Pipe span table

Using Equation 3-12, the approximate equivalent wall stresses for several span lengths of the pipe described in the problem are shown in Table 3-8. 

From Table 3-8 it becomes obvious that although a 15-ft. span between pipe supports would be satisfactory from a pipe-stress standpoint, excessive sag or deflection of the pipe between the supports would take place over the service life with this span length. To avoid exceeding the specified maximum deflection of 0.25 in.. Table 3-8 tells us that the span between supports should not exceed 6-8 ft. 

TABLE 5.56 Typical Recommended Maximum Support Spacing, in Feet, for Thermoplastic Pipe for Continuous Spans and for Uninsulated Lines Conveying Fluids of Specific Gravity up to 1.35... 

The spans in the table above are limited by longitudinal bending stress of <= 9,000 psi and by acceptable pipe defleaion between supports determined from past experience. 

The most common method in the United States is called intrinsic viscosity or IV, ASTM D1243, although relative viscosity is occasionally used. European manufacturers use A -value, a two digit number between 35 and 80 derived from soluhon viscosity measurements. By intrinsic viscosity determinahon, PVC resin spans 0.65 and 1.10. Pipe resin has an FV of 0.88-0.92. Resins of this IV and higher are used for flexible products. A sample of resin types and ap-plicahons can be found in Table 4.1. 

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