(available in ASME B36.10)
ΔP=ρ⋅g⋅hf=f⋅LD⋅ρv22cap delta cap P equals rho center dot g center dot h sub f equals f center dot the fraction with numerator cap L and denominator cap D end-fraction center dot the fraction with numerator rho v squared and denominator 2 end-fraction = Darcy friction factor = Equivalent length of the pipe ( = Acceleration due to gravity ( Determining the Friction Factor (
Pressure lost through fittings (elbows, tees, valves) and components. (available in ASME B36
The most accurate method for calculating frictional head loss ( ) in a pipe is the Darcy-Weisbach equation:
These are caused by components that disrupt the flow, such as valves, fittings (elbows, tees), and expansions or contractions in the pipe. They are often calculated as an equivalent length of straight pipe or by using a loss coefficient (K) in the equation h_minor = K (V²/2g) . | | Velocity Range (m/s) | Pressure Drop
| | Velocity Range (m/s) | Pressure Drop per 100m (kPa) | | :--- | :--- | :--- | | Liquids (pump discharge) | 1.5 - 3.0 | 10 - 30 | | Liquids (pump suction) | 1.0 - 2.0 | 5 - 15 | | Gases & Vapors | 15 - 30 | 5 - 20 | | Two-Phase Flow | 15 - 35 (design to avoid slug flow) | 5 - 20 | | Steam (low pressure) | 20 - 40 | 5 - 20 | | Steam (high pressure) | 30 - 60 | 5 - 20 |
): Flow fluctuates between laminar and turbulent conditions. Turbulent Flow ( such as valves
It's crucial to understand that all calculations for pressure rating and wall thickness are performed in strict accordance with the formulas and guidelines set forth in ASME B31.3 to ensure the integrity and safety of the system.
t=P⋅D2(S⋅E⋅W+P⋅Y)t equals the fraction with numerator cap P center dot cap D and denominator 2 open paren cap S center dot cap E center dot cap W plus cap P center dot cap Y close paren end-fraction = Internal design gauge pressure = Outside diameter of the pipe
Q=A⋅v=πD24⋅vcap Q equals cap A center dot v equals the fraction with numerator pi cap D squared and denominator 4 end-fraction center dot v