Unknown BRITISH STANDARD BS EN 50249 2002 Electromagnetic locators for buried pipes and cables — Performance and safety The European Standard EN 50249 2002 has the status of a British Standard ICS 17[.]
Enclosure
All enclosures shall be IP54, tested as specified in A.3.14.
Robustness
Receivers and transmitters must meet specific robustness requirements to avoid detrimental effects, as outlined in section A.3.12 These requirements include resistance to vibration (A.3.12.1), free fall (A.3.12.2), bump (A.3.12.3), and impact (A.3.12.4).
UV protection
Locators shall be ultraviolet (UV) protected
When tested in accordance with A.3.12.5, no cracking or distortion shall occur.
Controls
Operation
The receiver must be operable with the hand that carries the instrument for a specific mode of operation Controls should be durable and kept to a minimum Compliance will be verified through inspection.
Control size
Receivers and transmitters shall have controls of a size permitting easy and positive operation while the operator is wearing a pair of heavy-duty gloves
Conformity shall be checked by satisfactory operation of the receiver and transmitter, including adjustment of all controls, while wearing a pair of heavy-duty gloves.
Temperature range
The receiver and transmitter shall operate satisfactorily within at least the temperature range of –10 °C to +50 °C
Conformity shall be checked by the tests of A.3.8.
Relative humidity
The receiver and transmitter shall operate satisfactorily at 80 % RH
Conformity shall be checked by the test of A.3.15.
Battery housing access
Battery housings for receivers and transmitters must enable tool-free access for regular maintenance They should be designed to ensure that any cell decomposition does not impact the locator's components Additionally, clear indications of cell polarity and types must be displayed in or near the battery housing.
Conformity shall be checked by inspection.
Power supply polarity protection
The power supply of receivers and transmitters shall be reverse polarity protected
Conformity will be verified by ensuring that it is either physically impossible to install or connect the batteries and, if applicable, the battery assembly in a manner that does not meet the tests outlined in A.3.9, or by providing protection against incorrect installation or connection of the batteries and, where relevant, the battery assembly, ensuring compliance with the tests specified in A.3.9.
Power supply cell type
Receivers and transmitters shall use integral cell types conforming to EN 60086-2, or their secondary cell equivalent
Conformity shall be checked by inspection.
Battery operating life
A new set of primary cells or fully charged secondary cells, as specified by the manufacturer, must enable locator units to operate continuously in the highest consumption mode for at least 8 hours at a specified temperature.
20 °C ± 5 °C without replacement or low battery warning operation
Conformity shall be checked by the test of A.3.7.
Low battery warning
General
Receiver and transmitter units shall incorporate a means to warn the user to change the battery when in use
Conformity shall be checked by inspection
The unit shall continue to operate for at least 15 min at 20 °C ± 5 °C after activation of the warning
Conformity shall be checked by measurement
The unit shall operate within the performance specified in 5.11.2 for receivers and 5.11.3 for transmitters when applying the minimum voltage declared by the manufacturer + 0,5 % - 0 %.
Receiver test requirements
Depending on the mode of operation of the locator, conformity shall be tested in accordance with A.3.4.2.
Transmitter test requirements
Conformity shall be checked by carrying out the transmitter output level check specified in A.3.5.3 for an output load of 100 Ω.
Transmitter case buoyancy
The transmitter case shall not float when immersed in 25 mm depth of water
Conformity shall be checked by carrying out the test specified in A.3.11.
External electrical connector protection
Transmitters and receivers shall have all external electrical connections protected against the ingress of mud and debris (which prevent a connection being made) when not in use
Compliance shall be checked by inspection.
Hazardous electrical contact
All parts of receivers and transmitters which can be contacted by the jointed test finger of
EN 60529 shall operate at less than hazardous live voltage as specified in EN 61010-1
Conformity shall be checked by inspection.
Surface temperature
The surface temperatures of any parts of the locator shall not exceed those specified in
EN 61010-1 under normal or abnormal operation
Conformity shall be checked by measurement.
Electromagnetic compatibility
The receiver and transmitter shall conform to generic requirements for electromagnetic compatibility (EMC)
Conformity shall be checked in accordance with EN 61000-6-2 and EN 61000-6-3.
