AHU Ducting & Terminal Connection Setup: Constant Air Volume (CAV) Terminal Setup

In the 2026 Malaysian HVAC landscape, Constant Air Volume (CAV) Terminal Setups are specialized air distribution components used primarily in environments requiring a fixed air change rate, such as laboratories, hospital isolation rooms, and specific industrial "Safe Zones." While much of the industry has shifted to Variable Air Volume (VAV) for energy savings, CAV remains the statutory standard where Indoor Air Quality (IAQ) and pressure stabilization are non-negotiable.

At EKG (Malaysia) SDN BHD, our CAV terminal setups are engineered to be Sterile, Silent, and Statutory-Compliant, ensuring your facility meets the rigorous DOSH 2026 Industrial Code of Practice (ICOP).

1. The Engineering Principle: Mechanical Regulation

A CAV terminal (or CAV box) is designed to deliver a precise, constant volume of air regardless of the static pressure fluctuations in the main ductwork.

• Self-Acting Controller: Most modern CAV terminals utilize a mechanical or electronic controller. As the VFD-driven AHU modulates or other zones open/close, the CAV's internal damper automatically adjusts to maintain the pre-set airflow (e.g., 500 m³/h).

• Pressure Independence: This setup ensures that critical zones—like a surgery theater or a chemical exhaust hood—do not experience "airflow starvation" when the rest of the building's demand changes.

• Thermal Control: Because the airflow is constant, temperature is regulated by an integrated Reheat Coil (Electric or Hot Water) within the CAV box, which warms the air as needed to meet the room setpoint.

2. Statutory Framework: DOSH 2026 & EECA 2024

Under the Energy Efficiency and Conservation Act (EECA) 2024, CAV systems must be meticulously tuned to avoid excessive energy waste.

3. Installation Engineering: The Terminal Interface

A professional CAV outlet setup involves a coordinated sequence of components to ensure laminar flow.

1. Inlet Straight Run: To ensure the CAV’s internal flow sensor is accurate, we mandate a straight inlet duct run of at least 3 to 5 duct diameters. Turbulence at the inlet can cause the sensor to "drift," leading to statutory IAQ failures.

2. Cushion Head Plenum (CHP): On the discharge side, the CAV box is connected to a plenum box. This equalizes the pressure before the air enters the Ceiling Air Diffusers, ensuring a uniform throw.

3. VFD Coordination: Even with CAV boxes, the VFD Integrated Static Pressure Transducer is used to maintain a constant "static pressure setpoint" in the main duct, ensuring the CAV terminals have the necessary "driving force" to operate.

4. The "Fire Mode" Statutory Protocol

CAV terminal setups must comply with BOMBA (JBPM) 2026 fire compartmentation standards, which is particularly critical in laboratories.

• Fire & Smoke Dampers: CAV terminals serving different fire zones must be paired with a Motorized Fire Damper (MFD).

• Automatic Fire Signal AHU Shut-off: In a fire event, the AHU VFD initiates a full stop. The CAV damper is typically programmed to stay in its "Last Position" or "Fully Open" to allow for smoke purging, depending on the building's BOMBA-approved Fire Engineering Design.

• BOMBA Audit: JBPM officers will physically witness the fail-safe position of the CAV dampers during the annual Fire Certificate (FC) audit.

5. Why Partner with EKG (Malaysia) SDN BHD?

• Technical Integrity: Our CAV setups are led by mechanical specialists who perform Air Balancing (TAB) to verify that every terminal delivers its design airflow within a ±5% tolerance.

• Acoustic Excellence: We specialize in "Internal Acoustic Lagging" for CAV discharge ducts, ensuring that the sound of the regulating damper doesn't disturb occupants.

• EECA Compliance Support: We provide the "Flow Verification Certificates" required by your Registered Energy Auditor (REA) for mandatory statutory submissions.

Is your CAV terminal setup causing "airflow drift" or excessive reheat energy waste? Contact EKG (Malaysia) SDN BHD today for a specialized CAV Performance & Statutory Compliance Audit.