Re: Pipe definitions

[Dick Morrisson <rmorrisson@unidial.com>]

Ray,
You are correct.  The "sched" is short for schedule.  Schedule 40 is
standard pipe while schedule 80 is extra strong (thick walled pipe).  The
outside diameter stays the same regardless of schedule, for any particular
size.  The standard spells out the outside and inside diameters (o.d. and
i.d.) for various nominal diameters of pipe.  I say nominal because for the
smaller sizes on up to 12" there is no dimension equal to the size.  For
example, 4" schedule 40 pipe is 4.500 o.d. and 4.026 i.d.  All the i.d's
(through 12") are slightly larger than the noiminal sizes.  The actual i.d.
for these sizes was chosen such that water flow through 4" pipe, for
example, was approximately equal to that through smooth bore tubing with an
actual 4" i.d.  The rough cast inside surface of pipe having more flow
resistance meant a larger size would be needed to be equivalent.  1/8" pipe
is actually .269 i.d.!  By the time you get up to 16" pipe the percentage
difference was probably so small someone just decided to make the pipe size
the same as the o.d. for simplicity and ease of measurement.

I don't know for sure exactly what constitutes "black" pipe or "water"
pipe.  I believe it is the surface treatment, or lack of same, but will
defer to another person who may know with certainty (or you can check at
your local hardware store).

Dick Morrisson

p.s. did you get the sub pictures I sent last friday?

Ray Keefer wrote:

> Hi,
>
> > has it for $42/ft sched 40 and $74/ft sched 80.  Their toll free line
>
> What does "sched 40" and "sched 80" mean? I am sure it is the strength
> standard of some sort but what is the definition?
>
> Same question for "black" pipe as opposed to "water" pipe? What is the
> difference?
>
> Thanks,
> Ray