Flammable liquids and dip tank standards

April 26, 1990
Mr. Russell M. Kuroda
Chemist
EKC Technology, Inc.
[Recipient address omitted]
Dear Mr. Kuroda:
This is in response to your letter of January 8, in which you requested the Occupational Safety and Health Administration's (OSHA) interpretation of 29 CFR 1910.106 and [1910.123-1910.126], as they pertain to the use of flammable and combustible liquids in dip tanks. Your questions will be addressed in the order of their presentation. Please excuse the delay in our response.
In regard to your first question concerning the application of [1910.123-1910.126] to the volume of flammable and combustible liquid in this tank or other dip tanks, OSHA does not exempt dip tanks from coverage on the basis of size or the volume of liquids held. Your three to five gallon dip tank is regulated under our [1910.123-1910.126] standard. There is no volume limit at which this regulation applies.
Second, you asked whether one can use a solvent in a dip tank within 50 degrees of its flash point regardless of the design and the volume and class of liquids used. ~~The standard 1910.108(c)(7), means that one cannot allow a temperature rise greater than 50 degrees F. below the flash point of the heated liquid being used, regardless of the size or the configuration of the tank and the volume of the flammable or combustible liquid being used.~~

This document was edited on 4/29/99 to strike information that no longer reflects current OSHA policy.

In your third question, you asked what was the proper test method for a liquid with a viscosity of less than 45 SUS at 100 degrees and a flash point of greater than 200 degrees. OSHA consulted with Mr. E. M. Nesvig, who is a member of the American Society of Testing and Materials (ASTM) and that organization's expert on flash point determinations. OSHA was informed that the ASTM D93-85 Standard Test Methods for Flash Point by Pensky-Martens can be used as the test method. OSHA accepts the ASTM Flash Point test methods for flash point determinations. Please feel free to contact Mr. E. M. Nesvig, who is employed at the Erdco Engineering Corporation, at (708) 328-0550 for any additional information.
~~Finally, the answer to your question pertaining to the use or class IIIB liquids in a dip tank at a temperature greater than 150 degrees F. can be found at either 1910.108(c)(7) or National Fire Prevention Association (NFPA) 34-4.9 (enclosed). Both standards require that provisions must be made to prevent a temperature rise greater than 50 degrees F. below the flash point of the heated liquid.~~

This document was edited on 4/29/99 to strike information that no longer reflects current OSHA policy.

OSHA adopted the most current NFPA standards when it promulgated its 1910.106 and [1910.123-1910.126] standards (NFPA 30-1969 and [NFPA 34-1995], respectively). Since that time, changes may have occurred to reflect new findings in this area. Employers who comply with the latest national consensus standard, rather than with the OSHA standard in effect at the time of the inspection, may be charged with a de minimis violation. Such violations are not included in the citation and carry no penalty. The enclosed pages from OSHA Instruction CPL 2.45B, of June 15, 1989, further explains this policy.
Please feel free to contact [the Directorate of Enforcement Programs at (202)693-2100] if you have additional questions.
Sincerely,
Patricia K. Clark, Director
Directorate of Compliance Programs
[Corrected 4/17/2009]