of the tolerance (2.369), you would have a gap between the pipe and fitting of .006, meaning  insufficient  contact  between pipe and fitting for a strong weld (see box). Specifying  pipe  and  fittings  manufac- tured  to  the  nominal  standard  and  fol- lowing  these  simple  installation  steps will ensure a tight, reliable fit and a leak- free system every time.                         n Bill Morris is a technical sales manager at Charlotte Pipe and Foundry Company,  Charlotte,  NC.  He may be reached at bmorris@ charlottepipe.com.  For further information,  contact Charlotte Pipe and Foundry Company,   P.O.   Box 35430,   Charlotte,   NC 28235; (704) 372-5030,  www.charlottepipe.com. the iapd magazine • august/september 2002   27 ASTM D-2467 PVC                   NOMINAL               ALLOWABLE  VARIANCE SCHEDULE 80 2-inch Fitting (Socket Bottom) 2.370 2.370 Tolerance +/- (0.005) 0.000          +0.005         2.370 2.375 2-inch Pipe 2.375 2.375 0.000          -0.006           2.375 2.369 Resulting Fit Interference +.005 Gap              -.006 CIRCLE 1 ON READER SERVICE CARD CIRCLE 00 ON READER SERVICE CARD Specifying pipe and fittings manufactured to the “nominal standard.”