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...


  2. Shafts extend full height of building

  3. Convected heat, smoke, and gases will rise within and around shafts

  4. If shafts are not vented at top, fire will travel horizontally

  5. Pressure will force heat, smoke, and gases throughout upper part of building

  6. Shafts are capped at roof with various closures

C. Skylights

  1. Positioning of skylights can give idea of building layout

      a. In office or apartment building, row of skylights most likely located over corridor

      b. In shops or factories, line of skylights over work area

      c. Often located over stairways, corridors, elevator shafts, air shafts, and bathrooms

      d. Bathroom coverings may have louvered ends

      e. Area immediately below skylight usually boxed to separate cockloft or attic space

      f. Warning should be given to fire fighters below before removing skylights

  2. Opening skylights

     a. Preferred method of opening skylight is to lift from opening or tip over

     b. Flashing joining skylight to roof must be cut or pried away

     c. For skylights mounting on foundations, flashing must be cut or pried

     d. Lay skylight upside down as warning for fire fighters

     e. If skylight cannot be lifted or tipped, glass can be cut

     f. Less damage done by peeling back metal striping and sliding out panes

     g. If not removable quickly, knock glass out

     h. More than one or two fire fighters may be required

  3. Plastic skylights and roof panels

     a. Mounted same as glass skylights

     b. If skylight cannot be removed, frame should be cut where it meets plastic

     c. Avoid stepping on panels placed in a roof and serving as simple skylights

     d. Plastic panels can be pulled up after roof is cut or pried up along edge

  4. Effects of wind - keep backs or sides to wind

  5. Opening below the skylight

      a. Smoke should flow freely once skylight is opened

      b. May be swinging transom or panel at ceiling line

      c. Be careful to avoid heat and smoke from opening

     d. Cockloft must be vented from opening in roof

     e. Roof scuttle can be used for venting roof if not boxed

     f. Boxed area below skylight can be opened for venting

     g. If fire is directly under roof, make opening as close over fire as safety allows

D. Roof shuttles (hatches) - placed in a roof to allow access to the roof from the interior

  1. Opening scuttles

      a. If cover is not securely locked, can be pried off

      b. If not easily removable, cut off

  2. Opening below the scuttle

      a. Might be boxed to separate from cockloft

      b. Check to see if scuttle is open at ceiling level

      c. Building and/or cockloft may be vented by scuttle

      d. Ceiling closure must be removed

      e. Enclosure below scuttle must be opened to vent cockloft

E. Pre-fire inspection

  1. Every building has some natural openings

  2. Only sure way to know which natural openings can be used in fire fighting is by making prefire

      inspections

  3. Pre-fire inspections save time and effort on fireground

F. Cutting Through Roofs

  1. At times, only way to properly ventilate is cut hole in roof

      a. Roof made of boards can be cut with axe

      b. Roof may of plywood should be cut with power saw

      c. Care should be taken not to cut joists or other structural members

  2. Single large hole is more effective than several small holes

      a. One 4' X 8' hole has twice area of four 2' X 2' holes

      b. All roof boards should be cut through before any pulled up

      c. Keep back to wind when pulling boards

      d. When all boards ripped up, make opening in ceiling below

  3. Special care should be taken when fire is immediately below roof

      a. Open roof as close as possible to seat of fire

      b. If not, fire will be drawn across top of building to opening

      c. Hot spots may develop on roof