(1) Separation distance. When two or more storage magazines are located on the same property, each magazine must comply with the minimum quantity of explosives and separation distance requirements for:

(a) Magazines (Table H-21);

(b) Inhabited buildings, railways, and highways (Table H-20).

(2) Distances that do not meet requirements. If the separation distance between two or more magazines is less than the distance required (Table H-21), the magazines must:

(a) Be considered one magazine; and

(b) Comply with the minimum distance requirements for inhabited buildings, railways, and highways (Table H-20).

(3) Distance of grouped magazines to other magazines. Each magazine in a group must comply with minimum magazine distance requirements (Table H-21) in relation to other magazines not considered part of the group.

(4) Quantity of explosives.

(a) Magazine group. The total quantity of explosives stored in a magazine group (two or more) must:

(i) Be considered one magazine;

(ii) Not exceed the requirements of Table H-21 for one magazine.

(b) Detonator magazine. The quantity of explosives contained in a detonator magazine takes precedence over the minimum magazine distance requirements (Table H-21) when determining the separation distance required between a detonator magazine and magazines that contain other types of explosives.

(c) Detonator strength. Strengths of blasting and electric detonators:

(i) Up to #8 detonators must be rated as one and one-half pounds of explosives per one thousand detonators;

(ii) Detonators greater than #8 must be computed on the combined weight of explosives.