HTM 03-01 Part B: Specialised Ventilation for Healthcare Premises – Management and Maintenance
Health Technical Memorandum 03-01 Part B is the official guidance issued by NHS England and NHS Improvement concerning the management, operation, maintenance, and routine testing of existing healthcare ventilation systems. Published as part of the wider Health Technical Memoranda (HTM) framework, this 2021 edition supersedes the 2007 version of HTM 03-01, as well as older standards such as HTM 2025 and DV4. It establishes the technical standards required to ensure that ventilation plant in healthcare environments remains fit for purpose and compliant with statutory legislation, including the Health and Safety at Work etc. Act 1974 and the Health Act 2009.
The scope of this document encompasses all types of ventilation systems installed in healthcare premises, irrespective of their age. It focuses on systems provided to control airborne infection risks in acute care areas such as operating departments, critical care facilities, isolation rooms, and treatment areas. Regulatory domains covered include the management of Local Exhaust Ventilation (LEV) under COSHH regulations, fire safety protocols for ductwork, and the implementation of energy-efficient strategies to meet Net Zero Carbon targets. Key structural elements of the memorandum include specific guidance on functional responsibilities, minimum standards for Air Handling Units (AHUs), and detailed protocols for the Annual Verification of critical systems.
The following sections detail the mandatory and recommended procedures for estates managers, Authorising Engineers, and clinical staff responsible for the safety and resilience of healthcare ventilation.
Statutory Requirements and Legal Framework
Compliance with HTM 03-01 Part B is linked to several UK statutes that impose a duty of care on healthcare providers to maintain safe environments for patients and staff.
- Health Act 2009: Places a duty of care on providers; failure to maintain ventilation standards in areas like operating theatres can lead to increased surgical site infection risks.
- COSHH Regulations 2002: Requires specialized ventilation plant, such as fume cupboards and LEV systems, to be examined and tested at least every 14 months by a competent person.
- Workplace (Health, Safety and Welfare) Regulations: Mandates that enclosed workplaces are ventilated by natural or artificial means and maintained in efficient working order.
- Building Regulations: Sets minimum standards for air purity, access for maintenance, and precautions against Legionella.
Functional Responsibilities and the Ventilation Safety Group
The document introduces a multidisciplinary governance structure to oversee the safety and resilience of ventilation systems.
- Ventilation Safety Group (VSG): A multidisciplinary group responsible for assessing ventilation safety, prioritising plant replacement, and informing the design process for new or modified premises.
- Authorising Engineer (Ventilation) (AE(V)): An independent professional designated to provide auditing, advice, and to witness the validation and verification process.
- Authorised Person (Ventilation) (AP(V)): An individual with adequate technical knowledge responsible for the practical implementation of safety policies and procedures.
- Competent Person (Ventilation) (CP(V)): The person designated to carry out routine maintenance and periodic testing of the systems.
Minimum Standards for Ventilation Systems
Regardless of the date of installation, all existing ventilation systems are expected to meet minimum operational standards to ensure patient safety and energy efficiency.
- AHU Intakes and Discharges: Intakes must be positioned to avoid drawing in vitiated air or exhaust fumes; meshes should be between 6 mm and 12 mm to prevent vermin infestation.
- Plant Drainage: All moisture-producing plant must have a drainage system comprising a drip-tray (preferably stainless steel), a borosilicate glass trap, and an air break of at least 15 mm.
- Filtration: Filters must be of the dry type and securely housed in frames that minimise air bypass; HEPA filters in supply ducts require metal cases to prevent fungal growth.
- Control Systems: Critical systems must be capable of being switched to manual operation in the event of a computer control fault.
Annual Inspection and Verification Requirements
Critical healthcare ventilation (CHV) systems require more frequent and detailed assessments compared to general ventilation.
- Quarterly Inspection: A simple visual check for all Critical Healthcare Ventilation (CHV) systems.
- Annual Verification: A detailed inspection including measurements of supply and extract airflow rates, room air-change rates, and differential pressures.
- Operating Theatre Standards: Conventionally ventilated theatres should achieve not fewer than 18 air changes per hour.
- Noise Levels: Maximum permissible service noise levels are set, such as 50 dB(A) for operating suites and 35 dB(A) for treatment rooms.
Lifecycle Management and Energy Efficiency
HTM 03-01 Part B provides a timeline for the maintenance and eventual replacement of ventilation assets.
- 20-Year Lifecycle: Plant should generally be scheduled for replacement after 20 years of service.
- Mid-life Refurbishment: Systems should be refurbished approximately 10 years after installation, including deep cleaning and control system upgrades.
- Electronically Commutated (EC) Fans: The guidance recommends replacing belt-driven fans with EC plug fans or direct-drive fans to reduce energy consumption.
- Set Back Strategy: Systems should be switched to a lower output or 'off' when areas are not in use, provided a minimum background condition is maintained.
Frequently Asked Questions
What is the recommended replacement age for healthcare ventilation plant?
Ventilation plant should be scheduled for replacement after 20 years, with a mid-life refurbishment typically occurring at the 10-year mark.
Which areas are classified as having critical ventilation systems?
Critical systems include those serving operating suites, airborne isolation facilities, critical care units, neonatal units, and endoscopy or bronchoscopy rooms.
What are the required air change rates for an operating theatre?
A conventionally ventilated operating theatre should achieve no fewer than 18 air changes per hour.
How often should Local Exhaust Ventilation (LEV) systems be tested?
In accordance with COSHH regulations, LEV systems must be examined and tested at least every 14 months by a competent person.
What is the mandatory air break for AHU drainage traps?
Water from each trap must discharge via a clear air gap of at least 15 mm above the spill-over level of a tundish or floor gully.
Are belt-driven fans permitted in new or refurbished installations?
HTM 03-01 recommends that belt-driven fans should no longer be installed, favouring more energy-efficient electronically commutated (EC) fans.
How long must maintenance records for healthcare ventilation be retained?
All system records must be kept for at least five years, though manufacturing pharmacies require a retention period of 25 years.
What is the function of a Ventilation Safety Group (VSG)?
The VSG is a multidisciplinary group that assesses all aspects of ventilation safety, resilience, and prioritises plant replacement programmes within a healthcare organisation.
