Piping Engineering Deliverables

Hello dear readers, this is the first of many upcoming blog posts in which I will be providing brief description of key piping engineering deliverables. This series of blog posts will only focus on piping engineering deliverables. What are these deliverables? How are they prepared? What information each of these deliverables provide and how it is valuable for downstream engineering activities? What are the inputs or information required to prepare them? What are the key points you should keep in mind while preparing and reviewing these documents? etc... so, stay tuned.

In this particular post I will give brief idea about different knowledge areas of piping engineering and what type of the documents prepared by engineers working in those areas. Covering all the documents could be a huge and impractical task, so the aim is to cover only key, five to six documents from each area and try to write about them as much as possible from my side. I hope some of my writing could help new upcoming talent in the field.

Areas of Piping Engineering.

Piping engineering work can broadly be divided into three areas. Each one of them have their own documents, deliverables, standards, tools, knowledge areas, experience and skills.

  1. Piping Layout Engineering
  2. Piping Material Engineering
  3. Piping Stress Analysis Engineering

Piping Layout Engineering pertains to work related to planning and arrangement of pipes within plant scope. Engineers working in this area deals with questions like, from where to where the pipe need to be routed? How may pipes will be routed? How they will be grouped together? How to use minimum possible space without compromising accessibility, safety, operability and maintainability? How to find shortest possible route and lowest elevations to ensure less pump head requirements? How to ensure feasibility of pipe supports? How to ensure piping is not clashing with another piping or structure or equipment. The list goes on... As we will see in upcoming sections, there are many documents produced by this department and each of those documents have their own lengthy checklists to ensure their completeness and correctness.

Piping Material Engineering pertains to work related to creating piping material related specifications. This area of engineering deals with materials that are going to be used for pipes and all the inline components. Piping materials are determined based on the pressure, temperature and nature of fluid that is being handled by the piping system. Process department provides this information, and based on that, the material department develops material specifications that gives very specific information regarding materials to be used for pipes, fittings, valves and inline specialties. This specs contains information such as which material standards, material grades, thickness and rating of the components used. Whether they be forged or cast? Whether they need to have corrosion allowance or not? Their surface finish requirements, their connection requirements such as flanged, welded or threaded. And so on and so forth... when I shall write article on material engineering deliverables, I will write about it in detail.

Piping Stress Analysis Engineering pertains to work related to study and analysis of stresses and displacements developed in piping systems during various operating scenarios. This area also covers engineering of piping supports. Piping systems, due to their routing, geometry and material properties expands and contracts according to changing operating temperatures and ambient conditions. If the pipes not allowed to expand freely when temperatures and pressures are rising or falling, stresses are generated within piping. If these stresses are not managed properly it may result in failure of piping systems and could have catastrophic consequences to plant and people working around it. The objective of pipe stress analysis is to ensure that the piping systems have sufficient flexibility and stresses generated in pipes are kept within allowable limits recommended by piping codes. This objective is achieved by careful selection and design of piping supports at appropriate locations.

A good piping engineer should have sufficient knowledge of all three areas. In most cases people working as piping engineers come from Mechanical Engineering or Chemical Engineering background. When an engineer, fresh from engineering collage, starts his career as piping engineer, he would be working in either of these three areas. With passage of time, say five to six years, he acquires sufficient knowledge, expertise and skills specific to that area, to be able to work as an independent contributor who requires lesser and lesser amount of supervision. After attaining this level, he would be known as either "Layout Engineer" or "Material Engineer" or "Stress Engineer". It is rare, although not uncommon, for an engineer to have experience in all three of those areas during their careers. In smaller companies and smaller teams, it is possible for a person to get opportunity to work in all three areas but in larger companies this possibility is less likely. In my opinion, an engineer who is lucky enough to have worked in all three areas gets to have better and more detailed picture of this engineering field. His view of interactions and interconnections among these three areas gives him more profound understanding of piping engineering.

Piping Deliverables Categorization

Piping deliverables can broadly be categorized in following types. All three knowledge areas mentioned above has these type of documents.

  1. Design Basis & Specifications
  2. Calculations
  3. Engineering Drawings
  4. Piping 3D Models
  5. List Reports
  6. Piping Stress Analysis and Support Detail Engineering

1) Design Basis and Specifications

These documents are prepared at the very beginning of project. These documents contain basic technical information that is used throughout the project by various engineers. After reviewing contract documents, understanding technical requirements of the project and scope, exchanging technical queries and clarifications with client, taking approval for deviations if any proposed, these documents are prepared to form basis of all the engineering work that is going to be carried out by the engineering company. These documents are used as inputs to many downstream activities. Following are some of the key documents.

