Project delivery

MEP design through RIBA Stages 1–6 and BG6

MEPX structures building-services design to the RIBA stage framework, using BG6 principles to define the expected level of MEP information, coordination and responsibility.

Why the stages matter

Building services must develop with the building

MEP systems affect plant space, risers, ceiling zones, utility capacity, energy performance, fire interfaces and maintainability. Decisions made during Preparation and Briefing and Concept Design therefore shape what can be coordinated and delivered later.

The RIBA Plan of Work provides the overall project framework. BSRIA BG6 adds building-services-specific guidance for design activities, information and responsibility. MEPX structures appointments around both frameworks so the expected level of MEP design, coordination and information is clear at each stage, while the exact deliverables remain project-specific.

Scope note: the MEP items below are typical, original summaries. They do not replace a project-specific appointment, information schedule, responsibility matrix or the licensed BG6 guidance.

View the official RIBA Plan of Work
View BSRIA building-services design guidance

RIBA Stage 1

Preparation and Briefing

Approve an achievable Project Brief, with client requirements, site information, surveys, constraints and responsibilities established before design begins.

RIBA stage outcomeProject Brief approved and confirmed as capable of being accommodated on the site.

Typical MEP / BG6-aligned activities and information

MEP input to the Project Brief and client information requirements
Site information, utilities, surveys and existing-services requirements
Initial performance, energy, fire, sustainability and operational criteria
MEP responsibility matrix, programme and Stage 2 information requirements

ContinueStage 2 · Concept Design

RIBA Stage 2

Concept Design

Develop and test the building-services strategy alongside the Architectural Concept and Project Brief.

RIBA stage outcomeArchitectural Concept approved and aligned with the Project Brief, with a viable MEP strategy.

Typical MEP / BG6-aligned activities and information

Strategic mechanical, electrical and public-health system options
Initial loads, energy studies, utility requirements and performance targets
Plant-space, riser and principal distribution allowances
Concept diagrams, outline specification and Stage 2 report inputs

ContinueStage 3 · Spatial Coordination

RIBA Stage 3

Spatial Coordination

Resolve the principal systems and interfaces within the coordinated architectural and structural design.

RIBA stage outcomeArchitectural and engineering information spatially coordinated.

Typical MEP / BG6-aligned activities and information

Developed calculations and system selections
Coordinated plant, risers and distribution routes
Architecture, structure, builder's-work and specialist interfaces
Updated layouts, schematics, schedules, strategies and Stage 3 report inputs

ContinueStage 4 · Technical Design

RIBA Stage 4

Technical Design

Complete all design information required to manufacture and construct the project, to the agreed consultant, contractor and specialist boundaries.

RIBA stage outcomeAll design information required to manufacture and construct the project completed.

Typical MEP / BG6-aligned activities and information

Final calculations, equipment selections and performance criteria
Coordinated manufacturing and construction layouts, schematics and schedules
Final specifications, controls narratives and technical details
Contractor and specialist design integration, interfaces and Building Regulations evidence

ContinueStage 5 · Manufacturing and Construction

RIBA Stage 5

Manufacturing and Construction

Manufacture, construct and commission the building, with the design team responding to site queries and formally controlled changes rather than routinely developing the design.

RIBA stage outcomeManufacturing, construction and commissioning completed.

Typical MEP / BG6-aligned activities and information

Responses to site queries and formally instructed changes
Review of contractor and specialist information where appointed
Site observations, commissioning and defects inputs where appointed
Progressive verified construction, asset and Building Manual information

ContinueStage 6 · Handover

RIBA Stage 6

Handover

Hand over an operable, documented building, initiate aftercare and close the Building Contract.

RIBA stage outcomeBuilding handed over, aftercare initiated and Building Contract concluded.

Typical MEP / BG6-aligned activities and information

Commissioning, completion and outstanding-defects information review
Building Manual, O&M, record and asset-information inputs where appointed
Seasonal commissioning, aftercare and technical close-out support
Performance feedback and light-touch post-occupancy evaluation inputs

NextBG6 responsibilities

BG6 and responsibility

Define who produces each part of the technical design

Stage 4 is particularly sensitive to procurement and responsibility. Consultant design, contractor design and specialist design may develop in parallel, but the interfaces, review duties and final information ownership should be explicit.

A useful appointment identifies each required calculation, drawing, model, schedule, specification, selection and review activity together with its author, reviewer and issue stage. This reduces gaps and duplicated design effort without reproducing a generic BG6 responsibility table.

CalculationsWho authors and verifies?

Drawings and modelsWho coordinates and issues?

Specialist designWho completes each interface?

Reviews and recordsWhat is reviewed, and when?

Appointment timing

What changes when MEP advice starts later

Stage 1

Maximum influence

Requirements, surveys, energy objectives and responsibilities can be established before options are fixed.

Stage 2

System strategy

MEP options and spatial allowances can still be tested alongside the architectural concept.

Stage 3

Validation required

Existing assumptions and allowances may need checking before coordination can progress reliably.

Stage 4

Higher change risk

Earlier decisions, missing information and responsibility gaps may need resolution during technical design.

Common questions

Scope and responsibility

What does BG6 add to the RIBA Plan of Work?

BSRIA BG6 provides building-services-specific guidance that helps teams define design activities, information and responsibility in greater detail within the wider RIBA stages.

Why is MEP Stage 4 scope important?

Stage 4 can include different levels of consultant, contractor and specialist design. The appointment should state who produces each calculation, drawing, schedule, specification and coordinated detail.

Can MEPX be appointed after Stage 2?

Yes, but the available information, previous decisions and unresolved risks should be reviewed first. Late appointment may require validation or redevelopment of earlier assumptions.

Does every commission include all six stages?

No. The required stages, deliverables, reviews and responsibilities are agreed for each project and procurement route.

Project stage

Define the next MEP deliverable

Share the current RIBA stage, procurement route, available information and required decision. MEPX can help identify the scope needed to move forward.