This specification covers the polyethylene pipe grade material. dimensions, and design equations for the pressure rating applicable to the complex geometry of 45-degree and 60-degree lateral, equal outlet diameter WYES, based on the stress and strain limits of the WYE configuration. The WYES may be internally or externally reinforced to increase the pressure capacity of the WYE. The WYE pressure rating formula using a derived Geometric Strength Ratio (GSR) is included in the standard. This specification describes the requirements for 45-degree and 60-degree, equal outlet, lateral WYES fabricated from axially extruded polyethylene pressure pipe of standard OD and wall , or, custom OD and wall , as specified in ASTM F714, AWWA C906, ASTM D3035. The mitered pipe segments are heat-fused together using flat heater plates following a qualified fusion-joining procedure specification (FPS). The lengths of each outlet end are sufficiently long to enable heat-fusion, and, opening / removal of the fusion machine clamp from the WYE.
Polyethylene pipe has been made for 50-years, there are no standards for pressure pipe Wye's. Different manufactures rate WYE fittings inconsistently. Owners are confused. The industry needs to evaluate all the pipe research on WYEs and come to a consensus on the pressure limit of equal outlet WYES, Experience suggests the acceptable GSR is in the range of 25% to 40% of the pressure rating of the pipe from which the WYE is fabricated.
Wye; Wye branch outlet; equal outlet WYE; lateral WYE; 45-degree WYE; branch outlet.
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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