Liquid Line Sizing Calculator

Flow Conditions

Flow Rate

Specific Gravity

Water = 1.0, typical range: 0.7-1.6

Viscosity

Water @ 60°F ≈ 1.0 cP

Pipe Properties

Pipe Standard

Pipe Material

Roughness

Commercial steel: 0.0018 ft

Design Criteria

Max Velocity

ft/s

Typical: 5-15 ft/s

Max Pressure Drop

psi/100ft

Typical: 2-10 psi/100ft

Service Type

📚 Learn the Theory

Understand liquid line sizing principles, calculations, and industry applications

Read Engineering Guide →

🔬 Key Formulas

Reynolds Number

Re = 50.6 × Q × SG / (μ × D)

Q = Flow rate (GPM)
SG = Specific gravity
μ = Viscosity (cP)
D = Inside diameter (in)

Friction Factor (Swamee-Jain - CORRECTED)

f = 0.25 / [log₁₀(ε/(3.7D) + 5.74/Re⁰·⁹)]²

ε = Absolute roughness (ft)
Valid for: Turbulent flow, Re > 4000

Pressure Drop (Darcy-Weisbach)

ΔP = 0.0216 × f × SG × Q² / D⁵

Result in psi per 100 feet

⚠️ Important Notes

Formula Correction: Swamee-Jain equation corrected from original spreadsheet formula
Laminar flow (Re < 2000): f = 64/Re
Turbulent flow (Re > 4000): Swamee-Jain explicit equation
Typical velocity ranges: Suction 1-5 ft/s, Discharge 5-15 ft/s
Results are for preliminary design - verify with licensed engineer

💡 Quick Guide

✅ Works For:

• Water, crude oil, diesel, gasoline, fuel oil
• Any Newtonian liquid (single-phase)
• Viscosity range: 0.5 - 10,000 cP

❌ NOT For:

• Gas-liquid mixtures, steam, flashing liquids
• Slurries, polymers, non-Newtonian fluids
• Compressible flow

🎯 Velocity Guidelines:

• Pump suction: 1-5 ft/s
• Water discharge: 5-15 ft/s
• Oil pipelines: 3-8 ft/s
• Heavy oils: 2-5 ft/s

⚡ Key Tips:

• Use viscosity at actual operating temperature
• Target Re > 4000 for turbulent flow (more efficient)
• Cold oil = higher viscosity = higher ΔP
• Heating heavy oils reduces pumping costs
• Aged pipe: increase roughness to 0.003-0.005 ft

💧 Common Fluids @ 60°F

Fluid	SG	μ (cP)
Water	1.00	1.1
Gasoline	0.72	0.6
Diesel	0.85	4.0
Kerosene	0.81	2.2
Light Crude	0.86	10-20
Med Crude	0.92	50-100
Heavy Crude	0.95	200-1000
Fuel Oil #2	0.87	5
Fuel Oil #6	0.98	900*
Ethanol	0.79	1.2
Glycol (50%)	1.07	5.5

*Requires heating. μ varies greatly with temp.

Pipe Roughness Values

Material	ε (ft)
Commercial Steel	0.00015
Carbon Steel (new)	0.0018
Stainless Steel	0.00015
PVC	0.000005
Copper	0.000005

⚠️ Limitations

Newtonian liquids only
Single-phase flow
No gas-liquid mixtures
No slurries/polymers
Viscosity < 10,000 cP

🎯 Velocity Guide

Pump Suction	1-5 ft/s
Water Discharge	5-15 ft/s
Oil Pipelines	3-8 ft/s
Heavy Oils	2-5 ft/s

Target Re > 4000 for turbulent flow (more efficient)