# Calculators for Pumps, Piping, and Fitting

Calculators will help you to properly size up your pump, piping and fittings. With these tools, you can determine suction loss, friction loss, specific gravity, along with the useful conversion tables.

## Head & Pressure Formula

Head in Feet | = | (Head in psi) x 2.31
(Sp. Gr.) |

Head in psi | = | (Head in feet) x (Sp. Gr.)
2.31 |

## Net Positive Suction Head

**Suction Lift:**

NPSH = h

_{a}– h

_{v}– h

_{s}– h

_{l}

**Flooded suction:**

NPSH = h

_{a}– h

_{v}+ h

_{s}– h

_{l}

h

_{a}= the absolute pressure in feed of liquid on the surface of the supply liquid

h

_{v}= the vapor pressure of the liquid being pumped expressed in feet of head

h

_{s}= the height in feed of the supply liquid surface with respect to the pump inlet

h

_{l}= suction line friction losses express in feet of head

These calculations yield the available net positive suction head for a given system.

This must be compared to the required net positive suction head NPSHR calculated

by the manufacturer. NPSH

_{A}must exceed NPSH

_{R}.

## Affinity Laws

Centrifugal PumpsFor constant speed: |
||||

D_{1}
D _{2} |
= | Q_{1}
Q _{2} |
= | √H_{1}
√H _{2} |

BHP_{1} = (D1)^{3}
BHP _{2} = (D2)^{3} |

For constant impeller diameter: |
||||

S_{1}
S _{2} |
= | Q_{1}
Q _{2} |
= | √H_{1}
√H _{2} |

BHP_{1} = (S1)^{3}
BHP _{2} = (S2)^{3} |

D = Impeller diameter in inches H = Head in feet

S = Speeds in RPM Q = Capacities in GPM

BHP = Brake Horsepower

## Vacuum Pressure Equivalents:

1 Atmosphere = 29.92 in. Hg = 760mm Hg = 14.7 psi1 mm Hg = 1 Torr = (3.937x10-2) in. Hg = 1000µ Hg = 1.333 millibars

1 bar = 103 millibars = 106 microbars = 750.06 mm Hg

1 microbar = 0.75 micron

1 inch Hg = 2.54 x 101 mm Hg

x in. Hg vacuum = (29.92–x) in. Hg absolute

y mm Hg vacuum = (760-y) mm Hg absolute

z PSIG = (z + 14.7) PSIA

w PSIA = (w-14.7) PSIG

## PUMPING POWER FORMULA

Centrifugal pumps: |
||

Brake hp | = | gpm x H_{ft} x Sp. Gr.
3960 x Efficiency |

Rotary and reciprocating pumps: |
||

Brake hp | = | gpm x psi
1714 x Efficiency |

KW | = | pump bhp x 0.7457
motor efficiency |

## GENERAL INFORMATION

1 HP = .746 KW or 746 WattsGPM = Bbls. / Hr. x 0.70

GPM = Bbls. / Day x 0.2917

One Barrel Oil = 42 Gallons

## VISCOSITY

__Relationships__Centistokes | = | Centipoises
Density |
(usually the same as specific gravity) |

*ft*

^{2}/ sec = Centistokes x 1.07639 x 10

^{-5}

Centistokes = ft

^{2}/ sec x 92903.4

__Approximate Conversions__(50 < SSU ± 100) Centistokes = SSU x 0.226 – 205.3 / SSU

(100 < SSU ≤ 350) Centistokes = SSU x 0.220 – 147.7 / SSU

(SSU > 350 @ 100° F) Centistokes = SSU x 0.21576

(SSU > 350 @ 210° F) Centistokes = SSU x .021426

## FLOW

Lbs. Of Water / Hr x 0.002 = Gal Min.Gal / Min. x 500 = Lbs of Water / Hr

Lbs of Fluid / Hr
Specific Gravity |
= | Gal Min. |

Liter Min. x 0.264 = Gal / Min. (US)

GPM x 3.785 = Liters / Min.

Cu. Meters / Hr x 4.4 = Gal / Min. (US)

Gal / Min. x 227 = Cu. Meters / Hr

Kg of Water / Min. x 0.264 = Gal / Min. (US)

Gal Min. x 3.8 = Kg of Water / Min.

## PRESSURE

Ft of Water x 0.433 = PSIPSI x 2.31 = Ft of Water

Inches Hg. X 0.491 = PSI

Inches Hg. X 1.133 = Ft of Water

ATM x 14.7 = PSI

ATM x 33.9 = Ft of Water

Kg / Sq cm x 14.22 = PSI

Meters of Water x 1.42 = PSI

ATM x 760 = mm Hg.

mm Hg. X 0.39 = Inches Hg.

Bar x 14.5 = PSI

Newton / Meter2 x 1 = Pascal

PSI x 6.9 = kPa (Kilopascal)

kPa x 0.145 =PSI

## VOLUME

Lbs Water x 0.119 = GalGal (Brit) x 1.2 = Gal (US)

Gal x 128 = Fluid Ounces

Cubic Ft x 7.48 = Gal

Cubic in. x 0.00433 = Gal

Gal x 3.785 = Liters

Liter x 0.264 = Gal

Cubic Meters x 264.2 = Gallons

Cubic Meter x 1000 = Liters

Liters x 1000 = Cubic Centimeters

Cubic Centimeters x 0.338 = Fluid Ounces

Fluid Ounces x 29.57 = Cubic Centimeters

## MASS

Gal of Water x 8.336 = LbsCubic Ft of Water x 62.4 = Lbs

Ounces x 0.625 = Lbs

Kilograms x 2.2 = Lbs

Lbs x 0.454 = Kilograms

Metric Ton x 2205 = Lbs

## LENGTH

Mils x 0.001 = InchesMeters x 3.281 = Feet

Centimeters x 0.394 = Inches

Millimeters x 0.0394 = Inches

Microns x 0.0000394 = Inches