Vietnam's regulations on the safe distance from mining explosives to structures

According to Vietnam's regulations, a safe distance is the minimum necessary distance in all directions measured from the blasting site or from factories, warehouses, vehicles containing industrial explosives (IE), explosive precursors to buildings, objects that need protection to ensure that buildings, objects needing protection are not unduly affected by vibration, air shock waves, flying rocks when blasting or when there is a fire explosion incident, explosion of vehicles, factories, industrial explosive storage warehouses, explosive precursors.

Illustration (Internet)

The National Technical Regulation on Safety in the production, testing, acceptance, storage, transportation, use, destruction of industrial explosives and the storage of explosive precursors (Code: QCVN01:2019/BCT) issued together with Circular 32/2019/TT-BCT specifies the details about the safe distance as follows:

- To protect buildings and structures from being destroyed due to blast-induced vibrations, the safe distance must be determined according to the provisions of Appendix 7 of this Regulation.

- The safe distance to prevent explosion transmission for IE warehouses or outdoor IE storage sites is determined according to the provisions of Appendix 7 of this Regulation. The safe distance for preventing explosion transmission must select the largest value among the explosion transmission distances and must not be less than the fire prevention and fighting safety distance.

- To protect people and structures from the impact of air shock waves when blasting, the safe distance must be determined according to the provisions of Appendix 7 of this Regulation.

- The safe distance for flying rocks is determined according to the design or the blasting passport. In an open area, the distance for flying rocks must not be less than the value specified in Table 1. The safe distance for people must select the greatest value between the safe distance for air shock waves and the safe distance for flying rocks.

Table 1. Safe distance due to flying soil and rocks when blasting

Notes:

(1) The total mass of the clad blasts detonated simultaneously (by explosive cord or instantaneous electric detonator) must not exceed 20 kg;

(2) When blasting on mountain or hill slopes, the radius of the hazardous area in the downward direction must not be less than 300 m;

(3) To prevent boats from entering the hazardous area during river or lake bed blasting, signal buoys must be placed upstream and downstream of the boundary of the hazardous area no less than 200 m. In case of rivers or lakes with bamboo rafts, signal buoys upstream must be placed no less than 500 m from the boundary of the hazardous area. During flood season, upstream signal buoys must be placed 1,500 m from the hazardous area boundary;

(4) In the blasting design (especially when blasting in residential areas and on construction sites) there must be a separate section addressing measures to ensure human safety;

(5) The radius of the hazardous area can be reduced to 15 m after lowering the equipment into the borehole or well to a depth of more than 60 m.

Other provisions can be found in Circular 32/2019/TT-BCT of the Ministry of Industry and Trade of Vietnam, effective from July 1, 2020.

Thu Ba

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