5 replies to this topic

[jatinder]

Dear All,

 

I have a question regarding the discharge pressure for a deck wash pump that is delivering the water to Helideck.

 

Total elevation from pump discharge to helideck is 20 meter.

 

After 20 meter, there is a hose connection for further water delivery.

 

I would like to know if there are any standards for example NORSOK that explains about the minimum discharge pressure at the hose point. I was checking the DNV-OS-D301 but it only talks about fire water pump system to helideck. According to it, "if there are two pumps, each pump should be capable of delivering at least one jet simultaneously from each of the any two fire water hydrants, hoses and 19 mm nozzles while maintaing a minimum pressure of 0.35 N/mm2 (3.5 barg)at any hydrant.

 

But, this is for fire water and not to clean the helideck.

 

Any suggestions?

 

Thanks,

 

Jatinder

[S.AHMAD]

Jatinder

1. Why you want to know any standards for minimum pump pressure?

2. Pump pressure should be determined from elevation, pressure  drop at the required flowrate. This is the minimum pressure. If pressure is lower you may  not be able tom deliver the volume required. Higher pressure you may deliver more volume. However, the shut-off pressure shall be limited by the hose design pressure, if the hose has any valve at the end of the hose line

Edited by S.AHMAD, 25 November 2013 - 10:10 AM.

[jatinder]

Dear Ahmad,
Thannks for your post! I am totally agree with you that pump pressure could be determined from the elevation difference, pressure drop and flow rate. And I have already calculated it. It turns out to be 3.17 barg with 6.68 barg inlet pressure.
6.68 barg (pump operating pressure) is provided in the equipment list. But that is not the final operating pressure. I have to figure out that what should be my operating pressure.

As I have mentioned that I calcuated 3.17 barg as pump discharge pressure at the highest point and now I want to know if this is sufficient to remove all bird guano from the helideck ??

Thanks

[S.AHMAD]

1. So you are using it for cleaning purpose?

2. What you need is the water jet velocity which is related to jet size and vulumetric flowrate.

3. What you need to know is what velocity of water jet that can remove the things that you are cleaning rather than pressure since pressure can varies with hoze and nozzle size.

[jatinder]

Dear Ahmad,

Exactly, now you got my point. I need it for cleaning purposes.
Thanks for clearing the pressure change concept!
So, do you have any idea that what should be the velocity?

Thank you very much,

Jatinder

[jatinder]

Dear Ahmad,

Exactly, now you got my point. I need it for cleaning purposes.
Thanks for clearing the pressure change concept!
So, do you have any idea that what should be the velocity?

Thank you very much,

Jatinder