Safety
The receiver and transmitter shall conform to the safety requirements for electrical equipment for measurement, control and laboratory use
Conformity shall be checked in accordance with the general requirements specified in
EN 61010-1 and, where appropriate, with the particular requirements specified in EN 61010-2-031 and EN 61010-2-032
Transmitter case
The transmitter case shall be stable when it is standing on a surface which is inclined at 30° to the horizontal
Conformity shall be checked by testing (see A.3.10).
Weight
Transmitters, excluding accessories, should weigh no more than 4,0 kg, including batteries
7 Electrical characteristics of the transmitter
General
Unless otherwise specified, all electrical tests shall be carried out with a new set of primary cells or a set of fully charged secondary cells.
On/off indication
Transmitters shall have a clear indication of whether the unit is switched on or off The indication shall be either audio or visual or both
Conformity shall be checked by inspection.
Frequency band
Transmitters shall operate only within approved frequency bands for each country of use, and shall conform to EN 50065-1
Conformity shall be checked by inspection of the manufacturer’s stated operating frequency and evidence of the approved frequency band(s)
Data on transmitter signal characteristics shall be provided by the manufacturer in the technical data sheet, as specified in Annex C
Conformity shall be checked by inspection
The technical data sheet and operating instructions must clearly state that it is the operator's responsibility to obtain any necessary licenses from the relevant national regulatory authority for the countries where the equipment will be used.
Conformity shall be checked by inspection of manufacturer’s data sheet.
Output level
The manufacturer must specify the -3 dB points of the transmitter output level, including any modulations that may arise from low battery conditions This information should be included in the technical data sheet for all operational modes and output levels.
To ensure conformity with the -3 dB points, it is essential to measure the output frequency of the transmitter in all operational modes Compliance should be verified by connecting a 300 Ω ± 1% resistive load during the direct connection mode testing.
Output current
For each frequency, the manufacturer shall quote the following in the technical data sheet a) For a set of new primary cells, or a fully charged set of secondary cells:
In the direct connection mode, it is essential to provide a graph illustrating the output current in relation to load resistance, as specified in A.3.5.3 If the output is adjustable by the user, the graph must include both the maximum and minimum current levels.
2) for the induction mode, the current induced into the target line at a point 1 m below the transmitter, measured in accordance with A.3.5.2 shall be stated;
In clamp mode, the manufacturer must specify the current in the conductor passing through each clamp for every frequency of operation, as determined by method A.3.5.1 Additionally, for a set of cells discharged until the low-battery indicator activates, the data outlined in section 7.5 a) 1), 2), and 3) must be provided If the output is user-variable, both the maximum and minimum output levels should be clearly stated.
Conformity shall be checked by inspection of the technical data sheet.
Monitoring
Any communication between a transmitter and receiver used for monitoring and/or controlling the status of the transmitter, e.g battery condition, shall not adversely affect the location performance accuracy
Conformity shall be checked by the tests of A.3.4.2, with the communicator in operation.
Operation across live conductors – Safety
Transmitters shall continue to operate when the output is directly connected across a potential difference of 50 V d.c or 50 V a.c., 50 Hz
Conformity shall be checked in accordance with the requirement of A.3.5.3, whilst the potential difference is applied.
Operation across live conductors – Protection
The integrity of the transmitter shall not be degraded when the output is directly connected across a pair of live conductors with a voltage of 250 V d.c or 250 V a.c., 50 Hz
NOTE 1 It is permissible for a protection device to operate, subject to the protective device being able to be reset by the operator
To verify conformity, connect the transmitter output leads to a 250 V a.c., 50 Hz supply and switch on the transmitter After resetting any protective devices, conduct tests in accordance with the specifications outlined in A.3.5.2 and A.3.5.3.
NOTE 2 The test is not applicable if the transmitter incorporates an induction coil as aerial
Receivers, excluding accessories, should weigh no more than 3,5 kg, including batteries
9 Electrical characteristics of the receiver
General
All electrical tests shall be carried out with a new set of primary cells or a set of fully charged secondary cells, unless otherwise stated.
Visual/audio indication
Receivers must provide indications of buried line locations through visual and audio signals Specifically, the audio indication, using a fixed speaker, should have an output sound level of 85 dB(A) ± 10 dB(A) when measured at the loudest point under the testing conditions specified in A.3.6.
