AWWA C111

Applies to: Push-on and mechanical joints using rubber gaskets for ductile-iron pressure pipe (per AWWA C151) and fittings (per AWWA C110/C153) in water distribution service up to 350 psi; NPS 3–64.

Does NOT cover: Flanged joints for ductile-iron pipe (AWWA C115); restrained joints (addressed by supplementary products per AWWA C110 Appendix); joints in pipe other than ductile iron.

• Gasket material: SBR, EPDM, or neoprene rubber per ASTM C564
• Bell socket dimensions and tolerances for push-on assembly
• Lubricant specifications for gasket and spigot
• Angular deflection limits per nominal pipe diameter
• Mechanical joint bolts: T-head per AWWA C111 dimensions and torque limits
• Pressure test of assembled joint before backfill

AWWA C111 defines the standard push-on and mechanical joint used on virtually all ductile-iron water main projects. The push-on joint's compressive gasket seal provides flexibility for pipe movement, ground settlement, and slight misalignment. The mechanical joint adds bolted gland and T-bolts for supplementary restraint where angular deflection or vibration is a concern.

Engineering note: Standard push-on joints resist only compressive forces — they provide no thrust restraint at bends, tees, or dead ends. Unrestrained joints in systems above ~100 psi will blow apart at fittings without concrete thrust blocks or restrained joint systems. Engineers designing water mains must identify all thrust locations in the hydraulic model and specify either thrust blocking per AWWA M41 or restrained joints throughout the thrust zone.