Serving as the principal reference point for the Heat Network Technical Assurance Scheme (HNTAS), the heat network technical standard (TS1) will mandate technical requirements for existing and new heat networks.
While it will be hugely positive for the industry, there are concerns the approval process could create large project delays – similar to those seen with the Building Safety Regulator’s (BSR’s) gateway process.
HNTAS was introduced to establish consistent, mandatory technical standards for the UK’s heat networks, with the aim of improving energy performance and enhancing consumer protection. By ensuring consistent heat quality and performance, the standards will address issues with underperforming or unreliable networks, while improving system efficiency.
The HNTAS aligns with the CIBSE Code of Practice (CP1), which provides integrated checklists that ensure a more stringent and structured compliance toolkit. While CP1 requirements were sometimes open to interpretation, HNTAS auditing ensures all requirements are assessable, with operators providing proof – such as design data, commissioning records and performance logs – to check against TS1’s measurable criteria.
Key performance indicators and monitoring requirements will be upfront, enabling integration of performance validation early in design. Clearly defined ‘key failures’ will help set pass or fail thresholds, simplifying compliance management. The mandating of regular reporting will promote transparency, helping compliance and refining burdens to avoid excessive implementation costs. Having Ofgem as the statutory regulator for heat networks will also prevent consumers from paying over the odds for their heating.
The HNTAS will have a positive impact on design, but the multiple phases, extensive monitoring and additional certification steps may extend project timelines and inflate early-stage costs.
Technical specifications and assessment procedures also remain in draft and may be revised before finalisation. Similarly, a reliance on pilot programmes means some practical adjustments are pending.
Designers must navigate operator coordination, audits, ongoing compliance, data-collection processes and certification procedures, and there must be careful consideration of the resourcing and infrastructure needed to manage these requirements without incurring additional expense.
HNTAS Stage 1 concept design aligns with RIBA Stage 2 – but while RIBA Stage 2 is iterative and creative, HNTAS restricts design freedom through early performance obligations.
HNTAS describes Stage 1 as concept design, but it could be argued that the information required is more commonly provided during developed design stage. With this Stage 1 being seen as an HNTAS assessment point, projects may not be able to proceed until all information is issued, feedback received and non-conformities resolved.
If designers rely on old CP1-compliant but non-regulatory approaches, they may unintentionally produce a concept design that cannot gain HNTAS approval.
While these stringent standards will encourage consultancies to design heat networks to the same standards, this regulatory assessment could push all Stage Two applications back.
Developers must also be aware that most design work takes place early and nothing can change once design is approved. Consequently, they may consider alternatives, such as exhaust air heat pumps in individual units.
For new-build networks, eight phases of assessment will take place at four key stages of development – feasibility, design, construction and operation. While Ofgem will be the official regulator, a code manager will register independent professionals to carry out the assessments. This could be lengthy, however. Three validators could be checking one heat network, with the third signing off the two validation reports from the previous assessors.
Are there enough assessors ready to start work on the number of heat networks that need to be assessed? As highlighted with the BSR, a lack of knowledge or shortage of people can cause significant backlogs.
Sharpening the focus on heat network quality standards is crucial, but the built environment must work together to ensure the HNTAS approval process remains streamlined. This is where advice and guidance from heat network consultants will be critical.
About the author
Jason Tramontano is technical director at Whitecode Consulting