OVERHEATED PVC/LSF WIRE PERFORMANCE TESTS
E.1. System performance test using electrically overloaded PVC-coated wire (1m).
This method is suitable for the testing of high sensitivity (Class A) and enhanced sensitivity (Class B) fire detection systems.
To simulate the early stages of a fire, a length of wire is electrically overloaded so that smoke or vapours are driven off.
Warning. This test produces sufficiently high temperatures to generate small quantities of hydrogen chloride. However, test personnel are unlikely to be exposed to concentrations of hydrogen chloride that exceed the short term exposure limit (see HSE publication EH40) of five parts per million (5x10-6) in a 15-minute period unless they are directly exposed to the smoke plume. It is recommended that, where it is impractical to arrange for remote switching of the transformer, or where multiple tests are required, or where personnel stand within the immediate vicinity (eg 2m) of the smoke source, personnel should wear appropriate protective equipment, such as an E1 respirator confirming to EN140 and goggles without ventilation conforming to EN166.
E1.1 Apparatus.
E.1.1.1 Wire, either:
• 1m length, of ten 0.1mm strands insulated with PVC to a radial thickness of 0.3mm, the cross-sectional area of the conductor being 0.078mm2; or
• 2m length of single strand low smoke and fume (LSF) ethernet 24 AWG cable.
E.1.1.2 Transformer, 240 V to 6 V, capable of supplying at least 15 A.
E.1.1.3 Insulating board, of non-combustible material, of minimum size 600.600mm.
E.1.1.4 Stop clock or stop watch, capable of measuring in 1s intervals.
E.1.1.5 Arrangement to shield the overheating cable from the cooling effects of high airflows, where present.
E.1.2 Procedure
E.1.2.1 Connect the wire to the 6V output terminals of the transformer.
E.1.2.2 Ensure that the wire is laid on the insulating board so that there are no kinks or crossovers.
E.1.2.3 Connect 240V mains electricity supply to the primary terminals of the transformer for a period of 60s.
Note: After this period, most of the insulation is expected to have been burnt off.
E.1.3 Pass/fail criteria.
The system is deemed to have passed the test if the detection system registers a response within 120s of the power supply being switched off.
The response should be equivalent to at least a 15% increase in smoke reading over the background level (where 100% is the fire threshold) sufficient to signal a pre-alarm or warning.
E.2. System performance test using electrically overloaded pvc-coated wire (2m).
This method is suitable for the testing of high sensitivity (Class A) fire detection systems.
To simulate the early stages of a fire, a length of wire is electrically overloaded so that smoke or vapours are driven off. Unlike the test described in E.1, hydrogen chloride vapour is unlikely to be produced due to the relatively low temperatures reached. This test may also be undertaken in under- floor spaces or ceiling voids.
OVERHEATED RESISTOR PERFORMANCE TESTS
System performance test using electrically overloaded resistor(s).
Overheated resistor performance tests are suitable for the testing of ASD systems used for the protection of cabinets containing electronic/electrical equipment, such as computer servers or electrical switchgear. The tests are used in these applications in preference to the hot wire tests because the latter are too bulky and generate large volumes of smoke relative to the confined environment of a cabinet.
As a general guide, Test F2 produces about three times more smoke than F1 and F3 produces about three times more smoke than F2.
Warning: These test produces small quantities of noxious fumes which disperse quickly. However, where it is impractical to arrange for remote switching of the transformer, or where multiple tests are required, or where personnel stand within the immediate vicinity (eg 2m) of the smoke source then it is recommended that personnel wear appropriate protective equipment such as an E1 respirator confirming to EN140 and goggles without ventilation conforming to EN166.
F.1. Apparatus.
F.1.1 Resistors, 12 Ohm, 0.25W carbon film (one for tests F1 and F2; two for test F3).
F.1.2 Transformer, 240V to 6V, capable of supplying at least 15A.
F.1.3 Two ceramic terminal blocks, mounted 25mm to 35mm apart on a non-combustible board (at least 50mm x 50mm) to support and connect the resistors.
F.1.4 Shielding tube, consisting of a pipe (approximately 90mm diameter and approximately 100mm long) with eight 4mm holes around the base and a cap perforated with 12 twelve 8mm holes.
F.1.5 Stop clock or stop watch, capable of measuring in one second intervals.
F.2. Procedure.
F.2.1 Connect the resistor(s) to the ceramic terminal blocks. Use one resistor for tests F1 and F2 and two resistors in parallel for test F3.
F.2.2 Ensure the resistors are not touching anything other than the connections to the terminal blocks.
F.2.3 Place the shielding over the resistors to shield them from airflows within the cabinet.
F.2.4 Energise the resistor(s) as follows:
a. Test F1: Energise one resistor for a period of eight seconds.
b. Test F2: Energise one resistor for a period of 70 seconds.
c. Test F3: Energise both resistors for a period of 80 seconds.
F.3 Pass/fail criteria.
The system is deemed to have passed the test if the detection system registers a response within 60s of the power supply being switched off.
