Application cont'd - hdbk11010025

DOE-HDBK-1101-96

OSHA defines commercial grade as a typical maximum concentration of a chemical that is

commercially available, and shipped. The term commercial grade includes reagent grades that,

in some cases, differ in concentration from the typical commercial grades. In cases where

different concentrations for commercial and reagent grades are typically shipped, the lowest (or

lower) concentration (and any concentration greater) is covered by the PSM Rule. Where

covered, the total mass of the mixture is used for comparison with the applicable TQ.

Are processes involving flammable liquids (e.g., ethyl alcohol) covered by the PSM Rule?

Processes involving flammable liquids (e.g., a distillation process) in quantities at or above

10,000 lb. are covered. Flammable liquids in atmospheric storage tanks are considered a part

of a process if the storage tanks are interconnected with the process, or if they are sufficiently

near the process that an explosion, fire, or release could reasonably involve the storage area.

Flammable liquids that are stored in atmospheric tanks in a tank farm where only transferring

and storage are performed are not covered by the PSM Rule. They are, however, covered

under 29 CFR 1910.106.

Two flammable chemicals in quantities below 10,000 lb are combined in a process to form

a flammable liquid in excess of 10,000 lb. Is this process covered?

Based upon this consideration alone, yes.

10.

Are processes covered if they contain fuel used for process heating or drying only?

The PSM rule exempts processes using flammable liquids or gases solely as fuels in the work-

place. Thus, these processes are not covered unless they are covered for other reasons.

11.

There is an exemption for atmospheric storage and transfer of flammable liquids. Are all

atmospheric vessels excluded from coverage?

This exemption deals with storage and transfer of flammable liquids only. Atmospheric stor-

age and transfer of HHCs listed in Appendix A are not exempt. Further, atmospheric storage

tanks of flammable liquids may be covered if they are interconnected or in close proximity to a

covered process. Contractors should evaluate each situation based on local site-specific con-

siderations and document the technical basis for invoking this exemption.

12.

Are activities such as atmospheric mixing, and blending of flammable liquids covered

under the Rule?

The requirements of the PSM Rule apply to such operations. The exemption for atmospheric

storage and transfer of flammable liquids does not apply to mixing and blending operations,

because such operations may generate static charges capable of ignition.

13.

Are flammable liquids covered by the Rule when stored at atmospheric pressure in tanks

designed for pressure-service?

The Rule exempts storage of flammable liquids in atmospheric storage tanks in certain in-

stances. If a DOE contractor can reasonably show that the tank cannot be operated above