Transcript Ventilation Part C

FVCC Fire Rescue
Ventilation
Part C
CHARACTERISTICS OF ROOF TYPES
• Flat
▫ Commonly found on commercial, industrial and apartment
buildings
▫ May have a slight slope to it
▫ Roof may be surrounded or divided by parapets
▫ May support:
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Water tanks
Air conditioning units
Equipment
Antennas
Other obstructions
▫ Structural part similar to floor construction
PRECAUTIONS WHEN VENTILATING
• Flat
▫ Use roof ladder.
▫ Look for hot spots or sagging of the roof area
PRIOR to walking on surface and continually
during ventilation.
▫ Always sound roof PRIOR to walking on surface
and continually during ventilation.
PRECAUTIONS WHEN VENTILATING
▫ Look for roof additions or changes, such as
overhangs, inverted flat roofs, security measures,
parapet walls.
▫ Look for obstacles and excess weights on roof,
such as HVAC systems, skylights, vent pipes, other
openings.
▫ Provide two means of escape from the roof remote
from each other.
PROCEDURES
• Vertical
▫ Flat roof
 Determine location of opening
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Location of seat of fire
Direction of wind
Existing exposures
Extent of fire
Obstructions
PROCEDURES
 Locate supports by sounding with an
axe.
 Mark the location for opening by
scratching a line on the roof with the
pick head.
 Remove the built up material or metal
by cutting the materials and using the
pick head to pull the materials out of the
way.
 Cut the wood decking diagonally
alongside the joist towards the hole.
 Pry up the roof boards with the pick end
of the axe.
 After opening the roof, push the blunt
end of a pike pole or plaster hook
through the opening to penetrate the
ceiling below.
CHARACTERISTICS OF ROOF TYPES
• Shed
▫ Similar to flat except slopes from front to back
▫ Slope may be gradual or steep
PRECAUTIONS WHEN VENTILATING
• Shed
▫ Use roof ladder
▫ Look for hot spots or sagging of the roof area PRIOR to
walking on surface and continually during ventilation.
▫ Always sound roof PRIOR to walking on surface and
continually during ventilation.
▫ Look for roof additions or changes such as overhangs,
inverted flat roofs, security measures, parapet walls.
▫ Look for obstacles and excess weights on roof, other
openings.
▫ Provide two means of escape from the roof remote from
each other.
CHARACTERISTICS OF ROOF TYPES
• Pitched
▫ Elevated in the center
▫ Construction
 Rafters
 Run from ridge to top plate
 Made of wood, metal or combination
PRECAUTIONS WHEN VENTILATING
• Pitched
▫ Use roof ladders
▫ More profound incline; take extra precautions against
slipping
▫ Look for hot spots or sagging of the roof area PRIOR to
walking on surface and continually during ventilation
▫ Look for roof additions or changes such as overhangs,
inverted flat roofs, security measures, parapet walls
▫ Look for obstacles and excess weights on roof, such as
HVAC systems, skylights, vent pipes, other openings.
▫ Provide two means of escape from the roof remote from
each other
PROCEDURES
• Pitched roof
▫ Determine location of opening, usually the highest point
▫ Place a roof ladder on the roof so that personnel working off
it will be upwind from the hole.
▫ Locate supports by sounding with an axe.
▫ Mark the location for the opening by scratching a line on
the roof with the pick head
▫ Remove the shingles or roofing sufficiently to permit the
initial cut
▫ Cut the sheathing along side a rafter, the distance required
for the opening.
PROCEDURES
▫ Opposite side is then cut in a like manner.
▫ Remove sheathing boards with the pick of the axe
▫ After opening the roof, push the blunt end of a
pike pole or plaster hood through the opening to
penetrate the ceiling below
CHARACTERISTICS OF ROOF TYPES
▫ Sheathing
▫ Roofing materials
▫ Shingles
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Wood
Metal
Asbestos
Composition
Tile
Slate
▫ Pitch of roof may be gradual or steep
INTEGRITY OF A ROOF SYSTEM
• Construction
▫ Materials
 Wood
 Steel
▫ Type of roof support
 Rafters
 Truss
Commercial Structure Fire 11/11/04, Glenview, IL, US
INTEGRITY OF A ROOF SYSTEM
• Visual observation/warning signs
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“Spongy” roof
Melting asphalt
Smoke coming from roof
Fire coming from roof
Excess weight (ex. HVAC)
• Elapsed time of fire
▫ The longer the fire, the less the roof integrity.
