Register free!


Reply
 
Thread Tools   Display Modes
  #21  
Old 02-24-2013, 05:44 PM
woodlawnservice woodlawnservice is offline
LawnSite Senior Member
 
Join Date: Oct 2011
Location: oklahoma
Posts: 557
If say I do loose 15 lbs over the 400ft... and I have a static of 90psi at meter... I need a pressure reducer anyways but would u leave the pressure on the high side to compensate for the Loss at the end of the run... or u think I will have issues with water hammer and that jazz...
Posted via Mobile Device
Reply With Quote
  #22  
Old 02-24-2013, 06:14 PM
Mike Leary's Avatar
Mike Leary Mike Leary is online now
LawnSite Fanatic
 
Join Date: Mar 2007
Location: Cactus Hug, Arizona
Posts: 20,574
Quote:
Originally Posted by woodlawnservice View Post
If say I do loose 15 lbs over the 400ft... and I have a static of 90psi at meter... I need a pressure reducer anyways but would u leave the pressure on the high side to compensate for the Loss at the end of the run... or u think I will have issues with water hammer and that jazz...
You THINK you have 90 psi (so say the purveyors, who are liars), then you deduct at least 10 psi for the backfow, and another 10 for ancillary. The other lag is 90 psi means dick unless you can measure gpm at the source, as well as computing what you need at the last head after taking pressure loss calculations. Do the math; you may have 60 psi if you're lucky, but we have no clue what gpm is available. Hydro zones/sun/shade, etc. are very important, but unless you know the physical restraints of the supply system, you are pissing up a rope.

Last edited by Mike Leary; 02-24-2013 at 06:22 PM.
Reply With Quote
  #23  
Old 02-24-2013, 06:41 PM
woodlawnservice woodlawnservice is offline
LawnSite Senior Member
 
Join Date: Oct 2011
Location: oklahoma
Posts: 557
Yep.. do u prefer to upsize pipe to get more gpm and.more rotors on a zone or prefer small pipe (1") and just do less rotors? Or do smaller pipe with more rotors and.nozzle them down and have longer run times? The price difference between the two sizes 1.25 and 1 are pretty big around here... you get so muh more flow with the 1.25 though. I prefer less run times and put more water out quicker... soaking in the ground and runoff isn't an issue with this soil...
Posted via Mobile Device
Reply With Quote
  #24  
Old 02-24-2013, 07:10 PM
Wet_Boots's Avatar
Wet_Boots Wet_Boots is online now
LawnSite Fanatic
 
Join Date: Mar 2005
Location: metro NYC
Posts: 40,618
On a large system, you upsize the mainline pipe first. From source to the greatest distance, the pressure loss should be less than 5 psi, in order for you to obtain uniform performance from zone to zone. Also, a long mainline run greatly magnifies the effects of water hammer, to the point where you can blow apart the zone valves at the end of the line.
Reply With Quote
  #25  
Old 02-24-2013, 07:17 PM
woodlawnservice woodlawnservice is offline
LawnSite Senior Member
 
Join Date: Oct 2011
Location: oklahoma
Posts: 557
Well I will.have a master valve if a problem.ever does blow a mainline but I don't want that of course...the way this land is 150 wide 400 deep...there's not many options on how I can run this mainline to shorten it unless I want run my laterals longer which I don't think makes much sense either...
Posted via Mobile Device
Reply With Quote
  #26  
Old 02-24-2013, 07:32 PM
Wet_Boots's Avatar
Wet_Boots Wet_Boots is online now
LawnSite Fanatic
 
Join Date: Mar 2005
Location: metro NYC
Posts: 40,618
Quote:
Originally Posted by woodlawnservice View Post
Well I will.have a master valve if a problem.ever does blow a mainline but I don't want that of course...the way this land is 150 wide 400 deep...there's not many options on how I can run this mainline to shorten it unless I want run my laterals longer which I don't think makes much sense either...
Posted via Mobile Device
Valves malfunction. You don't design a system whose integrity depends on a master valve.

Water hammer is a function of water velocity and pipeline length. It doesn't take even a hundred feet of length to make for damaging hammer. Since you can't shorten the mainline length, you slow down the water velocity. Slow it way down.
Reply With Quote
  #27  
Old 02-24-2013, 07:37 PM
Mike Leary's Avatar
Mike Leary Mike Leary is online now
LawnSite Fanatic
 
Join Date: Mar 2007
Location: Cactus Hug, Arizona
Posts: 20,574
Quote:
Originally Posted by woodlawnservice View Post
Yep.. do u prefer to upsize pipe to get more gpm
You will never,ever, get more gpm than the service provides, nor will you get any more pressure. You design for what you got; then deduct for the friction loss and the demand of the zones, and, bingo, there's your system. Easy, we do it every day.
Reply With Quote
  #28  
Old 02-24-2013, 07:48 PM
woodlawnservice woodlawnservice is offline
LawnSite Senior Member
 
Join Date: Oct 2011
Location: oklahoma
Posts: 557
Yes sir so service being 1" and looks like ill.need to slow it down so upsizing isn't an option... may even.need to go up to 1.5 in. Need to run. Velocity numbers to make.sure Im not over 5...
Posted via Mobile Device
Reply With Quote
  #29  
Old 02-24-2013, 08:01 PM
Wet_Boots's Avatar
Wet_Boots Wet_Boots is online now
LawnSite Fanatic
 
Join Date: Mar 2005
Location: metro NYC
Posts: 40,618
With 90 psi street pressure, and 400 feet for the mainline, you want to forget about the usual velocity guidelines, and go even slower.
Reply With Quote
  #30  
Old 02-24-2013, 08:13 PM
Mike Leary's Avatar
Mike Leary Mike Leary is online now
LawnSite Fanatic
 
Join Date: Mar 2007
Location: Cactus Hug, Arizona
Posts: 20,574
Quote:
Originally Posted by Wet_Boots View Post
With 90 psi street pressure
IF is the question. PSI must be measured, as well as flow output. Anything less is lumpy gravy and guaranteed to fail.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump






Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 04:08 PM.

Page generated in 0.07125 seconds with 7 queries