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Head Placement Examples - You Decide

Discussion in 'Irrigation' started by Critical Care, Mar 24, 2005.

  1. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    The following are hypothetical but common problems requiring correct sprinkler placement. Out of curiosity, show or tell where you would place the heads, and what type of heads you would use.

    For the sake of simplicity disregard flow rates, but assume 50 psi pressure.

    Perhaps we can hash out why some designs will work, why some will not, and perhaps see some options.

    Figure 1.jpg

    Figure 2.jpg

    Figure 3.jpg
  2. Broker

    Broker LawnSite Senior Member
    Messages: 382

    I figured around 12 rotors for the first one with either drip or sprays for the beds. 2) figured on 14 rotors 3) 10 rotors. I will post the locations on the diagrams in little bit.
  3. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    I'm surprised that some people didn't jump on these. How about if we just look as the first example. The head placement below is simple but not good. How can we get away from having heads in the bark areas and still maintain our head to head coverage? Inquiring minds want to know...

    figure 1.jpg
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    I have some concerns for design questions like this, because of unspecified details. Is it fresh sod being watered during the windy daytime? What's in the beds? Is one of those sides a Belgian block curb? That can make a major difference. Just for the heck of it, I'll assume it's a well established lawn, and everything else just as simple as can be.. If 50 psi means the operating pressure at the heads, and not static supply pressure, and if only the basic rectangular area needs coverage, the job might accomplished with as little as seven heads, with the two interior heads of the design above being replaced with one in the dead center, and the four heads on the long sides moved a bit closer towards the beds, which would give you something near to 50 foot triangular spacing. With no more than 30 feet spray distance needed by any of the heads, and plenty of head pressure to spread the water, it isn't a problem to get total coverage without using head-to-head design. Drop down your pressure, or add parameters yet unstated, and it's a different story. An interesting question would be when or if one would deviate from the 'use more material' advice of many manufacturers.
  5. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    Not intended to be a trick question, and not intended to make much more out of this other than "where do you place the heads" type of thing. Basically, the idea with this first example is that "generally" mulched areas, and plants within mulched areas or beds, shouldn't get the same water as the turf - just the same as in the third example with the deck. No need to water the deck. So the question remains how to effectively water the turf without soaking these beds.

    Wet_boots, is this the layout that you have in mind?

    fig 1.jpg
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    Details, details. I see many ancient sprinkler systems that cover lawn and beds from the same heads, and the lawn and plantings couldn't look better. I don't advocate designing from other than textbook standards, but I note that a lot of those books come from manufacturers who sell more stuff when all sprinkler systems are laid out in head-to-head square patterns.
  7. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    Lets just say that we don't want to water these beds... if we can help it. Think of it this way, that instead of being beds just think of those areas as part of buildings.

    Both the triangular and square spacing will work to water the turf - to a point of course - but both will also do a good job of watering those areas in the corners that we don't need or want to be watered. So, the question remains how to cover the turf without soaking these other areas.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    I know this is getting close to beating a dead horse, but some building construction won't care about getting sprinkled, so the seven head design could work. If you make the beds off-limits, the design problem becomes much more complex. Obviously, in order to not wet something, you locate heads next to it, and spray away. But if a landscape actually had lawn located right next to a 'must-not-get-it-wet' building, like a stained wood exterior, and that exterior is curved, you would be by-and-large screwed. You would have to calculate wind drift from the heads spraying away from the building, locate them appropriately, and use subsurface drip lines to handle anything between the heads and the building.


    Now, I see a lot of lawns like the above, where the contents of the beds are fairly indifferent to the sprinkler system, being that they are mature shrubbery with established root systems that will draw water from deeper than the lawn sprinkler water will normally penetrate.

    When I see a landscape with carefully edged beds, and the homeowner makes the point of requesting that beds and lawn be covered separately, which can mean heads spraying away from curved edges of beds, (and sprinkler heads aren't designed to throw curve balls) I am happy to design and quote such a system, but they often gag at the price of design perfection, and I don't blame them.
  9. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    I think that the third example with the deck is surely more doable than the first example, that is if we try to keep from watering those corner areas. And needless to say, I'm still trying to figure out a way of throwing water around a curve. But hey, if a baseball pitcher can throw a curve ball why can't we throw water that way?

    And Wet Boots, just to let you know that yesterday I was walking some property with a client, collecting some info on an install for him. He pointed out a far flower bed of irises bordering his lawn that he would like watered. This situation is just like what we've been talking about, so I basically mentioned a few options... running another zone to it, or perhaps get by with a couple of the stream rotors hitting it. The third option would be to try to run different heads off of one of the stream rotor zones, which then becomes a precip rate problem.
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    Again, details. Going back to the first layout, with beds in the corners, your location and climate also would come into play. If you had shrubs or trees in those beds, and you're in a part of the country that sees no rain for six months at a time, you have to design watering for those plantings, and they would be running on a different schedule than the lawn. And sandy soil would work a bit differently from heavy clay.

    Sometimes, the needs of flowerbeds can be met by simply grouping together the adjacent lawn rotors that overthrow the bed(s). That way, if the flowerbeds need some extra water, a minimum of zones can supply the water. The lawn could care less if it gets extra.

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