AIR CONDITIONING OPERATING THEATRES
regimes need to be checked and managed as part of the air movement system design process to ensure that positive pressures in the operating theatre and anaesthesia areas aid infection control.
Keeping it ultra-clean To comply with the air-quality requirements in HTM0301, ventilation systems for standard procedure operating theatres must deliver a minimum of 25 air changes per hour. The volume of clean air circulated by the system must be calculated on the basis of the size of the space. It must also be distributed in a linear circulation from the grille to the fl oor, as well as balancing the extracted and clean air – to fulfi l pressure regime requirements. For ‘ultra-clean’ theatres, the required air
changes per hour leaps up substantially to 500 within a 2.7m zone around the operating table, refl ecting an increased risk of infection for certain types of operations. Typically used for orthopaedic procedures that involve deep incisions into the musculoskeletal system, ultra-clean theatres also require high effi ciency particulate air fi ltering to ensure that the air quality is as pure as possible.
www.cibsejournal.com
The system should be designed to eliminate as many colony-forming units (CFUs) of bacteria from the operating site as possible: a recent installation that we designed ensured that there were fewer than 10 CFUs per cubic metre of air for the fi rst 300mm of air circulating around the wound site, and fewer than 20 CFUs per cubic metre of air for the remainder of the ultra-clean zone. This ultra-clean zone uses a central air
change and fi ltration canopy, which manages the air-change regime from ceiling to fl oor. Typically such canopies have a screen that encloses and directs the upper fl ow of clean air, but a recent ultra-clean installation our
fi rm undertook included a screen-less canopy, which maximises head room for the surgical team and makes it easier to move around the service pendants.
Staying in control Of course, not all air-quality considerations in an operating theatre relate to infection control and air purity; temperature control is equally vital, for both the patient – whose core body temperature must remain stable – and the surgeon, who must be comfortable and have maximum dexterity. Patient and surgeon requirements will change with the individuals, so it is essential
March 2014 CIBSE Journal 61
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80