BSI Standards PublicationWorkplace atmospheres — Electrical apparatus used for the direct detection and direct concentration measurement of toxic gases and vapours Part 1: General requir
Introduction
Electrical assemblies and components shall conform to the construction requirements of 4.2, where applicable
Gas detection devices designed for potentially explosive environments must utilize specific materials and adhere to construction and explosion protection standards outlined in the EN 60079 series.
Construction
General
Each device must be designed to allow users to perform regular functional checks effortlessly, and it should be compatible with appropriate devices for applying test gas, such as a field calibration kit.
Gas detection devices, including components like remote sensors, must be designed to operate safely in environments with corrosive vapors or gases These devices should also be capable of handling corrosive by-products generated during detection processes, such as catalytic oxidation Therefore, it is essential that they are made from materials that are proven to resist corrosion from these harmful substances.
All materials and components used in the construction of the apparatus shall be used within the manufacturer’s ratings or limitations unless otherwise specified by appropriate safety standards
For aspirated apparatus, inlet and outlet ports shall be unambiguously marked to ensure the correct connection of any sample and exhaust lines.
Indicating devices
Readily distinguishable indications shall be provided to show that the apparatus is energized, in alarm or in a special state
Portable apparatus shall provide visual and audible indications for both faults and alarms
If audible indications are provided for transportable or fixed apparatus, alarms shall be indicated as a minimum requirement
For fixed apparatus the indications may be shown at the control unit
The display and all devices used to indicate the measured value must have a resolution of at least 1% of the upper limit of the measuring range.
For EN 45544-2 apparatus the resolution shall be 10 % of the volume fraction of the standard test gas or better
Measured values on the display and all other devices for indication of the measured value shall be identical within their tolerances
Any measurements under or over the indication range shall be clearly indicated
If the apparatus has more than one indication range, the range selected shall be clearly identified
If only one indicating light is provided for signalling alarms and special states, it shall be coloured red
When using separate indicating lights or a multi-coloured indicating light, the priority of colours must be followed: a) alarm indicators should be RED; b) special state indicators should be YELLOW; and c) power supply indicators should be GREEN.
In addition to the colour requirements, the indicator lights shall be adequately labelled to show their functions
Measured values within the measuring range shall be indicated
Measured values that fall below the lower limit of measurement can be represented in three ways: a) as zero; b) with an indication that the value is below the lower limit; or c) by displaying the actual measured value.
For personal and portable devices, it is essential that if the measured value falls below -5% of the upper measurement limit, the device must either display the measured value or issue a fault signal.
All apparatus shall provide a fault signal at measured values below −10 % of the upper limit of measurement
Users can configure the apparatus to permanently disable any dead band while in measuring mode, and in calibration mode, the dead band will be automatically disabled.
Alarm output functions
Alarm set points and TWA alarm set points shall not be adjustable outside the indication range
When multiple alarm set points are available, the alarm with the highest set point must be latching and necessitate a deliberate manual action for reset Additionally, all other alarms, including Time Weighted Average (TWA) alarms, can be configured as either latching or non-latching.
Alarms shall remain in operation while the alarm condition is still present An audible alarm may be silenced if this audible alarm is not the only alarm signal
Alarm devices can be temporarily deactivated, and this deactivation must be signaled For fixed systems, a contact or transmittable output signal is necessary However, if alarms automatically reactivate within 15 minutes, output signals or contacts are not required.
EXAMPLE It might be necessary to de-activate alarm devices for calibration purposes
For personal and portable apparatus, the sound output of audible alarms shall not be less than 70 dB(A) at 0,3 m from the apparatus.
Fault signals
For fixed and transportable apparatus a transmittable fault signal shall be provided in the following cases: – failure of power;
– open circuit or short circuit (i.e loop failure) in one or more of the wires to any remote sensor
It shall be distinguishable from any alarm signal
Under-range values (e.g caused by drift) shall be indicated by a fault signal in accordance with 4.2.2.2
Automatically aspirated apparatus shall be provided with an integral flow-indicating device that produces a fault signal in the event of low flow
For apparatus where the sensor can be disconnected without opening the housing, the apparatus shall provide a fault signal in the event of a disconnection of the sensor.
Adjustments
All adjustment devices shall be designed so as to discourage unauthorised or inadvertent interference with the apparatus
EXAMPLE Examples would include procedural devices, in the case of a keyboard instrument, or mechanical devices such as a cover requiring the use of a special tool
Fixed equipment within explosion-proof enclosures must be engineered to ensure that any features for field adjustments, resets, or similar operations do not compromise the explosion protection of the apparatus.
The design of zero and signal amplification adjustments must ensure that changes to one do not impact the other If this is unfeasible, a clear adjustment sequence should be established and detailed in the instruction manual.
The equipment will not automatically perform a zero adjustment upon start-up If the user is prompted for a zero adjustment and does not make a selection, the system will automatically choose the 'No' option after 15 seconds.
Battery-powered apparatus
Apparatus powered with integral batteries shall be provided with an indication of low battery condition.
Gas detection transmitter for use with separate control units
The apparatus must come with a specification detailing the transfer function that correlates gas concentration with the output signal This specification should provide sufficient detail to verify the accuracy of the transfer function At a minimum, it must include data illustrating the relationship between the output signal and gas concentrations at 0 %, 10 %, 30 %, 50 %, 70 %, 90 %, and 100 % of the indicating range, along with full-scale output and status signals.
EXAMPLE Fault and inhibit are examples of status signals
Where necessary, equipment shall be provided with the apparatus to interpret the output signal or indication, which will enable the accuracy of the transfer function to be verified.
Separate control units for use with gas detection transmitters
The apparatus must come with a specification that outlines the transfer function, detailing how the input signal correlates with the calculated gas concentration This specification should provide sufficient detail to verify the accuracy of the transfer function At a minimum, it must include data demonstrating the relationship between the input signal and gas concentrations at 0%, 10%, 30%, and 50%.
70 %, 90 % and 100 % of the indicating range Required inputs for full-scale indication and status signals shall also be included in the specification
EXAMPLE Fault and inhibit are examples of status signals
Where necessary, equipment shall be provided by the manufacturer to provide the input signals, which will enable the accuracy of the transfer function to be verified.
