Operating Theatre Filtration Level

[friartuck]

We do ventilation designs to lots of hospitals in the UK. One thing that has always puzzled me is the HTM2025 Hospital Technical Memorandum concerning ventilation and filters.

Surprisingly (To me anyway), there does not appear to be any preferred filtration efficiency requirement for operating theatres. Indeed, I have surveyed a number of theatre plants and the filtration on some systems is only F9 (Not even HEPA).

OK, on theatres requiring deep intrusive operations (Hip replacements etc) then we use HEPAs and laminar flow canopies, but again this is done on recomendations from clean room specialists and not the HTM2025.

Can anyone tell me why it is is permissible for 'standard' operating theatres that HEPA filtration is not a strict requirement.

Also, if you were to provide a new theatre for eye surgery, would this be treated as one that would require a higher level of filtration??



Friar Tuck of Sherwood

 

[cme]

On this side of the pond .... codes state 2 beds .... 30% dust spot (MERV-8) prefilter amd 90-95% (MERV-14) final filter ..... although physicians are calling for HEPA final filters in surgical suites ..... this is reviewed with them along with space temp/RH requirments

 

[SAK9]

The best person to answer this question is a surgen.I too have read in the HTM that HEPA filtration is not required.But most designers tend to err on the conservative side by opting for HEPA filters as there is not a significant installation cost difference.

 

[HVAC68]

I had done a couple of operation theatres few years ago. One was for an orthopaedic surgery theatre where a laminar flow with HEPA filtration was done. The second one was for an eye surgery theatre where HEPA filteration was not required and standard fine filters were only used. In both cases, we talked to the surgeons and this was done based on their recommendation.

HVAC68

 

[tombmech]

This is just a guess, but the application of HEPA filtration is an expensive proposition. If HEPA is incorporated into an air stream, it seems logical to expect that the rest of the environment is likewise controlled to that standard. If it isn't, then HEPA filtration is a waste.

For instance, are the personnel masks of HEPA quality? Is the theatre audience segragated from the operating environment? Certainly achieving sanitary and hygienic conditions are a primary concern. Yet, safe practices and a prudent level of not-quite HEPA filtration may statistically achieve the same result. Compared to sterilizing everything else that may enter the environment (as opposed to things that make direct contact), that may be a reasonable alternative.