Inside the data centre design support model

“You’re responsible, but you may not have the full picture.” – Neil Reguine, Senior Mechanical Engineer

That is a familiar position for contractors delivering data centres.

By the time a contractor is appointed, the design has usually progressed through Stage 2 and Stage 3. The fundamentals appear settled. A programme has been agreed. There is often an expectation that delivery can begin to accelerate.

Experienced teams recognise something else at this point. Responsibility has changed hands, and with it the nature of the decisions that now matter.

Responsibility changes how design needs to be understood

At Stage 4 and Stage 4A, the issue is rarely that a design is fundamentally flawed. More often, the problem is that the information now being relied upon does not fully explain how earlier decisions were reached.

Contractors may receive outputs without the workings behind them. Calculations may arrive as summaries rather than evidence. Assumptions and design and equipment sizing safety factors may not be visible. When questions surface, the team responsible for delivery is left reconstructing intent under time pressure.

“A lot of the time, we’re reverse-engineering decisions that were already made, trying to match final calculation values with what we believe as the design intent based on limited information on our hands.” – Neil Reguine, Senior Mechanical Engineer

That’s where uncertainty begins to creep into a programme. Not because capability is lacking, but because teams are being held accountable ahead of fully understanding what’s required.

Not every contractor treats this handover moment the same way

Some might move straight into delivery, trusting that gaps can be resolved later. More experienced teams recognise that this is the point where uncertainty is cheapest to address and if spatial planning risks are still lurking on the horizon. They slow down deliberately, not to delay progress, but to understand what they are now being asked to stand over.

This pause is not about redoing design work. It is about interrogating what has been inherited so delivery decisions are based on evidence rather than assumption.

At this stage, attention shifts to practical questions. Can the design be built as per the BIM model received? Are the specified systems available in the market, like-for-like? Will the plants function without issues and  be accessible for servicing/replacement once installed? Does the performance being promised still hold once the design meets reality?

When those questions are answered early, the tone of delivery changes.

When the dynamic of a project shifts

Instead of information being chased as issues arise, teams work through what has been inherited in a structured way. Gaps are identified early, while there is still room to respond. Assumptions are tested before they become commitments.

The focus moves away from reacting to individual problems and towards understanding the design as a whole. Buildability, PUE and sustainability goals alignment, access and long-term operation are considered together. Decisions are made with the right people involved, rather than passed between disconnected teams.

As a result, delivery starts from a more stable position. Fewer questions remain open. Fewer compromises are pushed downstream. By the time procurement and site activity begin, the design is no longer something to be interpreted. It is something the team understands and can stand over.

This is the difference between inheriting risk and actively managing it.

Scope clarity protects delivery as much as design quality

Unclear scope is one of the quickest ways for programmes to drift. When responsibility is assumed rather than agreed, effort is spent reacting instead of progressing. Commercial conversations begin late. Decisions are revisited. Work that should have been resolved earlier resurfaces at the point where change is most expensive.

A clear approach to ownership does more than tidy paperwork. It allows teams to price accurately, make decisions with confidence, and understand where responsibility truly sits.

In data centre delivery, where MEP systems dominate both cost, complexity, and building performance, clarity is fundamental.

Coordination fails when information fragments

Data centre projects involve many specialist contributors. Each brings their own submittals, assumptions and constraints. When those inputs are reviewed in isolation, coordination starts to break down.

Issues that could have been resolved earlier begin to surface just as procurement decisions are being made. By then, options are limited.

A single technical lens across submittals, models and interfaces changes that pattern. Decisions are taken once, with the right people involved. Downstream rework becomes far less likely because problems are surfaced before they harden into commitments.

Buildability shows up long before site activity

“It looks fine in the model, but you can’t maintain it in real life.” – Neil Reguine, Senior Mechanical Engineer

Many of the most disruptive issues are not compliance failures. They are practical problems that only become obvious when someone asks how the plant will actually be installed, accessed and serviced over time.

If those questions are not asked early, they do not disappear. They resurface later as redesign, delay or compromise.

Experienced teams understand that buildability is not a site issue. It is a design responsibility that needs to be tested before delivery begins.

Stage 4A as a point of confirmation

“The model becomes very critical once it’s handed over at 4A.” – Neil Reguine, Senior Mechanical Engineer

By Stage 4A, the focus shifts from intent to confirmation. This is where the design is reviewed with the understanding that it will shortly be built and operated.

When this stage is approached deliberately, it becomes a stabilising moment. Dimensions, access and coordination are checked against reality, not assumption. Outstanding questions are resolved while there is still flexibility in the programme.

“If it’s still being fixed at Stage 4, you’re already under pressure.” – Neil Reguine, Senior Mechanical Engineer

Handled well, Stage 4A gives delivery teams confidence that what they are about to commit reflects the performance and operational outcomes the project is meant to achieve.

Confidence comes from shared, current information

From a contractor’s perspective, confidence grows when everyone is working from the same information, at the same time.

A common data environment, visibility of relevant submittals, and models that reflect what is actually being proposed rather than what was assumed earlier.

When information flows this way, design support becomes a stabilising influence rather than a corrective one.

A more assured way to inherit design

“You want to catch problems when they’re still easy to fix.” – Neil Reguine, Senior Mechanical Engineer

For experienced contractors, this is not about being cautious. It is about being deliberate at the moment responsibility changes hands.

When inherited design is interrogated early, delivery starts from a position of understanding rather than assumption. Decisions are grounded in evidence. Coordination is intentional. Programmes are protected before pressure builds.

This approach does not slow projects down. It allows them to move forward with confidence.

About the author

Neil Reguine is a Senior Mechanical Engineer with close to two decades of experience delivering building services design for complex, mission-critical projects. A Chartered Engineer and International Professional Engineer, he has worked across data centres, healthcare, life sciences and commercial developments in Europe, U.S., the Middle East, Africa, Asia and Australasia.

His work focuses on how buildings actually perform in practice - particularly when projects are inherited mid-stream, programmes are tight, and decisions made early carry long-term consequences.