Three critical factors have influenced the growth and acceptance of the IPP Deltaflex® designed flanges or back-up rings in the piping industry.
- National standards for flanges, such as ANSI B16.5 and AWWA C-207, were developed many years ago. This was long before the sophisticated computer analytical tools available today, which can be utilized to design flanges. As a result, IPP has shown that the standard flanges called out were either over-designed, in the case of ANSI, or not applicable for modern piping materials such as thermoplastics, as is the case for AWWA.
- Historically, engineers have been under the impression that the only method to reduce the cost of standard flanges was to make them thinner. As a result flange-sealing performance has suffered.
- Standard back-up flanges utilized on high density polyethylene (HDPE) piping stub-end applications were assumed to safely perform at the stated AWWA pressure ratings. IPP research has shown that the AWWA piping industry standards are not applicable to HDPE pipe.