Managing critical systems is often a challenging task

Critical ventilation systems, i.e. those serving areas that cannot function safely without such systems (for a full list see HTM 03-01 a, paragraph 4.31¹) in healthcare premises, when designed, installed, and maintained correctly, help control the spread of airborne pathogens through the dilution and removal of contaminated air. Not all systems comply with current standards, and even some of those may not meet their design specifications — which may go unnoticed until their annual verification. For Estates teams, managing risks associated with legacy equipment is a significant and complex challenge. Assessing the condition of air-handling units (AHUs) regularly is important from a maintenance perspective, but is also crucial for effective lifecycle management, because early warnings can help avoid costly and sometimes catastrophic failure of the equipment, which in turn poses the risk of service interruption, infection control issues, and other safety considerations.

NHS Estates teams are often competing with other capital requests, and often clinical needs trump infrastructure, but is this because of a lack of understanding at a strategic level, and what happens when infection rates in operating theatres soar, and Infection Prevention and Control (IPC) teams investigate the root cause? From an Estates perspective, ensuring that AHUs have been maintained to the correct standard is vital, then. The plant should be performing to criteria laid out in HTM 03-01, but this might not always be the case — particularly with respect to plant installed prior to the most recent guidance. There should be annual verification and performance testing conducted, with performance compared with the validation figures obtained at the time of installation and commissioning. The values measured must achieve a minimum of 80% of the original air-change rate (HTM 03-01b, paragraph 4.16). The HTM makes the point that systems nearing their end of life may reduce in performance: "it is to be expected that over the lifetime (typically 20 years) of a ventilation system its performance will gradually reduce..." (paragraph 24, part B). However, the HTM is clear that equipment that is not performing to the required criteria should not be used. In this instance, what options should Estates teams consider?

In this article, we will discuss the pitfalls facing Estates teams, focusing on critical ventilation air plant, and suggest strategies for managing capital budget expectations, IPC risks, and operational and compliance considerations.