What is the difference between SCH-40 and SCH-80?
The wall thickness — same outside diameter, so the fittings are the same, but you cannot tell them apart by looking. The schedule is stamped along the pipe; read the stamp.
What we carry in each
Counted off the suppliers’ own headings — the schedule is printed above the rows on their price lists, so this is their word and not ours.
You cannot tell by looking
Both schedules have the same outside diameter — that is the point of the system, and it is why the same fittings go on both. What differs is the wall thickness, on the inside.
So read the stamp. The schedule is printed along the length of the pipe. A photograph of the outside cannot show it, and neither can a hand around it.
We hold ourselves to this. When the owner sent us his own photograph of a pipe stamped SCH-40, we refused to put it on the SCH-80 rows — right company, right size, wrong pipe. Those rows still carry a drawing instead, and they will until somebody photographs the actual pipe.
Which one does my job need?
We are not going to guess that here. It depends on the pressure, the depth and what the line is for, and that is a decision for whoever is doing the work — not for a web page that has never seen your site.
What we can do is tell you what is on the shelf, in which sizes, at what rate. Send us what the drawing or your plumber specified and we will price exactly that.