Apparatus using software and/or digital technologies
The apparatus shall conform to EN 50271.
Labelling and marking
General
The apparatus shall be marked legibly and indelibly with a minimum of the following: a) name and address of the manufacturer; b) designation of series or type; c) serial number;
The year of manufacture may be encoded in the serial number, and the apparatus must indicate conformity with standards “EN 45544-2” and/or “EN 45544-3.” If space limitations prevent this information from being displayed on the device, it should be included in the instruction manual Additionally, any applicable markings must comply with the extra requirements outlined in EN 60079-0.
Identification of the gas to be detected
Personal, portable and transportable apparatus shall be labelled with the gas(es) to be detected or the gas(es) shall be indicated on a display.
Instruction manual
A comprehensive instruction manual must accompany the gas detection apparatus, offering clear and precise guidance This manual should include detailed instructions, drawings, and diagrams for the safe operation, installation, and servicing of the device Additionally, it must outline adjustment procedures and provide recommendations for optimal use.
1) the procedure for initial and routine calibration;
2) the calibration gas, including warning notes concerning the hazards associated with the calibration gases;
3) humidity and application time(s) of the calibration gas(es)
4) the calibration period If the calibration period is longer than 6 months it shall also be stated that conformity to this standard is only given for a 6 months period;
5) methods for verification of the response time;
For personal and portable apparatus, it is essential to conduct a functional check with gas before each day of use Additionally, the field calibration kit should include instructions on its usage, particularly regarding sample flow rate limits, if applicable Operational details must also be provided to ensure proper functionality.
2) whether the apparatus is intended to be used in potentially explosive atmospheres;
3) measuring principles and description of the apparatus functions;
4) times of response t 90 and t 50; times of recovery t 10 and t 50 and information on how they vary with temperature and humidity;
5) for instruments measuring TWA concentration, the reference period(s);
7) humidity limits and transient effects from humidity changes, if any;
8) pressure limits and, if appropriate, correction factor for pressure dependence;
11) relevant characteristics and construction details of required interconnecting cables;
12) for battery operated apparatus, battery type(s) and operating time(s) until low battery condition;
13) nominal orientation and orientation limits;
14) safety-related significance of the measuring sequence in non-continuous operation and possibilities of adapting the measuring sequence to the monitoring tasks;
17) gas mixtures expressly prohibited by the manufacturer;
18) ingress protection (IP), if claimed;
19) response factors, where appropriate, of the gases for which the apparatus is suitable;
21) the gases for which the apparatus is suitable, and its specified indication and measuring range(s), including, in particular, the lower limit of measurement;
22) measurement accuracy under operating conditions outside the specification of this standard, if applicable (see 5.1);
The article should include a description of any dead band along with the methods for its activation and deactivation Additionally, it must provide details regarding the storage life and limitations of the apparatus, replacement parts, and accessories, specifying applicable limits where necessary.
Understanding the impact of poisons, interfering gases, and oxygen-enriched or deficient atmospheres is crucial for ensuring proper performance in various environments It is essential to be informed about the adverse effects these substances can have on health and safety.
The apparatus must include essential information regarding electrical safety, specifying whether interfering gases are additive, subtractive, or synergistic For aspirated devices, it should detail the minimum and maximum flow rates, pressure, and for automatically aspirated models, the nominal flow rate and settings for low flow signals Additionally, it should outline the tubing type, maximum length, and size necessary for optimal operation, along with instructions to ensure sample line integrity and proper flow Alarms and fault signals must be clearly defined, including low battery indications, their duration, and options for silencing or resetting The document should also provide troubleshooting procedures for identifying malfunctions, specify non-latching alarm devices, and include installation and maintenance instructions for battery-operated units If applicable, it should offer sensor replacement instructions, a recommended parts list, and details on optional accessories, including their impact on the apparatus's characteristics.
Optional accessories for the apparatus include collecting cones, weather-protecting devices, and selective filters, with part numbers provided in the manual for identification The standard requires information on type testing, including the gases, measuring range, and claimed compliance accessories, along with the test laboratory details It is essential to include any special conditions of use and warning notes regarding the limitations of the sampling probe Additionally, actions must be outlined for situations where gas concentrations exceed the measuring range, affecting sensor properties like sensitivity or response time If the apparatus has nonlinear responses or requires a specific sequence for zero and span adjustments, supplementary instructions or information must be provided beyond the standard requirements.
General requirements for tests
Apparatus shall be fully tested for all the gases for which compliance with this European Standard is claimed
Apparatus manufacturers must verify any claims made in the instruction manual about special construction features or enhanced performance that go beyond the minimum standards This verification process may require extending or supplementing test procedures to ensure the claimed performance is accurate.
EXAMPLE Extended performance can include operation over an extended temperature range
To validate a manufacturer's claimed performance and unique construction features, it is essential to meet the minimum requirements outlined in this standard as well as EN 45544-2 or EN 45544-3 Additionally, any asserted extended performance must be verified Any supplementary tests should be mutually agreed upon by the manufacturer and the testing laboratory and clearly documented in the test report.
Samples and sequence of tests
Test samples
For the purpose of type testing, the tests shall be performed on three apparatus The EMC test (5.4.7.3) may be performed on only one of the three apparatus
An additional set of three apparatus may be used for the stability test, 5.4.8
If an apparatus fails during testing, the test laboratory will determine which tests need to be repeated with a replacement device This decision, along with its justification, will be documented in the test report.
Sequence
The apparatus must undergo all relevant tests as outlined in section 5.4, with Test 5.4.2 (unpowered storage) being conducted first The subsequent tests can be carried out in any order, and the sequence of tests performed during type testing must be documented.
A recommended sequence is given in Annex B
When testing a modified design of an apparatus that has already been evaluated under this standard, the test laboratory must determine which tests need to be repeated This decision, along with its justification, should be clearly outlined in the test report.
Gas detection transmitters
For gas detection transmitters the following tests shall be performed: 5.4.2 - 5.4.4.1, 5.4.5, 5.4.6.2 - 5.4.6.6, 5.4.6.8 - 5.4.6.11, 5.4.7 - 5.4.9 (if applicable) using the parameters of the transfer function.
