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Interpretation Response #PI-76-0103

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date: 04-14-1976

Location state: MI    Country: US

View the Interpretation Document

Request text:

BASF Wyandotte Corporation

January 22, 1976

Mr. Cesar DeLeon, Acting Director
Office of Pipeline Safety
Department of Transportation
2100 Second Street SW
Washington, D.C.  20590

Dear Mr. DeLeon:

At a recent meeting in your office I agreed to formally request interpretations of the Gas Pipeline Regulations as they relate to facilities at our Geismar, Louisiana Works.  The regulations are written to describe residential areas and require interpretation when applied to chemical plant facilities.  The buildings and areas described below may be found on the attached portion of our site plan drawing.  In the present preliminary design phase, the areas shown represent the best guess of building areas according to the scale noted.

Section 192.5(c) uses the phrase "intended for human occupancy."  We request your interpretation as applied to the following:

1. Administration Building (ADMIN) - Normal daytime occupancy is thirteen people, plus visitors, plus locker room facilities for sixty-two men on day shift and twenty men on the odd shifts.  This means a normal occupancy at beginning and end of the day shift of ninety-five people.  Between second and third shifts, the combined occupancy is forty people.  In addition to the above questions, is this also considered normal occupancy by more than twenty people?

2. Warehouse (WHSE) - The warehouse will be used for the storage of equipment and supplies.  It will not have continuous occupancy but will have frequent in and out usage for storage and withdrawal of materials.

3. Maintenance Building (MAINT) - Normal occupancy of this building will be up to forty-four men on day shift and some lesser number during second and third shifts.

4. Control House - This building will be occupied on a continuous basis with twelve men on day shift and approximately eight men on the off shifts.

5. Boilers, Unit 1300 - Each of the three initial boilers, designed for alternate coal firing, will be approximately 55 feet in height and will have approximately five platform levels.  Two or three operators will be assigned on each shift for continuous operation.

6. Process Units (Units 100 and 200) - The process units will consist of multiple level structures, housing process equipment such as reactors, columns, rotating equipment, tanks, etc., and manned on a continuous basis by one or more people per unit.  Each unit will consist of multiple independent structures, some roofed, such as compressor house, vacuum pump house, etc.  The structures are typical of chemical process plants and are comparable in function and manning to those found in petroleum refineries.  (If the process units are determined "for human occupancy," should each independent structure or each level of structure be considered a unit in determining the class location?)

7. Meter Buildings - These are masonry block buildings housing gas metering equipment but not normally occupied.  The buildings are regularly visited for meter reading, calibration, and other maintenance activities.

Section 192.5 (d)(2)(ii) refers to "a small, well defined outside area that is occupied by twenty or more people during normal use ---."  The parking lot adjacent to the administration building is designed for 150 cars.  The normal daytime use will be ninety people plus visitors, and the off-shifts will have twenty people.  Similar to the case of the administration building, at either end of the day shift, the normal count of people will be 110, and between the odd shifts it will be a total of forty.

8. Parking Lot - Does the above described lot fall within the definition of a Class 3 location?

We will appreciate receiving your interpretations of these buildings and lot as they relate to pipeline class locations.  Your opinions will enable us to anticipate possible pipeline changes and the resultant construction activity within our plant areas.

I thank you for the courtesy extended to me on my visit to your office, and will look forward to receiving you opinions in the above matters.

Very truly yours,
John W. Milroy         
Chief Engineer - Design

Response text:


April 14 1976

Mr. John W. Milroy
Chief Engineer-Design
BASF Wyandotte Corporation
Wyandotte, MI  48192

Dear Mr. Milroy:

This is in response to your letter dated January 22, 1976, regarding interpretations of the Office of Pipeline Safety Operations (OPSO) rules and regulations, specifically Section 192.5, Class location.  Contrary to the statement in your letter, OPSO regulations were not written to just describe residential areas.  They are intended to include all types of locations including office buildings, factories, outside recreation areas, etc.  Your plant facilities can be included within a class location definition.

As set forth in Section 192.5 of the regulations, the class location of a pipeline is determined by the number of buildings intended for human occupancy within the class location unit, the normal human occupancy, and the number of stories of those buildings.

OPSO analysis of your plant diagram and corresponding description of facilities indicates that all of your eight buildings or units are intended for human occupancy.  The Administration Building and the Parking Lot lie within 100 yards of the pipeline and have a normal human occupancy of more than 20 persons.  Therefore, this area appears to be in at least a Class 3 location (refer to Section 192.5(d)(2)).  We cannot determine the class location for the areas adjacent to the other buildings from the data provided since that determination will depend on the building count in the remainder of the class location unit.

For purposes of determining class location, we do not consider the platform levels of the industrial facilities described in your letter to be the same as "stories above ground" set forth in Section 192.5(c).

If the pipeline is designed and qualified to meet the present day class location requirements then as your plant develops an more units are actually built, the pipeline may need to be reevaluated to determine if it satisfies the operating requirements for the new class location or it may require requalification or operating changes.  As an alternate you may design and qualify the pipeline now to meet the most severe class location requirements that may be anticipated for the future then increase in class location will have minimal effect on the operation of the pipeline.  This is a procedure many operators follow.  Requirements for class location changes are detailed in Sections 192.609 and 192.611 of the regulations.

OPSO regulations prescribe safety goals to be achieved, while permitting pipeline operators the flexibility of choosing the best method of accomplishment.  As this relates to your interest in class locations, the regulations do not limit the number of buildings, units, or occupants.  Instead, they prescribe safety requirements which vary by degree in many instances according to the characteristics of a pipeline's location.

We trust that this has answered your particular questions.

If we can be of further assistance, please let us know.

Cesar Deleon      
Acting Director   
Office of Pipeline
Safety Operations

Regulation Sections

Section Subject
§ 192.5 Class locations