The hospital has recently added a new suite of three operating theatres known as ‘H’, ‘J ’ and ‘K’ at first floor level, adjoining the existing Turnberg Building. Theatre H has been designed as an ‘ultra clean’ theatre, suitable for orthopaedic procedures and any surgery where there is a high infection risk. The remaining two theatres, meanwhile, have been designed as general surgery facilities with Theatre K fitted out for laparoscopic procedures and Theatre J semi-enabled for the addition of laparoscopic capabilities in the future.
HTM0301 is the Healthcare Technical Memorandum governing air quality requirements and ventilation systems for operating theatres and the project’s building services engineers, Steve Hunt Associates, developed an individual ventilation plan for each theatre suite in line with HTM0301. Each theatre has its own ventilation plant which is located in a plant room on the second floor, along with its own IPS (isolated power supply) with a common UPS which is designed to provide maximum resilience.
Explains Steve: “With individual ventilation plant and mains supply, each theatre can remain operational even if there is a problem with one of the others. A big part of our remit is to advise on ensuring that the installation is as robust as possible while leveraging our value engineering expertise to design the services in line with best value objectives.”
For Theatres K and J, 25 air changes per hour were needed in line with HTM0301 requirements for general surgery theatres and the ventilation requirements to achieve this were individually calculated according to the size of each room. In Theatre H, however, the requirements for an ‘ultra clean’ environment saw the air change regime increase to 500 air changes per hour and the ventilation system was even more sophisticated to protect vulnerable orthopaedic patients from the risk of infection.
The ultra clean zone is a 2.8 x 2.8m area in the centre of Theatre H where the system not only provides 500 air changes per hour but is also HEPA filtered (High Efficiency Particulate Absorption), removing 99.99% of microscopic particles from the air. The system has been designed to ensure that the risk of Colony Forming Units (CFUs) of bacteria that can lead to infections is minimised, with fewer than 10 CFUs per M3 of air within the first 300mm of the wound site and less than 20CFUs per M3 of air for the remainder of the ultra clean zone.
The ventilation system for each of the new theatres at Salford Royal is also the heating system and instant controllability for the surgical team is a critical part of the design.
Steve continues: “The surgical team needs to be confident that it can alter the temperature on the controls and that the heating and cooling system will respond instantly, not only to ensure patient welfare but to provide the right working conditions.”
To achieve this, temperature controls have been incorporated into the surgeon’s panel in all three theatres, ensuring that controls are accessible during a procedure. The surgical team can select a pre-set heating, cooling or lighting ‘scene’ or can adjust the settings individually. The panel also allows them to check temperature and humidity levels and the status of the ventilation system.
Energy efficiency has also been designed into the system, with heat recovered from the ventilation system via a heat plate exchanger being used to feed into the heating and invertor speed controls to prevent any drop off in ventilation efficiency.
Steve explains: “The invertor speed controls are linked to the site wide BMS system so the efficiency of the ventilation plant is constantly monitored. This means that if there should be any fall in efficiency, the maintenance team is alerted in real time and can take action quickly to address the problem.”
Air tight environments
To support effective pressure regimes and infection control, the theatre suites have been designed with a network of automated doors, enabling the theatre itself to become a sealed unit during any procedures.
Steve explains: “The configuration has been designed to reduce the risk of contamination from air circulating in the corridors into the theatre space by ensuring that the doors inbetween cannot open at the same time. The use of sliding doors also saves space and prevents the need to touch the doors to open them.”
The sliding doors feature two-position opening and the inner door between the theatre and the anaesthetic area cannot open until the outer door between the anaesthetic area and the corridor has been shut, helping to maintain pressure regimes within the theatre.
Best practice model
The three theatres are all now operational and have exceeded the expectations of both the hospital’s management team and its surgical teams.
Lindsay McCluskie, Associate Director of Capital, Estates and Facilities at Salford Royal said: “We believe we have created a best practice benchmark for operating theatres here that minimise infection risk and provide a better working environment for surgical teams.
“The ventilation systems are central to that achievement, enabling energy efficient compliance with HTM0301 pressure regimes and linking with our Building Management System to ensure effective fault monitoring.”