3 replies to this topic

[farid.k]

is it normal to have a deluge valve that has friction loss about 11bar? for me the figure is quite large. for info,

main header pressure is 16barg. this deluge valve supply fire water to 4 nos of pump. refer attachmment for the available datasheet for the deluge valve

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[fallah]

farid.k,

 

It's not normal having such pressure drop across a deluge valve; but the data sheet you attached isn't included this data. Indeed, the pressure of 16 barg appears to be high for fire water network. Anyway, if a simple sketch of the system being uploaded can help to submit better response...

[farid.k]

yea, i agreed with you.

 

However, it’s already stated in the datasheet as per attached which friction loss is 120m which is equivalent to 11bar. Yes, i agreed with you, 16 barg is high even already highlighted by client. Normally 10 barg. How do I confirm the operating pressure in the main ring? Is it by having fire water pump curve?

 

Refer attachment for the sketch. Refer point J6 in the red circle. At that point, (i assume after deluge valve) I do try and error by plug in any value for pressure at that point until i get the desired flow at the end of each spray. Normal flowrate for each spray is 20 liter/min. Based on calculation report (after insert all the value for the pipe length, fittings based on isometric dwg), calculated required pressure at that point is around 9 barg (which is the pressure drop across deluge valve should be 7barg if the upstream pressure is 16barg) to deliver 20 l/m for each spray. Does it look convincing? Appreciate to comment

 

farid.k,

 

It's not normal having such pressure drop across a deluge valve; but the data sheet you attached isn't included this data. Indeed, the pressure of 16 barg appears to be high for fire water network. Anyway, if a simple sketch of the system being uploaded can help to submit better response...

 

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[Ajay S. Satpute]

Farid,

 

We usually assign equivalent length for the deluge valve (equipment icon) in PIPENET model.

 

I believe that depending upon the deluge valve diameter, you need to select equivalent length and calculate the pressure drop using C-factor (or roughness)? C-factor is given as 120.

 

Regards.

 

Ajay S. Satpute