System Design Flashcards
Maximum fan diameter for HVLS fan
24’
The HVLS fan shall be centred between approximately how many sprinklers
4
The vertical distance from HVLS fan to sprinkler deflector shall be a minimum of
3 feet
What will HVLS fans do when a signal from alarm system is received
Shut down immediately
Where is the pipe schedule permitted
-additions/modifications to existing systems
- new systems under 5000sqft
-systems above 5000sqft if 50psi is available at highest elevation sprinkler
Residual pressure shall be met where
Elevation of highest sprinkler
Flow rate is measured in
GPM
Velocity is measured in
FPS (feet per second)
As pipe size decreases what happens to the velocity
Increases
Minimum required residual pressure in light hazard
15 psi
Minimum required residual pressure in ordinary hazard
20 psi
Acceptable flow at base of riser and duration of flow, supervised, light hazard
500gpm
30 minutes
Acceptable flow at base of riser and duration of flow, un-supervised, light hazard
750gpm
60 minutes
Acceptable flow at base of riser and duration of flow, supervised, ordinary hazard
850gpm
60 minutes
Acceptable flow at base of riser and duration of flow, un-supervised, ordinary hazard
1500gpm
90 minutes
Where must the residual pressure be evaluated
Highest sprinkler
Pipe sizes must be no less then ____ for steel pipe systems
1”
Pipe sizes must be no less then ____ in hydraulically calc. copper tubing and non-metallic pipe systems
3/4”
Smoother the interior of the pipe the more ____ flow will be
Smooth, laminar
The more rough that the interior is, the flow will be more ____
Turbulent
As pipe diameter becomes smaller, does pressure loss become more or less
Less due to friction
Increased velocity = increased _____
Turbulence
How does a looped system help reduce water velocity
By feeding the opened sprinkler from 2 directions
Define gridded system
Essentially series of loops in which all the branch lines serve as feed mains supplying any opened sprinkler
