Article 20 Occupancies Involving Storage of Nitric Acid

This article shall apply to the construction, alteration and use of buildings or spaces wherein nitric acid is stored.

Carboys containing nitric acid shall be stored in storage vaults.

(a) Vaults shall be constructed of incombustible acid-resistant material with a fire resistance of at least one hour.

(b) Doors opening into such storage vaults shall be self-closing, noncombustible fire doors with a fire-protection rating of at least three quarters of an hour.

(c) Vault floors shall be constructed of acid-resistant brick, concrete treated with sodium silicate or other acid-proof material and shall incorporate a dike constructed of the same material, whose height shall be adequate to contain the acid plus the neutralizing substance that would be necessary to neutralize said acid plus six inches.

(d) The floor shall be provided with a valved drain which shall be connected to the drainage system in accordance with the requirements of subchapter sixteen of this chapter.

Mechanical ventilation systems for storage vaults shall be adequate to effect ten complete air changes per hr. Exhaust shall be taken from within twelve inches above the level of the top of the dike. The exhaust system shall be independent of exhaust systems serving other parts of the building and the openings to the outdoors shall be located in accordance with the provisions of subchapter thirteen of this chapter for system conveying vapors.