Mike Dunne, Service and Aftersales Technical manager at Howorth Air Technology, discusses the company’s establishment and running of a dedicated CPD-accredited Ventilation Workshop, designed ‘to address the knowledge gaps’ among contractors and engineers, in both public and private healthcare organisations, ‘to help them fully understand the specific and detailed requirements of air ventilation systems’.
In 1961 Hugh Howorth – the son of James Howorth, an engineering pioneer that had vastly improved the air quality within the industrial setting of Greater Manchester’s milling and brewery industry – was summoned to Wrightington Hospital for a conversation with Professor John Charnley, a renowned orthopaedic surgeon. Professor Charnley was troubled by an issue he could not overcome. Seeing excessive post-operative infection rates, Professor Charnley commissioned Howorth Air Technology to provide a clean air ‘enclosure’ that would help to reduce the risk of surgical site infections (SSIs). The system that we developed radically changed the way orthopaedic surgery was conducted.
An underestimated relationship
The relationship between ‘engineer’ and ‘clinical expert’ was formed, but it is one that has often been underestimated. At Howorth Air Technology, we believe this relationship is fundamental to the future success of the NHS and better outcomes for patients. During my time as a commissioning engineer, it had become increasingly apparent that the majority of clinicians and people working within the healthcare sector do not understand the principles behind the ultraclean ventilation (UCV) equipment that is being installed: how it works, why it is there, and how it should correctly be tested and validated.
In 2019, just before the global pandemic, Howorth Air Technology went back to its roots for an inspirational strategy that would support not only the healthcare sector, but all of the people that operate within it. We felt compelled as a business to address the knowledge gaps among contractors and engineers, in both public and private health organisations, to help them fully understand the specific and detailed requirements of air ventilation systems. Working with one of our largest customers – Spire Healthcare – we created a dedicated CPD-accredited Ventilation Workshop, available free of charge.
One-day workshop
At the start of 2022 we started rolling out the one-day workshop, making it available to anyone within our industry.
In this article, I will explain the key issues covered in the workshop, and how we are trying to strengthen and re-establish the relationship between engineer and clinical lead in this very niche and specialist area of engineering. The workshop addresses the following topics:
The history of Howorth Air Technology – the emerging relationship between engineer and clinical expert.
HTM 03-01: Specialised Ventilation for Healthcare Premises: Part A – Design and Validation.
HTM 03-01: Specialised Ventilation for Healthcare Premises: Part B – Operational Management and Performance Verification.
Capital installation considerations.
Live demonstrations of the UCV testing sequence in a fully functional operating theatre
History of Howorth Air Technology
The session starts by examining the world’s first ultraclean ventilation (UCV) system, ‘The ‘Greenhouse’, developed by Howorth Air Technology and donated to Wrightington Hospital in 1961. We track the development of the UCV system from the 1970s to the present day. We start with the engineering philosophy behind ‘The Greenhouse’: how it is assembled, and how our philosophy – based on protecting people – is still in use to this day at Howorth. The session focuses on post-operative infection rates prior to and after ‘The Greenhouse’, along with another unique innovation – the Body Exhaust System.
Remote and integral UCV options are assessed, as well as research and development projects that Howorth Air Technology has delivered – in some instances based around ASHRAE standards in international markets. The session also focuses on our involvement in barn theatres, and the design elements and ventilation strategy that should be considered for these surgical facilities, which can be more complex and difficult to design and install.
A global business
Howorth Air Technology is a global business, with a reputation for high-quality engineered equipment. A small section of the session acknowledges our in-house expertise and our largest ever single order of US$13 m (£10.5 m), delivered by our pharmaceutical team in 2021. This session also addresses the complexities of delivering high-level, quality projects, and Howorth Air Technology’s inclusive culture, ‘The Howorth Way’, to invest in its people and increase its presence within the community.
Insights into HTM 03-01: Part A: Design and Validation
The main session of the day focuses on the design limitations and considerations of installing ultraclean ventilation (UCV) systems. However, before all this, we go back to basics to ask the question: Why do we ventilate a space? In the course of our work, we have seen hospital treatment rooms set up in what are little more than storage cupboards, with barely any ventilation at all. We have seen air-handling units coated in microbiological growth that are supplying filtered air to operating theatres. The importance of ventilation, indoor air quality, and its associated health benefits, are steadily growing for a number of reasons. The design philosophy of a conventional ventilated operating theatre is based on the need to dilute contaminants and control both the condition and movement of air within the operating theatre.
