Engineering drawings and vendor documents are the foundation of any successful project execution. A small error in a drawing, such as an incorrect nozzle location, mismatched equipment connection or missing load information, can create problems during fabrication, installation or commissioning.
Engineering Drawing Review and Vendor Drawing Reviews help identify these issues before they impact the project schedule or require costly site modifications. The review ensures that design documents and vendor submissions are technically correct, aligned with project requirements and properly coordinated between different engineering disciplines. At iFluids Engineering, our multidisciplinary team reviews engineering and vendor documents from process, mechanical, piping, instrumentation, electrical, civil and structural perspectives to support safe and efficient project execution.
What Is Review Engineering?
Review engineering, also called engineering drawing review, means checking the deliverables produced by the project’s own design team. The checker is an experienced engineer who didn’t prepare the drawing. They look at it with fresh eyes and ask three questions: Is it technically right? Does it follow the design basis? Does it agree with what the other disciplines have drawn?
This matters most during FEED and detailed engineering. A mistake made at those stages doesn’t stay in one drawing. It gets copied into material take-offs, purchase orders and construction packages.
Drawings Covered Under Engineering Drawing Review
Our engineering drawing reviews can include:
- Process Flow Diagrams (PFDs) and Piping & Instrumentation Diagrams (P&IDs).
- Plot plans and equipment layouts.
- Piping layouts, isometric drawings and pipe support drawings.
- Structural steel and civil foundation drawings.
- Electrical single-line diagrams and cable routing drawings.
- Instrument location plans, hook-up drawings and loop diagrams.
Recognized for excellence.
PROJECTS DELIVERED ACROSS THE GLOBE
What an Engineering Drawing Review Checks
The review focuses on technical accuracy, compliance and coordination between disciplines.
| Review Area | Key Checks |
| Design Compliance | Verification against design basis, specifications and applicable codes |
| Technical Accuracy | Checking dimensions, ratings, materials, line sizes and equipment details |
| Interdisciplinary Coordination | Ensuring piping, mechanical, electrical, instrumentation and structural drawings are aligned |
| Constructability | Confirming that the design can be installed, accessed and maintained safely |
| Drawing Quality | Checking revisions, references, symbols and document consistency |
Engineering drawing reviews are commonly performed as part of an Interdisciplinary Check (IDC) before documents are issued for approval or construction.
What Is a Vendor Drawing Review?
A Vendor Drawing Review is the technical evaluation of drawings and documents submitted by equipment manufacturers and package vendors during procurement. The purpose is to confirm that the supplied equipment matches the approved purchase order, datasheets, specifications and project requirements.
Vendor documents are normally submitted as per the Vendor Document Requirement List (VDRL) and may include GA drawings, datasheets, calculations, package P&IDs, electrical documents, foundation loads, inspection documents and operation manuals. The review also ensures that the vendor equipment can be properly integrated with the overall plant design.
Scope of Vendor Drawing Reviews
The scope depends on the equipment type, package complexity and project requirements.
1. General Arrangement Drawings
GA drawings are reviewed to confirm that the equipment dimensions, orientation and connection points match the project layout. Equipment weight, nozzle locations, lifting arrangements, access platforms, supports and maintenance clearances are also checked.
2. Mechanical and Equipment Drawings
Mechanical drawings are reviewed against approved datasheets and specifications. The review covers design pressure and temperature, material selection, equipment capacity, nozzle ratings, internal components, supports and inspection requirements. Where calculations are provided, they are reviewed against applicable design codes such as ASME, API or TEMA requirements.
3. Piping Interfaces
Vendor piping connections are checked to ensure they match the plant piping arrangement. This includes nozzle orientation, flange ratings, tie-in points, drains, vents, utility connections and allowable nozzle loads.
Vendor information is also compared with relevant P&IDs and piping layouts to identify possible clashes before installation.
4. Instrumentation and Control Interfaces
Instrumentation details are reviewed to ensure compatibility with the project control philosophy. Checks include instrument ranges, alarms, trips, control valves, package PLC panels, interlocks and signals connected to systems such as DCS, ESD and F&G.
5. Electrical Interfaces
Electrical details such as motor ratings, voltage, starting method, cable entries, earthing and hazardous-area requirements are reviewed to ensure compatibility with project requirements.
6. Civil and Structural Interfaces
Vendor-provided foundation and structural information is reviewed to confirm that equipment loads and supports are correctly considered. This includes static loads, dynamic loads, maintenance loads, anchor bolt details and support arrangements.
Engineering Drawing Review vs Vendor Drawing Review
| Aspect | Engineering Drawing Review | Vendor Drawing Review |
| Prepared By | Project engineering team | Equipment vendor or package supplier |
| Documents Reviewed | P&IDs, layouts, isometrics and structural drawings | GA drawings, datasheets, calculations and load data |
| Review Basis | Design basis, specifications and codes | Purchase order, datasheets and VDRL |
| Project Stage | FEED and detailed engineering | Procurement and detailed engineering |
| Main Objective | Confirm the plant design is correct | Confirm supplied equipment meets project requirements |
In practical projects, these two reviews are closely connected. Vendor information such as nozzle loads, foundation loads and control signals directly affects piping, civil and instrumentation design. Reviewing both together helps prevent interface issues during construction.
