Minimum user requirement specification (URS) focuses on Preventing Cross Contamination and Contamination of
ventilation systems in hospitals. It requires that supply and extract air in air distributing areas shall be designed, operated and serviced such that unacceptable contamination by inorganic or organic substances, e.g. harmful gases within the system, are controlled as required by control of substances harmful to health.
Recirculation of room air is not allowed except
- if the ventilation system serves only one room the room air can be circulated for the purpose of ait treatment and returned to the same room as the secondary air (as defined in EN 13779)
- other parts of this standard allow recirculation, then this requirement should be complied with, in non medical locations, where patients are not present, recirculation is permitted.
Find more information about standards in hospital in presentation by Jukka Vasara (link here).