HTM Explained: Health Technical Memoranda
Healthcare estates run to a layer of engineering guidance that does not exist in other sectors, and that layer changes what routine maintenance means. This guide explains what Health Technical Memoranda are, which series matter most to an estates team, and how the authorising engineer regime works.
In short
Health Technical Memoranda (HTMs) are guidance documents for the design, installation, and operation of engineering services in healthcare premises. They set out specialised requirements for systems where failure carries clinical risk — ventilation, medical gases, water safety, decontamination, and electrical resilience.
What HTMs are, and are not
HTMs are guidance rather than legislation. Their authority comes from adoption: NHS bodies and healthcare providers work to them, contracts specify them, and departing from them requires justification in the same way departing from any recognised standard does. In practice, within healthcare estates they function as the expected baseline, and an FM provider taking on a healthcare contract is generally committing to deliver against them.
What distinguishes HTM work from equivalent work elsewhere is the consequence of failure. Theatre ventilation is not a comfort system; a medical gas pipeline is a clinical delivery system; water safety in a building with immunocompromised patients carries a risk profile that a commercial office does not have. The maintenance tasks may look familiar, but the tolerances, verification, and record-keeping expectations are materially higher.
- Guidance documents, not legislation, but the expected baseline in healthcare estates
- Adopted through NHS policy and specified contractually
- Cover systems where engineering failure carries direct clinical risk
- Tolerances, verification, and records are more demanding than commercial equivalents
The series that matter to estates teams
A handful of series account for most day-to-day estates work. HTM 03-01 covers specialised ventilation, including the annual verification of critical ventilation systems such as operating theatres and isolation rooms. HTM 04-01 covers water safety in healthcare premises, sitting alongside the general legionella duties but with additional expectations reflecting patient vulnerability. HTM 02-01 covers medical gas pipeline systems, which bring their own permit and competence regime.
HTM 06-01 covers electrical services supply and distribution, where resilience and the integrity of essential supplies are the focus. HTM 05 addresses fire safety in healthcare premises, where evacuation strategy differs fundamentally from a commercial building because many occupants cannot self-evacuate. Alongside these, HTM 00 sets out the overarching policy and management framework, including the roles the other series rely on.
- HTM 03-01 — specialised ventilation, including annual verification of critical systems
- HTM 04-01 — water safety, additional to general legionella duties
- HTM 02-01 — medical gas pipeline systems and their permit regime
- HTM 06-01 — electrical supply resilience; HTM 05 — fire safety; HTM 00 — policy framework
The authorising engineer regime, and HTM alongside SFG20
HTMs rely on named competence roles, and this is the structural difference from commercial FM. An Authorising Engineer provides independent professional advice and audits the system; an Authorised Person is appointed and trained to carry out or control specific work; Competent Persons carry out the work itself. The appointments are formal, documented, and specific to a discipline — an AP for medical gases is not thereby an AP for ventilation.
HTM and SFG20 coexist rather than compete. SFG20 provides the task-level maintenance schedules across the asset base; HTM sets the healthcare-specific requirements, verification regimes, and competence structure that sit over the top. A healthcare estate typically runs SFG20-based PPM with HTM requirements layered onto the systems those memoranda cover. What that combination generates is a substantial evidence burden — verification reports, AP appointment records, permits, and validation data — which is why retrievability matters as much as the work itself.
Related maintenance checklists
How this applies by sector
Further reading
Sources
The regulatory positions on this page come from the following primary sources. Where guidance and legislation differ, the legislation governs — always confirm the requirements that apply to your own site and jurisdiction.
- Health Technical Memoranda — NHS England
- Legionnaires' disease: The control of legionella bacteria (ACoP L8) — Health and Safety Executive
Frequently asked questions
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