Piping Comparisons

Schedule against schedule, flange against flange, material against material — each comparison built on the published dimensions for both sides rather than on generalities.

How these comparisons are built

Most questions about piping components arrive as a choice between two things. Is Schedule 80 worth the extra weight over Schedule 40? Will a slip-on flange do where a weld neck was drawn? Each page here takes one such pair and answers it in the same order: a short answer first, then the dimensions of both options in every size where both are published, then the practical differences in cost, fabrication and service, and finally the cases where each one is the right choice.

The tables are not written by hand. They are generated from the same data files as the dimension pages, so a figure on a comparison page always agrees with the figure on the page for that size or class. Percentages and differences are calculated from those figures when the site is built.

Pipe schedules and weight classes

The outside diameter of a pipe never changes with the schedule, so choosing between two schedules is a trade between wall and bore. A heavier wall holds more pressure and leaves more metal for corrosion and threading; it also weighs more, costs more and carries less flow. These pages put the two walls side by side in every size where both exist.

Schedule 40 vs Schedule 80 Pipe23 sizes · +45% weightWall, bore, weight and pressure capacity, size by size.Schedule 10 vs Schedule 40 Pipe26 sizes · 41% lighterWhat the lighter wall saves and what it gives up.Schedule 40 vs Schedule 160 Pipe22 sizes · +122% weightHow far the bore closes up on the heavy wall.Schedule 5S vs Schedule 10S Pipe22 sizes · ASME B36.19MThe two light stainless walls side by side.STD vs XS Pipe30 sizes · +34% weightWhere the weight classes match the numbered schedules.XS vs XXS Pipe17 sizes · +72% weightExtra strong against double extra strong.

Flange types

All six ASME B16.5 flange types share one set of outside diameters, bolt circles and bolting in a given size and class, so any two will bolt together. What separates them is how each is fixed to the pipe, and that decides the pressure, temperature and cycling each one suits.

Weld Neck vs Slip-On FlangeHub length · fatigue · costOne butt weld against two fillet welds.Weld Neck vs Blind FlangeEnd load · thickness · blankingA flange that joins pipe against one that closes it.Slip-On vs Threaded FlangeIdentical dims · welded vs threadedWelded or screwed attachment for low-pressure service.Socket Weld vs Threaded FlangeSmall bore · vibration · hot workThe two small-bore options compared.Lap Joint vs Slip-On FlangeStub end · alloy saving · rotationA loose backing flange against a welded one.

Flange classes and facings

Moving up a pressure class changes almost everything about a flange: its diameter, its thickness, the bolt circle and the bolts. These pages show how much metal each step adds and what rating it buys, and compare the two common ways of seating the gasket.

Class 150 vs Class 300 Flanges285 vs 740 psig at 100 °FDimensions, bolting and ratings of the two commonest classes.Class 300 vs Class 600 Flanges740 vs 1480 psig at 100 °FWhat doubling the class does to the flange.Class 600 vs Class 900 Flanges1480 vs 2220 psig at 100 °FThe step into high-pressure bolting.Class 900 vs Class 1500 Flanges2220 vs 3705 psig at 100 °FWhere the two classes share dimensions and where they split.Class 1500 vs Class 2500 Flanges3705 vs 6170 psig at 100 °FThe heaviest two classes B16.5 publishes.Raised Face vs Ring Type JointRF vs RTJ · sealing · gasketsGasket seating at low and high pressure class.

Pipe materials and manufacture

Dimensions are the same whatever the pipe is made of. The material and the way the pipe is made decide the allowable stress, the temperature range and the resistance to corrosion, and through the joint factor they also change the wall thickness a given pressure calls for.

Seamless vs Welded PipeJoint factor E · wall thicknessJoint factor, size range and cost.Carbon Steel vs Stainless Steel PipeP-T curves · cost · temperatureStrength, temperature and corrosion trade-offs.ASTM A106 vs A53 PipeGrade B · seamless vs weldedTwo carbon steel pipe specifications that are not the same.304 vs 316 Stainless Steel PipeMolybdenum · chlorides · L gradesWhat the molybdenum in 316 buys.

Buttweld fittings

Fitting choices are mostly about space and flow: how much room a change of direction takes, how much pressure it costs, and whether a line will drain or vent once it is built.

Long Radius vs Short Radius Elbow1.5D vs 1.0D · 19 sizesSpace saved against pressure drop added.90° vs 45° Elbowtan 22.5° · offsetsCentre-to-end dimensions and when two 45s beat one 90.Concentric vs Eccentric ReducerSame length · FSU/FSD rulesWhich reducer goes where, and which way up.

Using a comparison

Start from the short answer at the top of the page, then check the row for your own size, because the gap between two options is rarely the same across the range. Schedule 40 and standard weight are the same pipe up to NPS 10 and different pipes above it; Class 400 and Class 600 flanges share dimensions in the small sizes and not in the large ones. Where a comparison depends on pressure, the rating has to be read at the design temperature and for the actual material, which the pressure-temperature tables give.

Every table on these pages is generated from the same data as the specification pages. Where a figure is derived rather than tabulated — bore, weight, flow area, end load — the formula is stated alongside it.