Description Standard Construction
Shell Steel
Bladder Heavy Duty Butyl
NSF/ANSI 61
Bladder Thickness .100 Minimum
System Connection Steel - ANSI Flange
Coating Red Oxide Primer
Factory Precharge 25 PSIG (1.7 bar)

Use:

SG = Specic gravity of uid: Water 1
Ethylene glycol 1.1
Propylene glycol 1.1
Glycerin 1.3
Qs = Fire pump ow rate in gpm
Qss = Fire pump ow rate in feet per second
L = Length of pipe in feet
a = Speed of pressure wave
in feet per second: Steel pipe 4500 ft/sec
Cast iron = 4500 ft/sec
Ductile iron 4500 ft/sec
PVC pipe = 1250 ft/sec
P2 = Maximum allowable pressure
P1 = Tank pre-charge pressure setting
n = Gas constant (pre-charge gas) dry air 1.2
nitrogen 1.4
A = Area of Pipe - pipe size
V = Velocity of water in feet per second

Precise Sizing For Pump Start-up:

Volume of Tank in Cubic Feet =
( SG x 2 x Qs x L ) ( P2 + 14.7 )1/n
449a P1 + 14.7
( P2 + 14.7 )1/n
P1 + 14.7
-1
NOTE: Set pre-charge pressure 15% below static pressure.
NOTE: To convert cubic feet to gallons multiply by 7.481.
SIZING THE SURGE-TROL™
Tank A B Sys. C D E Ship
Vol. Height Diameter Conn. Conn. Conn. Stand Wt.
Model Inset CtrLine Dia
No. Lit. Gal mm ins. mm ins. ins. ins. ins. ins. kg lbs.
SPT-7 200 53 1245 487/8 610 24 4 19/16 8
3/16 19 166 367
SPT-11 300 80 1600 627/8 610 24 4 19/16 8
3/16 19 208 459
SPT-14 400 106 1956 767/8 610 24 4 19/16 8
3/16 19 282 618
SPT-18 500 132 2311 907/8 610 24 4 19/16 8
3/16 19 333 731
SPT-21 600 158 1893 7411/16 762 30 4 13/8 7
1/4 24 433 950
SPT-28 800 211 2365 931/8 762 30 4 13/8 7
1/4 24 513 1125
SPT-35 1000 264 2086 821/8 914 36 6 31/4 7
1/2 30 693 1520
SPT-42 1200 317 2465 941/2 914 36 6 31/4 7
1/2 30 784 1720
SPT-50 1400 370 2781 1091/2 914 36 6 31/4 7
1/2 30 866 1900
SPT-56 1600 422 2178 853/4 1220 48 8 13/4 107/8 42 1049 2300
SPT-70 2000 528 2528 995/8 1220 48 8 13/4 107/8 42 1231 2700

Precise Sizing For Pump Shut-down:

Volume of Tank in Gallons = Vv
AF
AF - Acceptance Factor = 1 - ( P1 + 14.7)1/n
P2 + 14.7
Vv - Vacuum Volume = Qss x Tc x 7.481
Tc - Critical Time in seconds = 2L
a
NOTE: Set pre-charge pressure 50% below
static pressure.

Precise Sizing Example

For Pump Shut-down Based On:

Pump = 100 GPM
Pipe = 2” Steel Pipe; 1000 ft of pipe
Static Pressure = 100 psig
Max. Pressure = 150 psig
Pre-charge Gas = Dry Air
Tc = 2L = 2(1000) = 2000 = .444
a 4500 4500
Vv = Qss x Tc x 7.481 = 9.5 x .444 x 7.481 = 31.55
AF = 1 - ( P1 + 14.7)1/n = 1 - ( 64.7 )1/1.2 = .54
P2 + 14.7 164.7
Volume of Tank in Gallons = Vv = 31.55 = 58.4
AF .54
Recommendation = SPT-11