The response should be equivalent to at least a 15% increase in reading above the background level (where 100% is the fire threshold) sufficient to signal a pre-alarm or warning.
This method is suitable for the testing of high sensitivity (Class A) and enhanced sensitivity (Class B) fire detection systems.
To simulate the early stages of a fire, a length of wire is electrically overloaded so that smoke or vapours are driven off.
Warning. This test produces sufficiently high temperatures to generate small quantities of hydrogen chloride. However, test personnel are unlikely to be exposed to concentrations of hydrogen chloride that exceed the short term exposure limit (see HSE publication EH40) of five parts per million (5x10-6) in a 15-minute period unless they are directly exposed to the smoke plume. It is recommended that, where it is impractical to arrange for remote switching of the transformer, or where multiple tests are required, or where personnel stand within the immediate vicinity (eg 2m) of the smoke source, personnel should wear appropriate protective equipment, such as an E1 respirator confirming to EN140 and goggles without ventilation conforming to EN166.
E1.1 Apparatus.
E.1.1.1 Wire, either:
• 1m length, of ten 0.1mm strands insulated with PVC to a radial thickness of 0.3mm, the cross-sectional area of the conductor being 0.078mm2; or
• 2m length of single strand low smoke and fume (LSF) ethernet 24 AWG cable.
E.1.1.2 Transformer, 240 V to 6 V, capable of supplying at least 15 A.
E.1.1.3 Insulating board, of non-combustible material, of minimum size 600.600mm.
E.1.1.4 Stop clock or stop watch, capable of measuring in 1s intervals.
E.1.1.5 Arrangement to shield the overheating cable from the cooling effects of high airflows, where present.
E.1.2 Procedure
E.1.2.1 Connect the wire to the 6V output terminals of the transformer.
E.1.2.2 Ensure that the wire is laid on the insulating board so that there are no kinks or crossovers.
E.1.2.3 Connect 240V mains electricity supply to the primary terminals of the transformer for a period of 60s.
Note: After this period, most of the insulation is expected to have been burnt off.
E.1.3 Pass/fail criteria.
The system is deemed to have passed the test if the detection system registers a response within 120s of the power supply being switched off.
The response should be equivalent to at least a 15% increase in smoke reading over the background level (where 100% is the fire threshold) sufficient to signal a pre-alarm or warning.
E.2. System performance test using electrically overloaded pvc-coated wire (2m).
This method is suitable for the testing of high sensitivity (Class A) fire detection systems.
To simulate the early stages of a fire, a length of wire is electrically overloaded so that smoke or vapours are driven off. Unlike the test described in E.1, hydrogen chloride vapour is unlikely to be produced due to the relatively low temperatures reached. This test may also be undertaken in under- floor spaces or ceiling voids.
OVERHEATED RESISTOR PERFORMANCE TESTS
System performance test using electrically overloaded resistor(s).
Overheated resistor performance tests are suitable for the testing of ASD systems used for the protection of cabinets containing electronic/electrical equipment, such as computer servers or electrical switchgear. The tests are used in these applications in preference to the hot wire tests because the latter are too bulky and generate large volumes of smoke relative to the confined environment of a cabinet.
As a general guide, Test F2 produces about three times more smoke than F1 and F3 produces about three times more smoke than F2.
Warning: These test produces small quantities of noxious fumes which disperse quickly. However, where it is impractical to arrange for remote switching of the transformer, or where multiple tests are required, or where personnel stand within the immediate vicinity (eg 2m) of the smoke source then it is recommended that personnel wear appropriate protective equipment such as an E1 respirator confirming to EN140 and goggles without ventilation conforming to EN166.
F.1. Apparatus.
F.1.1 Resistors, 12 Ohm, 0.25W carbon film (one for tests F1 and F2; two for test F3).
F.1.2 Transformer, 240V to 6V, capable of supplying at least 15A.
F.1.3 Two ceramic terminal blocks, mounted 25mm to 35mm apart on a non-combustible board (at least 50mm x 50mm) to support and connect the resistors.
F.1.4 Shielding tube, consisting of a pipe (approximately 90mm diameter and approximately 100mm long) with eight 4mm holes around the base and a cap perforated with 12 twelve 8mm holes.
F.1.5 Stop clock or stop watch, capable of measuring in one second intervals.
F.2. Procedure.
F.2.1 Connect the resistor(s) to the ceramic terminal blocks. Use one resistor for tests F1 and F2 and two resistors in parallel for test F3.
F.2.2 Ensure the resistors are not touching anything other than the connections to the terminal blocks.
F.2.3 Place the shielding over the resistors to shield them from airflows within the cabinet.
F.2.4 Energise the resistor(s) as follows:
a. Test F1: Energise one resistor for a period of eight seconds.
b. Test F2: Energise one resistor for a period of 70 seconds.
c. Test F3: Energise both resistors for a period of 80 seconds.
F.3 Pass/fail criteria.
The system is deemed to have passed the test if the detection system registers a response within 60s of the power supply being switched off.
The response should be equivalent to at least a 15% increase in reading above the background level (where 100% is the fire threshold) sufficient to signal a pre-alarm or warning.
