Standard Interpretations - Table of Contents
• Standard Number: 1910.106

February 5, 1992

Mr. Donald J. Connolley
Central Engineering Department
Akzo Chemicals Inc.
Livingstone Avenue
Dobbs Ferry, New York 10522-3401

Dear Mr. Connolley:

Thank you for your letter of November 6, 1991 requesting interpretations and clarifications of 29 CFR 1910.106 standards on outside, above ground, tanks used for storage of flammable and combustible liquids. Responses to your questions follow. Please accept our apology for the delay in our response.

Question 1: Is the scope of 29 CFR 1910.106 intended to

be limited to the storage of non-reactive flammable and combustible liquids at low pressure (less than 15 psig), or is this standard applicable to these liquids regardless of system pressure?

Reply: The standards at 29 CFR 1910.106 apply to stable as well as unstable (reactive) combustible and flammable liquids as defined in paragraph 1910.106(a). The standards at paragraph 1910.106(b) apply to atmospheric tanks, low pressure tanks and pressure vessels, as defined in paragraph 1910.106(a) for tank storage of combustible and flammable liquids in the workplace. Pressure vessels which are designed, constructed, installed, operated and maintained in compliance with paragraph 1910.106(b) shall be used to store combustible and flammable liquids at (1.05 kilograms per square centimeter) gauge (p.s.i.g.).

Question 2: If the scope of 29 CFR 1910.106 is not limited

to a given system pressure range, is the method for sizing emergency relief devices for the storage of non-reactive materials at pressures above 15 psig presented in API-520 acceptable to meet the requirements of 29 CFR 1910.106? If API-520 is considered by OSHA to not meet these requirements, then I recommend OSHA and industry experts meet to discuss the issue and resolve the discrepancies.

Reply: Insta