If an adjustable volume control is provided, it shall provide an attenuation of at least 20 dB
Conformity shall be checked by the test of A.3.6 b) Audio indication (headphone) The output sound pressure level shall not exceed the following:
1) single headphone/detachable speaker: 95 dB(A);
2) double headset or headphone, fitted into hearing protection: 90 dB(A)
Conformity shall be checked in an anechoic chamber using an artificial ear as described in
For safety reasons, operators should avoid using double headsets or headphones integrated into hearing protectors while working on highways or in areas exposed to moving machinery Additionally, visual indications must be clearly visible when used according to the manufacturer's instructions by individuals with normal corrected eyesight in environments with a horizontal illuminance of 300 lx ± 10%, as well as in conditions of reduced horizontal illuminance.
For effective night-time visibility, supplementary lighting must ensure that the indication means meet detection criteria and remain clearly visible in a room illuminated by a low-pressure sodium luminaire, achieving a horizontal illuminance of 100 lx ± 10%.
Conformity shall be checked by inspection
NOTE 2 The test conditions simulate the following:
3) poor street lighting after-dark (nominally 100 lx with L.P sodium luminaire).
Sensitivity
The sensitivity at the rated frequency must meet specific criteria: in power mode, the detectable current range at 1 meter should be 10 mA ± 5 mA, with a maximum limit of 100 A r.m.s., as outlined in section A.3.4.2.1.
The technical data sheet must specify the detectable current range in accordance with 9.5 for depths of 250 mm, 500 mm, 1 m, and 2 m Additionally, if radio mode is available, the detectable current range at 1 m should be a minimum of 20 àA.
5 mA, at the test method specified in A.3.4.2.2
The technical data sheet must specify the detectable current range for depths of 250 mm, 500 mm, 1 m, 2 m, and 4 m Additionally, if active mode(s) are available, the minimum detectable current at a depth of 1 m should be clearly defined.
1) minimum current (Imin) shall be no greater than the constant K, as derived below:
Imin = test current in mA;
Kmin = 200; maximum current (Imax) shall be at least the constant as derived below:
Imax = test current in mA;
The detectable current range conforming to 9.5 shall be stated in the technical data sheet for depths of 250 mm, 500 mm, 1 m and 2 m
Conformity shall be checked in accordance with A.3.4.3.
Selectivity
The selectivity criteria state that external electromagnetic compatibility (EMC) influences should not impact the sensitivity or selectivity of the receiver However, during susceptibility testing, the receiver may be affected by frequencies that fall outside the designated stop bands of each operating mode.
Conformity shall be checked in accordance with EN 61000-6-2 b) Power mode (if provided) The stop band level shall be equal to or better than - 60 dB from
Conformity will be verified through frequency response measurements as specified in the relevant sections of the EN 60315 series In radio mode, the stop band level must meet or exceed -60 dB for all frequencies outside the manufacturer's declared response bands.
Conformity will be verified through frequency response measurements as specified in the relevant sections of the EN 60315 series In active mode, if applicable, the -3 dB points for each frequency specified by the manufacturer must not deviate more than ± 0.5% from the nominal center frequency or exceed ± 10 Hz, whichever is greater.
The frequency response must maintain a minimum of -60 dB from the maximum response at ±8% or 50 Hz, whichever is greater, across the d.c range up to 40 MHz Compliance will be verified through frequency response measurements.
Single target line performance
Response Width
The response width, over a single target line shall not exceed 500 mm (see Figure 1)
Conformity shall be checked by the test of A.3.4.2.
Location Accuracy
The located plan position shall be within 50 mm of the true plan position of the single target line, at a distance of 1 m (see Figure 2)
Conformity shall be checked by the test of A.3.4.2.
Depth Measurement Accuracy (if provided)
The accuracy of depth measurement to the centre of the target line at test depths of 0,5 m and
1 m, shall be within the range – 7 % to + 3 % of the depth
Conformity shall be checked by the test of A.3.4.2.
Multiple target line performance
Response width
The response width, over a target line buried at a depth of 1 m, shall not exceed 500 mm
Conformity shall be checked by the test of A.3.4.3.