Separate control units
For separate control units the following tests shall be performed: 5.4.2, 5.4.3, 5.4.4.1, 5.4.5.1, 5.4.6.1, 5.4.6.2, 5.4.6.4 - 5.4.6.6, 5.4.6.9, 5.4.7.2- 5.4.7.4 and 5.4.9 using the parameters of the transfer function pertinent to the specific type of gas detector
Test of compliance with general requirements
Tests must be conducted to verify that the apparatus meets the requirements outlined in Clause 4 While the testing requirements are generally clear, it is important to note that for short-circuit tests specified in 4.3, ballast resistors should replace each wire connecting the control unit to any remote sensor The resistor values must correspond to the maximum line resistances stated in the instruction manual to ensure compliance with this European Standard Additionally, the short-circuit device used should have negligible resistance and be applied at convenient points in the circuit, specifically at the sensor ends of the ballast resistors.
Apparatus with selectable range
Apparatus with multiple selectable gas indicating ranges must undergo testing for each range For the second and subsequent ranges, the testing requirements will be determined through an agreement between the manufacturer and the testing laboratory.
For EN 45544-2 apparatus, the most sensitive range specified in Annex A must be tested according to the entirety of section 5.4, while the calibration curves for the other ranges should be evaluated in accordance with section 5.4.3.2 as a minimum requirement.
For EN 45544-3 apparatus, it is essential to test the most sensitive range following the guidelines outlined in section 5.4, while the calibration curves for other ranges must adhere to section 5.4.3.2 at a minimum Additionally, the least sensitive range should be evaluated in accordance with section 5.4.6.9.
If the sensor changes with a range change, the apparatus shall be tested in accordance with the whole of 5.4 in the most sensitive range of each sensor.
Preparation of apparatus before each particular test
Dead bands shall be disabled
The device used for type testing must have a resolution of at least 10% of the indicated value for each test gas concentration Additionally, when clean air is tested, the resolution should be equal to or superior to that at the lowest test gas concentration.
Devices that meet the requirements of section 4.2.2.1 may not have adequate resolution for type testing Therefore, it may be necessary to enhance the number of decimal places displayed or to incorporate additional indicating or recording devices as outlined below.
The manufacturer must identify appropriate connection points for indicating or recording devices that have sufficient resolution to test the apparatus's compliance with the standard Additionally, the display and other output devices of the apparatus should align with the results from the indicating or recording devices.
The apparatus must be set up and configured for standard operation following the manufacturer's instruction manual, ensuring all required interconnections, initial adjustments, and calibrations are completed Adjustments can be made as needed at the start of each test.
Once a particular test has begun, further adjustments shall not be made except where specifically permitted by the particular test procedure
In particular, the following points shall be noted: a) Apparatus having remote sensors
In the tests outlined in section 5.4, the entire remote sensor, along with any attached protective components, must be exposed to the test conditions The test report should detail the specific configuration of the equipment, including any optional accessories that were used or removed during the testing process.
For devices equipped with connection options for multiple remote sensors, testing is required for only one sensor It is acceptable to replace all but one sensor with resistors that create the most challenging load conditions for the specific test The testing laboratory will establish these worst-case load conditions according to the guidelines outlined in the instruction manual.
For devices equipped with remote sensors, all tests must be conducted with resistances in the detector circuit that replicate the maximum line resistance indicated by the manufacturer However, if the minimum line resistance provides a more rigorous evaluation, the test laboratory may opt for that instead Additionally, this applies to apparatus with integral sensors.
The complete apparatus will undergo testing under specified conditions, excluding test gases, without detaching any standard components The test report will detail the precise configuration of the equipment, including the use or removal of any optional accessories.
Tests 5.4.6.3, 5.4.6.5 and 5.4.6.6 shall be performed without and with any sampling probe c) Alarm-only apparatus
Readings shall be taken using an external indicating or recording device connected to test points as specified in the third paragraph of this clause
The use of optional extra protective mechanical parts (e.g carrying case) shall be agreed between the manufacturer and the test laboratory
Optional accessories must be attached or removed based on which configuration yields the most unfavorable outcome for the test The specific setup of the equipment, including the use or removal of these accessories, will be documented in the test report.
EXAMPLE Weather protection is an example of an optional accessory.
Mask for calibration and test
The design and operation of a calibration mask must ensure that factors such as pressure and velocity within the mask do not affect the sensor's response or the accuracy of the results obtained when applying test gas.
A suitable mask may be provided with the apparatus together with details of suggested pressure and flow rate for application of calibration gases to the apparatus
If a suitable mask is provided with the apparatus then this mask may be used.
Normal conditions for test
General
The test conditions specified in 5.3.2 to 5.3.11 shall be used for all tests, unless otherwise stated in the particular test
Test gas(es)
The test gases shall be mixtures of clean air with the gas for which the apparatus is intended to be used
In cases where clean air is unsuitable due to the instability of the standard test gas, nitrogen will be utilized as the balance gas If the balance gas influences the sensor characteristics, the testing procedure must be mutually agreed upon by the manufacturer and the test laboratory, and this agreement should be detailed in the test report.
The tolerance on the nominal volume fraction of all test gases shall not exceed ± 10 % The volume fractions of all test gases shall be known to a relative expanded uncertainty of ± 5 %
For EN 45544-2 apparatus, the standard test gas must have a volume fraction as specified in normative Annex A For gases not listed in Annex A, an agreed value between the manufacturer and the test laboratory, taking into account the Limit Values, should be used and documented in the test report.
For EN 45544-3 apparatus, the standard test gas to be used shall have a volume fraction equal to the middle of the measuring range.
Flow rate for test gases
When the apparatus is exposed to the test gases, the flow rate of the gases shall be in accordance with the manufacturer’s instructions.
Power supply
Fixed AC or DC powered devices must operate within 2% of the manufacturer's specified supply voltage and frequency Battery-operated devices should start each test with new or fully charged batteries, although for extended testing, using a stabilized power supply is acceptable The temperature test (5.4.5.1) must be conducted using the battery supply.
NOTE Long term testing is deemed to last longer than the operating time with fully charged batteries.
