An interface may relate to definitions of scope of responsibility between two functional groups, exchange of information between two functional groups, or a physical interface between equipment supplied by two different functional groups. A key component of project success is managing interface differences. Interface differences among the various manufacturers, contractors, and subcontractors involved in a project can lead to serious problems such as complications with coordination of all interface activities. All interfaces between different work elements are identified and specified together with proposals for mutually acceptable solutions. The work element means full contract scope, well-defined partial or subcontract scope, or facility/operation. These are discussed with the respective parties and adjusted as necessary. The company specifies the agreed-on interface boundary limits and the exact engineering solution within the scope of work and supply. Each interface is then detailed and progressively agreed to with the respective party. An interface register is established and maintained to reflect the development and solution of each interface. The subsea facilities team should participate in the overall project management interface. The subsea facility interfaces should be managed by the team interface coordinator with a single point of contact who is responsible for maintaining an interface register and responding by assigning responsibility for follow-up action items. A management tool for this purpose is an interface responsibility matrix that allocates responsible key personnel to all activities through all project phases. Team members can input queries and/or answers into the interface database and then register and maintain the query until it is successfully closed out to the satisfaction and agreement of all parties. A register is a legally recognized entity, such as the Copyright Office, that makes a public record of ownership for the purposes of legal protection and recourse in the event of infringement. Registers normally charge a fee for the administrative work and issue a certificate and reference number for the ownership record. A database is merely a collection of records that is searchable. These records may be public records of ownership, books available for checkout from a library, or people looking for dates on the Internet. However, the presence of a record in a database does not confer on it the status of a public record of ownership.

Roles and Responsibilities

Project Manager

The project manager has the overall responsibility for the coordination of all interface activities and also delegates the day-to-day running of the interface system to a responsible member of the project team.

Interface Manager

The interface manager is responsible for managing and coordinating those project activities directly related to identification of interface issues, maintaining the interface register, organizing regular interface meetings, and facilitating the close-out of interface issues through the exchange of information among the various functional groups.

Interface Coordinator

An interface coordinator is designated within each functional group to be the point of contact with the interface manager for identifying interface issues, communicating those issues to other members within the functional group, and assisting in the close-out of interface issues through the exchange of information with the interface manager and other functional groups.

Lead Engineers

The lead engineers may be members of any of the functional groups engaged in the project. The lead engineers are responsible for identifying interface issues affecting the work for which they are responsible, and reporting these issues to the interface coordinator within their functional group. A lead engineer may also serve as an interface coordinator.

Project Controls Coordinator

The project controls coordinator is responsible for maintaining schedule and budget reports.

Interface Matrix

The subsea interface matrix defines the points of contact between the company and the main contractor engaged in the detailed engineering, construction, and installation of subsea facilities. The interface matrix is a list of all project interfaces, such that any member of the contractor’s team may obtain a reference to the latest project information for use within the project activities. The interface matrix is a living document and is to be continuously updated as new interfaces are highlighted and the status of existing ones changes. Each interface shown on the interface matrix is allocated a specific item number to remove the possibility of any ambiguity from interface queries, correspondence, and other references.

Interface Scheduling

Each interface is scheduled such that the company may receive information in sufficient time to be incorporated into the project activities. This date is called the required-by date on the interface register and within the interface matrix.

Interface Management Plan

The interface management plan addresses the management of the various functional and physical interfaces between organizations and equipment for the project. The goal of the plan is to ensure early communication between different parties regarding information on the systems and procedures and on activities or deliverables that are required to ensure timely completion and resolution of the interface. Identifying and declaring this information early also minimizes any potential disruption to the project scheduled effective handling of interface issues across the entire project will be to everyone’s benefit. Various functional groups are engaged in various aspects of the design, procurement, fabrication, installation, and commissioning of facilities for the project. The interface management plan establishes the methodology and tools for identifying interface issues among the various functional groups, recording and tracking the issues, and bringing the issues to closure.

Interface Management Procedure

All interface issues are entered into the interface database for tracking and reporting purposes. All of the interface managers and select others will be given access to the system.