Location accuracy
The located plan position shall be within ± 125 mm of the true plan position of the target line, buried at a depth of 1 m (see Figure 4)
Conformity shall be checked by the test of A.3.4.3
Figure 1 – Single target line – Response width
Figure 2 – Single target line – Location accuracy
Figure 3 – Multiple target lines – Response width
Figure 4 – Multiple target lines – Location accuracy
Depth measurement accuracy (if provided)
The accuracy of depth measurement to the centre of the target line buried at depths of 0,5 m and
1 m, shall be within the range – 14 % to + 6 % of the depth
Conformity shall be checked by the test of A.3.4.3
Receivers and transmitters must feature durable labels prominently displayed on their exterior or printed directly on the equipment, indicating the equipment type, serial numbers, and concise usage instructions Additionally, the transmitter label should include a warning about the precautions necessary before making direct connections to lines, as well as the operating frequency or frequencies.
Conformity shall be checked by inspection and durability shall be tested by the test of A.3.13
The manufacturer shall provide the documentation specified in Annex C
Conformity shall be checked by inspection
Cross-references between test requirements and test methods are listed in Table 1
Control operation and size 5.4 Inspection, operation
Power supply reverse polarity protection 5.8 A.3.9
Power supply cell type 5.9 Inspection
Battery low warning 5.11 Inspection, measurement,
A.3.4.2 for receiver, or A.3.5.3 for transmitter
External electrical connector protection 5.13 Inspection
Electromagnetic compatibility 5.16 EN 61000-6-2 and EN 61000-6-3
Transmitter on/off indication 7.2 Inspection
Transmitter frequency band 7.3 Annex C, inspection
Transmitter operation across live conductors – Safety
Transmitter operation across live conductors – Protection 7.8 IP2X, A.3.5.3
Receiver visual/audio Indication 9.2 A.3.6, EN 60318 series
Receiver selectivity 9.4 EN 61000-6-2, EN 60315 series
Single target line response width 9.5.1 A.3.4.2
Single target line location accuracy 9.5.2 A.3.4.2
Single target line depth measurement accuracy 9.5.3 A.3.4.2
Property Requirement clause Test method clause
Multiple target line response width 9.6.1 A.3.4.3
Multiple target line location accuracy 9.6.2 A.3.4.3
Multiple target line depth measurement accuracy 9.6.3 A.3.4.3
The inspections, and tests described in this annex are intended to establish whether an electromagnetic locator conforms with the performance and safety requirements given in this standard, as appropriate
Conformance tests for the receiver necessitate the creation of electromagnetic fields that accurately represent those encountered on both single and dual long straight pipes or cables Details of the test rig used for this purpose are outlined in section A.3.1.
The following requirements apply to all tests unless otherwise specified
Tests shall be carried out on one locator unless otherwise stated
A.1.2 Preparation of samples for test
The sample locator(s) shall be prepared, as nearly as possible, as for typical service, in accordance with the manufacturer’s published instructions
Locators may, for short-term tests, be fitted with fresh batteries at the commencement of each series of tests
A.1.3.2 Ambient temperature and relative humidity
The ambient air temperature and relative humidity shall be within the ranges specified in 5.5 and
5.6 respectively, throughout the duration of each test
The locator shall not be recalibrated once the sequence of testing has commenced
Before starting any test, the locator being evaluated must be calibrated according to the manufacturer's operating instructions However, once the test is underway, no additional adjustments should be made unless explicitly allowed by the specific test procedure.
Prior to undertaking any test, the locator shall be stored at the temperature and humidity specified in A.1.3.2 for a minimum of 4 h
Tests may be carried out in any sequence, unless otherwise specified in A.3
Tests shall be conducted operating the locator in accordance with the manufacturer's recommendations and instructions
There shall be no metallic structures within 30 m of the measurement section of the loop either above or below the ground
To ensure accurate test measurements, external electromagnetic interference must be minimized, remaining at least 40 dB below the field generated by the test cable within the operational frequency range.
The layout of the test rig shall conform to that shown in Figure A.1.a
Conductors 1-1 and 2-2 shall be in a single plane, at least 100 mm above the ground along their lengths The supports shall be fabricated from non-metallic materials
The test signal input shall be at point C (see Figure A.1.a) to minimize EMI/RFI from the test signal source
NOTE The test rig, as specified, incorporates two conductors between points A and C If these conductors are placed
100 mm above ground, they may be used for determining multiple line discrimination or resolution
Figure A.1.a – Test rig – Plan view
D Alternative positions for air- cored sense coil 1-1, 2-2 Target line conductors
The Test Rig must be validated to ensure it generates the appropriate electromagnetic field across the specified frequency range This verification can be achieved by measuring the field vector at a 45° offset angle from the conductor and at two different distances from it, as illustrated in Figure A.1.b.
