14 replies to this topic

[Lorean]

I have to size line system, firewater system. I have several questions. I have default sizing datasheet. 1)-do we add valve, fittings length to the pipe length? Do we add hydrant lenght, pipe branch length to the pipe length? In datasheet i have special fitting sections, so i ll add valves there for pressure drop. But should i add the valves length to the total length?2) - I have excell datasheet, and there i can only calculate every line individually. How can i size whole system?how to interconnect them, please help.

[Bobby Strain]

Take a look at Harvey Wilson's software. You shouldn't use spreadsheets that have not been validated and approved by your company.

 

Bobby

[Lorean]

Thanks Boby. Its indeed approved by my company. So should i add the branch length of the same pipe to the overall length? And should i add valve length too?

[breizh]

Hi Lorean,

It's difficult to support you without knowing the detail of your work and how the calculation is done .

To me you should have the pipe length and equivalent length of pipe corresponding to the valves and other fittings . All together will be the total length of the line .

 

I've attached an example of network calculation using excel .

note : don't duplicate the posts . better to delete the ones in excess.

 

Hope this is helping you.

Good luck

Breizh 

Edited by breizh, 14 July 2020 - 11:35 PM.

[Lorean]

Breith, tha k you a lot for your attention and time. Yes, i have pressure drop for fittings. Do i have to add branches from the main line to the line overall length?

[Lorean]

So there is main line(trunk), and there are several branches on the line. Should i include the length of these branches to the pressure drop calculation? Or i have to consider only main line length and fittings pressure drop? Thanks

[breizh]

Hi,

Branches are different lines , you need to perform calculation line per line , the connecting point being the nods .

Breizh .

[Lorean]

Breizh, thank you so much for detailed and quick replies

Edited by Lorean, 15 July 2020 - 07:07 AM.

[katmar]

If the design needs to be accepted by your insurance company be aware that many insurers insist on firewater systems being designed using the Hazen-Williams model.  This model is not as accurate or flexible as the Darcy-Weisbach formula that process engineers normally use.  When I have had to design these systems I have done it in duplicate - using Darcy-Weisbach to satisfy myself that it will work and then again with Hazen-Williams to satisfy the insurers.

[Lorean]

Katmar, thanks a lot i ll research about it further

[breizh]

https://www.canuteso...ler-system.html

 

Attached a link where you can find pointers to support your work.

Good luck

Breizh 

[Lorean]

Breizh, thank you for your kind attention and time, i have read it, its veey informative

[gegio1960]

Just to add that the big engineering company where I used to work, requests Hazen-William only for Cooling Water lines, not for Fire Water.

good luck!

[breizh]

Hi ,

To add to my previous answers a standard for reference .

Good luck

Breizh 

[Lorean]

Thanks everyone for taking time to reply