Pipe Chart, Pipe Dimensions, Pipe Wall Thickness

Technical Information View All Pipe

There are several common misconceptions about pipe. This short explanation of the pipe chart will attempt to correct these as well as introduce a few basic concepts regarding pipe.

Reading the Chart

First, what is this pipe chart showing? It describes the physical dimensions and weights of standardized pipe. All pipe manufacturers produce pipe according to these standardized physical characteristics.

When viewing the pipe chart, each NPS has two corresponding rows. The first row shows the wall thickness (in inches), and the second shows the weight (in lbs.) per foot of the pipe.

Pipe Diameters are not actually round numbers. Nominal Pipe Size (NPS) identifies pipe sizes, but they are not literal in description. For instance, a 2" NPS pipe actually has an outside diameter of 2-3/8". Accordingly, the pipe chart's second column displays the actual outside diameter (OD) of pipe relative to NPS.

The Outside Diameter (OD) does not change. As the pipe schedule increases or decreases, the outside diameter remains constant, and the inside diameter changes accordingly. For instance, a 2" STD pipe has an OD of 2-3/8" and an ID of 2.067" (2.375 - 2 X 0.154), and a 2" XH pipe has an OD of 2-3/8" and an ID of 1.939".

XH and XS are the same (so is XXH and XXS). This is simply a difference in terminology, where one group refers to "Extra Extra Heavy" and another refers to "Extra Extra Strong". The physical dimensions of each are the same, and the terms may be used interchangeably.

XH and STD are complicated. Schedule 40 is equivalent to STD until NPS greater than 10". After this, the two diverge, and either "True 40" or STD must be specified, as they each indicate distinct wall thicknesses. The same is true for XH and 80, whereas XH is equivalent to Schedule 80 until NPS greater than 8". True 80 and XH take hold thereafter. The same is not to be confused for schedule 160 and XXH, as though it is tempting to assume they have a similar relationship, XXH and 160 are two separate wall thicknesses for every NPS.

The weight can vary. The weights given are theoretical, but they can vary slightly due to acceptable manufacturing tolerances in the diameter and wall thickness of the pipe.

The pipe chart above approximates the weight (lbs/ft) of carbon steel pipe.  However, different materials will have different pipe weights.  To approximate pipe weights for other materials, simply multiply the weight in the chart above by the factor in the table below.