Before a process piping system is placed into operation, it must be free of contaminants, moisture and debris. Flushing, drying and cleaning ensure that pipelines meet cleanliness requirements essential for safety, reliability and long-term performance.
Why Cleanliness Matters
Contaminants such as rust, mill scale, welding slag, dust and moisture can:
- Restrict flow
- Damage pumps, valves and instrumentation
- Introduce corrosion
- Compromise product purity
- Cause startup delays
Ensuring internal cleanliness is therefore a critical step in any commissioning program.
Chemical Cleaning
Chemical cleaning removes internal contaminants that cannot be removed mechanically. It is effective for:
- Rust
- Mill scale
- Grease
- Hydrocarbons
- Residual fabrication debris
Chemicals circulate through the piping system under controlled conditions to dissolve and flush out impurities.
Flushing & Blow-Out
Flushing uses controlled flow rates to purge loose contaminants. Blow-out uses compressed air or nitrogen to remove lightweight debris or moisture. These methods are ideal for long pipe runs or smaller bore lines.
Drying Methods
Moisture must be removed to prevent corrosion or product contamination. Common drying techniques include:
- Desiccant drying
- Heated air drying
- Vacuum drying
Each method ensures the system meets clean-dry specifications before commissioning.
Documentation & Compliance
Every step of the cleaning, flushing and drying process must be documented, including:
- Procedures
- Flow rates
- Dryness levels
- Inspection logs
- Final acceptance sign-off
This documentation forms part of the commissioning hand-over pack.