This action is required to bring the standard in alignment with industry practice. Recommended Horizontal Hanger Spacing is given in the appendix, clause X3.1.5. This section was taken directly from the PEX standard when the standard was drafted. Industry practice, based on engineering calculations for allowable sag between hangers, allow larger spacing for pipe sizes 1 and larger. Since the range of material modulus and pipe dimensions for PEX and PE-RT piping are the same, it is desirable for the hanger spacing to be harmonized. Pipe sizes 1 and smaller are not changed from the current 32 minimum recommendation. However, for sizes 1 and larger where section modulus is a much larger contributor to stiffness than the material modulus, 48 minimum spacing is recommended. Manufacturer recommendations are also to be considered as sizes go up so that application specific engineering analysis may allow even longer spacing. There is a simultaneous ballot for the F876 PEX standard with exactly the same language used here.
Keywordshot water; hydrostatic stress; PE-RT; pipe; plastic pipe; polyethylene of raised temperature; PPI; pressure; potable water; PERT; tubing; Plastic pipe/tubing/fittings; Polyethylene of raised temperature; Potable water; Tubing;
Ballot Item Approved as F2769-2014 and Pending Publication