AMERICAN flanged pipe is manufactured in 4"-64" diameters according to requirements of ANSI/AWWA C115/A21.15-94. AMERICAN furnishes only ductile iron flanges, which are threaded onto the pipe. The threads are tapered per ASME/ANSI B1.20.1 and adapted to ductile iron pipe diameters. The flanged joint, properly assembled with the appropriate bolts, nuts and gaskets as shown in Appendix A of ANSI/AWWA C115/A21.15 is rated in the standard for 250 psi water service in the full size range. AMERICAN can rate flange joints to higher working pressures in special cases if the Toruseal® flange gasket (discussed below) is used. AMERICAN markets ductile iron flanged fittings as specified in ANSI/AWWA C110/A21.10-93 in sizes 4"-48" and ductile iron flanged fittings as specified in ANSI/AWWA C153/A21.53-94 in sizes 54"-64". All of these fittings are supplied with cast-on flanges; none are supplied with threaded-on flanges. These cast-on flanges are identical to pipe flanges in the following dimensions: thickness, outside diameter, bolt circle, and number and size of bolt holes. In addition, they are designed to assemble with the pipe flanges described above. All ANSI/AWWA C110/A21.10 ductile iron flanged fittings are rated in the standard for 250 psi working pressure. The 54"-64" flanged fittings shown in ANSI/AWWA C153/A21.53-94 are only rated for 150 psi working pressure. However, AMERICAN rates its 54"- 64" fittings for 250 psi operating pressure. We should note that AMERICAN does not market the ANSI B16.1 Class 250 Flange because it offers no advantage to the installer or the user. This is a larger, bulkier flange with a machined face. Because of its increased weight, additional machining requirements, and because it's rarely specified, it is a more expensive product. For water and wastewater service, it is rated 250 psi working pressure, so there is no technical reason it should be required. There are some types of water works equipment, such as valves and pumps, that might be supplied with the ANSI B16.1 Class 250 flange. However, this should present no problem to AMERICAN customers because AMERICAN can supply various types of connectors to accommodate this flange. Also related to the above information, the AMERICAN Toruseal® gasket is designed to enhance the installation and pressure rating of flanged piping and fittings. This gasket is full-faced, with an O-ring molded into the inside diameter to provide additional sealing. It is normally furnished as molded SBR rubber, but other compounds can be supplied. (Note: It is not supplied to fit ANSI B16.1 Class 250 flanges.) The Toruseal® gasket enhances installation by allowing a successful joint assembly with less bolt torque than normally required for flat gaskets. Suggested bolt torques are shown in theAMERICAN PIPE MANUAL. The Toruseal® flange gasket also provides improved joint sealing and, because of this, allows higher working pressures for flange joints. In fact, the latest (1995) edition of the AWWA C111 includes a statement that flange joints in 12" and smaller sizes may be rated for 350 psi with the useof special gaskets whose rating is supported by performance testing as described in Sec. 4.5 of that standard. AMERICAN Toruseal® gaskets qualify for this rating in that size range. AMERICAN should be contacted for any flange pipe or fitting requirement with working pressures greater than those shown in the AWWA Standards or the AMERICAN PIPE MANUAL.

Ben Helton, Technical Director, AMERICAN Cast Iron Pipe Company