Shelter-In-Place Guide - What is Shelter-in-Place

What is Shelter-In-Place

Shelter-In-Place is the practice of going or remaining safely indoors during an outdoor release of a hazardous substance. Sheltering has been demonstrated to be the most effective response during the first few hours of a substance release1 by creating an indoor buffer to protect you from higher concentrations of a hazardous substance that may exist outdoors. Sheltering guidelines are based on the use of building that is suited for typical Canadian winter weather conditions.

The goal of sheltering is to reduce the movement of air into and out of a building until the hazard has passed or other appropriate emergency actions can be taken.

An event such as a fire, motor vehicle accident, train derailment, industrial incident, or a natural disaster may cause a hazardous substance release. As a result, emergency responders may request that you shelter-in-place if one or more of the following criteria apply:

  • An outdoor release may affect your building.
  • There is not enough time or warning to safely evacuate.
  • The release is expected to pass over the area quickly.
  • The source and nature of the release has yet to be determined.
  • A safe evacuation route has yet to be verified.
  • You are waiting for evacuation assistance.

Those who have been advised to shelter will be notified if additional measures are required and when the emergency situation has ended.

Wilson, D.J. (1991) "Effectiveness of Indoor Sheltering During Long Duration Toxic Gas Releases", Emergency Response ER'91 Technological Response to Dangerous Substances Accidents, MIACC, May 28-30, Calgary, 10 pages

Wilson, D.J. (1988) "Variation of Indoor Shelter Effectiveness Caused by Air Leakage Variability in Houses in Canada and the USA", Proceedings U.S. EPA/FEMA Conference on the Effective Use of In-Place Sheltering as a Potential Option to Evacuation During Chemical Release Emergencies, Emitsburg, Maryland, Nov. 30 - Dec. 1, 1988.

Wilson, D.J. (1986) "Stay Indoors or Evacuate to Avoid Exposure to Toxic Gas", CPA/IPAC Petroleum Industry Annual Safety Seminar, Banff, Alberta, April 30-May 2, 1986. (published in Emergency Preparedness Digest 14 January-March, 1987, 19-24, by Emergency Preparedness Canada).

Walker, I.S. and Wilson, D.J. (1998) "A Field Validation of Algebraic Equations for Stack and Wind-Driven Air Infiltration Calculations", International Journal of Heating, Ventilation and Air Conditioning Research, 4, 117-138.

Walker, I.S. Wilson, D.J. and Forest, T.W. (1996) "A Wind Shadow Model for Air Infiltration Sheltering by Upwind Obstacles" International Journal of Heating, Ventilating, Air Conditioning and Refrigerating Research 2, 265-283.

Walker, I.S. and Wilson, D.J. (1993) "Evaluating Models for Superposition of Wind and Stack Effect in Air Infiltration", Building and Environment 28, 201-210.

Wilson, DJ and Morrison, B, (2000) Ordering Shelter or Evacuation during an Outdoor Toxic Gas Release Incident: The CAFC Decision Flow Chart@ Fire-Rescue 2000: Technical Paper: Annual Meeting of the Canadian Association of Fire Chiefs, Montreal, August 13 B 18, 2000, 11 pages.

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