Exhaust Fan Is Running but Fumes Are Still There What Should You Measure Malaysia

Exhaust Fan Is Running but Fumes Are Still There What Should You Measure Malaysia The exhaust fan is running. You can hear the motor. You can feel some air movement. But workers still complain: “There is still chemical smell.” “Smoke is escaping from the process.” “Dust is still coming toward us.” “The fumes are not being captured properly.” “This extraction used to work better.” A common response is: “But the exhaust fan is ON.” That does not prove the ventilation system is performing correctly. A better question is: How much air is actually moving, and is it capturing the contaminant at the source? A practical investigation may involve: Source → Hood / Capture Point → Air Velocity → Duct → Filter → Pressure → Exhaust → Worker Area → Contaminant Measurement This is where MTM should move beyond selling an anemometer. The real product is: Ventilation Troubleshooting. 1. Fan ON Is Not the Same as Airflow Verified An exhaust fan can rotate while actual system performance is poor. Possible reasons include: Dirty filter Blocked duct Damaged duct Loose connection Fan deterioration Incorrect damper position Poor hood design Hood too far from source Process volume increased Insufficient make-up air Therefore: Sound from Fan ≠ Measured Ventilation Performance 2. Start With the Worker Complaint Ask: What is escaping? Is it: Dust? Smoke? Chemical vapour? Gas? Heat? Then ask: Where are workers affected? The contaminant determines what else may need to be measured. 3. Identify the Source Find the actual process generating the problem. Examples: Welding Grinding Cutting Painting Coating Chemical mixing Soldering Powder handling Heating Laboratory process The extraction system should be evaluated in relation to that source. 4. Look at the Capture Point A ventilation system may have strong airflow somewhere in the duct but still fail to capture contaminant at the source. Why? Because the hood may be: Too far away Poorly positioned Blocked Facing the wrong direction The most important measurement point may therefore be close to the actual capture location. 5. Measure Air Velocity An anemometer can help quantify suitable air velocity at relevant points. Possible measurement locations include: Hood Opening Duct Exhaust Supply / Make-Up Air depending on the system and troubleshooting objective. Now maintenance has numbers rather than: “I think the suction feels weak.” 6. Compare Similar Extraction Points If the factory has several similar lines, comparison becomes powerful. For example: Line A Good capture Line B Poor capture Compare appropriate airflow measurements. If Line B differs significantly, maintenance has a clear lead. 7. Compare With Historical Baseline Even better: Normal Air Velocity Previous versus: Current Air Velocity This is why factories should keep baseline data. Without baseline: “Feels weaker.” With baseline: “Measured airflow has changed.” 8. Check the Filter Filters can affect ventilation-system performance. As filter loading changes, system pressure and airflow may also change depending on the design. Where appropriate, differential pressure measurement can help investigate filter condition. 9. Differential Pressure Adds Another Layer A digital manometer or differential pressure instrument may be useful for suitable: Filter Pressure Duct Pressure Room Pressure or HVAC troubleshooting applications. This is different from measuring air velocity. The two measurements can complement each other. 10. Air Velocity and Pressure Are Not the Same Thing This distinction matters. Anemometer Helps measure suitable: Air Velocity Differential Pressure Meter Helps measure: Pressure Difference in appropriate applications. Do not buy one assuming it automatically replaces the other. 11. Example: Filter Is Becoming Restricted Possible pattern: Worker Complaint Increasing ↓ Air Velocity Decreasing ↓ Differential Pressure Changing ↓ Filter Inspection ↓ Filter Maintenance / Replacement ↓ Air Velocity Re-Test ↓ Worker-Area Re-Test This is a complete maintenance loop. 12. Duct Problems Can Reduce Performance The fan may be fine. The filter may be fine. But the duct may have: Blockage Leakage Damage Poor connection Incorrect damper position Measure along the system where appropriate to narrow down the problem. 13. Factory Layout Changes Can Break a Previously Good System This happens often. The factory adds: A new machine A partition A rack A production enclosure and suddenly workers complain. The fan did not change. But: Air movement changed. Always ask: What changed before the problem started? 14. Production Increase Can Overload the Existing Extraction Suppose the ventilation system was designed when: Two machines were operating. Now: Four machines are running. The fan is still on. But the contaminant generation rate or ventilation demand may have changed. This is why production conditions must be recorded. 15. Make-Up Air Matters Exhaust removes air from a space. That air must be replaced appropriately. Poor building air balance can affect ventilation performance. A troubleshooting investigation may therefore need to look beyond the exhaust fan itself. 16. Dust Complaint? Add Particulate Measurement If workers say: “Dust is escaping from the hood.” appropriate PM screening can help compare: Process OFF versus: Process ON and: Near Source versus: Worker Area Then combine this with airflow measurements. 17. Chemical Smell? Identify the Chemical If workers report: “Solvent smell is escaping.” ask: Which chemical? Can the SDS be reviewed? Depending on the identified substance and objective, suitable: VOC or: Specific Gas / Vapour measurement may be considered. Do not use a generic detector without knowing what it actually measures. 18. Gas Problem? Match the Sensor If the process can generate an identified gas, the detector must have the appropriate sensor. For example, a detector configured for: CO does not automatically measure: VOC or: CO or every other gas. Ventilation measurement and gas measurement answer different questions. 