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Inter Discipline Check - It's Definition, Description And Importance

Inter Discipline Check - It's Definition, Description And Importance I had been thinking of writing on the subject of "Inter Discipline Check", familiar to many experienced engineers working in the engineering design and consulting field by its acronym "IDC", for quite some time, and today seems to be quite appropriate.

Today's blog entry is specifically targeted for new chemical engineers joining the engineering design and consulting field as freshers. Without further ado, let's get on with what IDC is all about.

An engineering design and consulting firm engaged in providing consultancy services in the chemical process industry is a multi-disciplinary organization. Typically the engineering disciplines that exist in an engineering design and consulting firm are "Process Engineering", "HSE Engineering","Piping Engineering", "Instrumentation Engineering", Mechanical Engineeering","Electrical Engineering", "Civil Engineering" "Project Engineering" and "Quality Assurance (QA)". Some companies may have even more such as "Telecommunications Engineering", "Costing Engineering" etc.

All the aforementioned disciplines prepare engineeering documents and deliverables during the execution of a project. However, it is important to remember that most projects are multi-disciplinary in nature, with a few exceptions. It means that drawings, documents, calculations are required from all disciplines for completion of the engineering activity. In a nutshell, the complete engineering package of any project comprises items from all disciplines.

When working for a project in a multi-disciplinary environment, drawings, documents and deliverable for all disciplines become to a great extent a joint or co-ordinated effort of all disciplines. Remember, the start point or initiation of any project is from the process engineering group. No wonder, good process engineers are prized possessions of any engineering consulting company.

The process of IDC is basically an activity which ensures the following:

1. Creating complete awareness about the project for the assigned multi-disciplinary team
2. Ensuring all critical documents / drawings / calculations are reviewed, marked and corrected as required by the multi-disciplinary team for correct inputs, removal of errors and ensuring that the project quality plan is folllowed for producing first-class project deliverables
3. Ensuring information flowing periodically during the project execution phase, for example vendor data, design review(s) / HAZOP is captured in the engineering deliverables, to bring these deliverables up to the level of being useful for the construction of the plant.

Since I am a process engineer, I will be talking more about process engineering in context to IDC. The engineering documents / drawings that a process engineering team prepares and that need an IDC from other disciplines are typically listed below:

a. PFDs (need IDC only from Instrumentation and QA and that too if PFD represents control logic)
b. Project Design Basis (Instrumentation, Piping, Mechanical, Electrical, HSE, Civil, Projects, QA)
c. P&IDs (IDC from Piping, Instrumentation, Mechanical, Electrical, HSE, Projects, QA, Civil)
d. Equipment Process Datasheets (Mechanical, Instrumentation, Electrical, Piping, QA)
e. Instrument Process Datasheets (Instrumentation, Piping, Electrical, QA)
f. Hazardous Area Classification Drawings prepared by Process / HSE (Electrical, Instrumentation, Mechanical, Piping. QA)
g. Operating, Control and Safeguarding Philosophy (Instrumentation, Mechanical, Piping, QA)
h. Pre-commissioning and Commissioning Procedures (Mechanical, Instrumentation, HSE, Piping, QA)
i. Plant Operating Manual (Instrumentation, Mechanical, HSE, Electrical, Piping, QA)
j. Design Review and Closeout Report (Instrumentation, Mechanical, HSE, Piping, Electrical, Projects, QA)
k. HAZOP Review and Closeout Report (HSE, Instrumentation, Mechanical, Piping, Electrical, Projects, QA)

The aforementioned deliverables are just a few of the important process/HSE deliverables that need an IDC. There can be many more and some of them could also be project specific.

Some of the deliverables from other disiplines that need IDC from process are:

1. Mechanical Material Requisitions or specifications
2. Instrument Material Requistions or specifications
3. Electrical Load List prepared by Electrical
4. Equipment (Static / Rotating / Package) Vendor Data
5. Instrument Vendor Data
6. Piping Material Requisitions or specifications
7. Pipe / Valve / special in-line fittings Vendor Data

A process engineer certainly does not need to do an IDC for a transformer or sub-station specification. A process engineer certainly does not require to do an IDC of civil foundation drawings and structural piles. Similarly, there is absolutely no sense of a process engineer reviewing an electrical single-line diagram or instrument loop drawings. It doesn't make sense for a process engineer to review cable schedules. What I am trying to say is that, there should be some analysis of what deliverable requires an IDC and from whom. Generally good engineering companies have an IDC matrix which specifies the discipline-wise individual deliverable which requires an IDC and from whom.

Well, I think I have written enough for a blog entry and I would be happy to entertain questions from the readers and members of "Cheresources" regarding IDC. In fact, I look forward to some queries from the young engineers who have just started their career in engineering consulting.



Very good explanation. We are also following IDC metrix in our organization.

This is a very good tool for improve quality of document with minimum error.

I feel that follwing deliverable also required IDC from process on & above you had explain.

- Equipment layout from piping
- Piping GA from piping\
- Alram & trip schedule form instrumentation


Agreed that Process has to perform an IDC on Plot plan / Equipment layout from Piping, Piping GA from Piping and Alarm & Trip schedule from Instrumentation. Thank you for adding these items that need a check from process.

Ankur, Its nice idea about IDC.
I am working in a consultancy firm from last five years. Here we also follow the IDC (named as "squad check" in our organization) but we don't have any IDC matrix, can i get it for further improvement in our documentation?
Jul 30 2012 04:08 AM

Dear Ankur sir,

I am preparing interface department document in which for process dept. e.g. PDS, PFD, P&ID from which dept. inputs are required & this document going to which dept i.e. output For reference see the attached file.

jitendraprocess, on , said:

Dear Ankur sir,

I am preparing interface department document in which for process dept. e.g. PDS, PFD, P&ID from which dept. inputs are required & this document going to which dept i.e. output For reference see the attached file.


I don't see any attachment with your comment.

Jul 31 2012 01:47 AM
Dear Sir,

How to attach the document ? there are no any options for attachment.

Thanks & Regards,


Dear Sir,

How to attach the document ? there are no any options for attachment.

Thanks & Regards,


If the document is intended for me to review and give my comments than send it by personal messenger as an ttachment to the personal message. That option is available.

Great Blog Entry Ankur!

I am a Junior Process engineer about to hit my 60 days employed with a design firm. On the few projects I have worked on so far I have participated in IDCs or as my organization calls them "squad checks."

The types of documents I have checked so far are:
  • PFDs.

  • Instrument data sheets.

  • Tie-in lists.

  • Line designation tables.

  • Formal calculations.
I'm not sure if we have a matrix that lists the applicable disciplines beside the different documents to be checked. I will have to take a look at the SOPs for the company.

If you have any other ideas for blog entries for Juniors starting out in the design and consulting business please share!
Another good article, Ankur! My current organization has an IDC matrix that we adhere to. I think many people tend to underestimate the importance of IDC then when something goes wrong, they point fingers when it was their responsibility to perform the check in the first place. Process engineers need to maintain a good connection with their counterparts, the project doesn't complete on the steam of just one discipline, it's the result of a united effort.
Request to all:
Please post the IDC matrix so that we get the benefits from this forum, alternatively you may email the matrix to the interested members like me.
Thanks in advance
With best regards

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