated steel controller enclosure, engineering-plastic HMI, sensor and actuator housings, copper conductors and flexible pressure tubing
Panel Thickness	3.0 mm nominal aluminum equipment mounting plate
Effective Width	900 mm assembled service-frame width for the selected twin-valve configuration
Maximum Length	Up to 1200 mm overall assembled frame height including the support feet
Steel Facing Thickness	1.5 mm nominal powder-coated controller-enclosure sheet
Core Density	2700 kg/m³ for representative EN AW-6063-T6 aluminum frame material
Thermal Conductivity	201 W/(m·K) for representative EN AW-6063-T6 aluminum at 20 °C
Surface Finish	Natural anodized aluminum frame, RAL 7035 light-gray powder-coated cabinet, neutral galvanized-silver valve bodies, blue actuator housings, a white sensor module, black tubing, a dark-navy HMI and green-amber-red indicators
Joint Type	Bolted T-slot frame joints, bolted cabinet and VAV brackets, gasketed cable entries, barbed differential-pressure tube connections, sleeve or flanged duct interfaces and removable terminal-block wiring
Customization	Available based on the intended application and operating environment.

Available Options

Room-pressure sensor range, reference pickup arrangement, redundant sensing and project-specific normal, warning and alarm setpointsSupply and exhaust VAV diameters, airflow ranges, measured-flow stations, standard-speed or fast actuators and fail-safe operating positionsBACnet IP, BACnet MS/TP, Modbus RTU or hardwired BAS points with additional remote I/O as requiredAudible or remote alarm devices, emergency-power monitoring, fume-hood or biosafety-cabinet coordination and occupied, standby or purge room states

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