19. Smoke Visible at the Source Is Useful Information If smoke or fumes visibly escape the capture area, that can indicate a control problem worth investigating. But visual observation alone does not quantify: Air velocity Pressure Particulate or: Gas concentration Measurement adds objective data. 20. Example: Grinding Extraction Feels Weak Customer: “The dust collector is running, but workers say there is much more dust now.” Possible pathway: PM Screening ↓ Air Velocity at Hood ↓ Compare With Normal Line ↓ Differential Pressure Where Relevant ↓ Filter / Duct Investigation ↓ Maintenance ↓ Airflow Re-Test ↓ PM Re-Test This is far stronger than simply selling a PM meter. 21. Example: Solvent Smell Escapes From Coating Area Possible pathway: Identify Chemical / Review SDS ↓ Appropriate VOC / Vapour Measurement ↓ Measure Capture Air Velocity ↓ Check Hood Position ↓ Check Duct / Filter / Exhaust ↓ Corrective Action ↓ Repeat VOC / Airflow Measurement The problem is solved as a system. 22. Example: Welding Fume Is Not Being Captured Customer: “The extraction arm is on, but the welding fume still goes toward the worker.” Possible investigation: Check Hood / Arm Position ↓ Measure Suitable Air Velocity ↓ Observe Capture Behaviour ↓ Check Duct / Filter ↓ Corrective Action ↓ Re-Test Under Actual Welding Condition The position of the extraction point can be as important as the fan itself. 23. Example: One Exhaust Line Is Worse Than the Others This is an excellent comparison opportunity. Measure: Line A/span> Line B Line C under similar operating conditions. If only one line performs differently, troubleshooting becomes easier. 24. Example: Problem Returns a Few Months After Filter Replacement This creates a preventive-maintenance opportunity. Instead of waiting for worker complaints: Measure Normal Airflow After Maintenance ↓ Record Baseline ↓ Repeat Periodically ↓ Detect Deterioration ↓ Service Before Complaint Now ventilation monitoring becomes predictive maintenance. 25. Before / After Verification Is Critical Suppose the contractor says: “We already repaired the exhaust system.” The factory should ask: Did performance actually improve? Where appropriate: Measure Airflow Before ↓ Repair ↓ Measure Airflow After and if relevant: Measure PM / VOC / Gas Before and After Now improvement is measurable. 26. This Creates a Recurring Monitoring Program Critical ventilation systems can be monitored periodically. Possible baseline parameters may include: Air Velocity Differential Pressure Relevant Environmental Parameter Then maintenance can detect change earlier. What Instruments Might Be Needed? Depending on the ventilation problem, a solution may include: Anemometer For suitable air-velocity measurements. Digital Manometer / Differential Pressure Meter For appropriate filter, duct or pressure investigations. PM2.5 / PM10 Meter For suitable particulate screening. VOC Meter For appropriate VOC screening. Specific Gas Detector Where an identified gas requires measurement. Temperature & Humidity Meter Where thermal conditions are part of the ventilation complaint. Data Logger Where supported parameters need trend monitoring. Calibration / Verification Support Where measurement reliability needs confirmation. Not every ventilation problem requires every instrument. The correct combination depends on: Source + Contaminant + Hood + Airflow + Filter + Worker Location Don't Search Only for “Exhaust Fan Not Working” The fan may actually be running. The real questions are: How much air is moving? Is the hood capturing the contaminant? Is the filter restricted? Is the duct blocked or leaking? Has production increased? Has the factory layout changed? What reaches the worker area? This is ventilation troubleshooting. From “Fan Is Running” to Root Cause The better pathway is: Workers Still Complain ↓ Identify Contaminant / Source ↓ Measure Air Velocity ↓ Check Hood / Capture Point ↓ Check Filter / Differential Pressure Where Relevant ↓ Check Duct / Exhaust ↓ Measure Worker-Area Condition ↓ Correct ↓ Repeat Under Same Production Condition ↓ Keep Baseline Now the factory has measurable ventilation performance. One Exhaust Complaint Can Connect Multiple MTM Solutions Environmental PM → VOC → Relevant Gas Safety Worker Exposure Area → Atmospheric Monitoring Facility Air Velocity → Differential Pressure → Ventilation Maintenance Filter → Duct → Fan → Hood Service Instrument Verification → Calibration This is exactly the MTM solution approach: “Don't tell us only that the fan is running. Tell us what is still escaping.” From there, MTM helps determine what needs to be measured. Factory Exhaust, LEV & Ventilation Troubleshooting Solutions Malaysia MTM Precision supports: Manufacturing plants Welding areas Grinding processes Coating and painting lines Chemical processes Powder-handling areas Laboratories EHS teams Safety officers Facility managers Maintenance departments with measurement solutions covering: Air Velocity Differential Pressure PM2.5 / PM10 VOC Gas Detection Temperature & Humidity Ventilation Monitoring Filter Investigation Instrument Calibration & Verification Exhaust Fan Running but Workers Still Smell Fumes or See Dust? Tell MTM: What process is generating the problem? Is it dust, smoke, vapour, gas or heat? Where is the extraction hood? Has airflow been measured? When was the filter last serviced? Has production volume increased? Did the factory layout change? Does the problem disappear when production stops? MTM can help build the measurement pathway around the complete ventilation system. MTM Precision Sdn Bhd Showroom & Service Centre No. 29-1 & 29-2, Jalan Bandar 18, Pusat Bandar Puchong, 47160 Puchong, Selangor, Malaysia WhatsApp: +6016-660 7346 Email: mtmpre@yahoo.com Website: www.mtmpre.com.my Fan ON does not mean ventilation verified. Measure airflow → Find the restriction → Correct → Measure the contaminant again.