Examination of air leakage in exhaust fans

Examination of Air Leakage in Exhaust Fans for Global Market Access

As an ISO/IEC 17025 accredited laboratory, we deliver a comprehensive examination of air leakage in exhaust fans that verifies casing integrity, sealing performance, damper tightness, and energy efficiency. Our examination of air leakage in exhaust fans is designed for manufacturers and exporters of ventilation equipment who must demonstrate compliance with the EU ErP Directive, North American energy codes, GCC building regulations, and international performance standards. Every test is conducted under our CNAS-accredited quality system, producing reports that are accepted by notified bodies, customs authorities, and procurement teams worldwide.

Product Samples We Regularly Test for Air Leakage Examination

• Axial exhaust fans — wall-mounted, panel, window, and shutter-mounted models for general ventilation
• Centrifugal exhaust fans — forward-curved, backward-inclined, and plug fans for ducted and commercial systems
• Mixed-flow inline exhaust fans — compact duct fans for residential, commercial, and industrial duct runs
• Kitchen range hood blowers and grease exhaust fans — integrated motor-impeller units and remote mounted fan assemblies
• Bathroom ceiling and wall exhaust fans — including models with integrated lights, sensors, and humidity controls
• Roof-mounted exhaust ventilators and upblast fans — for general, fume, and smoke extraction
• Smoke and heat control exhaust fans — certified emergency ventilation equipment for life safety applications
• Industrial process exhaust fans — for chemical fume, dust, and high-temperature extraction

Axial and Wall-Mounted Exhaust Fan Air Leakage Testing

• Fan housing air leakage classification per AMCA 511 — the housing is pressurized to a series of static pressure levels and the leakage flow rate is measured using precision flow meters. The fan is then assigned a Leakage Class from A to D, establishing its suitability for ducted applications where air loss must be minimized.
• Casing leakage test according to ISO 5801 Annex A — leakage flow is quantified as part of the aerodynamic performance test, allowing correction of the fan curve for casing losses and verification of the manufacturer's published performance data.
• Panel-to-wall-sleeve interface leakage per EN 13141-4 — testing the seal between the fan panel and the building sleeve under negative pressure to measure exfiltration and infiltration at the installation boundary, critical for building energy balance.
• Gravity and motorized backdraft damper leakage — the damper is closed and subjected to a pressure differential in the reverse flow direction according to EN 13141-4, measuring the leakage rate to ensure that outdoor air, insects, and heat loss are prevented when the fan is off.
• Shutter and louver seal tightness — visual and flow measurement assessment of shutter blade closure under both pressure and no-flow conditions to detect gaps that cause thermal bypass in wall-mounted exhaust installations.

Centrifugal and Inline Duct Exhaust Fan Air Leakage Examination

• High-pressure casing and scroll leakage test per AMCA 511 and ISO 5801 — for fans operating at elevated static pressures, the casing is sealed at inlet and outlet and pressurized to the maximum rated pressure while recording leakage flow to ensure that the welded or gasketed scroll does not leak conditioned air into the building cavity.
• Inlet and outlet duct connection leakage — assembled fan with duct spigots and flexible connectors is tested using the pressure decay method or a calibrated flow meter per EN 1507 and EN 12237, verifying that site-installed duct joints will not become the dominant leakage source.
• Split-housing and access panel seal integrity — soap bubble application, ultrasonic leak detection, or trace gas testing along the split line and access covers of inline fans to identify localized leaks that compromise system efficiency.
• Impact of casing leakage on the fan performance curve — comparison of the catalog aerodynamic curve with measurements taken with and without casing leakage correction according to ISO 5801, quantifying the actual airflow delivered to the duct system versus the bare fan performance.
• Thermal and condensation bypass leakage — examination of cold-side and warm-side seal paths in thermal break fan housings to confirm that moist indoor air is not drawn into the insulation cavity, avoiding hidden condensation damage.

Kitchen Range Hood and Grease Exhaust Fan Leakage Assessment

• Grease enclosure tightness and welded seam integrity — the grease collection chamber and welded seams are subjected to a static pressure test with visual inspection for leakage, ensuring that grease-laden air cannot escape into the building structure or electrical compartments.
• Grease filter bypass and edge leakage measurement — tracer gas or aerosol challenge tests quantify the fraction of airflow that bypasses the grease filter, confirming that the stated filtration efficiency is achieved in practice and that ductwork remains protected.
• Backflow prevention and fire damper leakage — motorized fire dampers integrated into the exhaust fan are tested for blade leakage at ambient and elevated temperatures per EN 12101-3 and UL 762, verifying that smoke and flame cannot propagate through a closed damper.
• Housing leakage after accelerated grease loading — repeated simulated cooking cycles followed by leakage reassessment to demonstrate that gasket materials and seals maintain integrity under real-world kitchen operating conditions.

Bathroom, Domestic, and Light Commercial Exhaust Fan Air Leakage Inspection

• Housing leakage classification for Energy Star and ErP compliance — testing in accordance with AMCA 511 to achieve Leakage Class A or B, the typical requirement for low-energy residential fans, with measurements taken at the pressure differences specified by the Energy Star program and EU Regulation 1253/2014.
• Integral backdraft damper and duct adapter leakage — the factory-fitted damper and duct connector are tested as an assembly per EN 13141-4 and relevant sections of the UK Building Regulations Part F, measuring air loss that would otherwise reduce installed specific fan power.
• Sound-attenuated housing and acoustic lining bypass — verification that noise-reducing foam or baffle arrangements do not create internal short-circuit leakage paths that allow air to recirculate inside the housing rather than being discharged.
• Total system leakage simulation — testing the fan together with a representative length of flexible or rigid duct as sold in a kit, determining the system leakage factor to support accurate airflow prediction in multi-family and hotel ventilation designs.

Industrial and Smoke Control Exhaust Fan Leakage Verification

• High-pressure casing leakage for hazardous fume fans — fans handling toxic or corrosive gases are pressurized to a minimum of 1.5 times the maximum operating pressure per AMCA 511 Class A criteria, with helium leak detection used to identify micro-leaks at flanges and shaft seals.
• Smoke leakage test for emergency exhaust fans — pressurization with visible smoke or a tracer gas to demonstrate that the fan casing, access doors, and flexible connectors meet the leakage limits specified in EN 12101-3 and ISO 21927 for smoke and heat control systems.
• Flanged joint and gasket leakage measurement — calibrated flow meter testing of individual flanged connections and shaft penetrations to quantify leakage contributions from each potential pathway, supporting targeted design improvements.
• Post-durability leakage assessment — casing leakage is remeasured after vibration endurance, thermal cycling, and corrosion tests to confirm that sealing performance does not degrade over the required service life of the exhaust fan.
• Cleanroom and containment exhaust fan integrity — HEPA-filtered exhaust fan assemblies are tested for bypass leakage using aerosol photometry per ISO 14644-3, ensuring that unfiltered air cannot escape into the surrounding clean zone.

Report Recognition and ISO/IEC 17025 Compliance

All test methods referenced in this examination of air leakage in exhaust fans are covered by our ISO/IEC 17025 accreditation scope. Our technical reports are accepted by European notified bodies for CE marking and ErP compliance, by North American energy regulators and certification programs, and by building authorities across the Middle East, Asia Pacific, and Australia. Whether you need a first-article qualification for a new exhaust fan platform, batch verification of production units, or a failure investigation of field leakage complaints, our laboratory provides the measurement accuracy and regulatory knowledge that the global ventilation industry requires.