Standard Operating Procedure (SOP)
Bolt Torquing and Tensioning – Flanged Joint Assembly
1. Pre-Work Preparation
- ✅ Safety and Documentation:
- Conduct Toolbox Talk (TBT)
- Review Job Hazard Analysis (JHA)
- Obtain Permit to Work (PTW)
- Ensure PPE is worn (Helmet, Gloves, Goggles, Safety boots, FR coverall)
Equipment Checklist
- Calibrated torque wrench or hydraulic torque tools
- Hydraulic tensioner (for tensioning jobs)
- Lubricant (e.g., moly-based or specified grease)
- Flange alignment tools
- Dial indicators (optional)
- Studs, nuts, washers (as per spec)
2. Inspection of Components
- Verify flange face condition (no pitting, scratches, warping)
- Check gasket type and rating
- Inspect studs and nuts for corrosion or deformation
- Confirm bolt/stud material and size per P&ID or flange spec
- Clean threads with wire brush and apply specified lubricant
3. Bolt Installation
- Insert studs through flange holes
- Place washers and nuts on both ends
- Hand-tighten in star sequence (opposite bolts)
4. Torquing Procedure
Torquing in Steps (for uniform loading):
Use star or cross pattern for circular flanges. Example (3-Step Method):
- Step 1: Torque to 30% of final value
- Step 2: Torque to 60%
- Step 3: Torque to 100%
- Final Pass: 100% in circular pattern (clockwise)