14. Foam equipment and systems Flashcards
__ Foams are the most common foams in use
Mechanical
Class __ Foams are designed solely for use on hydrocarbon fuels and are not effective on polar solvent products regardless of the concentration that is applied
B
How foam works
Separating
cooling
suppressing or smothering
Class A foam
The shelflife of properly stored foam solution can be as long as 20 years making it an economical choice to purchase in bulk quantities.
0.1-1%
Most stable at 1%
$$$
The ___ ___ for foam also plays a major role in the effectiveness of the product.
Drain time
$$$
A __ duration drain time provides the most rapid wetting, while a __ drain time provides an insulating layer for a longer period of time.
Short
longer
When ready for immediate use during emergency operations, similar type concentration such as a ___ and ___ may be mixed together immediately before application.
AFFF
fluroprotien
Class B
The concentration of ___ is normally 1 or 3%, while 3 or 6% is used for ___, based on the manufacturers recommendation.
Hydrocarbon fuels
Polar solvents
___ ___ foam generally has good heat stability and burn back resistance.
Regular protein foam
Notes
Fog nozzles are not in acceptable choice for delivery of fluroprotien foams or polar solvents
Durable or gelling agents
Fluoroprotein foam may be made of alcohol resistant with the addition of ammonia salts suspended in organic solvents making it effective for approximately 15 minutes
Batch mixing is only useful with class A and AFFF. Class A only good for 24 hrs.
A simple and common method of foam proportion involves the use of a __ foam proportioner.
Portable
$$$
The in-line eductor uses the __ principal to draft foam concentrate into the water stream.
Venturi
Back pressure
The pressure at the discharge side of the enductor must not exceed __% of the enductor inlet pressure.
70%
The foam concentrate eductor should be no more than __ feet above the liquid surface of the foam concentrate.
6 ft
Master stream nozzle is deployed wheb flows of excess of __ GPM is required.
350 gpm
$$$
Type of foam eductor that is used to supply self educting master stream nozzles may be located at distances up to 3000 feet from the nozzle.
Jet ratio controller
Are one of the most common types of installed proportioners used in modern fire apparatus.
Around the pump proportioner
Proportioner has the ability to allow foam discharge from some outlets, and plain water from others simultaneously.
Bypass type balance pressure proportioner
The only nozzles that should be used with protein and fluroprotien concentrates.
Air aspirating foam nozzle
Four ways of applying foam
Direct application
roll on
bank down
rain down
Most common method of application for above ground storage tanks
Rain down
