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Aisles beside flammable-liquid containers

Summary An aircraft manufacturer asked how the flammable-liquid storage rule treats obstructions and wall aisles. OSHA said an obstruction is something that impedes water from sprinklers or hose streams, and a wall aisle is required only for material that expands when wet. It said metal flammable-liquid containers do not require a wall aisle under that provision.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1975-09-02-0
Date issued
September 2, 1975
Status
Active
Status last verified October 10, 2026
Topics
Workplace Safety OSHA 1910 Flammable Liquids Fire Protection
Source
View the official document

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About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

September 2, 1975

Mr. E.F. Makin
Manager-Plant Security & Safety
Piper Aircraft Corporation
[Recipient address omitted]

Dear Mr. Makin:

Your letter dated August 20 regarding storage of flammable liquids was referred to this office for reply.

The "obstructions" mentioned in 29 CFR [1910.]106(d)(5)(vi)(e) are those that would impede the flow of water from sprinklers or hose streams when combating fires. Space between containers of flammable liquids and a wall is required only when the material is subject to expansion when wet with water. Metal containers of flammable liquids do not require a wall aisle.

Sincerely yours,

David H. Rhone
Assistant Regional Director for
Occupational Safety and Health

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