Isolation & Protective Environments · Conceptual Tool

Isolation Room Dynamics

Visualize airflow patterns for Airborne Infection Isolation Rooms (AIIR) and Protective Environments as room pressure shifts from negative to positive.

Room Pressure Simulator

Slide between negative and positive pressure to see how air moves through the doorway and hallway.

Pressure Control

Negative (-) Neutral Positive (+)
Relative Offset: 0 Conceptual – not a measured Pa value

Slide left to simulate an AIIR (negative pressure).

Slide right to simulate a Protective Environment (positive).

Current Status

NEUTRAL PRESSURE

Airflow is balanced. No strong directional movement between room and corridor.

Top-Down View
Hallway
DOOR
Exhaust / AIIR
Supply / PE
PATIENT

How to Interpret the Patterns

This is a conceptual tool – not a CFD model. It’s designed to help explain pressure relationships to clinicians, IPAC teams, and facility staff.

Negative Pressure (AIIR)

Air is drawn from the hallway into the room, then exhausted. This helps contain infectious aerosols. You should see air “pulling in” at the door in the simulator when you move the slider left.

Positive Pressure (Protective Environment)

Clean, filtered air is supplied to the room and pushed out through the door gap. This helps protect immunocompromised patients by keeping corridor air out.

How This Connects to TAB Work

In the field, an isolation room is not just “negative” or “positive” – it is a set of measurable relationships between supply, exhaust and leakage paths. TAB technicians verify that those relationships hold under realistic operating conditions, not just at design.

What Gets Measured

  • Supply & exhaust airflows (L/s or CFM)
  • Room pressure differential (Pa)
  • Air changes per hour (ACH)

Typical TAB Checks

  • Verify exhaust > supply for AIIR rooms.
  • Verify supply > exhaust for PE rooms.
  • Confirm minimum ACH is being met.
  • Confirm directional airflow at the door.

Common Field Issues

  • Door sweeps or seals added after TAB.
  • Supply diffusers swapped or rebalanced.
  • Shared exhaust risers impacting rooms.
  • Controls sequences that fight the design.

When Do You Need TAB?

  • Persistent “door pull” complaints from staff or patients, or doors that won’t stay closed.
  • Isolation rooms that are failing or only meet pressure targets at certain fan speeds or occupancy conditions.
  • Renovations that changed doors, undercuts, wall openings or connected spaces.
  • Accreditation findings related to pressurization, ACH, or directional airflow.

In those cases, TAB work typically includes a combination of direct airflow measurement, pressure mapping, door testing, and coordination with controls/BAS to develop practical corrections.