Why is pipe thickness mentioned by schedule and what does it mean?

Answer 1

schedule is thickness of the inside diameter of the pipe,schelude 40 is usually a standard thickness for most applications which is normally 1/4" wall,as the schedule number increases or decreases so does the wall thickness,the outside diameter remains the same,standard piping schedules are 10,40,80,120,160 ========================================= ***This question came up at work the other day and in searching for an answer I found that a lot of people have the same question... I finally found an explanation on a website (I have included the paragraph and link below). I can not confirm its accuracy; however, it makes more sense than anythign else out there that I've read. Schedule is NOT directly a measure of thickness, it is a measure of the pressure a pipe can withstand without deflection or failure. When you are talking about pipes constructed of the same materials (i.e. PVC) a thicker pipe would be able to withstand higher pressures. As a result, many people have taken "schedule" to be synonymous with thickness. "For the purpose of standardizing pipe dimensions, the American National Standards Institute (ANSI) sponsored by the American Society for Testing Materials (ASTM) and the American Society of Mechanical Engineers (ASME), published ANSI B36.10. To broaden the range of wall thicknesses, schedule numbers from schedule 10 (S.10) thru schedule 160 (S.160) were adopted for steel pipe. These schedule numbers indicate approximate values for 1000 times pressure-stress ratios." From http://www.durovac.com/industrial-vacuum/tubing-fittings/stuff-about-pipe.htm