Polyethylene Water/Sewer - JM Eagle

y the pipe area.For manually operated fusion machines, a torque wrench may be used toaccurately apply the proper force. For manual machines without force readingcapability of a torque wrench, the correct fusion joining force is the forcerequired to roll the melt beads over to the pipe surface during joining. Forhydraulically operated fusion machines, the fusion force can be divided bythe total effective piston area of the carriage cylinders to give a hydraulicgauge reading in psi. The gauge reading is theoretical; the internal and externaldrag need to be added to this figure to obtain the actual fusion pressurerequired by the machine.6.2.6 HoldThe molten joint must be held immobile under pressure until cooled adequatelyto develop strength. The designs of the machines vary from a leverarm-assistto manual or automatic locking devices that assist the operatorto accomplish this step. The proper cooling time is until the joint is coolto the touch. Allowing proper times under pressure for cooling prior to removalfrom the clamps of the machine is important in achieving joint integrity.Do not apply water, wet cloths or similar items to shorten cool time. Thepulling, installation or rough handling of the pipe should be avoided for anadditional 30 minutes.6.2.7 Visual InspectionVisually inspect and compare the joint against a properly made joint. Visually,the width of butt fusion beads should be approximately two to two andone-half times the bead height above the pipe and the beads should berounded and uniformly sized all around the pipe circumference. The v-groovebetween the beads should not be deeper than half the bead height above thepipe surface. When butt fusing to molded fittings, the fitting-side bead maydisplay shape irregularities such as minor indentations, deflections and nonuniformbead rollover from molded part cooling and knit lines. In such cases,visual evaluation is based mainly on the size and shape of the pipe-sidebead. Visually unacceptable joints should be cut out and re-fused using thecorrect procedure.32 HDPE WATER/SEWER PIPING SYSTEM TECHNICAL & INSTALLATION GUIDE