Temperature
The ambient air and test gas shall be held at a constant temperature ± 2 °C within the range of 15 °C to 25 °C throughout the duration of each test.
Pressure
Tests will be conducted at pressures ranging from 86 kPa to 108 kPa, maintaining a maximum fluctuation of ± 1 kPa during each short-term test For long-term tests, it is essential to consider the effects of pressure variations, utilizing the outcomes from the pressure test (5.4.5.2).
Humidity
The relative humidity (r.h.) of the ambient air shall be within the range stated in the instruction manual throughout each test
It is recommended that the relative humidity is between 30 % to 80 % r.h
The relative humidity of clean air and test gases must be maintained between 40% and 60% throughout each test Additionally, the pressure test should be conducted using clean air and test gases that contain a constant volume fraction of water vapor.
The use of dry gases is permitted for types of apparatus where the test results are not affected by relative humidity
For brief test gas applications, the use of dry gases is allowed with mutual agreement between the manufacturer and the testing laboratory, considering the sensor's properties.
EXAMPLE Drying out is an example of a property of the sensor.
Stabilization
In each instance where the apparatus is subjected to a different test condition, the apparatus shall be allowed to stabilize under these new conditions before measurements are taken.
Orientation
The apparatus shall be tested in the orientation recommended in the instruction manual.
Communications options
For gas detection devices equipped with wired or wireless communication options, it is essential to conduct tests as outlined in sections 5.4.3, 5.4.5.1, 5.4.6.2, 5.4.6.5, 5.4.6.6, and 5.4.7.3 with all communication ports connected Ensure that the maximum transaction rate, cabling characteristics, and activity levels specified in the instruction manual are utilized during these tests.
Gas detection apparatus as part of systems
Gas detection systems must undergo testing as specified in sections 5.4.3, 5.4.5.1, 5.4.6.2, 5.4.6.5, 5.4.6.6, 5.4.7.2, and 5.4.7.3, ensuring that evaluations are conducted at the highest system communications transaction rate and activity level These tests should reflect the most extensive and intricate system configuration allowed by the instruction manual.
Tests
General
Stabilize the apparatus, including the battery when fitted, prior to the commencement of the tests, unless otherwise stated
Take one reading in clean air and in the standard test gas before and after each test, unless otherwise stated
The values of the indications used for verification of compliance with the performance requirements shall be taken after stabilization (see 3.36), unless otherwise stated
If the sensor characteristics prevent the apparatus from stabilizing within 7.5 minutes, the manufacturer and test laboratory must agree on a stabilization time, which should not exceed 7.5 minutes and must be documented in the instruction manual This agreed stabilization time will also be applicable for calibration, adjustment of the apparatus, and during tests 5.4.6.5 and 5.4.6.6.
Unpowered storage
The apparatus must undergo sequential exposure to specific ambient air conditions: first, a temperature of (−20 ± 3) °C for (24 ± 0.5) hours; second, a temperature of (20 ± 5) °C for (24 ± 0.5) hours; third, a temperature of (40 ± 2) °C for (24 ± 0.5) hours; and finally, a return to a temperature of (20 ± 5) °C for a minimum of 24 hours.
The humidity requirement of 5.3.7 does not apply at the temperature of −20 °C The humidity of the ambient air shall be such that condensation does not occur
Temperature variations can only occur with mutual consent between the manufacturer and the testing laboratory Any temperatures outside the specified range must be documented in the test report.
Measurement of deviations
5.4.3.1 Zero uncertainty, relative expanded uncertainty and calibration curve for EN 45544-2 apparatus
Each reading must be conducted after a time interval of 10 times the response time (t50) for the test gas application and 10 times the recovery time (t50) for the clean air application, as outlined in the instruction manual.
The apparatus should be tested with gas volume fractions of 0.1, 0.5, 1, 2, and 5 times the standard test gas volume fraction, as well as at 90% of the upper measurement limit It is important to avoid using test gases with volume fractions outside the specified range For each volume fraction, the apparatus must be exposed to clean air followed by the test gas, and this cycle should be repeated six times to ensure accurate results.
For gases that are challenging to manage at low volume fractions, it is essential to utilize the minimum test gas volume fraction that is below the standard This minimum volume fraction must not exceed 0.2 times the standard test gas volume fraction.
For each test gas volume fraction, determine the relative expanded uncertainty as outlined in section 6.2.3 Additionally, calculate the lower limit of measurement according to section 6.3, utilizing the clean air readings alongside the test gas volume fractions, extending up to twice the standard test gas volume fraction.
5.4.3.2 Calibration curve for EN 45544-3 apparatus
Each reading should be conducted after a time interval of 10 times the response time (\$t_{50}\$) for test gas applications and five times the recovery time (\$t_{10}\$) for clean air applications, as outlined in the instruction manual.
The apparatus should be tested by exposing it to gas volume fractions of 0%, 10%, 30%, 50%, 70%, and 90% of the upper measurement limit, beginning with the lowest fraction and progressing to the highest This procedure must be repeated three times consecutively to ensure accuracy and reliability of the results.
Mechanical tests
The vibration test machine must include a vibrating table that can generate vibrations with adjustable frequency and amplitude, ensuring that the test equipment is securely mounted, in compliance with EN 60068-2-6 and the specified testing procedures.
The requirements for ambient temperature (5.3.5) and humidity (5.3.7) need not be fulfilled; the temperature and humidity conditions shall not result in damage to the sensor
The test shall be performed in accordance with EN 60068-2-6
The apparatus must be securely positioned on the vibration table, utilizing any standard resilient mounts, carriers, or holding devices that come with the equipment.
The apparatus will be powered and securely attached to the vibration test machine, undergoing sequential vibrations in three distinct planes, each aligned with one of the apparatus's three major axes.
The alarm set point shall be set:
– for apparatus specified in EN 45544-2, at 80 % of the standard test gas volume fraction;
– for apparatus specified in EN 45544-3, at 10 % of the indicating range
If the alarm set point cannot be set at this volume fraction, the alarm set point shall be set as close as possible to this volume fraction
Before and after the test, measurements shall be taken in clean air and then with standard test gas
During vibration, the apparatus shall be operated in ambient air If necessary, clean air may be applied to the sensor in order to obtain a stable reading
The apparatus must be vibrated for one hour in each of the three mutually perpendicular planes, covering the specified frequency range at the designated excursion or constant acceleration peak The frequency will change continuously in an exponential manner over time, with a rate of one octave per minute.
