California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 7 - General Industry Safety Orders
Group 18 - Explosive Materials
Article 122 - Ammonium Nitrate Storage
Section 5363 - Bulk Storage

(a) Bulk storage may be in piles or bins in warehouses, or in separate, bin-type structures.

(b) Unless constructed of noncombustible material or unless adequate facilities for fighting a roof fire are available, bulk storage structures shall not exceed a height of 40 feet.

(c) Bins shall be free of materials which may contaminate ammonium nitrate.

(d) Due to the corrosive and reactive properties of ammonium nitrate, and to avoid contamination, galvanized iron, copper, lead and zinc shall not be used in bin construction unless suitably protected. Aluminum bins, and wooden bins protected against impregnation by ammonium nitrate, are permissible.

NOTE: Steel or wood can be protected by special coatings such as sodium silicate (water glass), or epoxy coatings, or polyvinyl chloride coatings.

(e) The warehouse may be subdivided into any desired number of ammonium nitrate storage compartments or bins. The partitions dividing the ammonium nitrate storage from the storage of other products which would contaminate the ammonium nitrate shall be of tight construction to eliminate cracks or crevices.

(f) The ammonium nitrate storage bins or piles shall be clearly identified by signs reading: "AMMONIUM NITRATE" with letters at least 2 inches high.

(g) Piles or bins shall be so sized and arranged that all material in the pile is moved out periodically in order to minimize possible caking of the stored ammonium nitrate.

(h) Height or depth of piles shall be limited by the pressure-setting (caking) tendency of the product. However, in no case shall the ammonium nitrate be piled higher at any point than 36 inches below the roof or supporting and spreader beams overhead.

NOTE: Pressure-setting (caking) is a factor affected by humidity and temperature in the storage space and by pellet quality. Temperature cycles through 90° F. and high atmospheric humidity are undesirable for storage in depth.

(i) Ammonium nitrate shall not be accepted for storage when the temperature of the product exceeds 130° F.

EXCEPTION: Manufacturing or processing.

(j) Explosive materials shall not be used to break up or loosen the caked, bagged, or bulk ammonium nitrate.