Testing & Commissioning (T&C): AHU Sound Power Level ($L_w$) Verification

In the 2026 Malaysian corporate and industrial landscape, Sound Power Level ($L_w$) Verification is a critical T&C requirement for high-spec office environments, hospitals, and luxury residences. Under MS 1525:2024, noise control is no longer just a comfort metric; it is part of the building's statutory Indoor Environmental Quality (IEQ) audit. Failure to verify sound levels can result in non-compliance with the NC 30-35 (Noise Criteria) targets required for Grade-A building certification.

At EKG (Malaysia) SDN BHD, we perform $L_w$ verification to ensure your VFD-driven AHU operates with Acoustic Excellence, preventing mechanical "rumble" from disrupting workplace productivity.

1. The Engineering Principle: $L_w$ vs. $L_p$

It is critical to distinguish between these two metrics during a statutory audit:

• Sound Power Level ($L_w$): The total acoustic energy emitted by the AHU itself. This is an inherent property of the unit and does not change based on the environment. It is expressed in decibels (dB) with a reference of $10^{-12}$ watts.

• Sound Pressure Level ($L_p$): What the occupant actually hears in the room. This is affected by the AHU Ducting Service, the distance from the vent, and the room's absorption materials.

Verification Goal: We verify the $L_w$ at the AHU discharge, inlet, and casing to ensure the manufacturer’s data matches the "As-Installed" reality.

2. Statutory Framework: MS 1525 & IEQ 2024

Under current 2026 enforcement, acoustic verification is a prerequisite for high-performance building ratings.

3. The EKG Acoustic Verification Protocol

Our mechanical specialists utilize Class-1 Sound Level Meters and Octave Band Analyzers to map the AHU’s acoustic signature.

1. Octave Band Analysis: We measure noise across frequencies from 63Hz to 8,000Hz. High-frequency noise (whistling) usually indicates a leakage in the Zero-Leakage Snap-Lock Duct Collars, while low-frequency noise (rumble) indicates an issue with the IE5 EC Fan Wall.

2. Casing Breakout Test: We measure the noise "breaking out" through the AHU panels into the plant room. This ensures the plant room's acoustic insulation is sufficient to protect adjacent office zones.

3. VFD Frequency Sweep: We ramp the VFD through its operating range to identify "Resonant Frequencies"—specific speeds where the AHU might vibrate excessively. We then program the VFD to "skip" these frequencies for silent operation.

4. The "Fire Mode" Statutory Witness Test

Even during emergency operations, acoustic integrity must be monitored per BOMBA (JBPM) 2026 standards.

• Smoke Spill Acoustic Limit: While noise limits are relaxed during "Fire Mode," the AHU must not exceed structural vibration limits that could lead to a mechanical collapse or "shaking" of the fire-rated ductwork.

• Automatic Fire Signal AHU Shut-off: We verify that when the fire alarm is triggered, the immediate cessation of fan noise allows for the building's Voice Alarm (VA) System to be clearly heard by occupants (typically requiring a reduction to <45 dBA).

• BOMBA Audit: JBPM officers verify the mechanical security of the AHU's acoustic attenuators during the annual Fire Certificate (FC) audit.

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

• Technical Integrity: We are T&C and Acoustic specialists, not fabricators. Our verification is an objective, empirical assessment of your system’s sound profile.

• Acoustic Problem Solving: If a unit is too loud, we don't just report it; we use Acoustic Sound-Attenuated Lining and Cushion Head Plenums to treat the source.

• Audit-Ready Reporting: We provide a comprehensive Sound Power Level Verification Report, including NC-Curve plotting required by your Registered Energy Manager (REM).

Is your AHU system creating distracting noise or failing its acoustic audit?

Contact EKG (Malaysia) SDN BHD today for a professional AHU Sound Power Level ($L_w$) Verification & Statutory Audit.