GB/T 39996-2021Fireworks and firecrackers—Determination of calorific value of pyrotechnic powder (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the method for determining the calorific value of pyrotechnic powder for fireworks.

This standard applies to the oxygen bomb calorimetry method.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 601 Preparation of Standard Titration Solution for Chemical Reagents

GB/T 7899 Gas cylinder pressure reducer for welding, cutting and similar processes

GB/T 8170 Numerical rounding rules and the expression and determination of limit values

3 Terms and definitions

The following terms and definitions apply to this document.

4 Principle

Fill a sealed and constant volume oxygen bomb with a certain pressure of oxygen or air, ignite the quantitative sample and completely burn it, and measure the oxygen bomb calorimeter (Constant temperature or adiabatic type) The temperature rise value of the water in the inner cylinder is calculated according to the heat capacity of the calorimetric system to calculate the calorific value of the sample.

5 Reagents or materials

5.1 Oxygen. purity >=99.5%, no combustible components, electrolytic oxygen should not be used.

5.2 Sodium hydroxide standard solution [c(NaOH)=0.1mol/L]. Prepared and calibrated according to GB/T 601.

5.3 Phenolphthalein indicator. 5g/L.

5.4 Benzoic acid. benchmark calorimetric substance, second-class or above.

5.5 Ignition wire. nickel-chromium wire with a diameter of 0.1mm~0.2mm and a calorific value of 6000J/g or a molybdenum wire with 7566J/g.

5.6 Lens wiping paper. Measure the heat of combustion before use, take 3 to 4 sheets of paper, group them tightly, weigh them accurately, put them in a burning dish, and measure them according to conventional methods. Calorific value, take the average of the three results as the calorific value of lens cleaning paper.

6 Equipment