1. Application It is used to evaluate the ability of vertically installed bundle wires or cables to suppress flame vertical spread under specified conditions. This equipment is widely used in wire and cable industry, colleges and universities and commodity inspection departments. The experimental device is a self-supporting box with length of (1000±100) mm, width of (2000±100) mm and height of (4000±100) mm. The bottom of the box is above the ground. The circumference of the test box is sealed, and the air flows into the box from an inlet of (800±20) mm x (400±10) mm, Open a vent (300±30) mm x (1000±100) mm at the rear of the top of the box. Thermal insulation with heat transfer coefficient of 0.7Wm2K1 is adopted on the back wall and both sides of the test box. The distance between the steel ladder and the back wall of the test box is 150 mm, the lowest transverse gear of the steel ladder is (400±5) mm from the ground, and the lowest part of the cable sample is about 100 mm from the ground. 2. Standards This bundle cable burning tester is manufactured in strict accordance with GB/T 18380.31-2008 and other standards. 3. Main Technical Parameters (1) Shape (overall space) size: 3200mm (long) *2500mm (wide) *4500mm (high). (2) Air Source: The air inlet is equipped with a digital anemometer which can measure the air velocity. The air flow rate is (5000±500) L/min. (3) Steel ladder type: wide (500±5) mm standard steel ladder, wide (800±10) mm wide steel ladder. (4) The size of the air inlet at the bottom of the combustion chamber is (800±20) x (400±10) (mm). (5) Ignition Source: two belt propane gas burner and its matching flowmeter and Venturi mixer. The fire surface should be a flat metal plate drilled with 242 holes of 1.32 mm in diameter. The holes are arranged in three rows with the center distance of 3.2 mm. Each row is 81, 80 and 81, respectively, and distributed in the nominal size of 257 x 4.5 mm. In addition, a small number of holes are arranged on both sides of the flamethrower, which can maintain stable combustion of the flame. Each burner uses a rotator to control the flow rate of propane and air. (6) Ignition source position: Spray lamp is placed horizontally, away from the front surface of cable sample. The burning point of the spray lamp is located in the center between the two transverse gears of the steel ladder and is at least 500 mm from the lower end of the specimen. The spray lamp is installed on the trolley. (7) Combustion Gas: propane with a purity of 95%. (user provided) (8) Combustion Supporting Gas: compressed air. (9) Air Flow: 20~150L/min adjustable, equipped with pressure gauge and regulating valve. (10) Propane Flow Rate: 2~20L/min (flowmeter is rotator flowmeter); equipped with pressure gauge and regulating valve. (11) Power Supply: AC380V, 50HZ; total power is 5KW.