Increasing the dilution effect
Ultraclean ventilation (UCV) is a means of substantially increasing the dilution effect, by circulating large volumes of clean filtered air over the operating zone. During the session, we explain the need to dilute viable and non-viable contaminants, create clean airflow paths, manage the Control of Substances Hazardous to Health, provide cross-flow ventilation, provide comfort, a stable temperature, and humidity, as well as to dilute and control contamination
In June 2021, the revised Health Technical Memorandum 03-01 (HTM 03- 01) – Specialised ventilation for healthcare buildings, was released by NHS England and NHS Improvement. It provides comprehensive advice and guidance on the legal requirements, design, installation, maintenance, and operation, of specialised ventilation in healthcare premises
During the workshop we also assess previous Health Technical Memoranda, going all the way back to HTM 2025, and HTM 03-01 (2007), addressing the rationale in line with clinically-led research, as well as CIBSE Commissioning codes of Practice, BSRIA BG49:2015, HTM 00, and HBN 04-01.
New ventilation installations
The main document of HTM 03-01 covers new ventilation installations, and consists of 13 chapters and 10 appendices – a significant increase in both from the 2007 document. It provides a much more detailed approach to design, and gives clinical reasons why ventilation is required.
Under the new guidance, each hospital or Trust now needs to have a Ventilation Safety Group. During the pandemic, many hospitals and Trusts started to create their own informal groups on ventilation, and to see this formalised is a major step forward, and without doubt one of the highlights of the new HTM 03-01
The Ventilation Safety Group
A Ventilation Safety Group includes a microbiologist and representatives from theatre management, estate management, finance, an Authorised Engineer (Ventilation), and an Authorised Person (Ventilation). It can act as an essential forum to address failures and maintain safety across the Trust. For example, when verification checks are conducted by ventilation engineers, if the equipment is not compliant, the hospital can refer to its Ventilation Safety Group to take remedial action based on the recommendations made – whether this is in connection with sourcing funds to procure new equipment, or scheduling maintenance work. A major part of the discussions also focus on the new air change rates noted in HTM 03-01.
Alterations in fan technology
We discuss the reasons for alterations in fan technology directly related to air change rate calculations and the requirements set out in original theatre research, working through the history of HTM 2025 and HTM 03-01 all the way to the current day. The session also focuses on system replacement and upgrade, a requirement of CIBSE Guide M for some time, but now a significant inclusion in the new HTM.
Under the new guidance, AHU equipment now has to be replaced every 20 years, and undergo a major service every 10 years. Air-handling units (AHU) are often ‘out of sight and out of mind’, and it is not unusual for equipment to be 30 to 40 years’ old. New-build environments where a series of AHUs are installed at the same time will require significant planning and forward thinking to avoid operational downtime to meet the guidance.
HTM 03-01 sets out the best practice methods of design, installation, and validation. We discuss how and where we can implement this guidance. Any deviation or contractual derogation away from HTM 03 should be carefully considered and discussed with the hospital Authorised Engineer (Ventilation) AE (V) and Ventilation Safety Group to allow scrutiny from key people within the organisation.
Sustainability
Net Zero plans – the balance between the amount of greenhouse gas produced and the amount removed from the atmosphere – and what the NHS may look like in 10 years, form a key part of our discussions during the workshop. We showcase examples of good practice – hospitals already focused on meeting the objective – including a Manchester-based hospital looking to achieve Net Zero in its anaesthetic teams and the gases that they use. We assess how air-handling unit (AHU) technology can support Net Zero ambitions, and what is available in critical systems, heat recovery options, control philosophy, and refurbishment options. We debate the pros and cons of components including runaround coils, heat plate exchange, thermal wheels, and cabinet AHUs
Operating theatre layouts are assessed, as well as the implications of ultraclean ventilation installations, including ductwork layout configuration and the mathematical calculation for air change rates. We discuss how the centrifugal fan sits in position, and how it interacts with the system’s supply duct in any ultraclean ventilation arrangement
Validation
Howorth regularly attends sites on behalf of NHS Trusts to validate newly designed and installed equipment. As a result we can provide real-life, detailed insights into best practices, what to avoid, and how the Authorised Person (Ventilation) should manage the situation when new equipment is handed over to clinical teams. Filter testing is discussed (DPC highlighted in HTM 03, but we also cover DOP for H14/EU14 Filtration), and how the AP(V) should witness the situation on site to ensure that the equipment under assessment is correctly tested, using the correctly calibrated equipment. We explain the airflow measurement test, and how we arrive at 80% of the terminal footprint at 2.0 m and 36% at 1.0 m. We also discuss exponential airflow, which is a new addition to our CPD sessions this year; it features specific sections on laminar and turbulent flows off the UCV terminal, and how this can be impacted.
