I'm posting at the top because I didn't want to delete any part of
this message. My opinion is more geared to the type of head these
systems use down here in Texas. The "pop up spray." About half the
water evaporates before it reaches the ground with these cheap
sprinkler heads. FAR more effective are impulse heads which go back
and forth and have much larger drops which gives a much more even
watering, and deeper. I would never install pop up heads, ever. So,
if impulse heads are more expensive, it's well worth it.

Victoria


On Sat, 16 Jul 2005 00:27:02 GMT, "James Lee Johnson"
wrote:

After many hours of research (days, my wife may say) on plastic pipe, I
discovered that Schedule 40 pipe only means that it has the same physical
dimensions as metal pipe of the same inside diameter (I.D.). It is possible
to have a Schedule 40 pipe which is weak. Indeed at the local handyman
center you can often find Schedeule 40 pipe which is for low pressure use
only, and Schedeule 40 pipe which can pressurized. The advantage to this
approach is that the vender only has to stock one size of connectors for
each I.D. pipe. The disadvantage is that Schedule pipe is typically very
heavy for its performance and wasteful of raw material. Class is a method of
grouping pipe by working pressure. Neither Schedule nor Class directly
specifies the impact strength, which was one of your concerns. The only way
to discover that is to look up the full specification of the pipe or to
visit the manunfacter's web site. Plastic pipe and plastic tubing are
treated differently, making matters even more confusing.

Typically, properly assembled and buried plastic pipe will not deteriorate.
Only disturbances, like driving over it, will cause a problem. It doesn't
take much to protect plastic pipe from the weight of a car. Heavier
vehicles like dump trucks and tractors might crack a buried pipe. UV light
is the primary ememy of most plastic pipe, and buried pipe is, of course,
protected from UV. Here is a trick: put some iron rebar in the trench with
the plastic pipe so you can find it later with a metal dector rather than a
pick axe :-)

This is a web site that has some basic landscape irrigation terminology:

http://www.multiservices.4t.com/terminology.html

Here are a couple of sites which have more than I ever wanted to know about
plastic pipe:

http://www.millardlumber.com/HowTo/plpipe/plastic.htm

http://www.charlottepipe.com/

Personally I have never been impressed by in-ground sprinkler systems. They
always seem to be wasting water and are often too complicated for the
homeowner to control. That aside, if you can locate a good contractor, you
should ask him why certain components are used and go with his
recommendations or find another contractor.

Hope this helps.

jjhnsn