Chapter 7 Fire Hose Nozzles and Flow Rates Flashcards
During the time a stream of water or extinguishing agent passes through space, it is influenced by what?
Velocity, gravity, wind, and friction
pg. 165
What are the three basic types of fire streams used by the fire service?
- solid
- fog
- broken
pg. 165
What is a solid stream?
a fire stream produced from a fixed orifice, smoothbore nozzle.
pg. 165
What equipment/ hose types are solid stream used on?
handlines,
portable or apparatus mounted master streams,
elevated master streams
pg. 165
What determines the flow and stream reach from a solid stream nozzle?
nozzle pressure and the size of the discharge opening
pg. 166
When used on handlines, what psi should solid streams be operated at?
50 psi
pg. 166
A solid stream master stream device should be operated at what psi?
80 psi
pg. 166
What is the formula to determine the amount of water in GPM being discharged from a solid stream device?
GPM=29.7 x d² x √NP
d=diameter of orifice in mm
NP= nozzle pressure in kPa
What is periphery?
the line bounding a rounded surface; the outward boundary of an object distinguished from its internal regions
What is deflection?
A turning or state of being turned; a turning from a straight line or given course; a bending; a deviation.
What is meant to impinge?
To strike or dash about or against; clashing with a sharp collision; to come together with force
What determines the stream pattern of a periphery-deflected nozzle?
Position of the deflection stem and
exterior barrel
pg. 167
A wide-angle deflection produces a ______ angle fog, and a narrow-angle defection produces a ______ angle fog.
Wide
Narrow
pg. 167
How does an impinging stream nozzle form a fog pattern?
defects several jets of water together
pg. 168
What is the result of water being discharged at angles to the direct line of discharge?
the reaction forces largely balance each other, reducing nozzle reaction
pg. 168
Constant flow nozzles are designed to what?
flow a specific amount of water at a specific nozzle discharge pressure on all STREAM PATTERNS.
pg. 168
Constant flow nozzles discharge the same volume of water regardless of what?
nozzle pattern setting
pg. 168
What pressure are most constant flow nozzles intended to be operated at?
100 psi
pg. 168
With an _________ nozzle, the selected flow remains constant whether a straight stream, narrow fog, or a wide fog is selected.
adjustable flow
pg. 169
The automatic nozzle maintains the same ________ and ______ if the gallonage supplied to the nozzle is changed.
nozzle pressure
pattern
pg. 169
What psi are most fog nozzles designed for?
100 psi
pg. 169
What is the minimum flow setting for interior structural fire fighting?
95-100 gpm
pg. 169
No matter how much the pump discharge pressure, an automatic nozzle maintains a constant nozzle pressure of approx. what psi?
100 psi
pg. 170
What psi do high-pressure fog nozzles operate at?
800 psi
pg. 170
What are high-pressure fog nozzles primarily used for?
wildland fire fighting
pg. 171
What is the maximum amount of water that can safely flow through a handline nozzle?
350 gpm
pg. 171
What is the term “master stream” applied to?
any fire stream that is too large to be controlled without mechanical aid.
pg. 171
What psi are smoothbore master streams operated at?
80 psi
pg. 171
What psi are fog master streams operated at?
100 psi
pg. 171
What are the 4 basic types of master streams?
- Monitor
- Turret pipe
- Deluge set
- Elevated master stream
pg. 172
How do monitors and deluge sets differ?
Monitor streams can change direction and angle while water is being discharged.
pg. 172
How are broken streams created?
When water is forced through a series of small holes on the discharge end of the nozzle.
pg. 175
What type of heat is a water curtain only effective in absorbing?
convected heat
pg. 176
Piercing nozzles may be used to deliver what type of foam?
AFFF (aqueous film forming foam
pg. 176
What GPM will a chimney nozzle generate at 100 psi?
- 5-3 GPM
pg. 177
What is the practical working limits for velocity of fire streams?
60-120 feet per second
pg. 178
If greater reach and volume is needed from a solid stream handline, what can the nozzle pressure be raised to?
65 psi
pg. 178
What is the rule of thumb for approximating nozzle reaction of a solid stream nozzle?
NR=Q/3
Q=flow in GPM
pg. 179
What is the rule of thumb for approximating nozzle reaction of a fog stream nozzle?
NR=Q/2
Q= flow in GPM
pg. 179
