Engineering Interfaces: Resolving Complex Dependencies Between EPC Contractors

Challenge Scenario:

In a recent onshore oil and gas processing facility project, there was the interface between two EPC contractors with interdependent scopes:

• EPC-A: Responsible for process engineering, equipment selection, and procurement (e.g., compressors and heat exchangers).

• EPC-B: Tasked with civil and structural design, including equipment foundations and pipe racks.

The interface relied on EPC-A providing detailed equipment specifications, including critical data such as weights, dynamic loads, anchor bolt arrangements, and vibration analysis. To facilitate this, EPC-B issued formal interface queries to EPC-A, specifying the required data and requesting clarity on any preliminary assumptions. Each interface query carried a contractual response deadline of two weeks. Delays or incomplete responses from EPC-A would directly impact EPC-B's ability to finalize the foundation and structural designs, creating potential knock-on effects on construction schedules and material procurement. This dependency highlighted the need for timely and accurate information exchange to maintain project momentum.

Complication: Delays from EPC-A in delivering finalized equipment data created a cascade of issues:

1. Design Bottlenecks: EPC-B couldn't finalize foundation and structural designs, leading to construction delays.

2. Misaligned Assumptions: In an attempt to stay on schedule, EPC-B began working with preliminary assumptions, which later conflicted with the actual equipment specifications.

3. Cost Overruns and Rework Risk: Adjustments to accommodate revised specifications threatened the project’s budget and timeline.

4. Accountability Conflicts: Both EPCs blamed each other for the delay, escalating tensions and straining collaboration.

Action Plan:

1. Revised Interface Agreement:

• Collaborated with both EPCs to redefine the Interface Management Plan (IMP), including:

-- Clear deadlines for critical equipment data submissions + follow-up via Interface Planning registers and monitoring the IQ response and target dates through Interface tools.

-- Agreed-upon interim assumptions to allow preliminary designs to proceed without risking rework.

• Documented mutual responsibilities in interface agreements, ensuring alignment with the project schedule.

2. Data Staggering Milestones:

• Broke down the equipment data submission into stages:

-- Stage 1: Preliminary data (weights, approximate dimensions, and estimated load ranges) for EPC-B to start foundation designs. + Separate IQ (Interface Query) exchange for future reference need to be included to IA (Interface Agreement).

-- Stage 2: Detailed specifications (bolt patterns, vibration analysis) at a later stage for final adjustments. + Separate IQ (Interface Query) exchange for future reference need to be included to IA (Interface Agreement).

3. Collaborative Workshops:

• Conducted joint workshops every two weeks, involving process engineers from EPC-A and structural engineers from EPC-B. These workshops:

-- Resolved ambiguities in design assumptions.

-- Created a forum to discuss risks and develop immediate action plans for open issues.

• In case agreement is not reached, Company (PMT) has to take decision based on collected inputs by EPCs.

4. Risk Mitigation and Adjustments:

• Advised EPC-B to integrate flexibility into foundation designs (e.g., oversized bolt slots and additional reinforcement allowances) to reduce rework risks when final data arrived.

• Used progress dashboards to track data submission and design progress, ensuring transparency and accountability.

5. Escalation Mechanism:

• Established an escalation protocol involving the client’s technical team as a neutral mediator for unresolved disputes.

• This avoided prolonged delays by ensuring decisions were made swiftly without compromising quality.

Outcome:

• The staggered data release and adaptive design measures allowed civil works to proceed with minimal delays.

• Rework was limited to minor adjustments, saving approximately 10% of the foundation budget.

• Both contractors acknowledged the benefits of structured collaboration, and the project achieved a milestone completion within one week of the original schedule.

• Lessons learned were documented to improve interface management in future multi-EPC projects.

Key Takeaways: This experience reinforced the importance of:

• Early and detailed interface planning.

• Flexible and adaptive design approaches.

• Proactive, transparent communication across engineering teams.

This example provides detailed insights into the technical and management aspects of resolving an engineering interface challenge.