  1. Piping Design Basis (Design Criteria)
  2. Piping Material Specification Including Material Classes.
  3. Valve Material Specification including Valve Datasheets
  4. Piping stress Anslysis Design criteria.
  5. Piping Insulation Specification.
  6. Specification for inline speciality items such as strainers, expansion joints, flexible hoses, silencers, etc.

2) Calculations & Analysis

Purpose of the calculations is to size various piping components and form necessary basis to prepare specifications, RFQs, Bid Evaluation Reports, Engineering Drawings, 3D models and so on. Calculations are prepared based on design basis documents, technical requirements communicated by client, recommendations as per codes and standard, safety directives, assumptions and engineering judgements. Some of the key calculations for piping are,

  1. Pipe Sizing Calculations
  2. Pipe Thickness Calculations
  3. Piping Pressure Drop Calculations
  4. Pipe Miter Bend Calculations
  5. Pipe Branch Reinforcement Pad Calculations
  6. Pipe Rack Width Calculations

3) Piping Engineering Drawings

Engineering Drawings are the most crucial documents that are actually going to be used on site for construction. Of all the documents, these documents take more time and effort to prepare, review and issue for construction. One might even say they are the final products of all the engineering activities. In large engineering companies, very large teams of designers work in shifts under guidance of few engineers and their manager. Expensive 3D environment softwares are used to make the preparation process less time consuming and efficient. Some of the key piping engineering related drawings are,

  1. Piping General Arrangement Drawings.
  2. Piping Isometric Drawings
  3. Pipe Rack GA Drawings.
  4. Equipment Nozzle Orientation Drawings.
  5. Piping Support Drawings
  6. Piping Pressure Test Markups.

4) Piping 3D Models

Another most important deliverable of piping engineering which demands most time, effort, accuracy, skill, collaboration and above all a supervisor who has excellent people management skills and experience in handling 3D modeling software. 3D modeling requires expensive 3D softwares and skilled designers to run them effectively. Some of the key activities involved in creating 3D models are listed below.

  1. Prepare CAD plan as per project requirement.
  2. Setting up 3D environment as per project CAD plan.
  3. Setting up material spec catalogues in 3D environment as per piping material specification.
  4. Pipe Routing as per P&ID.
  5. Pipe Support Modeling.
  6. Clash detection and resolution.
  7. 30%, 60%, 90% model review activity with internal teams and client. And comment resolution.
  8. Isometric extraction.
  9. GA drawing extraction.
  10. BOQ extraction.
  11. Various Lists and Reports Extraction.

5) List Reports

There are some important lists that generated by piping and process departments. Some of these lists can directly be prepared based on available P&ID, whereas BOQs and support lists can be prepared after 3D model achieves certain level of maturity. These lists provide important data for other engineering deliverables. Some of the key list reports are mentioned below.

  1. Line List
  2. Valve List
  3. Equipment List
  4. Speciality Item List
  5. Instrument List
  6. Pipe Support List
  7. Bill of Materials for piping, valves, fittings, specialty items, insulations

6) Piping Stress Analysis and Pipe Support Detail Engineering

As mentioned before, this is in itself a separate area of expertise. Once the piping routing reach certain level of maturity, stress analysis of the stress critical lines are performed using pipe stress analysis software such as CAESAR II, Auto Pipe, Rohr2, PASS START PROF etc... Stress analysis design criteria document provides the necessary basis to perform analysis. Number of pipelines that are connected together and have been identified as stress critical are considered under one stress system and are analyzed together in single calculation. At the end of analysis, a report is prepared for each such stress systems. These reports contain following information or documents.

  1. Pipe system PID markup.
  2. Stress isometric markup.
  3. Pipe geometry used for analysis.
  4. Snapshots of stress profiles.
  5. List of inputs considered for stress analysis. (Input Datasheet)
  6. Vendor information considered.
  7. Stress Summary Reports
  8. Restraint Summary Reports
  9. Equipment Nozzle Load Data
  10. Flange Leakage Check Reports
  11. Any manual calculations that have been carried out for piping system.
  12. Pipe Support Schedule.

All above documents forms the bases for pipe support detail engineering activities. Support schedule lists all the supports on stress critical lines. Their types, their primary and secondary steel support requirements, type of support, Anchor, Guide, Limit Stop, resting support, Any special supports such as snubbers, struts, hangers and spring supports are used or not? if yes then their specifications need to be prepared separately. Their RFQs, Bid evaluations, Vendor documents reviews need to be done separately. I will write in more detail in my blog posts regarding stress analysis. My next posts will be focused on any one specific document. Thanks for reading.