Interface management requires the early identification, prioritization, and quick resolution of interfaces to avoid any negative impact on a project’s cost, schedule, and quality. The overall interface management process involves the planning, identification, assessment, monitoring and control, and closeout of all interfaces that also affect other company and contractor processes, such as document control, project control processes, and knowledge management systems. Interface management influences all phases of the project from detailed engineering through start-up and final handover to operations. Interfaces exist in all phases of the project and need to be proactively managed and resolved to support the contractors’ progress and execution of the work.


Open communications among all contractors and client companies are required to identify interface issues at the earliest possible time and to afford timely resolution of the issues. In fact, open communications should be encouraged between all interface personnel contractually involved in the project. It is also advisable for the external interface teams to meet with each other on a regular basis during both the co-located and virtual team phases. Face-to-face meetings are important to facilitate and maintain communication among the contractors and a client company.


Weekly meetings are to be held with all of the interface managers in attendance. The purpose of the meetings is to conduct direct discussion regarding existing interface issues, determination of “Need” and “Forecast” dates and the status of close-out items.

Database Tool

For staff working outside of the company network, access to the database will commonly be made through shared documentation and the Internet.

Interface Queries

Each interface issue should be raised as a specific interface query. The interface queries may be raised by any functional group, but must be submitted by the group’s interface coordinator. The query numbers are assigned in sequential receiving order after the query is submitted by the interface manager, and a copy of the query is transmitted to all involved parties.

Action Plans

Complex or difficult interface issues may require a multistep solution that is best presented via an action plan. One of the functional groups should be responsible for developing the action plan and noted in the interface register.

Closeout of Interface Issues

When an interface issue is closed it should be noted in the interface register with a date in the “Date Closed” column, and a close-out reference should be cited. The close-out reference may be a correspondence number or document number reference.

Freezing Interfaces

An interface is considered “frozen” when the documents that define the interface have been issued as “Approved for Design” or “Approved for Construction.” Unresolved interface areas should be identified with a “HOLD” notation, and a corresponding interface issue should be entered in the interface register for follow-up.

Interface Register

The interface register should comprise a list of all interface queries raised by the contractor, with a separate interface register for queries received from company, such that any missing queries may be easily identified.

Internal Interface Management

An internal interface is defined as an interface that occurs within a specific company and the design disciplines. The responsibility for internal interface management usually falls on the contractor, whether it is a full engineer, procure, install, and commission project or only a portion of a larger contract.

External Interface Management

An external interface is defined as an interface that occurs between a specific company and external organizations. External interface management can be applied as a policy tool by the production company or as a control tool operating within the project group.

Interface Resolution

Resolution of external interfaces should first be attempted between the parties involved in the respective interface, but subteams can be utilized to help resolve specific issues. If this team is unable to achieve a resolution, it should become the responsibility of the external interface team. If the interface conflict still cannot be resolved, then the client company should act as mediator and force resolution of the issue.

Interface Deliveries

For the project, the company should devise an interface deliverable database, which is to be maintained and administered. The database contains a list of all highlighted interfaces between the various contractors, with associated need and source dates.


[1] H. Frederick, L. Dennis, Advanced Project Management: A Structured Approach, fourth ed., Gower Publishing, Aldershot, 2004.

[2] A.B. Badiru, Project Management in Manufacturing and High Technology Operations, John Wiley & Sons, New York, 1996.

[3] N.G. Gregory, Diana Subsea Production System: An Overview, OTC 13082, Offshore Technology Conference, Houston, 2001.

[4] International Association of Oil & Gas Producers, HSE Management-Guidelines for Working Together in a Contract Environment, OGP Report No. 423, 2010, June.

[5] M.G. Byrne, D.P. Johnson, E.C. Graham, K.L. Smith, BPTT Bombax Pipeline System: World-Class HSE Management, OTC 15218, Offshore Technology Conference, Houston, 2003.

[6] J.J. Kenney, K.H. Harris, S.B. Hodges, R.S. Mercie, B.A. Sarwono, Na Kika Hull Design Interface Management Challenges and Successes, OTC 16700, Offshore Technology Conference, Houston, 2004.

[7] U. Nooteboom, I. Whitby, Interface Management-the Key to Successful Project Completion, DOT 2004, Deep Offshore Technology Conference and Exhibition, New Orleans, Louisiana, 2004.