Ventilation Considerations
• High rise structures:
• Stack effect: fire/smoke spread rapidly via
stairways, elevator shafts, pipe shafts, air
handling systems, and other vertical openings.
• Smoke & other fire gases will travel through a
high building until their temperatures come to
equilibrium with ambient air. This is the floor
you will find the maximum amount of smoke.
Ventilation Considerations
• High rise structures: (cont.)
• Before doors leading to the involved fire
floors are opened, the door roof must be
blocked opened or removed.
• Ventilation in high rise buildings should be
considered during pre-incident planning.
• If the building has a complicated HVAC
system, in order to control ventilation you
should call a building engineer.
Considerations involved
in Ventilation
Parapet
1. Age of Building (1921)
2. Over Bow String Truss
3. head wires
4. Placement of aerial (only way
this roof structure should be ventilated)
Bow string truss: can be difficult to ventilate
Because lower chord of the truss may be covered
With a ceiling to form an enclosed roof space.
This space is called a cockloft
PRECAUTIONS WHEN VENTILATING
• Arched
▫ Be conscious of danger of sudden and total
collapse.
▫ Roof ladders useless, recommend aerial devices.
▫ Be aware of concealed voids, such as cocklofts and
attic spaces covered by ceilings.
VS 10-10
FLAT ROOF CONSTRUCTION
Parapet
Sheathing
Bar Joist
Felt
Slag or Gravel
Flat (Hung) Ceiling
Metal Deck
False (Hung) Ceiling
Parapet
Flat roof most often found on commercial, industrial,
and apartment buildings.
VS 10-11
PITCHED ROOF CONSTRUCTION
Ceiling Joist
Rafter
Wall Plate
Siding
Yes, this is a residence!!!
So, how do you vent this
person’s home? Tin roof
should be sliced open with
tin snips & peeled back.
Extra Bits of Important Test Stuff
Balloon Frame? Basement Fire? Attic Fire?
First choice in ventilating a basement fire?
What might be the last resort in ventilating a structure to reduce
Vertical extension during a basement fire?
What is horizontal extension? Name some methods?
Know your roof types!
Know your roof materials!
JOURNAL BUILDING FIRE TUSCOLA, ILLINOIS
Less than 15 minutes after the building`s
evacuation, the roof collapsed, issuing a ball of fire
100 feet in the air. Another four minutes passed, and
the entire front wall collapsed into the street. Then
the upper portion of the side walls of the fire
building collapsed onto the exposures. This sent
another fireball into the air, enveloping a firefighter
operating at the tip of the ladder pipe. Fortunately,
he was wearing full protective clothing (including
SCBA) and was not injured.
Photo 7. With positive tip load improvements come some operational
impediments. Note the deployment of the outriggers on the heavy-duty aerial
ladder in this common suburban/urban setting. The street is completely
blocked off.
This multiple-dwelling stucture's very irregularly shaped roof could prove hazardous during
nighttime or smoky conditions. The skylight over the main stairwell has apparently been
tarred over. At the rear behind the chimney is a scuttle hatch over the rear stairwell
Homework
Match types of ventilation to their descriptions. Write the correct
letters on the blanks.
1. Process of placing a smoke ejector in a door or window blowing outward to
pull smoke, heat, and gases from a structure and eject them to the exterior
2. Process of venting heat, smoke, and gases, usually through created or existing
roof openings above the seat of the fire
3. Process of directing a water stream through a door or window to draw heat,
smoke, and gases from the structure
4. Process of trying to stop the spread of fire by cutting a large roof hole — at
least 4 feet wide — that extends from one exterior wall to the opposite exterior
wall slightly ahead of the advancing fire; particularly useful in long, narrow
structures
5. Process of venting heat, smoke, and gases through existing wall openings such
as windows and doors
6. Process of placing a fan outside a structure and blowing air into the structure
in which an opposite door or window has been opened to allow smoke and
gases to escape
a. Vertical b. Horizontal
c. Trench (strip) d. Forced pressure e. Hydraulic
Homework
• Identify signs of potential backdraft. Mark an “A” on the
blank before each sign of backdraft potential. Mark a “B”
before each sign that does not relate to backdraft.
