A new design for hospital isolation rooms has been found to minimise the risk of infection transmission between adjacent spaces.
Built, commissioned and validated by BSRIA on behalf of the Department of Health,the Positively Pressurised Ventilated Lobby (PPVL) room was found to offer protection from an infectious patient to an immune-compromised patient by maintaining the access lobby at positive pressure from the patient’s room and the rest of the hospital, but also by maintaining the room at a neutral pressure.
BSRIA also quantified the protection the room offers to visitors and staff. The ventilation strategy was found to dilute the contaminant concentration inside the room, as well as provide a well-mixed space with no areas of higher contaminant concentration.
This novel design challenged the traditional design approach to isolation rooms – positive isolation rooms for immune-compromised patients, and negative isolation rooms for infectious patients.
Blanca Beato-Arribas, BSRIA asset performance team leader, said: “A full-size physical model including ventilation systems, pressure stabilisers, hospital furniture, and heat loads was built and commissioned in BSRIA’s laboratories. Multiple test methods were used to investigate and challenge the design, including anemometry testing, air tightness, commissioning of specialist ventilation devices (pressure stabilisers), heat load tests, gas tracer tests and smoke tests.
“The mock-up enabled the measurement of the ventilation patterns inside the room, the airborne infection risks within and outside the room, and the thermal comfort of the occupants in the room. BSRIA also carried out the study of ‘what if’ failure scenarios, namely the assessment of the infection risk in the event of fan failure or doors that were left open.
The facility’s design consisted of a PPVL, a neutral pressure patient’s room and a negatively-pressurised en-suite. The room was intended to be used to accommodate either infectious or immune-compromised patients, therefore acting as a typical negative pressure isolation room or positive one, respectively."
