Basic Fire Science (TEST 5) Flashcards
But on the fire ground of today, we cannot afford to standby waiting for things to happen and then adjust our tactics to fit the requirements of the moment. Rather, we must anticipate present and future changes and take __________________.
pre-emptive action
(Variables that influence air) Reminder:
A fire grows in _________________ to the volume of oxidizer available to it.
direct proportion
(Variables that influence air) Modern Container Design
Design elements such as:
- __________________
- __________________
- Open floor plans
- Tall, vaulted ceilings
(Variables that influence air) Modern Container Design
Can produce hazards such as:
- _________________ far from the fire’s point of origin
- Heat build-up _________________ due to convection currents
- Unimpeded ________________ throughout the structure
- Prolonged ________________
- Toxic environments
- in remote locations
- smoke spread
smoke fill times
(Variables that influence air) Modern Container Design
These structures are also:
-______________________
-______________________
-______________________
—Number, size, location of openings
- More energy efficient
- More encapsulating
- Less structurally restrictive
(Variables that influence air) Modern Contents
- _________________ and/or hydrocarbon-based materials
- Far more plentiful
- _______________________
- _______________________
- Primarily synthetic
- Increasingly energy dense
- Highly volatile (High HRR)
(Variables that influence air) Occupants
-Distracted
-Lacking:
•___________
•___________
•___________
- Knowledge
- Understanding
- Ability
Occupants variables: When combine, these…
- ________________________________
- __________________________ structures
- Distracted, underinformed people (being people)
…Often produce a hazard far beyond what we might expect
- Energy dense, high release rate fuels
- Encapsulating, energy efficient
(Variables that influence air) Flashover Comparison
Modern structures, furnished with modern fuels are capable of creating flashover conditions _____________ than their legacy counterparts
8X faster
Every kilogram of oxygen used in the combustion of common organic materials results in the release of ________ of energy
13.1 MJ
(Flow Paths) Definition:
“The movement of heat, smoke and air _______________________________________ both inside and outside of a fire building.”
from areas of higher pressure to all other lower air pressure areas
(Flow Paths) Frequency of Occurrence
Part of every fire environment as a result of natural and/or artificial means:
- Natural - __________________ flows
- Artificial - _________ flows
- Buoyancy-induced
- Forced
(Flow Paths) Incipient Stage
Difficult to detect due to:
- ______________________
- _________ of products of combustion (P.O.C.) into the surrounding atmosphere
- Minimal smoke production
- Diffusion
(Flow Paths) Incipient Stage
Developing in the form of:
- Heated gases _________ and _________ above the fire
- Cooler gases being __________ and __________ the fire below
- rising
- mixing
- displaced
- drawn into
(Flow Paths) Incipient Stage
As compartment temp. increases:
- ______________________
- ______________________
- Heat release rates increase
- Flame height increases
(Flow Paths) Incipient Stage
Leading to increases in:
- ________________________
- ________________________
- Visible smoke production
- Intra-compartmental pressure differentials
(Flow Paths) Growth Phase, Transitioning into Growth Stage
If O2 is adequate:
_____ from the fire ______________________
This fuel will combust resulting in __________
- Heat
- will evolve additional fuel
-more heat
(Flow Paths) Growth Phase
This can be visualized by observing the smoke:
- ___________________
- ___________________
- ___________________
- Increasing in volume
- Increasing in velocity
- Establishing the neutral plane
Visualization of the neutral plane provides information about:
- _____________________
- _____________________
- _____________________
- _____________________
- The fire’s location
- The fire’s state of development
- The efficiency of openings
- The type/direction of flow
Despite the wide variety of containers and fire types, there are only a few basic types of air/fire flow that we need to be concerned with:
- ______________
- ______________
- ___________________
- Bi-directional
- Unidirectional
- Multidirectional (i.e. overflows)
(Bi-Directional) Variables that can affect this type of flow:
- HRR, pressure differentials
- Opening - size, proximity, _________
- Interior layout, etc.
location
(Unidirectional)
Each opening involved will develop in natural inward (cold) or outward (hot) flow bases upon such variables as:
- Exterior wind and humidity
- _____________________ and __________ of openings
- Configuration of interior pathways (i.e. barriers)
- Initiating _________________
- Size, proximity, elevation
- location
-pressure differential