MEC/General/TBT-MEC-017
Pipe Fitting Flange and Gasket Safety
MEICA Works › General › Pipe Fitting Flange and Gasket Safety
Toolbox Talk
Pipe Fitting Flange and Gasket Safety
Flange connections are used extensively on MEICA installations to join pipe sections, connect to valves, and interface with process equipment. Incorrect bolt tightening, wrong gasket selection, and misaligned flanges can cause leaks of pressurised fluids, gases, or chemicals during commissioning and operation. Flange assembly requires precise torque sequences and trained personnel. On wastewater and chemical dosing installations, leaking flanges can release hazardous substances putting workers at immediate risk.
Key Hazards
Pressurised fluid or gas leak from improperly assembled flange joints
Chemical exposure from flange failure on chemical dosing pipework systems
Hand crush injuries during flange alignment using levers and chain blocks
Bolt failure from incorrect torque causing sudden and uncontrolled joint separation
Control Measures
- Ensure flanges are correctly aligned before inserting bolts and never use force to close misaligned faces.
- Select the correct gasket type and material specified in the design for the fluid and pressure rating.
- Tighten bolts using the approved cross-pattern torque sequence to achieve even compression.
- Use calibrated torque wrenches set to the specification value for the bolt size and grade.
- Inspect flange faces for damage, scoring, or contamination before assembly and clean if necessary.
- Wear chemical-resistant PPE when assembling flanges on chemical dosing or hazardous fluid systems.
- Support heavy valves and pipe sections to prevent load being transferred through the flange connection.
- Record the torque values applied to each flange joint for the commissioning quality records.
- Re-torque flanges after the initial thermal cycle as specified in the commissioning procedure.
Remember
- Misaligned flanges forced together with bolts will leak under pressure and eventually fail.
- The correct gasket must be used for the fluid, temperature, and pressure — substitution is not permitted.
- Cross-pattern bolt tightening ensures even gasket compression and prevents distortion.
- Chemical dosing flanges carry concentrated acids or alkalis that cause severe burns on contact.
- Calibrated torque wrenches are essential because over-tightening damages gaskets and under-tightening leaks.
- Re-torquing after the first thermal cycle is critical because gaskets settle under initial loading.
Applicable Legislation: Pressure Systems Safety Regulations 2000 · COSHH Regulations 2002 · CDM Regulations 2015 · BS EN 1591 (Flanges and Joints)
Delivered By
RAMS Builder
Generate professional Risk Assessment and Method Statements in minutes. 10 document formats, site-specific content, instant Word download.