What is a Piping Specification?
Piping Specification ( pipe spec, in abbreviated form ) is the most important piping documents for a project that is prepared during the design phase of any project. They provide all the basic guidelines that need to be followed while proceeding in the design of the project.
The function of Piping Specification
Piping Specifications are engineering documents, generated by design consultancies to cover additional requirements applicable to a specific product or application. Piping Specs provides specific/additional requirements for the materials, components or services that are beyond the code and standard requirements and based on engineering experience and best practices of the design companies.
Various types of Piping Specifications
In Piping Design Companies/Consultancies, more than twenty-five (25+) Specifications (most of the time they are referred to as pipe spec, in abbreviated form) are used that cover piping related issues. There will be a “piping specification” for:
- Piping Layout and Design
- Engineered Spring Supports
- Site Fabrication and Installation
- Hydrotesting and Pneumatic Testing of systems
- Shop Fabrication
- Hot, Cold and Acoustic Insulation
- Pipe Support Standard
- Pipe/Line Class Material
- Special Pipe Supports Design
- Valve Purchasing
And the list does not end here…….
This partial list provides some of the specific piping specifications that are found on most projects in design companies.
How to make pipe material specifications?
All Piping Material Class Specification must have a front cover with a written section containing the following:
- Document Title
- Document Number along with Revision history
- Name of Responsible person, checker, approver along with creation date
- Contents in Tabular or properly arranged format
- Functional or Purpose Statement
- General Notes
- A list mentioning all the applicable Codes that apply to the materials added in the specification
- A list specifying the Line Classes with data like Material, Commodity, Flange Rating, etc.
- All individual Line Class sheets
- All common drain, vent, and other miscellaneous details with the proper connection.
- Header and Branch Connection Tables
All of this will then be issued as a single document with the title “Material Specification”
Basic data required for Material Specification
The piping material engineer will need the following information:
- List of all commodities like the feed, all products, all waste streams, all utilities, and all additives that are part of the project.
- Complete chemistry of each commodity which includes Toxic classifications and reactions to changes in temperature.
- Maximum sustained operating pressure and temperature of every commodity. Also, Any short term or upset condition that may cause an increase or decrease in pressure or temperature.
- Corrosion rate for different pipe materials when in touch with the above commodities.
- Expected maximum and minimum pipe size (Nominal Bore) for the project.
- Jobsite Location with environmental conditions.
This is just the start. Now the engineer should know the governing piping code:
- ASME B31.1 i.e, Power Piping
- ASME B31.3 i.e, Process Piping
- Or any other Code?
The next importance is in knowing the Client’s preferences and or restrictions for materials, valves, flanges or any other items.
Next, required to know is the expected “Design Life” of the plant to determine the corrosion allowance for selecting the final pipe schedule.
Now to prepare the finished “ Piping Line Class” or “piping material specification”, The Engineer may create a word or excel document with following headers:
- Pipe Nominal Size (in inches or Metric unit)
- Wall Thickness or Pipe Schedule
- End Connection Type
- A short description of a piping component, not a full purchase description.
Vertically the first column (Item) will be divided into “Pipe”, “Fittings”, “Flanges”, “Gaskets”, “Bolts” and “Valves”
With-in this column the “Fitting” section and the “Valve” section would be divided to cover the various items normally required based on size.
“Fittings” would include:
- 90 degree ELLs
- 45 degree ELLs
- Straight TEEs
- Reducing TEEs
- Unions Etc.
“Valves” would include:
- Check Etc.
Other information that needs to be included in a line class/ material class includes.
- Temperature Limits
- Basic Construction of 2” and smaller Screwed/ 3” and Larger Flanged and Butt-welded, etc.
- Flange Rating, etc.
About the Author: This article has been prepared by Dr. Javier Blasco Alberto, Associate Professor, School of Engineering and Architecture, University of Zaragoza. He also collaborates actively with InIPED.