Process safety coverage for synthetic fuel handling systems

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

January 11, 1996

Mr. James A.J. Connell
USA Engineering, Inc.
[Recipient address omitted]

Dear Mr. Connell:

This is in response to your May 26, 1994, letter requesting an interpretation of the process safety management (PSM) of highly hazardous chemicals (HHCs) standard, 29 CFR 1910.119. Process scenarios at work sites and associated questions are noted below. Our corresponding replies follow. Please accept our apology for the delay in responding.

Scenario: Our Client, a multi-plant operator, has in some plants a product used as an alternative "synthetic" fuel. This product fuel is used to fire boilers and industrial furnaces. The synthetic fuel is delivered to the plant in 55 gallon D.O.T. approved drums. The drums enter a drum handling system which involves a volume corresponding to weight which exceeds the threshold quantity of 10,000 pounds (4535.9kg) of flammable liquid (having a flashpoint below 100 degrees F) in one plant area. In essence, this is a fuel compositing operation of various stocks which must meet the contract requirements for fuel value and flashpoint.

Note that the incoming feed stocks are, in general, free of any of the compounds listed in Appendix A of OSHA 1910.119 and in any case the amount present in the most heavily contaminated feed stock would not reach the threshold quantity (TQ) listed. Such compounds are, if found at all, present in trace quantities - perhaps in the parts per million by weight level.

The question of applicability arises at the point where the various source liquids are emptied into the holding tanks. The holding tanks are designed for operation at atmospheric pressure and they are provided with standard breathers. The tanks are provided with agitators to minimize problems of stratification or setting of any solids which may be present.

The tanks are located at a site sufficiently separated from the drum processing area that an incident at the drum unloading operation should not have any impact on the storage tank(s). The transfer of the fuel stock is made via a pipeline which is normally isolated by valves except for those periods of short duration when the transfers are made. Subsequently, the fuel stock is loaded on tank transports for delivery to the user's work site.

Upon arrival at the fuel user's site, the tank transports are pumped into day tanks which are designed to accept direct shipments of "pre-qualified" in-specification fuel stock from multiple sources. These day tanks are of low pressure design for operation at atmospheric pressure and they are provided with standard breathers. They are also provided with agitators to reduce stratification and to disperse and suspend any solids present. The contents of these day tanks are analyzed to certify that the material meets any permit restrictions as well as the fuel value, quality and composition stipulated in the contract with the fuel user. The fuel is pumped from the day tanks to bulk fuel storage tanks of a similar design but larger volume. These feed tanks are used to supply the fuel to the burner assemblies at each boiler or furnace.

Question 1: Would the atmospheric tanks system at the drum handing/unloading facility be classified as a covered process?

Reply: The 55 gallon drums of flammable liquids, the drum handing system, the holding tanks where the flammable liquids are mixed, the storage tanks and interconnecting piping are considered a single process. (See the definition of "process" under 1910.119(b)). Please note that a process which contains a threshold quantity (TQ) or greater amounts; that is, 10,000 pounds (4535 kg) of flammable liquids at any one point in time would be covered by the PSM standards with exceptions.

Also, the aggregate amount of flammable liquids in the process is the basis for determining TQ. As such, the aforementioned process is covered by the PSM standard. Since the process involves the activities of handling (in addition to mixing or blending) and on-site movement as well as storage in atmospheric tanks or transfer of flammable liquids which are kept below their normal boiling point without benefit of chilling or refrigeration, the exception under paragraph 1910.119(a)(1)(ii)(B) does not apply.

Question 2: Would the process which includes day tanks and interconnected bulk fuel storage tanks at the fuel user's work site be classified as a covered process?

Reply: There is insufficient scenario information to determine whether this process would be covered by the PSM standard. The following clarification is intended to assist you in this determination.

The process you described supplies fuel (flammable liquid), presumably by interconnected piping, to boilers and furnaces. Under the paragraph 1910.119(b) definition of "process", vessels interconnected to other vessels are considered a single process. When this single process involves stored flammable liquids in activities including use, handling, on-site movement or manufacturing, the exception under paragraph 1910.119(a)(1)(ii)(B) would not apply. Unless one of the other exceptions, for example, hydrocarbon fuels used solely for workplace consumption as a fuel, applies, the single process you described would be covered by the PSM standard. Also, this single process would be covered when a boiler or furnace is part of a process containing another HHC covered by the PSM standard.

We appreciate your interest in employee safety and health. If we can be of further assistance, please contact the Office of General Industry Compliance Assistance, Mr, Ronald Davies, telephone (202) 219-8031, extension 110.

Sincerely,
John B. Miles, Jr., Director
Directorate of Compliance Programs

[Requester letter reproduced on OSHA page; omitted here.]