Problem with pump foundation following ANSI/HI 1.4

[NguyenNhat]

Hi everyone, standard ANSI/HI 1.4 stated that:
"A.4.3 Foundation: The foundation should be sufficiently substantial to absorb vibration (e.g., at least five times the weight of the pump unit) and to form a permanent, rigid support for the baseplate." so does the five times the weight means either magnitude of vibration or the mass of foundation? I think the standard talking about just an example of the magnitude of vibration, but in a white paper of Grundfos pump, it said that is mass of foundation "The mass of the concrete foundation is great enough that it absorbs any of the dynamic and static forces previously described. The Hydraulic Institute recommends in its Standards that the mass of the concrete foundation should be on the order of five (5) times that of the equipment it is supporting." . Please explain to me, thank you very much

 

[LittleInch]

I think you've worked it out yourself

It means the mass of the foundation is in the order of five times the mass of the pump and motor.

Ideally there is no vibration in operation, but that is an ideal world and there are always start / stop transient forces to deal with. There is no way for a general guideline to determine the actual vibration and other forces on pumps.

Clearly over time there is an acceptance that with a foundation of this magnitude, most of the vibration can be absorbed in the foundation without the pump imposing forces on nozzles and pipework which could lead to failure.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[pumpingtips]

Compare this to large pumps that we install on skid frames, without concrete mass to hold things down!!... Hmmm. Pump vibrations are not that great anyway so providing the connecting pipework is well supported and protected, all should be fine.

 

[desertfox]

Hi NguyenNhat

So if the mass of the equipment is say 1tonne the concrete mass needs to be 5 Tonne its as straight forward as that.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[NguyenNhat]

Thank you very much. But the noticeable point is that ANSI standard use "the weight"-means force, i think it doesn't equal with "the mass"

 

[desertfox]

Hi

You are right that mass doesn't equal weight but mass x gravity accel = weight.
So if the weight is fives times mass the ratio still holds, i.e. Both masses can be multiplied by gravity

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[NguyenNhat]

Desertfox, I mean the intent of standard is foundation's bearing force ability, so this isn't a "mass race", because the strength of foundation(usually concrete foundation) is not only depend on it's mass.

 

[desertfox]

I think you will find that mass and weight are used very often for the same meaning, I would just use it as mass.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein