Edwards ModuLaser Installation Manual page 82

Chapter 3: Configuration and Commissioning
Wire burn test
This test is typically used for Class A and Class B installations.
The wire burn test is considered the most representative test of incipient fire
hazard detection in telecommunications or computer room environments.
The test is performed by applying a voltage to a piece of PVC-insulated cable.
Smoke is produced from the overheated PVC insulation by evaporation and
condensation of the plasticiser.
As the wire becomes hotter, hydrogen chloride (HCl) gas is emitted from the
insulation. The by-products of overheated PVC insulation can be detected by the
system.
Performing a wire burn test (option 1)
The following test is considered unlikely to produce hydrochloric acid vapour.
This test may be undertaken in underfloor spaces or ceiling voids.
1. Connect a 2 m (6.5 ft.) length of wire to a 6 VAC source of at least 16 A rating
per wire for a period of 3 minutes.
2. The system should respond within 120 seconds of cessation of energization.
After this period, very little smoke is given off.
Notes:
The wire is subject to cooling if positioned in direct contact with air flows and may
need to be shielded.
The wire cross-section should be AWG 10 with the following diameter and area:
• Diameter 2.59 mm (0.10189 in.)
• Cross-Section Area 5.0 mm² (0.00775 in.²)
Performing a wire burn test (option 2)
WARNING: The following test is likely to produce a sufficiently high temperature
to generate small quantities of hydrogen chloride or hydrochloric acid gas. Be
sure to maintain a safe distance from the wire while voltage is applied.
Perform this test in underfloor spaces or ceiling voids where rapid air flow may
render the previous test unsuitable.
1. Connect a 1 m (3.25 ft.) length of wire to a 6 VAC source of at least 16 A
rating per wire for a period of 1 minute.
2. The system should respond within 120 seconds of cessation of energization.
After this period most of the insulation should be burned off.
Notes:
The wire cross-section should be AWG 10 with the following diameter and area:
• Diameter 2.59 mm (0.10189 in.)
• Cross-section area 5.0 mm² (0.00775 in.²)
76 ModuLaser Modular Aspirating Smoke Detector Installation Manual