BS EN ISO 1182:2020 pdf – Reaction to fire tests for products – Non-combustibility test

BS EN ISO 1182:2020 pdf – Reaction to fire tests for products – Non-combustibility test.
7.2.4 Furnace stabilization Adjust the power input to the furnace such that both furnace temperatures (T 1 and T 2 ) (see 4.4), are stabilized for at least 10 min at (750 ± 5) °C. The individual drift (linear regression) of T 1 and T 2 shall be not more than 2 °C during these 10 min and there shall be a maximum deviation of T 1 from the average temperature of T 1 and a maximum deviation of T 2 from the average temperature of T 2 of not more than 10 °C in 10 min (see Annex D). Take a continuous record of the temperatures. 7.3 Calibration procedure 7.3.1 Furnace wall temperature 7.3.1.1 When the furnace temperatures are stabilized as given in 7.2.4, measure the temperature of the furnace wall using a contact thermocouple of the type specified in 4.6 and the temperature indicator specified in 4.13. Make measurements on three vertical axes of the furnace wall, such that the distances separating each of the axes are the same and that each measuring point is turned 60° to the nearest furnace thermocouple. Record the temperatures on each axis at a position corresponding to the mid-height point of the furnace tube and at positions both 30 mm above and 30 mm below the mid- height point. Use the thermocouple scanning device with the thermocouple and insulating tubes described in Figure 4. Particular attention should be paid to the contact between thermocouple and furnace wall which, if poor, can lead to low temperature readings. At each measurement point the temperature recorded by the thermocouple shall be stable before a temperature reading is taken
7.3.1.3 The average wall temperature at level (+30 mm), T avg,levela [see Formula (9)], shall be less than the average wall temperature at level (−30 mm), T avg,levelc [see Formula (11)]. 7.3.2 Furnace temperature 7.3.2.1 When the furnace temperatures are stabilized, as given in 7.2.4, and when the furnace wall temperature is as given in 7.3.1, measure the temperature of the furnace along its central axis using the thermal sensor specified in 4.5 and the temperature indicator specified in 4.13. The following procedure shall be achieved using a suitable positioning device to locate precisely the thermal sensor. The reference for the vertical positioning shall be the top surface of the copper cylinder of the thermal sensor when mounted in the furnace. Record the temperature of the furnace along its central axis at a position corresponding to the mid- height point of the furnace tube. From this position, move the thermal sensor downwards in steps of maximum 10 mm until the bottom of the furnace tube is reached and record the temperature at each position once it has stabilized. Move the thermal sensor from the lowest position upwards in steps of maximum 10 mm until the top of the furnace is reached and record the temperature in each position once it has stabilized.
7.4.1 Stabilize the furnace as described in 7.2.4. If the recorder used does not allow a real-time calculation, the temperature stabilization shall be checked afterwards. If the conditions specified in 7.2.4 are not satisfied, the test shall be repeated. 7.4.2 Before starting the test, ascertain that the whole equipment is in good working order, for example, that the stabilizer is clean, the specimen insertion device is working smoothly and the specimen holder exactly occupies the required position in the furnace. 7.4.3 Insert one specimen prepared and conditioned as specified in Clause 6 into the specimen holder (4.3) suspended on its support. 7.4.4 Place the specimen holder in the furnace in the position specified in 4.3.2, taking not more than 5 s for this operation. Make sure to place the specimen holder as accurately as possible in the furnace because slight differences in position of the specimen holder might change the temperature exposure of the specimen. 7.4.5 Start the timing device (4.14) immediately following the insertion of the specimen into the furnace. 7.4.6 Record throughout the test the temperature measured by the furnace thermocouples (4.4) and, if required (see Annex C), the temperature measured by the surface thermocouple and centre thermocouple (4.4). The temperature measured by the two furnace thermocouples shall be corrected according to the calibration (see 4.4).