HTM 03-01 Hospital Air Handling

HTM, or Health Technical Memoranda, give comprehensive advice and guidance on the design, installation and operation of specialised building and engineering technology used in the delivery of healthcare.

HTM Stands for “Health Technical Memorandum” with HTM 03-01 applying to new Air Handling Unit installations and major refurbishments. The document was first published on the 22 June 2021, and updated on 31 August 2021.

Health Technical Memorandum 03-01 (2021) supersedes all previous versions of Health Technical Memorandum 03-01 – ‘Specialised ventilation in healthcare premises’ (2007). It also supersedes HTM 2025 (1994) and DV4 (1983).

HTM 03-01 is the latest standard for specialised ventilation for healthcare buildings. The 213-page document highlights a number of legal requirements and provides comprehensive advice on the design implications, maintenance and operation of specialised ventilation in healthcare premises providing acute care. The use of these premises is very intense, the occupancy level high and the patients may be particularly susceptible to airborne infection risks. Their condition may also require close control of the environment

HTM 03-01 is split into two sections;

• HTM 03-01: Specialised Ventilation for Healthcare Premises: Part A – Design and Validation. This applies to new AHU installations and major refurbishments of existing installations
• HTM 03-01: Specialised Ventilation for Healthcare Premises: Part B – Operational Management and Performance Verification. This applies to the management, operation, maintenance and routine testing of existing healthcare ventilation systems.

HTM 03-01 was updated in 2021, with main changes since the 2007 edition

• Design information for specific healthcare applications has been revised and information on the reason for ventilation given. For example, endoscopy rooms are now negative pressure to contain and remove odours and manage airborne risks to staff. These endoscopy-specific risks (i.e. waste anaesthetic gases and pathogenic material (for example, multi-drugresistant tuberculosis) discharged by the patient during the procedure being undertaken) were identified prior to the SARS-CoV-2 pandemic. As with other elements in Part A, the application of this change is not retrospective but applies to new installations and major refurbishments (see Preamble above).
• The client’s needs and legal requirements are more clearly explained.
• This edition of Health Technical Memorandum 03-01 introduces the concept of the Ventilation Safety Group in healthcare organisations (similar to the Water Safety Group in Health Technical Memorandum 04-01 and the Electrical Safety Group in Health Technical Memorandum 06-01). This is a multidisciplinary group whose remit will be to assess all aspects of ventilation safety and resilience required for the safe development and operation of healthcare premises.
• The HTM introduces a standard method of identifying and labelling ventilation systems and the creation of an inventory of installed systems.
• The issues of resilience and diversity are addressed.
• Guidance is provided on refurbishments or when changing the use of an existing installation.
• Guidance is given on lifecycle and the updating of mid-life plant.
• Design information for specific healthcare application has been extensively revised.
• Issues around rooms where anaesthetic agents are used are addressed.
• Airflow rates are more tailored to the applications to take advantage of new fan and control technology and so reduce energy consumption.
• Revised air quality and filter standards are given.
• New and emerging technologies are catered for.
• Advice is given on installation standards and the appointment of an independent validator.
• More detailed information is given on the commissioning process.
• Validation acceptance standards and methodology has been completely revised.
• Routine inspection and maintenance guidance has been revised and updated.
• Health Technical Memorandum 03-01 supports UK legislation to bring all greenhouse gas emissions to net zero by 2050, and promotes sustainable methods of ventilation in healthcare facilities.There have been many legislative changes aimed at reducing energy consumption and technical advances that have increased operational efficiency. This revised HTM incorporates those changes and has amended many of the design parameters for healthcare ventilation. Designs that are simply repeated from previous installations designed to superseded standards and guidance will not meet the revised energy or operational standards and will not produce a compliant result.

HTM 03-01 states where any loss of service to the hospital ventilations system would seriously degrade the ability of the premises to deliver optimal healthcare should be classified as critical systems. This includes, but not limited to;

• Operating theatres of any type, including rooms used for interventional investigations (eg catheter laboratories)
• Patient isolation facility of any type
• Critical care, intensive treatment or high-dependency unit
• Neonatal unit
• Category 3 or 4 laboratory or room
• Pharmacy aseptic suite
• Inspection and packing room in a sterile services department
• MRI, CAT and other types of emerging imaging technologies that require particularly stable environmental conditions to remain within calibration
• Any system classified as a lev system under the COSHH regulations

The ventilation of non-healthcare facilities within the hospital should be designed to suit the application and specific guidance relating to the activity should be followed, for example pharmacy, sterile services department, etc. However, as they are on the hospital site, the means of providing ventilation should not adversely impact upon the hospital (for example, evaporative cooling towers should not be installed, sound levels should be appropriate and if the facility is within or attached to an area accessed by patients, their needs and the risk of airborne contamination should be considered).

In other types of healthcare facility that are outside of the hospital, for example GP practices, health centres, minor injuries units, dental, ophthalmic and podiatry clinics, mental health facilities, respite and long stay care homes and hospices, a risk assessment of the nature of the treatment being delivered, condition of the patients and intensity of use needs to be undertaken by those responsible for the facility in order to determine the extent to which this guidance will be applicable.

Acute care is considered short-term; the opposite of chronic care or long-term care, and describes a level of healthcare where a patient needs immediate yet brief treatment, including a severe episode of illness, conditions resulting from disease or trauma, and during recovery from surgery.