subject: "air Determination Of Explosion Indices Of Combustible Gases" - Means The Combustible Gas [print this page] GB 803? 89 The People's Republic of China Ministry of Public Security 1989-02-01 1989-09-01 approved the implementation of
Introduction The standard equivalent to using ISO6184 / 2? 1985 s? Edition "explosion protection system?? Part II: air Determination of explosion indices of combustible gases."
For flammable gas / air mixture explosion hazard evaluation and protection, the needs of pre-determination of explosion indices of these mixtures. For explosion protection system performance verification, also need to test explosions of known strength.
Flammable gas / air mixture explosion index and the following factors:
A. The chemical nature of the combustible gases;
B. Combustible gases in the combustible gas / air mixture in the concentration;
C. Flammable gas / air mixture in the uniformity and turbulence;
D. The type of ignition source, the energy and location:
E. Geometric shape and size of the container;
F. Flammable gas / air mixture temperature and pressure.
Given in accordance with this standard method of determination of the explosion index and its relationship with the scene of explosion, particularly dangerous turbulence of the impact of the explosion should be described by the experts.
Industry commonly encountered extreme turbulence the following two situations:
A. Gas in a container or space in a static state;
B. Gases in the exhaust area of high turbulence conditions.
Generated turbulence has the following two ways:
A. Under normal working conditions in the plant, due to the formation of the gas turbulent air flow;
B. Device internal expansion of a gas explosion Difficult, causing turbulence.
1 Subject Matter and Scope This standard specifies in a sealed container, flammable gas / air mixture explosive index determination, and gives an explosion index was determined using other criteria to be followed.
This standard applies only to the determination of the limited space, flammable gas / air mixture is ignited after the explosion index, does not apply to ignite the mixture necessary for the other indices. If the experimental operation in accordance with this standard does not ignite flammable gas / air mixture can not be that the mixture will not explode, should circumstances be explained by the experts.
2 Definition 2.1 explosion explosion
Basically in a sealed container or sealed containers, flammable gas, suspended dust, flammable vapors, spray or their mixture, in gaseous oxidants such as air in the premix flame propagation is called an explosion.
2.2 explosion index explosionindex 1m3 container in accordance with the provisions of this standard method, the determination of explosion characteristics of a certain reactant concentration value of the various number.
Note: Figure 1 shows a typical blast pressure? Time curve.
2.2.1 Explosion Index Pm
Container Explosion, relative to the maximum ignition pressure of overpressure.
2.2.2 Explosion Index Pmax
Different concentrations of mixed gas, measured by test explosions index value among the maximum value Pm.
2.2.3 explosion index K
Container V maximum pressure within the explosive rate of increase (dP / dt) m constants determined. Satisfy the following equation;
Note: The above formula applies to volume of not less than 1m3, ratio of length and diameter of the container does not exceed 2:1.
2.2.4 explosion index Kmax
Different concentrations of mixed gas explosion index K the maximum value for the valuation of the explosion severity.
Figure 1 explosion pressure - time curve
2.3 turbulence index turbulenceindex Explosion index test that measured the extent of the amount of turbulence value.
2.3.1 turbulence index tv (ignition delay)
Began spraying gas containers and ignition time interval between the start, it said the turbulence of the instant ignition
2.3.2 Turbulence Index Tu
In accordance with the requirements of this standard measured in the turbulent state of Kmax, turbulence and measured in the static state of Kmax, the ratio of rest.
