8 replies to this topic

[nhuthoahuynh13]

Hello everyone,

 

I am calculating pipe size for my project. One of the steps is to compare the velocity and dressure drop with the criterion, but I don't know where this "criterion" comes from  ? There are many tables on Internet but they do not mention a specific criterion (eg API, ASME,...).

If you know where this standard comes from, please let me know.

 

Many thanks. 

 

 

 

 

 

[shvet1]

I don't know where this "criterion" comes from  ? 

 

Safety, reliability, investment return. Which one are you interested in? Note that there are many criteria of velocity range: vibration, erosion, settling, stratification, etc. For example SimSci Pipephase uses erosion as per API 14E.

 

Start with safety, industry practice, money (chap. 5)

Edited by shvet1, 28 November 2023 - 12:14 AM.

[nhuthoahuynh13]

 

I don't know where this "criterion" comes from  ? 

 

Safety, reliability, investment return. Which one are you interested in? Note that there are many criteria of velocity range: vibration, erosion, settling, stratification, etc. For example SimSci Pipephase uses erosion as per API 14E.

 

Start with safety, industry practice, money (chap. 5)

 

I mean like this table (Link: https://www.google.c...AAAAAdAAAAABAD)

 

I do not know where this criteria comes from?

[fallah]

 

Hello everyone,

 

I am calculating pipe size for my project. One of the steps is to compare the velocity and dressure drop with the criterion, but I don't know where this "criterion" comes from  ? There are many tables on Internet but they do not mention a specific criterion (eg API, ASME,...).

If you know where this standard comes from, please let me know.

 

Many thanks. 

 

 

Hi,

 

The project you are involved on should have Process Sizing Criteria including Line Sizing...hence you cannot refer to any taken criteria from internet with unknown source and basis...

[nhuthoahuynh13]

 

 

Hello everyone,

 

I am calculating pipe size for my project. One of the steps is to compare the velocity and dressure drop with the criterion, but I don't know where this "criterion" comes from  ? There are many tables on Internet but they do not mention a specific criterion (eg API, ASME,...).

If you know where this standard comes from, please let me know.

 

Many thanks. 

 

 

Hi,

 

The project you are involved on should have Process Sizing Criteria including Line Sizing...hence you cannot refer to any taken criteria from internet with unknown source and basis...

 

Yes, I undestand that. I have researched how to line sizing on the internet, one step is to compare velocity and Pressure Drop with "criteria", but the source on the internet does not clearly where this standard comes from.

[shvet1]

I do not know where this criteria comes from?

 

from investment return. See the link above.

[snickster]

There are many different sources that may give the recommended maximum velocity and pressure drop in piping depending on what industry you are in.

 

In the oil and gas industry API 14E provides recommended maximum velocity in pipelines based on errosion/corrosiobn considerations.  For instance the maximum liquid velocity is limited to 15 ft/sec.

 

In gas flow the maximum velocity is typically limited to 60 ft/second based on noise generation above this velocity.  I am not sure what code this comes from but it is a very accepted value.

 

These values can be further limited by other considerations.  For instance in pumping systems the velocity is usually about 7 to 10 ft/sec on discharge.  This is based on economics of the cost of pump versus the cost of the piping.  For smaller piping it is less expensive but pressure drop goes up and so does pump horsepower size, cost of pump, and lifetime operational costs.  For larger piping the pipe cost increase but pressure drop and pump size/power decreases and so does lifetime operational costs.  It has been determined that best comprimise is at about 7 to 10 ft/sec on discharge piping.  However on the suction side of pumps the limit is about 3 ft/sec based on minmizing pressure drop and providing smooth flow into the pumps suction.

 

When you do work for clients in oil and gas, refining and chemical plant industries they normally will have guidelines of what would be the maximum allowable velocities in the piping.  Normally pressure drop per hundred feet of piping is sometimes used a  criterion but instead of stating pressure drop/100 ft, limits in pressure drop is still stated as limits in velocities.

Edited by snickster, 28 November 2023 - 01:10 PM.

[snickster]

Here is link to Saudi Aramco Standard SAES-L-132 that provides guidance on velocity limits in piping.

 

Material Selection for Piping Systems | SAES-L-132 [PDF] PAKTECHPOINT

 

SAES-L-132 - Free Download PDF (kupdf.net)

Edited by snickster, 28 November 2023 - 01:26 PM.

[Asisraja]

We in India use 2.5m/s velocity for discharge side of the pump but I don't know what standards we follow. It works well in 80NB line size now we introduce this to 250NB line for pumping cooling tower water to the plant. Anyway you can contact your vendor who provide pipe sizing based on velocity for your plant if you don't have any vendor then you can contact your pump manufacturer and describe your need they might help you.