7. Smoke-stained windows
8. Dense white smoke billowing from lower levels
9. Broken windows
10. Smoke puffing at intervals from the building
11. Pressurized smoke coming from small cracks
12. Deep orange/blue flames shooting from roof
Homework
Select true or false for the statements about ventilation decisions. Write an “A” in the
blank for each true statement and “B” in the blank before each false statement.
13. Ventilation must be started before the requirements for a plan of attack are
considered.
14. The first ventilation consideration is the safety of firefighters and occupants.
15. Depending on fire conditions, ventilation may need to be performed before
rescue operations begin.
16. Before ventilating, the firefighter must consider the insured value of the
materials and contents within the building.
17. The need to ventilate is based on heat, smoke, and gas conditions within the
structure, and on personnel resources available.
Homework
Select true or false for the statements about ventilation decisions. Write an “A” in the
blank for each true statement and “B” in the blank before each false statement.
18. A firefighter can make some ventilation decisions based on visible smoke
conditions.
19. Building type and design are the initial factors to consider in determining
whether to use horizontal or vertical ventilation.
20. The extent to which a building is connected to adjoining structures has a
bearing on the decision to ventilate.
21. Pre-incident planning should include tactics and strategy for ventilating
residential buildings.
22. Basements and windowless buildings generally require hydraulic ventilation
for the removal of smoke.
Homework
• Select from a list building factors that aid the firefighter in
determining whether to use vertical or horizontal
ventilation. Write an “A” on the blank before each factor that
helps to determine whether to ventilate a structure and an
“B” if not.
23. Age of structure
24. Building type and design
25. Number and size of wall openings
26. Number of occupants
27. Number of stories
28. Number of staircases, shafts, dumbwaiters, ducts, roof openings
29. Accessibility to water source
30. Availability of exterior fire escapes
31. Exposure involvement
Homework
• Select from a list ways in which vertical fire extension
occurs. Write an “A” on the blank before each way in which
vertical fire extension occurs and a “B” if it does not.
32. Through stairwells, elevators, and shafts by direct flame contact or
by convected air currents
33. Through hallways and passageways by radiation
34. Through partitions and walls and upward between the walls by
flame contact and convected air currents
35. Through windows or other outside openings where flame extends to
other exterior openings and enters upper floors
36. Through interior doorways and archways
37. Through ceilings and floors by conduction of heat through beams,
pipes, or other objects that extend from floor to floor
Homework
• Mark “A” for true and “B” for false statements about safety precautions
that should be observed when performing vertical ventilation.
38. Start power tools on the ground to ensure operation
and keep them running while hoisting or carrying them
to the roof.
39. Work with the wind at your back or side to provide
protection while cutting the roof opening.
40. Note the existence of obstructions or excess weight on
the roof.
41. Make sure that the angle of the cut is toward the body.
42. Provide a secondary means of escape for crews on the
roof.
Homework
• Mark “A” for true and “B” for false statements about safety precautions
that should be observed when performing vertical ventilation.
43. Extend ladders no more than four rungs above the
roof line and secure the ladder.
44. When using elevating platforms, the floor of the
platform should be slightly below roof level.
45. Use lifelines, roof ladders, or other means to protect
personnel from sliding and falling off the roof.
46. Work in groups of at least two, with at least one more
person than absolutely necessary to get the job done.
47. Ensure that all personnel on the roof are wearing full
personal protective equipment including SCBA.
VS 10-16
TYPES OF FORCED VENTILATION
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a. Horizontal Mechanical b. Hydraulic c. Positive Pressure
Homework
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a. Butterfly b. Flat c. Lantern d. Mansard
Homework
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a. Arch b. Gable c. Gambrel d. Hip e. Shed
VS 10-9
EXISTING ROOF OPENINGS
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a. Monitor b. Ventilator c. Scuttle Hatch d. Stairway Door With Skylight
Homework
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a. Bow String Truss
b. Flat roof
c. Pitched Roof
d. Trussless
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