hydrostatic test pack

Deepu:
For clarification, this web site does not belong to me. It belongs to Anton Dooley. I am just another contributor like anyone else.

Testing of Piping Systems (Hydrotesting)

Most people refer to the testing of piping systems as “Hydrotesting” but this is only partially correct. In most types of process plants there are systems that require or allow testing by other means or methods. Some of these other means and methods include; Pneumatic pressure testing; Air & Soap testing, Nitrogen & Soap testing and Commodity testing. With this in mind I prefer to address the subject as “Piping System Testing”
Glossary:
• AFC – This means issued “Approved for Construction”
• Client – This refers to the Owner/Operator of the finished Plant
• E&C – This refers to the Engineering and Construction company who is designing and building the Project
• DH – This refers to employees that are on the payroll of and a part of the E&C Company
• Plant – This refers to the total facility where the testing will be conducted
• Project – This refers to the current Project
• PST – Piping System Testing
• RFI – This refers to “Request for Information “ procedure used for most all sub-contract situations.
• STP – System Testing Package
• Sub – This refers to a Sub-Contractor hired to conduct the “PST” and is separate from the E&C
• Unit – This refers to an individual part of the total Plant

Piping System Testing can be accomplished by specialist hired by the E&C Company who are trained and experienced in PST. They might be some of the same pipe fitters who fabricated and installed the piping. This method of doing the PST is often called “Direct Hire”. On the other hand the PST may be handled by an outside company who specializes in doing piping testing. This latter method would be done under a “Contract” and this special company would be a “Sub-Contractor”. Please note there are things you must do differently when you are dealing with a Sub that you would not need to do with the DH.

It does not matter which way (DH or Sub) you do the PST there are still some things that are the same. The first requirement for preparing your Piping System Testing packages is the Piping System Testing Specification. I use the term “Specification” (or Spec) but it does not need to be an actual Specification. This document can be called “Piping System Testing Mandatory Technical Requirements” or “Mandatory Technical Requirements for Piping System Testing”. It is not important what you call it but you need to be able to define what the stated mandatory action requirements are and what are optional actions that may be taken based on certain specified conditions.
The “Spec” needs to cover the following:
1. The Project Identification
2. The Scope (of the Spec)
3. The definition of the Piping Code that applies to the Project
4. The clear definition of the different types of tests (Hydrotest, Pneumatic, A&S, N&S, Commodity, etc)
5. A definition of what will constitute a system test package (including when lines may be connected with temporary piping to reduce the total number of tests)
6. Pre test action or preparation (the number and location of test gages)
7. Test execution
8. Definition of “Hold” times and when they start for the different types of tests
9. What constitutes a successful/unsuccessful test (Pass or Fail)
10. Post test action
11. Water quality standards for Hydrotest
12. Air quality for Pneumatic testing
13. Nitrogen quality for testing
14. Kind and quality specifications for the Soap used for the testing
15. Reporting Requirements
16. Third party inspection or monitoring (Client or other)
17. (If done via Subcontract) A copy of the “RFI” Procedure and the forms for the individual question and the log to keep track of the ones submitted and answered.

Additional items that may be in the Spec (in the Contract or a separate document) would be the following”
• A listing of the number of Test packages expected for each type of test
• A schedule of when these packages are expected to be issued
• A schedule of when the piping is expected to be ready for turn-over for testing
• A schedule of when the piping system tests must be completed


Pre Test Action listed above should include such things as:
• A system-walk down to insure that all valves are installed and all flanged connections are tight.
• Adding temporary piping jumpers to facilitate greater system testing
• Installation of any temporary supports required to support the added weight of the test water

Test execution action should include:
• How to bring the system up to pressure ( incremental steps and check points)
• Venting
• Walk-downs to check for leaks at each incremental pressure step
• Final test pressure level venting and walk-down
• Hold time verification
• Approval check and sign-off

Post test action:
• Venting and draining of test water (or nitrogen) to clear the system
• Remove all temporary piping added to facilitate greater system testing.
• Removal of ant temporary supports



Test package preparation
The preparation of the actual test packages can only be done by the Piping group of the E&C Company. The criteria for this is based on the fact that all Isometrics for a system must be issued “AFC”.
Each individual test package should contain the following:
1. A Copy of the Spec
2. A copy of the P&ID’s showing the lines to be included in “this” test package
3. A copy of the Line List (showing the Commodity and the test pressure)
4. A copy of all the piping isometrics for “this” test package ( must include the test pressure on each isometric)
5. A copy of the required test sign-off forms
6. Names and contact information for questions (If done via “Direct Hire)
7. The RFI procedure, instructions and forms



I hope this is of some help to you (and others). I am sure I have left out some very important item but I am equally sure other people will fill in the gaps so that you will get what you need.

I also have some more questions.

A1) I have never heard of this (Flange Summary) or done it for any of my past projects even Modular projects. My thought is that if you use a Blind flange the same rating as the flange at the module boundary then you should be correct. Maybe (just a guess) your module fabricator asked for this so they would know how many and what ratings of Blind Flanges they needed to buy for their shop test.

A2) If you elect to mark-up the P&ID for Piping System Testing then limit it to just "Yellow" high lite of the lines for a specific type and pressure test.

A3) The Testing Contractor (or supervisor) should be the ones to define the limits of a test.

A4) You said the "spools" have already tested. Do you mean the individual spools were tested. or do you mean that after module assembly the whole module was tested?
- If you meant that the individual spools were tested then you should have the total module and the connecting spools tested.
- If you meant that the total module was tested in the fab shop then you should be able to test only the field fabricated connecting spools. This can be done using blind flanges or you could use paddle blinds to isolate them from the module and test them in place.