11 Ventilation Size Up Flashcards
Tactical ventilation
Methodical thought out approach to changing the vent profile of a structure.
Natural ventilation
Profiles composed of factors that occur without outside intervention. Any efforts or actions taken by firefighters are tactical vent, because they are done with intent and purpose
Delicious on how to implement tactical ventilation efforts should be determined by
The IC
Ventilation contributes to incident stabilization by
Improving visibility and releasing heat, allowing attack crews to locate and control fire
Vent contributes to property conservation by
Drawing heat and fire out and away from other parts of the building, reducing property loss
Whenever possible, vent should take advantage of
Natural ventilation, implemented in concert with existing atmospheric conditions.
In some situations, natural vent may be inadequate and therefore what must be used
Mechanical ventilation, aka forced ventilation, using fans, blowers, smoke ejectors and hydro vent/ hose streams
Before ventilation, consideration must be given to the readiness of
Fire attack crews, search and rescue, and exposure protection.
Questions, whose answers, provide a general outline for vent size up
What do we have,
What are we going to do
What do we need
Four stages of fire development
Incipient
growth
Fully developed
Decay
Fire is fuel controlled during what stages of fire development
Incipient and early growth stages
Introducing air into a fuel controlled compartment will
Initially slow the progression to flashover by removing hot gasses and cooling interior, but will grow soon if not controlled
Fire is likely to become vent controlled during what stages of development,
Through growth stage and toward fully developed
From a size up perspective, one of the most important indicators of fire conditions inside is
The behavior of visible smoke outside
In regard to breathing smoke, firefighters should
Never breathe smoke
Whitish great smoke generally indicates what type of fire
Celluloid or class a materials burning is oxygen abundant atmosphere
Black smoke is an indicator of
Petroleum based products, plastics, anything burning in oxygen limited environment.
Two categories of smoke density
Optical density and opacity
Physical density
Optical density and opacity
How difficult it is to see through smoke
Physical density of smoke
How buoyant the smoke is. If it’s quick rising- buoyant. Related to temperature of smoke.
Light haze of smoke lazily moving on the top floor could indicate
Intense attic fire
For vent purposes, size up should consider four factors
Age and type of building
Positive construction features
Negative construction features
Occupancy specific construction features
When burned by fire, full dimension lumber behaves how in comparison to nominal dimension lumber
Full dimension holds its strength better than nominal. But because it’s older and therefore dryer, is more susceptible to ignition than newer nominal.
Although lightweight and cost effective construction methods are used to save money, they often increase
Increase collapse potential because of longer spans and enclosed void spaces with structural members having more surface area or mass ratios
Positive construction features
Of some help to ff. tend to resist effects of fire, reduce spread, and reduce collapse potential. Steel members Self closing fire doors Sprinklers Built in fire suppression Smoke vents, Elevator shafts
Built in fire suppression systems
Halogenated system,
Co2
Dry chem
Protect single compartment like hood over stove or computer bank
Elevator shafts can be a ventilation hinderance and benefit because
Hinderance when providing avenue for fire and smoke spread to other levels
Benefit when providing a means to vent thought passing through other floors
Ideally, roofs with panelized systems or other systems prone to early collapse should have
Automatic smoke vents, thereby preventing firefighters from walking on dangerous roof surfaces to vertical vent
Firefighters should frequently visit and pre plan beguiled kings undergoing modification because
They will be familiar with changes and possible hinderance to operations and Id ways to mitigate the problem.
Negative building features are
Ones that do not resist effects of fire, promote fire spread, increase collapse potential, and make entry more difficult.
Negative building features
Elevator shafts Synthetic materials Planters and other landscape features Security measures Occupancy related features
Planters and other landscape features can be a hinderance to firefighting because
They may keep apparatus further from building and make placement of ladders difficult.
Establishing and maintaining the required level of coordination, demands that everyone on the fire ground know and understand what
The incident action plan. IAP and how it affects each part of the operation
Coordinating vent with rescue and fire attack generally involves three components
Timing,
Location
Method
Some factors that have a bearing on where to ventilate
Location of fire Location of occupants Linters or and exterior exposures Type of construction Purpose or use of occupancy Extend of fire progression Condition of building and contents Existing openings, skylights, vents, monitors Direction and velocity of wind Resource availability and capability
Firefighters can sometimes use what to locate the fire from the outside if smoke and fire aren’t visible
Tic, or feeling, looking for discoloration or blistering
If an area of the roof is unsafe due to fire conditions below, the vent hole should be made between
Between the fire, and uninvolved portion of the building.
If the fire is below the top floor, vertical vent may not be possible unless
An elevator shaft or other vertical channel is available
Structures in which horizontal vent may be appropriate
Fires not large enough to necessitate roof opening
Windows or doors close to seat of fire
Seat of fire below top floor
Fire has not entered structural voids or concealed spaces
Structures in which vertical vent may be appropriate
Fire in attic cockloft or top floor
With no windows and few exterior doors
With large vertical channels like, light wells, elevators, hoist ways etc
Fire has entered structural voids and concealed spaces.
If conditions allow, natural vent is the best option because
It does not require additional personnel or equipment to set up and maintain
In general mechanical or forced ventilation is indicated when
Location and size of fire is determined
Layout of building doesn’t lend to natural vent
Natural vent slows, becomes ineffective, needs support
Fire burning below grade
Compartment with fire is so large natural vent is inefficient
Dictated by type of building and fire
Consideration. It’s be given to the path of ventilated gases because
They can damage property, cause fire to extend, put egress paths in danger, and externally ignite surfaces or features, cause lapping or autoexposure
Emitting products of combustion from vent holes can cause what to nearby exposures
Ignition to exposures or extension to grass and other exposures form burning debris flying.
Two Important weather considerations for ventilation
Wind
Temperature
Wind can feed a fire and hinder
Ventilation efforts by forcing smoke and gas back into building
Temperature of outside conditions on roofs can cause what to firefighters operating on roofs
Fatigue and heat exhaustion from weather temp
Cons temp can effect vent efforts by
Snow and increasing live loads on roof- collapse potential
Conceal potential hazards
Slippery surfaces
Factors that contribute to the ventilation of a fire are known as
A ventilation profile
