Airflow and pressure measurements provide the technical evidence needed to judge whether an LEV system continues to operate in accordance with its design information. Among the located UAE sources, Sharjah OSHJ-GL-12 gives the fullest description of what an LEV performance test should address. It names measurement locations and plant functions, but it does not prescribe a measuring instrument, a universal numeric pass value or a permissible deviation.
OSHJ-GL-12 Local Exhaust Ventilation, Version 1 Rev 0, September 2021, was issued by the Sharjah Prevention and Safety Authority under the Occupational Safety and Health System in Sharjah. It is a Sharjah Prevention and Safety Authority Guideline setting minimum acceptable requirements rather than federal law. Section 5.6.2.2 states: "The entity should measure the technical performance of the LEV system, including but not limited to: Measuring the air velocities at suitable test points indicated in the system documentation and includes hood faces, branch ducts and the main duct; Measuring static pressure at suitable test points indicated in the system documentation and includes all hoods, ducting, across the air cleaner and fan; Checking the fan speed, motor speed and electrical power consumption; Checking the replacement or make-up air supply; Testing alarms by simulating a failure, and the alarm's ability to detect the failure; Measuring air temperatures; Testing the air cleaner performance."
The clause links measurements to suitable test points indicated in the system documentation. It does not create a single generic location for every system. Hood faces, branch ducts and the main duct are identified for air-velocity measurements, while all hoods, ducting, the air cleaner and the fan are included in the static-pressure description.
The listed checks extend beyond velocity and pressure. Fan speed, motor speed, electrical power consumption, replacement or make-up air, alarm response, air temperature and air-cleaner performance all form part of the stated technical picture. The Guideline does not publish a numeric acceptance value for any of these items, and no averaging period or sampling basis is stated because no numeric measured limit is given.
The Sharjah provision does not use a single velocity term as a universal substitute for system performance. It requires air velocities to be measured at suitable test points identified in the system documentation and expressly includes hood faces, branch ducts and the main duct. Readings are therefore tied to the installed network and its records.
A hood-face reading concerns conditions at the interface where air enters the hood, while branch-duct and main-duct readings concern movement through different parts of the duct system. OSHJ-GL-12 does not publish a numeric pass value, a permissible deviation, an averaging period or a sampling basis for those readings. It also does not state how many readings are needed at a hood face or within a duct.
The absence of prescribed values makes the system documentation important. Design specifications, manufacturer information and commissioning data provide the intended reference identified elsewhere in the Guideline. Where suitable test points are not marked or documented, the resulting limitation should be stated rather than concealed by presenting an unsupported reading as a complete system test.
Section 5.6.2.2 also calls for static pressure to be measured at suitable test points indicated in the system documentation and includes all hoods, ducting, across the air cleaner and fan. This allows pressure information to be considered across the plant rather than at only one isolated point.
Pressure readings can reveal differences between parts of the system and can support examination of the air cleaner and fan. The Sharjah Guideline does not publish a numeric pressure criterion, a permissible departure from baseline, an averaging period or a sampling basis. It also does not state the form of pressure connection, the instrument range or the number of readings.
The reference to pressure across the air cleaner is particularly relevant where filter loading or cleaner condition changes system resistance. However, OSHJ-GL-12 stops at identifying the performance item to be measured. It does not prescribe a replacement threshold, a cleaning frequency or a universal pressure-drop value.
The same section continues: "The examiner should calculate volume flow rates, including: Comparing the results of testing with the LEV design specification as identified in the system manufacturer's manual; Diagnosing the causes of any discrepancies, the examiner may make simple alterations that restore the required performance."
This wording moves the work from isolated readings to engineering interpretation. Volume flow rates are to be calculated, results are to be compared with the LEV design specification identified in the manufacturer's manual, and discrepancies are to be diagnosed. The Guideline does not prescribe a calculation formula, a numeric tolerance or a universal percentage deviation.
The reference point is therefore system-specific rather than a single UAE-wide pass number. A meaningful record should identify the design or manufacturer information used for comparison and make clear whether the installed system still corresponds with that information. Alterations, extensions, changed hoods, replaced fans or modified air cleaners can affect whether older documentation remains representative.
The clause permits the examiner to make simple alterations that restore required performance, but it does not define the boundary of a simple alteration. Any adjustment and its effect should therefore be recorded, together with the results obtained after the change, so that a restored condition is demonstrated rather than merely asserted.
Section 5.6.2.2 states: "If a defect is fundamental or obscure, the examination should stop until the system has been repaired and its original performance restored." This stop rule deserves separate treatment because it prevents an incomplete or poorly understood defect from being normalised through continued testing.
