Canterbury DHB


B6 Maintenance

In This Section

HEPA Filter Maintenance

Isolation Room Maintenance

Temperature Maintenance

Microbial Testing

HEPA Filter Maintenance

Air is filtered into the isolation rooms through a High Efficiency Particulate Air (HEPA) filter. Each isolation room has its own filter which is a high grade H13 filter which can remove at least 99.97% of airborne particulates 0.3 micrometres (µm) and larger in size. The patient’s bed should be located under the air vent in the isolation room, so that the patient is ‘washed’ with clean air.

Engineering department organises an external company to conduct tests on the efficiency of the HEPA filters on an annual basis. The tests include a particle count method, checking how many particles and what size they are (in microns), and an air change rate test, measuring how much air is passing through the HEPA filter, the room volume and from this the number of air changes that occurs in the room per hour. These tests give a good indication of the cleanliness of the isolation room.

Isolation Room Maintenance

A positive pressure drop across the room is checked, typically corridor to anteroom, anteroom to isolation room. For positive pressure rooms there must be a pressure gradient with the room being 15 Pa positive to the anteroom and the anteroom being 15 Pa positive to the corridor.

The anteroom door and isolation room door are set up so that both doors are unable to be opened at the same time. An over-ride button exists outside the doors so that in certain situations (e.g. emergencies, or moving large equipment) both doors can remain open at the same time. If the over-ride button is used, staff must be aware that this will defeat the purpose of the patient being in isolation and the patient will be at risk of being exposed to contaminated air drawn from outside the room thus placing an already high-risk patient at greater risk.

Room pressures, fan status and air flows are monitored on Maintenance and Engineering’s building management system (BMS). Alarms are set up for the various monitored points and if the values deviate into the alarm threshold for a predetermined time, BMS will alert the Shift Engineer to investigate the problem 24/7.

Isolation Room 7 operates with a positive pressure patient room and negative pressure anteroom to ensure infectious patients are held in protective isolation in respect to the other isolation rooms.

Temperature Maintenance

The temperature of each room can be read and adjusted on a central control panel, to either heat or cool the incoming air to the rooms. Alarms are set up so that if the temperature deviates by a set amount, the BMS will generate an alarm for Maintenance and Engineering to investigate.

Microbial Testing

The Microbiology department, in conjunction with Infection Prevention and Control (IP&C), conduct monthly air sampling for fungal spores in B6 (isolation rooms, non-isolation rooms, nurses' stations, and corridors). This is a way of protecting patients by checking that:

Reports are sent to B6, IP&C, and Microbiology staff. They are also tabled at the bi-monthly IP&C Construction and Renovation meeting.

Three-monthly sampling of hot water in B6 occurs for Legionnella testing. Legionnella reports are held by Microbiology. The Clinical Director is only notified about positive results.

See Infection Prevention and Control Manual - Surveillance.

About this Canterbury DHB document (60136):

Document Owner:

Andrew Butler (see Who's Who)

Last Reviewed:

May 2021

Next Review:

May 2023


Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document. Disclaimer

Topic Code: 60136