In the 2026 Malaysian engineering landscape, AHU Casing Air Leakage Testing for SMACNA Class C is the fundamental verification for standard commercial installations. Under the Energy Efficiency and Conservation Act (EECA) 2024, even Class C (the standard leakage class for low-to-medium pressure units) is subject to rigorous audit. A "leaky box" is categorized as systemic energy waste, as the VFD-driven AHU must ramp up its fan speed to compensate for air lost through the casing, directly inflating your Building Energy Intensity (BEI).
At EKG (Malaysia) SDN BHD, we utilize precision pressure-testing rigs to ensure your AHU casing meets the airtightness requirements mandated by the Suruhanjaya Tenaga (ST) and MS 1525:2024.
Under the SMACNA HVAC Air Duct Leakage Test Manual, Class C represents the allowable leakage for rectangular ductwork and AHU casings. In the context of a 2026 statutory audit, failing to meet this benchmark can lead to the rejection of your building's energy efficiency certification.
| Metric | SMACNA Class C Target | 2026 Statutory Context |
| Leakage Class ($C_L$) | 24 (Rectangular) | Standard for general office & retail AHUs. |
| Max Allowable Leakage | Calculated via $F = C_L \times P^{0.65}$ | Proof of performance for the REM. |
| SFP Impact | Contribution to 1.6 kW/m³/s cap | Minimizing waste to ensure SFP compliance. |
We treat the AHU casing as a pressurized vessel, performing a "Static Pressure Test" to quantify the $m^3/h$ of air lost through seams, door gaskets, and panel joints.
System Isolation: All AHU openings (supply, return, and fresh air) are hermetically sealed using temporary blanking plates or high-tack adhesive films.
Pressurization: A calibrated DALT (Duct Air Leakage Testing) rig is connected to the casing. We pressurize the unit to its Design Operating Pressure (typically 500 Pa to 1,000 Pa).
Data Capture: We measure the steady-state airflow required to maintain that pressure. This value is our "Measured Leakage," which is then compared against the SMACNA Class C allowable limit based on the unit's total surface area.
Leak Detection: If the unit exceeds Class C, we utilize non-toxic theatrical smoke or ultrasonic leak detectors to pinpoint failures in AHU Body Restoration or panel seals.
Meeting Class C is about more than just energy; it is about protecting the building from the 90% humidity of KL and Selangor.
Vapor Barrier Protection: A casing that leaks air out also allows moist air to be sucked in during "Off-Cycles." This leads to internal condensation, violating DOSH 2026 hygiene codes.
Condensate Pan Integrity: During the leakage test, we specifically monitor the area around the drain pipe penetration. A leak here can cause "Air-Locking" in the P-trap, leading to pan overflows and mold.
Acoustic Containment: Air leaks are "Sound Leaks." By achieving a Class C seal, we ensure the unit maintains its NC 30-35 acoustic signature, preventing mechanical noise from polluting the office.
The casing's ability to hold pressure is vital for the life-safety requirements of BOMBA (JBPM) 2026.
Smoke-Tight Integrity: In the event of a fire, the AHU casing must act as a barrier. A unit that fails Class C leakage tests may allow smoke to bypass the Motorized Fire Dampers (MFDs) through the casing joints.
Pressure Spike Resilience: We verify that the casing and its AHU Box Repair patches can withstand the sudden torque and pressure surge that occurs during an Automatic Fire Signal AHU Shut-off.
BOMBA Audit: JBPM officers often review casing leakage certificates during the annual Fire Certificate (FC) audit to ensure the mechanical "envelope" is secure.
Technical Integrity: We are installation and T&C specialists, not fabricators. Our testing is an objective, third-party validation of the unit's real-world seal.
Audit-Ready Documentation: We provide a formal AHU Casing Leakage Test Report, including pressure-leakage curves and pass/fail certification for your Registered Energy Manager (REM).
BEI Optimization: By ensuring your casing meets Class C (or better), we help your facility achieve a higher BEI Star Rating, avoiding the statutory fines associated with the 2024 Energy Act.
Is your AHU "whistling" away your energy budget through leaky seams?
Contact EKG (Malaysia) SDN BHD today for a professional AHU Casing Air Leakage Test (SMACNA Class C) & Statutory Compliance Audit.
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