While designing a piping system, many inputs are required from other disciplines and also inputs are given to other disciplines. There are also few outputs generated by piping which are required for procurement, erection and fabrication of the piping system.



Inputs to Piping discipline:

1. Requirement from client:
Plot area and location, statutory requirement, special requirements etc.

2. Process licensor:
Project design basis, plot plan, PFDs(Process Flow Diagram), P&IDs (Process and Instrumentation Diagram), PDS (Process Data Sheet), process description, equipment list, line list, site data, licensor, capacity etc.

3. Process information:
Process data sheet showing overall dimensions, supporting arrangement, all nozzles location, size, rating, etc. for equipment.

4. Civil/Structural layout, drawing:
Effluent & drain sewers layouts and manholes location.
Civil drawings (plan and elevation) for the facilities within the unit like instrumentation control room, electrical sub-station, and laboratory.
Pipe racks and technological structure foundation drawings.
Civil drawings for platforms.
Tank settlement data.

5. Instrument drawing:
Tray width requirement on pipe rack/sleepers.
Instrumentation hook-up drawing.
Instruments drawings for control valves, safety valves, inline instruments etc.

6. Electrical layout:
Tray width requirement on pipe rack/pipe sleepers and cable trenches width in units/off-site.
Electrical cable tray layout.

7. Mechanical (Static/Rotary/Package) layout:
Mechanical datasheets for equipment like columns, vessels, tanks etc.
Layout drawing of packages items showing auxiliary equipment.

8. HVAC: (Heating, Ventilation, and Air conditioning)
Layouts showing the HVAC duct size and the location.

Outputs from Piping discipline:

• Overall plot plan showing location of various units, tankfarms, offsite, package units, non-plant buildings, roads, culverts, piperacks, sleepers, etc.
• PMS (Piping Material Specification)& VMS (Valve Material Specification).
• Equipment general arrangement drawing/layouts indicating the location of all the equipment within the unit, platforms , ladders, overhead crane elevation, monorail location, cutouts for piping.
• Piperack general arrangement drawing & structures for equipment support
• Piping general arrangement drawing/Layouts showing all the piping and equipment.
• Piping Bill of Materials (BOM) with technical evaluation and technical bid analysis (TBA).
• Piping stress analysis report for the critical lines.
• Drawing showing the vessel cleats location for pipe supports and platform/ladder.
• Layout for underground services.
• Piping isometrics with bill of material.
• Support location plan, support schedule, pipe support drawings.
• Purchase specification for insulation, painting, wrapping and coating.
• Material handling study.

In recent times, various types of projects are executed in the oil and gas, petrochemical, chemical, metallurgy, pharmaceutical industries etc. such as conceptual study, FEED (front end engineering development), EPC (Engineering, procurement and construction), EPCM (Engineering, procurement, construction management), Lump sum turnkey etc. Due to recession in current economic situation even though the projects have become less profitable still all those phases are very important.

Phases and various disciplines in projects:

Different phases during the life of a project are conceptual study, feed (front end engineering development), detail engineering, construction, mechanical completion, pre-commissioning, commissioning and start-up. For executing above mentioned projects different engineering disciplines involved are process, piping, civil/structural, instrumentation, electrical, mechanical (static/rotary), HVAC etc. Every discipline plays a vital role during each phase of the project.

Cost of piping in projects: a major component:

The capital cost of piping is a major factor in almost all chemical plants investment. Fig 1 shows a chart based on oil refineries, chemical and petrochemical complexes.

Fig 1 shows that, apart from other equipment costs, piping is the largest plant cost component which is double the combined cost of all others.



Piping engineering :

Piping Engineering is a study and development of Piping layout, material selection and behavior of the piping system under prevailing process conditions and design parameters. It is the study for developing an efficient and economical way for the transport of fluid from the source to the destination as indicated in the Piping and Instrumentation Diagram (P&ID). Since the piping systems are subjected to all severest condition of plant such as high temperature, high pressure flow, erosion, corrosion, high toxic condition and the combination of all, which makes it more difficult while designing a piping system. The Piping system has to designed for taking in to account all the conditions and the desire life of the plant.

Role of a piping engineer:

While carrying out piping design work, a piping engineer has to consider the design requirement for piping and also for the other disciplines in the project. So a piping engineer needs to have overall knowledge of all the disciplines and requirement in the project. Besides, a piping engineer should also have good knowledge of operation, maintenance, safety, fabrication, erection, availability, cost and client requirement which would help to develop a efficient and economical design. Piping engineer needs to have a good planning, scheduling and vision for the timely completion of any project. He also needs to provide timely input for the other discipline to complete their tasks and activities within the project schedule.

Since piping holds a major part of the cost and the man-hours required in a project so it is the key discipline in the timely execution and completion of any project.