For portable and transportable apparatus, remote sensors, and apparatus with integral sensors, the vibration shall be as follows:
– 10 Hz to 31,5 Hz, 0,5 mm displacement amplitude (1,0 mm peak-peak total excursion);
– 31,5 Hz to 150 Hz, 19,6 m/s 2 acceleration amplitude
For control units, the vibration shall be as follows:
– 10 Hz to 31,5 Hz, 0,5 mm displacement amplitude (1,0 mm peak-peak total excursion);
– 31,5 Hz to 100 Hz, 19,6 m/s 2 acceleration amplitude
This test is applicable exclusively to portable and transportable equipment If the instruction manual indicates that parts of fixed equipment can function as portable or transportable, those parts will be treated as such for testing purposes Additionally, if the manufacturer advises using the equipment within its carrying case, the test must be conducted with the case included.
Portable apparatus shall be released, while operating, from a height of (1 ± 0,05) m above a concrete surface and allowed to free fall
Transportable apparatus with a mass less than 5 kg shall be released, while not operating, from a height of (0,3 ± 0,03) m above a concrete surface and allowed to free fall
Other transportable apparatus shall be released, while not operating, from a height of (0,1 ± 0,02) m above a concrete surface and allowed to free fall
The test must be conducted three times, with the portable apparatus released each time on a different side facing down, while ensuring the transportable apparatus is oriented for standard transport.
Before and after the test, measurements shall be taken in clean air and then with standard test gas.
Environmental tests
The test must be conducted in a temperature chamber that can maintain the specified temperatures within ± 2 °C Both the clean air and standard test gas should match the chamber's atmospheric temperature Additionally, the dew point of the test gases must remain below the lowest temperature of the chamber and be kept constant throughout the test.
While waiting for the apparatus to stabilize at the new temperature, the sensor shall be exposed to the ambient air inside the temperature chamber
The requirement of 5.3.7 relating to the ambient air does not apply The humidity of the ambient air shall be such that condensation does not occur
At each temperature record the indication in clean air and standard test gas and then perform test 5.4.6.2 Tests shall be carried out:
– For control units: at temperatures of 5 °C, 20 °C and 55 °C;
– For personal and portable apparatus:
– For all other types of apparatus: at temperatures of −25 °C, 5 °C, 20 °C and 55 °C
Where the manufacturer specifies another temperature range, the apparatus shall be tested at 20 °C and at the upper and lower limits of this temperature range
To achieve the desired volume fraction of substances with low vapor pressures in the test gas, it may be necessary to raise the minimum temperature.
To observe the effects of pressure variation, the apparatus, including the aspirator, must be placed in a test chamber that allows for pressure adjustments The pressure should be stabilized at specified levels of 80 kPa, 90 kPa, 100 kPa, 110 kPa, and 120 kPa for a duration of 5 minutes before any readings are taken or tests conducted.
The pressure shall be changed with a rate less than 20 kPa/h
The requirement of 5.3.7 relating to the ambient air does not apply The humidity of the ambient air shall be such that condensation does not occur
The apparatus shall be exposed sequentially to clean air and then standard test gas at each pressure
For EN 45544-2 apparatus only, calculate the differences between the measured values in standard test gas for each 10 kPa step, i.e 80–90 kPa, 90–100 kPa, 100–110 kPa, 110–120 kPa
The apparatus shall be allowed to stabilize at 40 °C After a stabilization time of at least 2 h at (40 ± 1) °C, the equipment shall be calibrated and adjusted as specified in the instruction manual
NOTE The instruction manual includes the humidity of the test gases and the application times
The test will be conducted at relative humidities of 20%, 50%, and 90% at a temperature of 40 °C Each humidity level requires the apparatus or sensors to stabilize in clean air for a minimum of 15 minutes before being exposed to the standard test gas It is essential that the relative humidity levels are accurately known within ± 5% r.h.
The volume fraction of the standard test gas must remain constant, or adjustments should be made to account for variations in volume fraction caused by the water vapor pressure in the test gas.
To prepare a stable test gas mixture for specific gases, it may be essential to lower the temperature and/or maximum humidity level The instruction manual will detail the tested temperature and highest humidity level required for this process.
The effects of air velocity on diffusion apparatus shall be determined by the following test with clean air and standard test gas
The remote sensors of apparatus with remote sensors and, when practicable, the entire apparatus if the sensors are integral shall be tested in a flow chamber
For apparatus with integral sensors that are too large for testing in a flow chamber, alternative flow equipment may be used for the test The test report must include a description of this alternative flow equipment.
The apparatus or sensor shall be operated in the orientation recommended by the manufacturer If there is no such recommendation, e.g for portable apparatus, a typical orientation shall be used
Irrespective of whether a flow chamber or other flow equipment is used, the direction of the air flow with respect to the sensor inlet shall be as follows:
1) flow directed at the sensor;
Each orientation is given with a tolerance of ± 5°
Measurements shall be made under no forced ventilation conditions, at (0,5 ± 0,1) m/s, (3 ± 0,3) m/s and at
Directions of flow not likely to occur in practice due to the design of the apparatus or expressly prohibited within the instruction manual shall not be tested.
Performance tests
When equipment includes user-adjustable alarm set points or pre-set alarm points, the activation of these alarms by gas at the designated set point values must be confirmed using test gas and air mixtures.
For apparatus of type a) above with a single alarm set point, set it to a point equivalent to 80 % of the volume fraction of standard test gas
For apparatus of type a) above with more than one alarm set point, set all of the alarm set points separately to 80 % of the volume fraction of standard test gas
If an alarm set point cannot be set at this volume fraction, the alarm set point shall be set as close as possible to this volume fraction
For apparatus of type a), the alarm set points are configured at 80% of the volume fraction of the standard test gas In the case of apparatus of type b), the pre-set alarm point is established within the range of 70%.
