Building healthcare facilities for the future: Embodied carbon in the NHS Net Zero Building Standard

Compliance with the NHS Net Zero Building Standard has been mandatory for two years now. Since 1st October 2023, compliance with the NHS Net Zero Building Standard has been compulsory for all new NHS buildings and major upgrades to existing NHS facilities that are subject to the HM Treasury business case approval process.

This isn’t just guidance to consider - it’s a formal funding requirement. Projects must demonstrate compliance throughout the business case lifecycle, from early design through to handover. This includes meeting bespoke upfront embodied carbon targets for superstructure and substructure elements - a responsibility that falls squarely within the structural engineer’s remit – as well as the façade.

Unfortunately, it seems to me that we’re not actively discussing embodied carbon on our healthcare projects early enough, or how our healthcare projects will comply, and this is worrying.

At Curtins, we’ve committed to calculating and reducing embodied carbon on every project we deliver, across all sectors, regardless of compliance requirements. In the NHS context, that commitment aligns perfectly with the Standard’s ambitions - but also requires deep technical understanding of the requirements and a proactive, collaborative approach from everyone involved.

Why embodied carbon matters in healthcare infrastructure

Buildings contribute a large share of the UK’s total carbon emissions. While operational carbon — emissions from running a building - is now widely discussed and understood, embodied carbon is perhaps less obvious. It’s the carbon ‘locked in’ to a building before anyone uses the facility, and is the sum of emissions from material extraction, manufacture, transport, construction, maintenance, and eventual end‑of‑life processing.

In a hospital, where civil and structural elements are substantial, the embodied carbon contribution from the superstructure and the substructure can be especially significant. Limiting the upfront embodied carbon it is no longer optional; it’s a formal requirement under the NHS Net Zero Building Standard.

What the Standard requires - and what it means for the structural design

The Standard sets out that all new NHS projects must limit upfront (i.e. ‘cradle to handover’ or modules A1-A5) embodied carbon for the superstructure, substructure and façade. There’s a key detail that’s often overlooked though - a specific project embodied carbon limit must be calculated for each project based on the gross internal floor area and the use of each floor. And this limit must be set for the project at the start of RIBA Stage 2.

The use of each floor, termed the space-type technology category in the Standard, directly impacts the project specific upfront embodied carbon target. These space-type technology categories are labelled Support, Low Tech, Medium Tech, High Tech and Ultra High Tech, and each has a different embodied carbon target benchmark.

To help calculate a specific project embodied carbon target, the NHS has produced a straightforward Excel‑based calculator - part of its Whole Life Carbon Compliance Tool — that should be used to determine the embodied carbon target for each project. By entering the floor area of each space-type technology category, the spreadsheet automatically calculates the bespoke project target, making the process transparent and straightforward.

The logic is sound as well, as the upfront embodied carbon target for a large acute hospital heavy on high‑tech surgical areas will differ from a smaller community hospital with mostly low and medium‑tech clinical spaces - even if their total floor areas are similar. This calculation method therefore tailors the embodied carbon limit to the building’s actual functional profile, not just its size.

We can no longer rely on generic ‘industry best practice’ embodied carbon limits; we must calculate and evidence our target or limit for each NHS scheme.

The Curtins approach: measuring and reducing on every project

At Curtins, we’ve committed to calculating and reducing embodied carbon on every project we deliver regardless of compliance requirements and across all sectors. Our process starts with calculation — you can’t manage what you haven’t measured. We use recognised lifecycle assessment tools to quantify the embodied carbon in our civil and structural engineering proposals.

From there, we work iteratively with the design team to reduce the number through:

• Optioneering at concept stage - comparing structural forms and materials side‑by‑side, with carbon as a key decision metric alongside cost and programme.

• Supply chain engagement - talking early to fabricators and material suppliers about low‑carbon options — so specifications are achievable in the real market.

• Continuous review - revisiting carbon calculations at design gateways, ensuring value‑engineering doesn’t inadvertently push emissions up.

From a civil and structural engineering perspective, typical strategies for embodied carbon reduction include the following, but each must be considered in conjunction with the functional requirements of the healthcare facility:

• Material efficiency as a design driver - efficient structural members, optimised spans, and efficient load paths can all reduce tonnage — and therefore carbon.

• Foundation strategy and ground conditions - substructure choices must balance stability, cost, and carbon. Piling, for example, may be unavoidable on certain sites, but alternatives or optimisations should be explored.

• Low‑carbon material specification - cement replacements (GGBS, PFA), high‑recycled‑content steel, engineered timber (where appropriate) — each must be considered against performance criteria and supply chain availability.

A concern worth voicing

From my perspective there’s something a little troubling: we’re not talking about embodied carbon and compliance with the Standard early enough on NHS projects. I don’t honestly know why this is the case, but it’s likely a combination of a lack of awareness and competing priorities. The lack of early discussion is a risk however. If the conversation doesn’t happen early, compliance becomes harder, and the opportunity to make meaningful carbon savings decreases.

Raising embodied carbon at the right time isn’t just professional diligence — it’s integral to delivering the NHS estate the country needs in a net‑zero future.

Looking ahead

The NHS Net Zero Building Standard signals a shift in what ‘good’ design looks like in healthcare. It asks more of us as engineers and designers — not just to ensure buildings stand the test of time, but to ensure they do so within the carbon budget of a sustainable future.

That’s a challenge we welcome here at Curtins. Every hospital and healthcare facility we design is an opportunity to improve not only the care it delivers, but the legacy it leaves.

Key Takeaways

• Compliance with the NHS Net Zero Building Standard is mandatory for all new NHS buildings and major upgrades subject to HM Treasury business case approval

• Embodied carbon targets for superstructure and substructure are project‑specific, based on floor area and use type

• The NHS provides a simple Excel‑based calculator to determine each project’s bespoke embodied carbon target

• Early measurement and optioneering are essential to allow meaningful carbon reduction

• Curtins calculates and works to reduce embodied carbon on all projects, using recognised assessment methodologies

• We’re not having the embodied carbon conversation early enough on NHS projects at the moment, and that needs to change