Airborne Infection Isolation Room

Applicaton Summary

The purpose of an airborne infection isolation room (AII) is to contain the infectious disease so that it does not spread to healthcare workers, other patients and the community.

An AII room draws airflow in, keeps contaminates in, and exhausts to outdoors. Key room control parameters are Negative Airflow and Pressure Differential (Pa) which depends on:

  • Exhaust – supply flow differential (L/s). This must be monitored to verify room remains at negative airflow from cleaner corridor
  • Room envelope leakage area (cm²)

Volumetric Flow Tracking Control
We recommend volumetric flow tracking as this method measures both exhaust and supply airflow and controls the negative airflow to maintain a minimum room pressure. Flow tracking can provide more stable control and is independent of room door operation compared to traditional negative pressure rooms in local hospitals.

Engineering parameters can be easily pre-set, and extremely tight construction is not necessary for operation.

The negative air flow stepoint (L/s) as a minimum must be greater than the accuracy of the flow measurement and associated control error. We recommend a minimum of 75 L/s (0.075 m3/sec) to ensure good reliable directional airflow.

Advantages of volumetric flow tracking include the following:

  • Low pressurisation level (normally -2 to -10 Pa)
  • Less tight construction required
  • Simple set of relative pressurisation levels (one or two levels)

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