80 % of the volume fraction of the standard test gas, the activation of the alarm shall be checked by exposure to standard test gas
For apparatus types a) and b), any alarm with a set point below 70% or above 80% of the standard test gas volume fraction should have the sensor exposed to a test gas/air mixture that is equivalent to the specified conditions.
(120 ± 10) % of the volume fraction corresponding to the individual alarm set point
If a latching alarm is provided, the latching and the manual reset action shall be checked
5.4.6.2 Time to alarm or alarm reading
This test is part of the temperature test, see 5.4.5.1
Set the alarm to 15% of the upper measurement limit Then, introduce a step change from clean air to a test gas at 75% of the upper measurement limit.
If the alarm set point is pre-set by the manufacturer and cannot be changed, a test gas equivalent to five times the pre-set set point shall be used
Introduce the test gas by means of a mask or a chamber filled with this test gas into which the sensor is rapidly introduced
Measure the time from the step change to the alarm activation, or if an alarm is not available, track the duration until the measured value reaches 15% of the upper measurement limit.
This test shall only be performed for aspirated apparatus
For automatically aspirated apparatus, an adjustable low flow signal shall be set to the minimum set point
To evaluate the low flow signal, reduce the clean air flow rate until the low flow signal activates Subsequently, expose the apparatus to a standard test gas and adjust the flow rate accordingly.
– from 130 % of the nominal flow rate or, if this is not possible, from the nominal flow rate,
– to 110 % of the flow rate at which the low flow signal is set
All other aspirated apparatus shall be tested by varying the flow rate of standard test gas from the maximum to the minimum value as specified in the instruction manual
Expose the apparatus to clean air and standard test gas until stabilized and record the reading
After turning off the apparatus, allow it to sit in ambient air for at least 24 hours Next, expose the apparatus to clean air for a minimum of 1 hour Once the warm-up time specified in the instruction manual has elapsed, switch the apparatus back on and record the reading Finally, expose the apparatus to the standard test gas until it stabilizes, and document the reading.
The apparatus shall be in its normal operating state, without optional accessories attached to the apparatus for special purposes
Expose the apparatus to a step change from clean air to standard test gas
The relative humidity of clean air and the standard test gas must meet the specifications outlined in section 5.3.7 for ambient air Additionally, the humidity difference between the clean air and the test gas should not exceed 5% relative humidity.
To evaluate the diffusion apparatus, conduct a test using a chamber filled with the test gas, enabling exposure to a step change An example of this test chamber is provided in Annex C If the characteristics of the test gas prevent the use of the chamber, an alternative method is to utilize a mask.
EXAMPLE Examples of such properties are absorption and stability
For aspirated apparatus, the step change shall be applied at the gas inlet
Measure the time intervals t50 and t90, from making the step change to obtaining 50 % and 90 % of the final indication
The apparatus shall be in its normal operating state, without optional accessories attached to the apparatus for special purposes
Expose the apparatus to a step change from the standard test gas to ambient air or clean air
The difference in humidity between ambient air, clean air and test gas shall not be greater than 5 % r.h
Perform this test for diffusion apparatus by applying standard test gas using the mask then suddenly removing the mask
Perform this test for aspirated apparatus by applying the step change at the gas inlet
Measure the time intervals t10 and t50 from making the step change to obtaining 10 % and 50 % of the initial indication
It is recognized that the time of recovery is not defined for irreversible measuring techniques, and when this is the case, this test shall not be performed
EXAMPLE Some paper tape instruments are irreversible measuring techniques
5.4.6.7 Addition of sampling probe (portable and transportable apparatus only)
The apparatus shall first be exposed to clean air and the standard test gas without the sampling probe The sample probe shall then be added, and the exposures repeated
Calibrate the apparatus with clean air and standard test gas using the field calibration kit according to the instruction manual
Apply clean air and standard test gas to the apparatus as in normal operation
The relative humidity of clean air and standard test gas must comply with section 5.3.7 regarding ambient air humidity Additionally, the humidity difference between clean air and the test gas should not exceed specified limits.
EXAMPLE A mask for calibration and test is an example of a field calibration kit
5.4.6.9 Gas concentrations above the full scale indication
Measurements shall be taken in clean air and standard test gas
Expose the apparatus to a sudden change from clean air to a test gas at a volume fraction twice the full-scale indication Maintain this condition for 10 minutes for personal and portable devices, and for 30 minutes for fixed and transportable equipment.
Expose the apparatus to clean air for 60 min and record the final indication Expose the apparatus to standard test gas until stabilized and record the indication
5.4.6.10 Extended operation in test gas
Measurements shall be taken in clean air
Operate the apparatus for 8 hours daily using standard test gas for a duration of 3 days, or until the end of the calibration period for devices with a calibration time shorter than 3 days During the remaining hours of each day, ensure the apparatus is turned off and stored in ambient air.
For each 8 h period, record the indication after 10 min, at 4 h and at the end of the period
After the final 8 h period, expose the apparatus to ambient air for 60 min and then record the indication in clean air
Measurements shall be taken in clean air and standard test gas
Operate the apparatus continuously for 7 days in test gas, or for a duration less than 7 days if the apparatus has a shorter calibration period, until the calibration period concludes The test gas volume fraction must be maintained at (20 ± 2) % of the standard test gas volume fraction.
NOTE A more precise volume fraction is not needed This test is only to determine the effect on the apparatus of continuous exposure to a background level of toxic gas
Expose the apparatus to ambient air for 60 min and then record the indication in clean air and standard test gas
Rotate the apparatus 360° in 45° increments around each of its three mutually perpendicular axes while applying clean air followed by standard test gas Record the stabilized indication for each position.
The sensors must be tested within the orientation limits specified in the instruction manual, rotating in 15° increments around each of the three perpendicular axes If the manufacturer specifies orientation limits of ± 15° or less, testing should occur within ± 15° of the nominal orientation During each orientation, clean air and standard test gas should be applied.
Electrical tests
5.4.7.1 Battery capacity for battery-powered apparatus
The apparatus shall be fitted with new batteries or rechargeable batteries shall be fully charged at the beginning of the test
Expose the apparatus to clean air for at least 1 hour After switching it on, conduct an initial measurement in both clean air and standard test gas Operate the apparatus in ambient air for a total of 7 hours, or for a shorter duration as indicated in the instruction manual Following this period, expose the apparatus to clean air for another hour before taking measurements in clean air and standard test gas again.
