GB/T 34710.3-2018Classification of the mixture gas—Part 3: Flammable classification (English PDF)

2.1 Flammable mixture gas

A mixture gas which can be ignited in air at atmospheric pressure and at 20 °C.

2.2 Nonflammable mixture gas

A mixture gas which does not conform to 2.1.

3.1 Classification

The flammability of mixture gas is divided into the following two categories.

- Flammable mixture gas;

- Nonflammable mixture gas.

3.2 Conversion coefficient of some nonflammable gases equivalent to nitrogen

The conversion coefficient Kk of some nonflammable gases equivalent to nitrogen is shown in Table 1.

Kk - Conversion coefficient of nonflammable gas k in mixture gas equivalent to nitrogen.

Note: The mole fraction of all gases in this Part is equivalent to the volume fraction under atmospheric conditions.

3.3.1.2 Determination

When x is less than or equal to 1, the mixture gas is nonflammable, otherwise it is flammable.

3.3.2 Determination method 2

The mixture gas which conforms to formula (3) is nonflammable, otherwise it is flammable.

3.4 Calculation and determination examples

3.4.1 Example 1

Calculate the flammable gas content in the mixture gas having a hydrogen content of 7 x 10^-2 (mole fraction) and a carbon dioxide content of 93 x 10^-2 (mole fraction), equivalent to that in nitrogen. The flammability of the mixture gas is determined.

a) Calculation steps

1) Hydrogen in the mixture gas is a flammable gas; and the carbon dioxide is a nonflammable gas. According to Table 1, the Kk value of carbon dioxide is 1.5. According to formula (2), calculate A'i as follows.

2) Refer to Appendix A; the Tci value of hydrogen is 5.5 x 10^-2 (mole fraction). Calculate according to formula (1) as follows.

b) Flammable determination […]