Document ID: SOP-TEMP-001 (Example)

Revision Number: 01 (Example)

Effective Date: 2024-03-08 (Example)

Author: [Your Name/Department]

Approver: [QA/QC Department]

1. Purpose:

This SOP outlines the procedure for cleaning, derouging, and passivating the stainless steel components of the purified water system to ensure the removal of organic and inorganic contaminants, including rouge (iron oxide), and to establish a passive chromium oxide layer for corrosion resistance and maintaining water purity.

2. Scope:

This procedure applies to all stainless steel components of the purified water system, including but not limited to:

• Piping
• Valves
• Tanks
• Filters (housings)
• Heat exchangers
• Pumps (wetted parts)

3. Responsibilities:

• Qualified Personnel: Responsible for executing the cleaning, derouging, and passivation procedures according to this SOP.
• Quality Assurance (QA): Responsible for reviewing and approving this SOP, verifying the completion of the procedure, and reviewing the associated documentation.
• Maintenance: Responsible for assisting with the isolation and disassembly/reassembly of system components.

4. Safety Precautions:

• Wear appropriate Personal Protective Equipment (PPE), including chemical-resistant gloves, eye protection, and a face shield.
• Work in a well-ventilated area.
• Handle chemicals according to their Material Safety Data Sheets (MSDS)/Safety Data Sheets (SDS).
• Ensure proper grounding and electrical safety when working with electrical components.
• Follow lockout/tagout procedures before working on any system components.
• Neutralize and dispose of waste chemicals according to local and national regulations.

5. Materials and Equipment:

• Cleaning agents (e.g., alkaline detergents, enzymatic cleaners)
• Derouging agents (e.g., citric acid, oxalic acid, proprietary derouging solutions)
• Passivation agents (e.g., nitric acid, citric acid, proprietary passivation solutions)
• Neutralizing agents (e.g., sodium hydroxide, sodium bicarbonate)
• Deionized water (DI water)
• pH meter
• Conductivity meter
• TOC analyzer (Total Organic Carbon)
• Rouge test kits (if applicable)
• Circulation pump
• Hoses and fittings
• Collection containers
• Spray equipment (if applicable)

6. Procedure:

6.1. Preparation:

• Isolate the section of the purified water system to be cleaned.
• Drain the system completely.
• Disassemble components as necessary for thorough cleaning.
• Inspect the system for visible contamination and damage.
• Document the initial condition of the system.

6.2. Cleaning:

• Rinse the system with DI water to remove loose debris.
• Circulate or spray a suitable cleaning agent through the system according to the manufacturer’s instructions.
• Maintain the cleaning agent circulation for the specified time and temperature.
• Monitor the effectiveness of the cleaning process by measuring parameters such as pH and conductivity.
• Rinse the system thoroughly with DI water until the rinse water reaches acceptable conductivity and TOC levels.

6.3. Derouging (If Applicable):

• If rouge is present, circulate or spray a derouging agent through the system according to the manufacturer’s instructions.
• Maintain the derouging agent circulation for the specified time and temperature.
• Monitor the effectiveness of the derouging process using rouge test kits or visual inspection.
• Rinse the system thoroughly with DI water until the rinse water reaches acceptable conductivity and pH levels.

6.4. Passivation:

• Circulate or spray a suitable passivation agent through the system according to the manufacturer’s instructions.
• Maintain the passivation agent circulation for the specified time and temperature.
• Monitor the passivation process by measuring parameters such as pH and conductivity.
• Rinse the system thoroughly with DI water until the rinse water reaches acceptable conductivity and pH levels.

6.5. Neutralization and Final Rinse:

• Neutralize any residual chemicals with a neutralizing agent according to the manufacturer’s instructions.
• Rinse the system thoroughly with DI water until the rinse water reaches acceptable conductivity, pH, and TOC levels.
• Perform a final rinse with high purity water that meets the final water quality specification.

6.6. Reassembly and Inspection:

• Reassemble the system components.
• Inspect all connections for leaks.
• Perform a visual inspection of the internal surfaces for cleanliness and passivation.

6.7. Documentation:

• Record all steps of the procedure, including:
  • Date and time of each step
  • Chemicals used (concentration, batch number)
  • Circulation time and temperature
  • pH and conductivity readings
  • TOC readings
  • Rouge test results (if applicable)
  • Any deviations from the SOP
  • Personnel performing the work.
• Attach copies of MSDS/SDS for all chemicals used.
• Attach calibration certificates for all measuring instruments.
• Obtain QA approval for the completed procedure.

7. Acceptance Criteria:

• The system must be free of visible contamination and rouge.
• The rinse water must meet the specified conductivity, pH, and TOC limits.
• The system must pass a visual inspection for cleanliness and passivation.
• The system must pass all applicable water quality testing.

8. Deviations:

• Any deviations from this SOP must be documented and approved by QA.

9. Revision History:

• Document the date and nature of any revisions to this SOP.

10. Attachments:

• MSDS/SDS for chemicals used
• Calibration certificates for measuring instruments
• Record of cleaning, derouging, and passivation.

This SOP provides a general guideline. Specific procedures and parameters may vary depending on the specific system, chemicals used, and manufacturer’s recommendations. Always consult the manufacturer’s instructions and relevant industry standards.