The apparatus will be operated in ambient air, and measurements in clean air and standard test gas will be repeated 10 minutes after a low-battery condition is indicated.
For long life batteries, suitable methods for shortening the test period may be agreed between the manufacturer and the test laboratory
The apparatus must be configured at the nominal supply voltage and, for a.c powered devices, at the rated frequency Additionally, for apparatus equipped with remote sensors, testing should be conducted using both the maximum and minimum resistance of the interconnecting cable.
The alarm set point must be established at 10% of the upper measurement limit If this concentration cannot be achieved, the set point should be adjusted to the closest possible value.
The apparatus must be tested with clean air and standard test gas, recording readings at 115%, 100%, and 80% of the nominal supply voltage If the instruction manual indicates a different supply range, testing should occur at both the upper and lower limits of that specified range.
It is essential to confirm that all output functions operate correctly at the minimum supply voltage, even under the most challenging load conditions Additionally, the analog outputs must be evaluated at their maximum output level, and relays should successfully energize at the minimum supply voltage.
The apparatus must be configured under standard conditions as outlined in section 5.3, followed by the tests detailed in EN 50270 It is not necessary to meet the ambient temperature (5.3.5) and humidity (5.3.7) requirements, provided that the temperature and humidity levels do not cause any damage to the sensor.
If local legislation for electromagnetic compatibility permits the manufacturer to declare conformity to legal requirements by complying with EN 50270, this test may be omitted
5.4.7.4 Time-weighted average (TWA) function
The test method of this clause shall only be performed on apparatus that has a TWA function
Apply the following regime over the TWA measuring period using test gas:
— the standard test gas volume fraction for 25 % of the period;
— 50 % of the standard test gas volume fraction for 50 % of the period;
– clean air for 25 % of the period
Record the indicated value expressed as the time-weighted value of the test gas volume fraction
The apparatus must be activated in a clean air environment After the warm-up period, a test gas with a volume fraction twice the TWA alarm set point should be introduced until the TWA alarm is triggered or the TWA duration has expired.
Stability
Battery powered apparatus shall be operated for 8 h per working day in ambient air All other apparatus shall be operated continuously in ambient air
The apparatus must undergo six exposures to clean air and the standard test gas throughout the specified calibration period The initial exposure occurs at the start of the calibration, while the final exposure takes place either at the end of the calibration period or after six months, depending on which is shorter The four intermediate exposures should be evenly spaced during the calibration timeframe.
Record the readings after each exposure to clean air and the standard test gas.
Verification of software and digital components
Design and function of the apparatus using software and/or digital technologies shall be evaluated and tested in accordance with EN 50271
6 Uncertainty of measurement and lower limit of measurement
General
The calculations in this clause shall be performed for apparatus that conform to EN 45544-2
Method of calculation of uncertainty of measurement
General
Random sources of uncertainty shall be assumed to be normally distributed Non-random sources of uncertainty, or bias, shall be treated as rectangularly distributed in accordance with EN 482
The uncertainty estimation for electrical devices that directly detect and measure the concentration of toxic gases and vapors is based on a cause and effect analysis, which identifies both random and non-random components of uncertainty.
A rectangular probability distribution with a range of ± A should be converted into a non-random uncertainty equal to A/√3
Clause 5 of this document identifies factors which shall be included in the expanded uncertainty estimate
A summary of these is provided in Table 1 below
Table 1 — Factors to be considered in the expanded uncertainty estimate
Clause Title Inclusion Type of uncertainty
5.4.3 Measurement of deviations Yes Yes Yes
5.4.5.4 Air velocity Yes No Yes
5.4.6.2 Time to alarm (reading) No
5.4.6.3 Flow rate Yes No Yes
5.4.6.7 Sampling probe Yes No Yes
5.4.6.8 Field calibration kit Yes No Yes
5.4.6.9 Gas concentrations above the full scale indication No
5.4.6.10 Extended operation in test gas Yes No Yes
5.4.7.1 Battery capacity Yes No Yes
5.4.7.2 Power supply variations Yes No Yes
Sources of uncertainty
When performing the calculations of 6.2.2.3 to 6.2.2.14, x range and x max shall be calculated for each test sample and the maximum value shall be used in the formula
However, when performing the calculations of 6.2.2.2, the measured values from all test samples shall be combined to give one value for the uncertainty of each indicating device
The following calculation shall be performed for each indicating device
All these calculations shall be performed for each test gas concentration combining the values from all test samples
The uncertainty of the random element of the repeated measurements, u rdev , shall be calculated in accordance with Formula (1):
In this study, we analyze repeated measurements denoted as \( x \), where \( i \) represents the individual measurements The mean of these repeated measurements is calculated at a specific test gas volume fraction, represented as \( x_{\text{ref}} \) Additionally, \( n \) indicates the total number of repeated measurements taken at this test gas volume fraction.
The uncertainty of the non-random element in repeated measurements, denoted as \$u_{nrdev}\$, depends on the deviation of the mean measurements from the test gas's volume fraction and the resolution of the indicating device This uncertainty can be calculated using Formula (2).
* 3 2* 3 * ref res nrdev ref ref x x x u x x
38 x res = the resolution of the indicating device
The uncertainty associated with the measurement of deviations, u deviation , shall be calculated in accordance with Formula (3):
The non-random uncertainty associated with the influence of temperature, u temperature , shall be calculated in accordance with Formula (4):
(4) where range x the difference between the maximum and minimum values in standard test gas over the entire temperature range
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of pressure, u pressure , shall be calculated in accordance with Formula (5): max * 100 2* * 3 pressure std u x
The formula for \( x_{\text{max}} \) incorporates the differences between measured values in standard test gas at each 10 kPa increment, specifically for the ranges of 80–90 kPa, 90–100 kPa, 100–110 kPa, and 110–120 kPa Here, \( x_{\text{std}} \) represents the volume fraction of the standard test gas.