A fundamental defect may affect the basic ability of the plant to operate as intended, while an obscure defect may prevent a reliable diagnosis from being reached. The Guideline does not define either expression and does not provide a numeric trigger. The decision must therefore be documented in terms of the actual defect and the reason that meaningful examination cannot continue.
The required sequence is repair, restoration of original performance and then continuation of the examination. The clause does not authorise a final pass based on partial measurements taken while the defect remains unresolved. Where original performance cannot be established because baseline information is missing, that evidential gap should be recorded plainly.
No located UAE instrument names a measuring instrument for LEV testing generally. The words "anemometer", "Pitot" and "manometer" each appear zero times in ADPHC Code of Practice CoP 52.0 Local Exhaust Ventilation, Version 4.1, dated 27 February 2026, and each appears zero times in Sharjah OSHJ-GL-12 Local Exhaust Ventilation, Version 1 Rev 0, September 2021.
The Sharjah Guideline lists what should be measured, including air velocity, static pressure, speeds, electrical power consumption, air temperature and air-cleaner performance. It publishes no numeric pass value, no permissible deviation and no instrument. ADPHC CoP 52.0 is also silent on anemometers, Pitot devices and manometers, so no UAE authority identified in these LEV sources names an instrument for LEV testing generally.
The single located UAE instrument requirement for any ventilation plant appears in Dubai Municipality DM-HSD-GU42-PSB2 Technical Guidelines for Paint Spray Booths V4.0, Section 4-2-4: "A dial gauge or manometer should be fitted to indicate static pressure drop across the filters". This is a Dubai Municipality technical guideline and not federal law, it applies to paint spray booths rather than LEV generally, and the modal word is "should". Static pressure drop is named, but the quoted clause states no numeric limit, averaging period or sampling basis.
That paint-spray-booth provision should not be generalised into a UAE-wide instrument rule for LEV. It is the only located UAE requirement that names an instrument for any ventilation plant, while no located UAE authority names an instrument for LEV testing generally. Instrument selection for an LEV test therefore remains a technical decision that must suit the quantity being measured, the expected operating range, the test location and the system information, without claiming that the selection is expressly prescribed by the cited UAE sources.
Related subjects sit on sibling resources covering respirable crystalline silica, industrial hygiene including ventilation and LEV assessment from the occupational hygiene angle, VOCs and indoor chemicals including adhesives, sealants and solvents, and construction dust; this page remains limited to LEV as engineering plant.
Sharjah OSHJ-GL-12 is a Sharjah Prevention and Safety Authority Guideline setting minimum acceptable requirements in the Emirate of Sharjah. Dubai Municipality Technical Guidelines are Dubai Municipality technical guidelines and apply in the Emirate of Dubai.
Sharjah OSHJ-GL-12 Section 5.6.2.2; ADPHC CoP 52.0 Version 4.1; Dubai Municipality DM-HSD-GU42-PSB2 V4.0 Section 4-2-4.
Answer: OSHJ-GL-12 Local Exhaust Ventilation, Version 1 Rev 0, September 2021, was issued by the Sharjah Prevention and Safety Authority under the Occupational Safety and Health System in Sharjah and is a Sharjah Prevention and Safety Authority Guideline setting minimum acceptable requirements, not federal law. Section 5.6.2.2 identifies air velocities at documented points including hood faces, branch ducts and the main duct, static pressure at documented points including hoods, ducting, across the air cleaner and fan, and checks of speeds, electrical power consumption, make-up air, alarms, temperatures and air-cleaner performance. The Guideline gives no universal numeric pass value, permissible deviation or measuring instrument.
Answer: No located UAE authority does so. ADPHC Code of Practice CoP 52.0 Local Exhaust Ventilation, Version 4.1, dated 27 February 2026, was issued by the Abu Dhabi Public Health Centre under ADOSH-SF and is mandatory for employers in the Emirate of Abu Dhabi, while OSHJ-GL-12 Local Exhaust Ventilation, Version 1 Rev 0, September 2021, was issued by the Sharjah Prevention and Safety Authority under the Occupational Safety and Health System in Sharjah and sets minimum acceptable requirements in Sharjah. The words "anemometer", "Pitot" and "manometer" each appear zero times in both LEV sources.
Answer: Dubai Municipality DM-HSD-GU42-PSB2 Technical Guidelines for Paint Spray Booths V4.0, Section 4-2-4, says that a dial gauge or manometer should be fitted to indicate static pressure drop across the filters. It is a Dubai Municipality technical guideline and not federal law, applies only to paint spray booths rather than LEV generally, and uses the modal word "should". The quoted clause gives no numeric static-pressure-drop limit, averaging period or sampling basis, and it is the only located UAE instrument requirement for any ventilation plant.
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