We emphasise how the AP(V) should ‘witness test’ the procedure so that there is absolute certainty of compliance and patient and surgical site protection prior to final, independent validation. Finally, we explain the non-entrainment test, its rationale, and how it is executed. The test is commonly misunderstood, and is much clearer with a visual demonstration
Closing out the Part A section are the design requirements of operating theatre control panels, and how they should be validated and assessed.
HTM 03-01: Part B: Operational Management
We assess the legal requirements of HTM 03-01: Part B, and the operational management of critical ventilation systems. We also assess areas not covered by HTM 03-01, such as the CIBSE Lighting Design guide LG2: Lighting for healthcare premises (2019), a critical area of engineering requirements in spaces such as operating theatres. Part B ties responsibilities back to HTM 00, and covers areas of testing that AP(V) engineers may not be exposed to, such as microbiological testing and how it is carried out.
Capital installations and live demonstrations
During the day there is also a session delivered by Howorth Air Technology’s Group Sales director, Tom Ford. During it, he shares his extensive experience of designing operating theatres to be ergonomically satisfactory for the requirements of the Operating department practitioner team
It is not untypical for equipment to be installed without considering important factors such as air flow and patient positioning. We highlight the importance of working with contractors and architects to consider the location of critical equipment such as a fixed CT scanner, medical gas pendants, and monitoring arms. During his part of the workshop, Tom Ford also looks at future-proofing in line with ‘intelligent engineering’, remote monitoring, and continuous innovation.
Once the presentations have been delivered, delegates move on to practical demonstrations in our fully functional, HTM 03-compliant, UCV operating theatre. Demonstrations are led by our technical team leaders, and cover the three UCV tests: filter testing (both DOP & DPC), downflow grid testing, and a nonentrainment demonstration.
We use smoke visualisations to illustrate the movement of air in an operating theatre, and how individual items of equipment in the theatre interact with one another – for example how open door protection works, and the differences between the ‘prep’ area of the OR and the theatre itself, and how that impacts UCV considerations. We also assess how different types of operating lights have an impact on airflow.
Cementing relationships
Howorth Air Technology has now delivered the CPD-accredited sessions to over 150 healthcare professionals, including Operating department practitioners, infection control specialists, Chartered Mechanical Designers, estates management personnel, apprentices, and entry-level engineers. We have had some great feedback, and we will continue to develop the sessions to ensure that healthcare providers understand the complex and specialist air ventilation equipment that they commission, design, and install. We have a firm belief that knowledge-sharing will eventually result in a higher calibre of product for the NHS and healthcare sector, with less downtime, happier environments, and a sustainable future
For further information, email Mike Dunne at mike.dunne@howorthgroup.com, or alternatively liaise directly with the CPD Certification Service at: https://cpduk. co.uk/providers/howorth-air-technology-ltd
Mike Dunne
Mike Dunne, Service and Aftersales Technical manager, joined Howorth Air Technology in 2009 as an electrical engineer in the company’s Production team. Early in his career he became a Medical Commissioning engineer, delivering over 300 UCV systems across three continents.
After several years in the role, he became Medical Commissioning Team leader, supporting both the Capital and Aftersales teams on compliance issues and integration of BMS systems in line with HTM 03. He subsequently became Howorth’s Technical manager, working directly with Service and Aftersales director, Claire Fenlon, to expand the business’s Service and Aftersales capabilities.
He has continued to progress his professional development, completing an HNC in Electrical and Electronic Engineering, an ILM Level 5 Diploma in Leadership and Management, and gaining P601 and P602 (in relation to LEV Systems), NEBOSH, and IOSH qualifications. He is in his final year of a BEng (Hons) degree in Building Services and Sustainable Engineering at the University of Central Lancashire, where his dissertation focuses on how the UK healthcare sector can reduce consumption to support the NHS’s Net Zero goals.
As Howorth’s Technical manager, he has compiled and delivered CPD sessions, is responsible for assessing the performance of the Engineering team and ensuring any skill gaps are adequately filled, and acts as the main technical contact for many UK hospitals. He represented Howorth Air Technology on the Working Task Group for the collation of HTM 03-01 (2021). He is registered with the Engineering Council, is a Technical Member of the Institute of Engineering and Technology, and is a member both of IHEEM, and of the Institute of Local Exhaust Ventilation Engineers via CIBSE.