Build Energy provided technical consultancy for the New Visitors Building at HMP Exeter, a new-build facility on the existing prison site at New North Road, Exeter.
The building delivers modern, purpose-built accommodation for prisoner family visits, replacing outdated visiting facilities with a structure that meets current standards for welfare, family contact, and operational security. Vinci Construction UK Ltd was the principal contractor, with Mace Group acting as project manager on behalf of His Majesty’s Prison and Probation Service.
The project targeted BREEAM Excellent under the BREEAM New Construction 2018 scheme, a rating that required technical evidence across multiple credits – all of which formed part of our scope.
About the Project
HMP Exeter is a Category B local prison holding adult male prisoners on remand and serving short to medium sentences. The new visitors building sits physically separate from the main prison buildings and forms part of HMPPS’s capital investment programme to modernise visiting facilities across the estate. Construction ran from late 2022 into 2023, with commissioning and post-construction verification extending into 2024.
The BREEAM Excellent target reflects both HMPPS sustainability requirements and the Ministry of Justice’s broader commitment to reducing the environmental impact of the prison estate. Achieving that rating on a secure custodial site brings specific logistical constraints. All personnel require escorts, working hours are governed by the prison regime, and access to plant rooms and service voids must be planned carefully around operational demands.
Build Energy’s scope covered six distinct BREEAM credit areas, each requiring independent evidence prepared separately and submitted to the BREEAM assessor for scoring.
Our Role
Our role was to provide the specialist technical reports, calculations, and test data that the BREEAM assessor required to evaluate each credit. A licensed BREEAM assessor independently reviews that evidence and submits to BRE for certification – a separation of roles that is standard practice on BREEAM Excellent projects. Several services involved both design-stage and post-construction work. Two of them – the Indoor Air Quality Plan and the Commissioning Stage Services – ran across the full construction and handover period.
Energy Modelling – BREEAM Ene 01
The energy calculations for the visitors building supported BREEAM Ene 01 – Prediction of Operational Energy Consumption, covering building fabric, heating and ventilation, and lighting. BREEAM awards credits on a sliding scale against a notional baseline, so model accuracy directly affects the credits achieved.
Thermal Comfort – BREEAM Hea 04
A thermal comfort assessment supported BREEAM Hea 04, assessed against CIBSE TM52 and EN 15251. Visiting sessions bring high occupant density within a short window, so the model accounted carefully for peak heat gains. The design met the required thresholds.
Indoor Air Quality – BREEAM Hea 02
Our Hea 02 scope covered an Indoor Air Quality Plan before construction and Indoor Air Quality Testing after completion. The Plan covers material selection, ventilation management, and the pre-occupancy flush-out programme. Testing measured VOCs, formaldehyde, and CO2 against BREEAM and British/European limits, with remedial advice given where levels were elevated.
Commissioning Stage Services – Pol 05 & HMPPS Requirements
Commissioning stage services at RIBA Stage 6 covered BREEAM Pol 05 and HMPPS-specific requirements. Pol 05 measured noise from installed air handling units, fans, and other plant against design criteria. HMPPS’s own testing and verification regime covers building services performance against operational demands, with evidence provided to both the BREEAM assessor and HMPPS.
Air Permeability Testing
A post-construction air permeability test to measure air leakage through the building envelope, demonstrating compliance with Part L and contributing to BREEAM Ene 02 credits on a sliding scale.
Thermographic Survey – BREEAM Man 04
A post-construction thermographic survey supported BREEAM Man 04, using infrared imaging to identify heat loss, air infiltration, thermal bridging, and defective insulation. The survey identified remedial areas before handover and provided the photographic evidence for the Man 04 submission.
Our MOJ Framework Experience
HMP Exeter is one of a number of Ministry of Justice projects where Build Energy has, and continues to provided technical consultancy. Other examples include the HMP Norwich Video Conferencing Centre, the HMP New Hall, Wakefield new houseblock, and the HMP Wayland, Norfolk houseblock expansion. Across all four projects we deliver services within the principal contractor’s supply chain, covering BREEAM evidence, energy compliance, and air tightness testing.
Working across multiple contractors within the justice estate has given Build Energy a detailed understanding of the HMPPS capital programme. We know the specific commissioning requirements that apply to new-build prison facilities, the security protocols that govern site access and working hours, and the documentation standards expected by both HMPPS client teams and BREEAM assessors. Find out more about our work across the justice estate on our justice and MOJ framework practice page.
Frequently Asked Questions
How does Build Energy approach BREEAM evidence delivery on a live operational prison site?
Working on a live prison site requires careful planning around the establishment’s operational regime. All personnel require escort, and access to plant rooms and service voids must be pre-approved and scheduled. Testing activities that generate noise or require extended equipment set-up need to be agreed with the site team in advance. We are experienced in coordinating this kind of access across multiple site visits and credit types, building the necessary lead times into our programme from the outset, so delays to the BREEAM submission are avoided.
Can Build Energy cover multiple BREEAM credits on a single project, and is that more efficient than using separate specialists?
Yes – on HMP Exeter we covered seven distinct credit areas under a single appointment. These ranged from design-stage energy modelling and thermal comfort through to post-construction air permeability testing, IAQ testing, thermographic survey, and commissioning stage services. Consolidating technical services in this way reduces the number of appointments the principal contractor has to manage and gives the BREEAM assessor a consistent point of contact for the evidence package. Interdependencies between credits – for example between the IAQ Plan and IAQ Testing, or between Pol 05 and the wider commissioning programme – are managed by a single team.
What makes Build Energy’s approach to MOJ and HMPPS projects different from standard BREEAM consultancy?
Prison projects combine the technical rigour of a BREEAM Excellent target with the operational constraints of a secure custodial environment and the specific requirements of an HMPPS client. Our commissioning scope on HMP Exeter included HMPPS-specific testing requirements that go beyond the standard BREEAM credit specification – covering building services performance against the establishment’s operational needs, not just the credit criteria. Having delivered multiple projects across the MOJ estate, we understand how to align the BREEAM evidence programme with the contractor’s construction and commissioning schedule.
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