Flange Torque Specifications
Recommended torque specifications for flange bolting on plastic tanks.
Proper torque specifications are critical for flange connections on plastic tanks to ensure leak-free seals without over-tightening.
General Guidelines
- Always use a calibrated torque wrench - Tighten bolts in a star (cross) pattern - Apply torque in incremental stages (typically 3 passes) - Allow 24 hours for gasket seating, then re-torque - Never exceed recommended torque values for plastic flanges
Polyethylene Flange Torque (150# ANSI)
- Use flat-face flanges only against polyethylene - Full-face gaskets recommended (not ring gaskets) - Torque range: 15-20 ft-lbs for most sizes - Maximum: 25 ft-lbs for larger flanges (10"+)
Important Notes
- Over-torquing can crack or deform polyethylene flanges - Under-torquing causes leaks - Temperature cycling may require periodic re-torquing - Gasket material affects required torque values - Consult Tank Systems for application-specific recommendations
Re-Torque Schedule
- Initial installation: torque to spec - 24 hours after: re-torque to spec - After first thermal cycle: verify torque - Annually: check and re-torque as needed
Contact our engineering team for specific torque recommendations for your installation.
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