The conductor section 2-2 in Figure A.1.b shall be isolated
Position an air-cored sense coil symmetrically at a height of 1.0 m above conductor 1-1 The signal from the sense coil will decrease by 50% (-6 dB) when it is shifted along line D-D to an offset angle of 45° from conductor 1-1.
The sense coil shall then be repositioned 1,0 m above conductor 1-1 When the sense coil is moved to a position 0,5 m above conductor 1-1, the received signal shall increase by 100 % (+ 6 dB)
The equipment being tested shall be set in its normal location orientation and moved along the line x-x and at distances specified for each test
All components of the locator, including batteries, must undergo sequential testing under specific conditions: exposure to -40 °C for 24 hours, followed by at least 24 hours at ambient temperature, then +70 °C for 24 hours, and finally another 24 hours at ambient temperature.
For effective target line detection, the minimum changes in receiver output must be recognized as positive when the receiver is moved across the target line These changes should be evident on both sides of the identified plan position, and the extent of these changes will define the response width This applies specifically to receivers that operate with a two-state output.
This type of output gives a positive indication which is acceptable as means of determining positive detection Examples of two state outputs are
1) a visual display designed to show one symbol when the receiver is over the target line, and another when the receiver into one side of the target line,
2) an audible output, designed such, that it is only activated when the receiver is passed over a target line (i.e the audible output is silent) irrespective of any operator adjustments, when the receiver is to one side of a target line b) For receivers having an audio output only
A change of 3 dB(A) is required
A change in pitch exceeding one standard tone
NOTE This corresponds to a frequency change of ± 12 % being required c) For receivers having an analogue, or pseudo analogue (e.g bar display), output only
A clear and stable indication of a 3 dB change is required d) For receivers having a digital numeric output only
A change of 30 % of the full-scale indication is required e) For receivers having more than one type of output
Where the manufacturer specifies one particular output to be the primary output, this output shall be monitored in accordance with the above criteria
When a manufacturer treats each output equally, testing must be performed on both outputs If logistical constraints allow for only one output to be tested at a time, the tests should be repeated for the remaining output(s).
When a receiver offers multiple operational methods, such as peak and null, the manufacturer must designate one specific method as the primary This primary method will be utilized to assess the receiver's performance.
When a manufacturer views all operational methods as equally valid, the sensitivity of the receiver must be assessed for each method If logistical constraints allow for testing only one method at a time, the tests should be conducted repeatedly for each operational method.
Receiver performance tests shall be conducted on a test rig, consistent with that specified in
All test rig current measurements shall be made at point A, as shown in Figure A.1.a
The receiver will be moved along the target line in both directions at the same point along its length It will be rotated 180° between traverses and will remain powered on throughout each traverse While adjustments to the receiver gain can be made between traverses, no manual gain changes are permitted during the individual traverses of the target line.
For each traverse, the following criteria shall be satisfied, unless otherwise stated a) Response width
The response width shall not exceed that specified in 9.5.1, when measured in accordance with A.3.3.1 b) Location accuracy
The accuracy of location is assessed by evaluating the distance between the midpoint of the response width and the actual position of the target line, ensuring it remains within the specified limits.
9.5.2 or 9.6.2 for a single target line and multiple target line, respectively c) Depth measurement accuracy
Depth measurements taken with the receiver positioned at the midpoint of the response width must adhere to the limits outlined in sections 9.5.3 and 9.6.3 for single and multiple target lines, respectively.
The receiver shall be tested using the procedure specified in A.3.4.1, on the single target line 1-1 shown in Figure A.1.b, with conductor 2-2 isolated
Positive detection, as defined in A.3.3.1, shall not be possible, irrespective of the receiver's gain setting, when a 50 Hz sinusoidal current of 5 mA is applied to the target line
Positive detection, as defined in A.3.3.1, shall be possible when a 50 Hz sinusoidal current of
15 mA is applied to the target line
Positive detection, as defined in A.3.3.1, shall be possible when a 50 Hz sinusoidal current of
100 A is applied to the target line
Positive detection, as defined in A.3.3.1, shall be possible when a sinusoidal current of
+ àA is applied at the frequencies for which the receiver is designed to the target line whose impedance is increased by the addition of a 10 kΩ resistance