Chapter 8 Offensive Operations Flashcards
The objective of an offensive fire attack is to do what?
Apply enough water directly to the burning fuel to achieve extinguishment
Extinguishment provides what three things?
A safer work environment for FFs
Facilitating rescues
Reducing property damage
What method is probably the most commonly used method of determining flow rate?
The trial-and-error method
What is the Royer/Nelson Formula for GPM calculations?
V/100 = GPM (V = L x W x H)
What is the National Fire Academy Formula for GPM calculations?
A/3 = GPM (A = L x W)
The Royer/Nelson formula believes that the fuel load and fire type are not as important as the room volume because fires are what?
Ventilation controlled.
The Royer/Nelson formula will be valid for most fires where what is advisable?
An interior attack
Rate of flow calculations are used to determine what two aspects of fighting fire for an interior attack?
- Whether the fire is beyond the capacity of the standard attack
- How many and what size hose lines are needed
Royer and Nelson recognized that the V/100 rate of flow formula is primarily a what?
Planning tool
What do both the Royer/Nelson and Fire Academy formulas ignore?
Fuel load
Fuel type
What calculation may prove useful in preincident planning?
Sprinkler System calculations
The National Fire Academy rate of flow formula is based on the ________________ rather than the volume of the enclosure.
area of involvement
During the ignition phase, most fires can be controlled with how many GPM?
1
This text recommends the ________ for preincident planning.
V/100
If the A/3 calculation is used at the incident scene, how should it be modified?
Using a percentage involvement modifier
A valid assumption for a sprinkler system but not for manual firefighting is what?
The assumption that a sprinkler system will operate early in the fire to limit fire extension.
Sprinkler flow densities should be applied to the entire compartment when used to determine what?
Rate of flow using hose lines
When the average hose lay exceeds _________ it would be wise to use 2-in or larger preconnected lines to compensate for the additional friction loss.
250 ft
V/100 is based on extinguishment within how long?
30 seconds.
Flow rates will vary based on what?
- Nozzle pressure
- pump discharge
- length of the hose lay
Some examples where softening the target may NOT be applicable include:
- A fire that is inaccessible from the outside at ground level
- A compartmented area with no outside access point
- A small fire that fails to gain intensity
In the absence of visible fire or heavy and/or pushing smoke conditions, what does not apply?
the soften the target tactic
Class A fuels must be vaporized by heating the solid materials until combustible vapors are emitted. This process is known as?
Pyrolysis
What are some factors in evaluating the need to defend nearby buildings with additional hose lines?
- Life hazard in the exposure
- Proximity to the fire building
- Wind direction
- Height of the exposure compared to the level of fire in the fire building
- Hazard presented by the exposed occupancy
What is the FIRST consideration for protecting an exposure?
The threat to human life.
What is the defined purpose of a backup hose line?
Provide flow in addition to what is needed to extinguish the fire, thus providing a measure of protection for FFs combating the fire.
What are the only two reasons it is sometimes necessary to place another pumper in a large-diameter hose water supply layout?
- Where flows in excess of 1000PGM are anticipated from a single pumper
- For extremely long relay lines (over 700 ft)
Horizontal and vertical ventilation should be _______________.
- Timed
- Reversible if possible
Which venting tactic is NOT considered an offensive tactic?
The trench cut
How much faster did a four-person crew complete the primary search in relation to a two-person crew?
30%
Friction loss in the hose varies by
- Size
- Hose type
- Manufacturer
- Age.
- And condition.