The non-random uncertainty associated with the influence of humidity, u humidity , shall be calculated in accordance with Formula (6):
(6) where range x the difference between the maximum and minimum values in standard test gas over the entire humidity range
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of air velocity, u velocity , shall be calculated in accordance with Formula (7):
(7) where range x the difference between the maximum and minimum values in standard test gas over the entire range of air velocities and flow directions
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of flow rate, u flow , shall be calculated in accordance with Formula (8):
(8) where range x the difference between the maximum and minimum values in standard test gas over the entire range of flow rates
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of the sampling probe, u probe , shall be calculated in accordance with Formula (9):
(9) where range x = the difference in measured values in standard test gas with and without the probe x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of the manufacturer’s field calibration kit, u field , shall be calculated in accordance with Formula (10):
(10) where range x the difference in measured values in standard tes the field t gas with an calibrat d w io ithout n kit
= x std = the volume fraction of the standard test gas
6.2.2.10 Extended operation in test gas (from 5.4.6.10)
The non-random uncertainty associated with the influence of extended operation in test gas, u ext , shall be calculated in accordance with Formula (11):
(11) where range x the difference between the maximum and minimum values in test gas during the extended operation test
= x test = the volume fraction of the test gas
The non-random uncertainty associated with the influence of orientation, u orientation , shall be calculated in accordance with Formula (12):
(12) where range x the difference between the maximum and minimum values in standard test gas over the entire range of orientations
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of battery capacity, u battery , shall be calculated in accordance with Formula (13):
= x (13) where range x the difference in measured values in standard test gas with a fully charged battery and 10 min after the indication of the low battery condition
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the influence of power supply variations, u power , shall be calculated in accordance with Formula (14):
(14) where range x the difference between the maximum and minimum values in standard test gas over the entire range of supply voltages
= x std = the volume fraction of the standard test gas
The non-random uncertainty associated with the stability, u stability , shall be calculated in accordance with Formula (15):
(15) where range x the difference between the maximum and minimum values in standard test gas over the entire calibration period
= x std = the volume fraction of the standard test gas
Calculation of relative expanded uncertainty
The following calculation shall be performed for each indicating device
For each test gas volume fraction, calculate the sum, u total , of the uncertainties, u i , in accordance with 6.2.2.2 to 6.2.2.14 in accordance with Formula (16):
For the uncertainties derived from extended operation in test gas (6.2.2.10) and stability (6.2.2.14), only the uncertainty with the largest value shall be used in the calculation above
NOTE Extended operation in test gas and stability are complementary tests which estimate the “stability” of the apparatus in test gas or clean air respectively
For each test gas volume fraction according to 6.2.2.2, calculate the relative expanded uncertainty U using a coverage factor of 2 in accordance with Formula (17):
Method of calculation of lower limit of measurement
When performing the calculations, the measured values from all test samples shall be combined to give one value for the lower limit of measurement of each indicating device
The following calculations, Formula (18) to Formula (21), shall be performed for each indicating device
The random element of the zero uncertainty shall be calculated in accordance with Formula (18):
(18) where x the repeated zero measurements i = x the mean of the repeated zero measurements =
The non-random component of zero uncertainty is determined by the deviation of the mean of repeated measurements from zero, as well as the resolution of the indicating device This calculation follows Formula (19).
(19) where x res = the resolution of the indicating device x the mean of the repeated zero measurements =
The total zero uncertainty shall then be calculated in accordance with Formula (20):
2 2 zero zero zero u = ur + unr
(20) and the lower limit of measurement, U zero , shall be calculated in accordance with Formula (21), i.e by 2 times u zero using a coverage factor of 2
The test report must comply with EN ISO/IEC 17025 and include essential information such as the specification, uncertainty, and validation of the test gas mixtures It should detail the test parameters and conditions employed, including t 90 and t 50, along with justifications for any deviations from standard testing methods Additionally, the report must specify tests conducted with dry gases and those utilizing a calibration and test mask as outlined in section 5.2.8.
Standard test gas volume fractions for EN 45544-2 apparatus
Table A.1 — Standard test gas volume fractions and minimum requirements for the lower limit of measurement for EN 45544–2 apparatus
Number Formula Volume fraction of standard test gas Lower limit of measurement
Xylene 1330–20–7 C6H4(CH3)2 50 5 a No EU IOELV (European Union Indicative Occupational Exposure Limit Value) b Value chosen in order to be able to generate stable test gases
For gases not included in this table, a value agreed between manufacturer and the test laboratory considering the Limit Values shall be used and specified in the test report
It is recommended that the tests are performed in the following sequence:
Verification of software and digital components (tested in parallel with other tests) [5.4.9]
6 Extended operation in standard test gas [5.4.6.10]
Gas concentrations above the full scale indication [5.4.6.9]
Figure C.1 — Example of a test chamber
Table of significant changes in comparison to EN 45544-1:1999
Minor and editorial changes Extension Substantial change
EN 45544 Part 2 and Part 3 renamed and their scope changed Part 2 defines requirements for apparatus used for exposure measurement according to EN 482
Part 3 defines requirements for apparatus used for general gas detection
Modification of the scope: not applicable to apparatus used in car parks and tunnels and open-path (line of sight) area monitors
EN 50271 added; EN 60073 deleted; ISO 3534–1, ISO
6141, ISO 6142, ISO 6143 deleted; EN 60079–0 added,
Definitions modified and extended In particular, definitions of uncertainty and lower limit of measurement modified and figures added X
General requirements modified and extended
The article introduces new clauses regarding dead bands, gas detection transmitters designed for use with separate control units, and the integration of software and digital technologies in related apparatus.
Test methods and test conditions revised In particular:
Test methods are aligned as far as possible with
Tests to be performed on three apparatus while the
EMC test may be performed on only one of the three apparatus
A new test clause on EN 50271 introduced
Specific test conditions introduced which are related to communications options for apparatus having wired or wireless communications options and for gas detection apparatus as part of systems
Extensive, new clause on calculation of uncertainty and lower limit of measurement based on current version of
Number of gases reduced and test gas volume fractions modified in Table A.1
New Annex B (informative) showing recommended sequence of tests X
New Annex C (informative) showing example of a test chamber X