Temperature calibration device for flammability testing equipment of building materials

KTR031Temperature calibration device for flammability testing equipment of building materials

I. Overview

This temperature measuring device is used for the calibration of combustion test flames and complies with JJF (Building Materials) 168-2020 Calibration Specification for Flammability Test Devices for Building Materials.

2、 Assembly

Refer to the following figure and Figure A.2.

Install the thermometer and thermocouple on the bracket and fix them (be careful not to damage the imported thermocouple during operation!).

3、 Temperature calibration at a fixed position above the flame

1. Calibration method

a) Using propane with a purity of ≥ 95% as fuel, under the specified gas pressure (10kPa~50kPa), adjust the air flow rate in the box flue to (0.7 ± 0.1) m/s;

b) Ignite the burner located in the vertical direction, wait for the flame to stabilize, adjust the burner fine-tuning valve to maintain the flame height at (20 ± 1) mm, and the flame should have no significant disturbance;

c) Tilt the burner horizontally forward at a 45 ° angle along the vertical axis of the burner, so that the vertical height between the center position of the lower edge of the copper block and the inner side of the top lower edge of the burner is 10mm;

d) Record the temperature T when the flame impacts the copper block for 30 seconds.

2. Repeatability

The temperature measurement of the copper block should be carried out 5 times, and between the two measurements, the copper block is allowed to cool naturally in the air to below 25C.

Note: If the copper block has never been used before, the surface of the copper block should be pre treated during initial operation without considering the results.

The relative standard deviation of five consecutive measurement results shall not exceed 5%. If any abnormal values occur during the calibration process (with a deviation of more than 5% from the average of the other four groups), a new measurement can be made. Without a clear reason, no data shall be discarded.

4、 Relative standard deviation of temperature at a fixed position above the flame

The arithmetic mean of the temperature T at a fixed position above the flame is calculated according to formula (4), the relative standard deviation is calculated according to formula (5), and the relative standard deviation is calculated according to formula (6).

In the formula:

N - number of repeated measurements;

Ti - i-th measurement of flame temperature, ℃;

-The average value of T-n measurements, ℃;

SD - standard deviation of n flame temperature measurements, ℃;

RSD - the relative standard deviation of flame temperature measured n times.