Ventilation

Session Reference: 1-3 Topic: Ventilation Time Required: 90 Minutes References:    • Truck Company Fireground Operations, Second Edition, Chapters 4 and 5    • Essentials of Fire Fighting, Third Edition, Chapter 7...


  7. Should be short term operation

NOTE: The instructor may want to discuss applying natural and forced ventilation to particular situations.

V. Smoldering Fires (1-3-5)

A. Indications

  1. Much smoke visible, but no open fire can be seen or heard

  2. Smoke rising rapidly from building, indicating that it is hot

  3. Smoke leaving building in puffs or at intervals

  4. Some smoke being drawn back into building around windows, doors, and eaves

  5. Although no flames are showing, windows stained brown from intense heat

  6. Occasionally, one or more panes broken by heat

  7. Small rim of fire can appear around edges of broken glass

  8. Smoldering fire has sufficient heat and fuel to become free burning

  9. Smoldering fire needs only oxygen to burst into flame

  10. Fire can be smoldering in building of any size or type or in only one area of large structure

B. Backdraft

  1. Smoldering fire must be ventilated before it is attacked

  2. Addition of oxygen to heat and fuel will lead to immediate ignition

  3. Sudden ignition can take any form

      a. Gases and heated combustibles simply burst into flame

      b. Force of ignition might be enough to blow windows, doors, and fire fighters out of building

      c. Could be explosion strong enough to cause structural damage

C. Venting

  1. An opening must be made as high on the building as safely possible to release gases and allow them

      to move out of structure

  2. Difference between free burning and smoldering fire is that venting must be done before entering

      structure in smoldering fire

  3. Natural roof openings can be used for ventilation

  4. If roof venting seems particularly dangerous, knock out tops of highest windows with ladder or

      solid stream

  5. Avoid approaching building directly to avoid violent explosion - approach from oblique angle or

      parallel to building

  6. Attack lines should be charged and ready for use during building ventilation

  7. If there is a possibility of backdraft, apparatus should not be positioned in direct line of building

  8. Once ventilated, fire will burn freely

SUMMARY:

Review:

Ventilation

   • Definition

   • Basic principles

   • Natural ventilation

   • Forced ventilation

   • Smoldering fires