Why Engineering and Vendor Drawing Reviews Matter
Finding an issue during drawing review is usually much easier and less expensive than correcting it after fabrication or installation.
A detailed review helps project teams:
- Identify deviations before equipment fabrication starts.
- Resolve interface issues while drawings can still be modified.
- Reduce site rework and construction changes.
- Improve compliance with project specifications.
- Maintain clear technical records.
- Support smoother procurement and construction activities.
Common Issues Identified During Vendor Drawing Reviews
Some frequently observed issues include:
| Issue Identified | Possible Impact |
| Incorrect nozzle orientation | Piping modifications during installation |
| Incorrect flange rating | Connection problems and replacement requirements |
| Unapproved material changes | Reliability and corrosion concerns |
| Missing foundation loads | Foundation redesign or structural issues |
| Incorrect motor rating or Ex classification | Equipment installation problems |
| Incorrect instrument signals | Delays during loop checking and commissioning |
| Insufficient maintenance clearance | Difficult or unsafe maintenance activities |
Equipment and Packages Reviewed
Our Vendor Drawing Reviews cover various equipment and packaged systems, including:
- Pressure vessels, columns, separators and storage tanks.
- Pumps, compressors, blowers and rotating equipment.
- Heat exchangers, air coolers and fired equipment.
- Chemical injection and metering packages.
- Instrument air, nitrogen and utility packages.
- Firewater and deluge systems.
- Electrical panels, MCCs, VFDs and control panels.
Applicable Codes and Standards
Reviews are performed based on project requirements and applicable industry standards, including:
| Standard | Application |
| ASME | Pressure vessels, piping and mechanical design |
| API | Pumps, compressors, tanks and rotating equipment |
| TEMA | Heat exchanger design requirements |
| IEC | Electrical equipment and hazardous area requirements |
| ISA | Instrumentation and control systems |
| NFPA | Fire protection and electrical safety |
| ISO | Quality and engineering practices |
Client specifications, datasheets and project-specific requirements are also considered during the review.
Our Review Process
Our Vendor Drawing Review process includes:
- Understanding project requirements by reviewing specifications, datasheets, drawings and design documents.
- Checking technical compliance against approved design conditions and project requirements.
- Reviewing engineering interfaces between different disciplines.
- Checking installation and maintenance requirements including access, lifting and clearances.
- Preparing review comments with clear technical observations and references.
- Following up revised submissions until comments are addressed.
Review Stages
Vendor documents are normally reviewed at different project stages:
- Issued for Review (IFR): Identify major technical and interface issues early.
- Revised Submission: Confirm incorporation of previous comments.
- Approved for Manufacture (AFM/AFC): Verify critical issues are resolved before fabrication.
- Final / As-built Submission: Confirm final documents match the supplied equipment.
Key Deliverables
At the end of each review, you receive records your team can act on straight away:
- Marked-up drawings: Comments placed right where the change is needed.
- Comment Resolution Sheet (CRS): Our comments, the vendor’s replies and the status for each revision.
- Consolidated comment register: Review codes and open items for every document in one list.
- Technical query (TQ) list: Questions that need an answer from the vendor or client.
- Deviation list: Places where the design departs from the PO or specification.
- Interface observation report: Clashes between vendor data and other discipline drawings.
- Review status tracker: Submission dates, review codes and outstanding comments.
- Review summary report: The key findings, risks and recommended actions for each package.
- Close-out confirmation: Confirmation that everything is resolved before AFC or as-built release.
Industries We Serve
Our review experience supports industries including:
- Oil & gas facilities.
- Refineries and petrochemical plants.
- Power and energy projects.
- Offshore platforms and FPSO facilities.
- Gas processing and fertilizer plants.
- Water treatment and utility facilities.
Conclusion
iFluids Engineering provides independent Engineering Drawing Reviews and Vendor Drawing Reviews to help clients identify technical issues before they affect fabrication, construction or commissioning. With support from multidisciplinary engineering specialists, we ensure vendor documents and project drawings are properly coordinated, technically compliant and suitable for practical implementation. Whether the requirement is for a single equipment package or a complete project document review, iFluids provides clear, traceable and practical engineering support.
Contact our team to discuss your Vendor Drawing Review requirements.
Frequently Asked Questions
Review engineering is the independent checking of design drawings produced by the project engineering team. It confirms they are accurate, comply with specifications and agree with other disciplines before approval.
A vendor drawing review checks supplier drawings and documents against the purchase order, datasheets and project specifications. It confirms the equipment meets requirements and fits correctly with the plant design.
An engineering drawing review checks drawings made by the project design team. A vendor drawing review checks documents submitted by equipment suppliers. Both are needed so that vendor equipment matches the plant design.
They find specification deviations and interface errors before fabrication. This reduces site modifications, rework and schedule delays.
At the initial submission, at each revision, before approval for manufacture, and at the final or as-built stage.
A Vendor Document Requirement List (VDRL) lists every document a vendor must submit, when it is due, and whether it needs approval or is for information only.