Details

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Ventilation Systems Audit by EKG | AHU Fresh Air Intake Volume Measurement

In the tropical climate of Kuala Lumpur, the Fresh Air Intake is the most critical part of an Air Handling Unit (AHU). It is the "lungs" of the building, responsible for bringing in oxygen and pressurizing the space to keep out humidity and dust. If the intake volume is too low, the building becomes "stuffy" (high CO2); if it is too high, your cooling coils will freeze and your energy bills will skyrocket.

As part of a Mechanical Fan Overhaul, EKG performs precision Fresh Air Audits to ensure your building meets ASHRAE and DOSH (JKKP) ventilation standards for 2026.

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1. Why Measure Fresh Air Intake?

Most AHUs have "Fixed" or "Motorized" dampers that slip or clog over time. Without physical measurement, you are guessing your air quality:

• The "Sick Building" Risk: Low fresh air leads to the buildup of Volatile Organic Compounds (VOCs) and moisture, causing mold growth in ductwork.

• Infiltration Control: A building must be "Positive Pressure." If the intake volume drops, hot outside air leaks in through doors and windows, causing "sweating" on vents.

• Damper Linkage Failure: We often find that while the BMS (Building Management System) says the damper is 20% open, the mechanical linkage has snapped, and the damper is actually 100% closed.

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2. The EKG "Air-Flow" Audit Protocol

We use professional-grade metrology to capture the actual volume of air entering the system:

• Pitot-Static Traverse: We measure the "Velocity Pressure" at multiple points across the intake duct. This accounts for turbulence and provides a true average of the air speed.

• Thermal Anemometry: For low-velocity intakes, we use heated-wire sensors that can detect even the slightest breeze, ensuring accurate readings during "Low-Load" periods.

• Damper Hysteresis Check: We move the dampers from 0% to 100% and measure the volume at every step. This identifies "Dead Zones" where the motor is moving but the air volume isn't changing.

• Filter Pressure Drop Sync: We measure the "Resistance" (Static Pressure) across the pre-filters. If the filters are clogged, the intake volume will drop regardless of how wide the damper is open.

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3. The Energy Impact: The Cube Law

Fresh air is the most expensive air to cool because it is hot and humid. Balancing this volume is the fastest way to save energy.

• Demand Control Ventilation (DCV): By accurately measuring the intake, we can tune your Variable Frequency Drive (VFD) to pull in only the amount of air needed based on current occupancy.

• The Math: Reducing the total fan speed to compensate for an over-ventilated space yields massive savings. According to the Cube Law, a 20% reduction in fan speed results in a nearly 50% reduction in power consumption.

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4. Technical Audit Matrix

Audit Feature	Standard "Visual" Check	EKG Ventilation Audit
Air Volume	Estimated by damper %	Measured CFM / CMH (Traverse)
Air Velocity	Not Checked	Multi-point Anemometry
Dampers	Visual movement	Linkage & Seal Integrity Test
IAQ Correlation	None	CO2 & Humidity vs. Intake Volume
BMS Sync	Assume correct	Physical Calibration vs. Digital Readout

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5. Why Trust EKG for Ventilation Audits?

• NIST Calibrated Tools: We use sensors that are calibrated to international standards, ensuring your data is accurate for Green Building (GBI) or fire safety audits.

• BOMBA & Health Compliance: We ensure your "Make-up Air" meets the minimum requirements for life safety and occupant health.

• Vibration Signature Correlation: If the fan is vibrating excessively, it often creates "Pulsating Airflow" that ruins intake measurements. We solve the mechanical vibration before taking the final audit.

• Digital Reporting: You receive a full "Air Balance Report" showing the design volume versus the actual measured volume, with clear recommendations for VFD tuning.