DQ) FOR PURIFIED WATER STORAGE & DISTRIBUTION SYSTEM
1.0 INTRODUCTION
The Purified Water (PW) Storage and Distribution System is designed to store and distribute purified water for manufacturing and washing applications.
Purified water is generated from the PW Generation System and stored in a 3000 L storage tank . It is then distributed to various user points through a closed-loop distribution system using sanitary pumps.
The system is designed in compliance with USP (United States Pharmacopoeia) requirements, ensuring water quality at point of use (POU) within the following limits:
| Parameter | Limit |
|---|---|
| pH | 5.0 – 7.0 |
| Conductivity | ≤ 1.3 µS/cm @ 25°C |
| TOC | ≤ 500 ppb |
| Microbial Count | ≤ 100 CFU/ml |
The objective of this Design Qualification is to verify and document that the system design meets the User Requirement Specification (URS) and regulatory requirements.
2.0 SCOPE
This document covers the complete design qualification of the Purified Water Storage and Distribution System, including:
- System design and configuration
- Equipment and instrumentation specifications
- Control philosophy and operational logic
- Compliance with URS and GMP requirements
3.0 RESPONSIBILITY
3.1 Vendor
- Design system as per URS, GMP, and applicable standards
- Provide drawings (P&ID, GA, layout) before execution
- Ensure compliance of materials and components
- Supply complete documentation
- Provide training to operating personnel
3.2 Client
- Review and approve design documents
- Provide site readiness and utilities
- Ensure inspection of materials if required
- Provide necessary permits for installation
- Ensure safe storage and handling at site
4.0 BASIS OF DESIGN
4.1 Quality Requirements at Point of Use
| Parameter | Design Limit | Alert Limit | Action Limit |
|---|---|---|---|
| Conductivity | <1.3 µS/cm | >1.1 | >1.2 |
| Microbial Count | <100 CFU/ml | >80 | >90 |
| TOC | <500 ppb | >350 | >450 |
| pH | 5–7 | <5.5 / >6.5 | <5 / >7 |
4.2 User Points
Total 14 user points across production areas including sterile room, wash areas, IPQC, vial washing, and utility systems.
4.3 Pump Design Calculation
- Peak Consumption: 2.59 m³/hr
- Return Loop Flow: 4.12 m³/hr
- Total Flow: 6.71 m³/hr
- Pump Capacity Selected: 6.8 m³/hr @ 63 MWC
DESIGN QUALIFICATION (DQ) WFI STORAGE & DISTRIBUTION SYSTEM
5.0 SYSTEM DESCRIPTION
The system consists of:
- PW Storage Tank (T-601) – 3000 L, SS316L
- Distribution Pumps (P-601/P-602) – sanitary centrifugal type
- Closed-loop piping system with continuous circulation
- UV system for microbial control
- Online instruments (flow, temperature, conductivity)
Key Features:
- Minimum loop velocity: 1.2 m/sec
- Slope: 1:100 for drainability
- Electro-polished internal surface (≤ 0.4 Ra)
- Orbital TIG welding
5.1 Sanitization
- Hot water sanitization at 80–85°C
- Duration: 1 hour after reaching setpoint
- Trigger: Microbial count >100 CFU/ml
6.0 TECHNICAL SPECIFICATIONS
6.1 Equipment
PW Storage Tank
- Capacity: 3000 L
- MOC: SS316L (contact), SS304 (non-contact)
- Finish: ≤0.4 Ra (internal)
- Jacketed and insulated
PW Distribution Pumps
- Make: Fristam
- Capacity: 6.8 m³/hr @ 63 MWC
- Quantity: 2 (1 working + 1 standby)
UV System
- Wavelength: 254 nm
- MOC: SS316L
Control Panel
- PLC: Siemens S7-1200
- HMI: Siemens KTP-900
- VFD: Siemens SINAMICS V20
6.2 Instruments
- Level Transmitter (Capacitance type)
- Pressure Gauges
- Temperature Sensors (PT-100)
- Conductivity Meter
- Flow Transmitter
6.3 Valves
- Diaphragm valves (SS316L, EPDM/PTFE)
- Zero dead leg valves at user points
- Flow diverter valve (FDV)
- Safety and control valves
6.4 Piping
- Material: SS316L
- Finish: ≤0.4 Ra
- Connections: Tri-clamp
7.0 WELDING AND CLEANING
- Orbital TIG welding
- Argon purging (99.9%)
- Weld inspection (endoscopic)
- No ferrous contamination
Passivation
- As per ASTM A967
- Nitric/Citric acid treatment
- Mandatory before commissioning
8.0 CONTROL PANEL DESCRIPTION
- PLC-based automation
- HMI-based monitoring and control
- IP54 SS304 enclosure
Features:
- Auto and manual operation modes
- Sanitization cycle automation
- Alarm and interlock management
- Password-based access (4 levels)
9.0 DOCUMENTATION
Documents provided include:
- P&ID
- GA Drawings
- DQ, IQ, OQ protocols
- Calibration certificates
- Welding records
- Operation manuals
10.0 INTERLOCKS AND OPERATIONAL LOGIC
Critical Interlocks:
- Low level → Pump trip
- High conductivity → Water diversion
- Low velocity → VFD speed increase
- Power failure → System shutdown
- Emergency stop → Full system trip
11.0 UTILITY REQUIREMENTS
| Utility | Specification |
|---|---|
| Power | 415V, 3 Phase, 50Hz |
| Steam | 2–3 bar |
| Compressed Air | 6–8 kg/cm² |
12.0 ENCLOSURES
- P&ID Drawing
- Tank Drawing
13.0 REVISION HISTORY
14.0 ABBREVIATIONS
15.0 SUMMARY AND CONCLUSION
SUMMARY
The Purified Water Storage and Distribution System has been designed considering:
- Regulatory compliance with USP standards
- User Requirement Specifications (URS)
- Hygienic design principles
- Continuous circulation with controlled velocity
- Online monitoring of critical parameters
- Automated control system with safety interlocks
All equipment, piping, instrumentation, and control philosophy have been selected to ensure consistent delivery of purified water meeting required quality standards at all user points.
CONCLUSION
Based on the design evaluation:
- The system design is adequate and compliant with GMP and USP requirements
- All critical parameters affecting water quality are properly controlled and monitored
- The design ensures safe, reliable, and hygienic operation
- The system is fit for installation and further qualification (IQ/OQ/PQ)