LINE NUMBERING

Piping lines shall be numbered in the following manner:

a) Numbering of All Lines Excluding Steam Tracing Spools

1. Piping serial number, in general, is started from 0001 onwards except for the units that are characterized by more than one section, such as crude and vacuum distillation units. In such cases, the splitting of piping serial numbers to be assigned for each section of the unit shall be determined by the contractor. Special number 7001 : 9999 shall be used for all drains, relief headers and utility services, including fuel oil and fuel gas for all units, except for the units that are producing the subject utility services. For assigning the piping serial number, the following items should be taken into consideration:
   1. Pipe line numbers shall be prefixed, from source to unit battery limit, with the unit number of the unit of origin.
   2. The individual line number shall be held up to the point where the line ends at the inlet of equipment, such as a vessel, exchanger, pump, etc. Another number is required for the line downstream of the equipment.
   3. A new line number is required when the pipe design condition can vary (e.g., downstream of the control valve assembly) or when a new piping class is to be specified.
   4. Line number shall be held up to the point where the line ends to the header or unit battery limit block valve. All branches to and from header shall have an individual line number.
   5. All utility headers (systems) shall be numbered with their respective units. All branches serving a specific unit shall be numbered with that unit.
   6. All fire water and sewer branches serving a specific unit shall be numbered in accordance with the note above.
2. Piping class code shall be in accordance with the line classes utilized in project piping material specification.
3. Piping components not identified by instrument or mechanical equipment numbers, etc., and not covered by the piping material specification, are identified by a special item number.
4. Unit number of the plant shall start from 1 (not from 01).

b) Steam Tracing Spools

For steam tracing spools for steam tracing numbering and material takeoff, the contractor can use their own system.

Example

3"-P-12007-A11A-H30

• 3" – Signifies the line size in inches
• P – Signifies fluid service
• 12007 – 12 signifies unit or facility number, 007 denotes the serial number
• A11A – Denotes the piping service class
  • A – denotes the flange rating
  • 11 – denotes the piping material
  • A – a suffix qualifying the piping material
• H – Denotes the insulation type
• 30 – Denotes the insulation thickness