DQ FOR PURE STEAM DISTRIBUTION SYSTEM (PSDS)
Pure Steam is a critical utility used in pharmaceutical and biotechnology industries for sterilization and sanitization processes. It is generated from purified water or Water for Injection (WFI) and is free from contaminants such as pyrogens, chemicals, and microorganisms.
Pure Steam is primarily used where direct contact with product-contact surfaces or sterile systems is required, ensuring compliance with regulatory standards such as cGMP and pharmacopeial requirements.
2. DEFINITION
Pure Steam is defined as steam generated from feed water that meets WFI or Purified Water standards, and when condensed, it complies with pharmacopoeial specifications for WFI.
3. APPLICATIONS
Pure Steam is widely used in pharmaceutical facilities for:
- Sterilization of equipment (SIP – Sterilization in Place)
- Sterilization of pipelines and vessels
- Sterilization of filters and tanks
- Humidification in sterile areas
- Autoclave sterilization
- Sterilization of WFI storage and distribution systems
4. QUALITY REQUIREMENTS
The condensate of Pure Steam must meet WFI specifications:
| Parameter | Limit |
|---|---|
| Conductivity | ≤ 1.3 µS/cm @ 25°C |
| TOC | ≤ 500 ppb |
| Microbial Count | ≤ 10 CFU/100 ml |
| Endotoxins | < 0.25 EU/ml |
Additionally, Pure Steam must be:
- Pyrogen-free
- Free from non-condensable gases
- Free from particulate contamination
- Free from chemical additives
5. GENERATION OF PURE STEAM
Pure Steam is generated using a Pure Steam Generator (PSG).
Process Overview:
- Feed water (WFI or Purified Water) is supplied to the evaporator
- Water is heated using plant steam
- Steam is generated and separated from entrained droplets
- High-efficiency demisters ensure removal of impurities
- Clean, dry Pure Steam is delivered to the distribution system
6. DESIGN FEATURES OF PURE STEAM SYSTEM
- Constructed using SS316L material
- Electro-polished internal surfaces (Ra ≤ 0.4 µm)
- Sanitary design with zero dead legs
- Proper slope for condensate drainage
- Use of sanitary diaphragm valves
- Insulated pipelines to maintain temperature
7. DISTRIBUTION SYSTEM
- Designed to maintain dryness and sterility
- Equipped with steam traps for condensate removal
- Includes pressure and temperature monitoring
- Proper routing to avoid condensate accumulation
- Maintains required pressure and temperature
8. CRITICAL PARAMETERS
Key parameters to be monitored:
- Temperature
- Pressure
- Non-condensable gases
- Steam dryness fraction
- Condensate quality
9. TESTING REQUIREMENTS : Pure Steam quality is verified through:
- Non-condensable gas test
- Dryness value test
- Superheat test
- Condensate analysis (for WFI compliance)
10. SAFETY FEATURES
- Pressure safety valves
- Steam traps
- Insulated pipelines
- Pressure gauges and transmitters
- Emergency shutdown provisions
DESIGN QUALIFICATION (DQ) WFI STORAGE & DISTRIBUTION SYSTEM
TABLE OF CONTENTS for DQ
- Introduction
- Scope
- Responsibility
- Basis of Design
- System Description
- Technical Specifications
- Welding and Cleaning Details
- Documentation
- Utility Requirement Specification
- Enclosures
- Revision History
- Abbreviations
- Summary and Conclusion
- Design Qualification Approval
1. INTRODUCTION
The Pure Steam Distribution System (PSDS) is designed to distribute pure steam generated from the Pure Steam Generator to various user points within the facility.
The system ensures that pure steam quality complies with pharmacopeial standards such as USP and EP. The maximum allowable limits at the point of use are:
- pH: 5 – 7
- Conductivity: NMT 1.3 µS/cm at 25°C
- TOC: NMT 500 ppb
- Total Bacterial Count: < 10 cfu/100 ml
- Endotoxin: < 0.25 EU/ml
The purpose of this Design Qualification is to define design criteria and ensure the system meets user requirements, regulatory standards, and cGMP guidelines.
1.1 System Information & Protocol Data
- Equipment: Pure Steam Distribution System
2. SCOPE
This document defines the design basis for the Pure Steam Distribution System, including:
- Compliance with User Requirement Specification (URS)
- Adherence to cGMP and regulatory standards
- System design, materials, and operational philosophy
- Qualification support for validation activities
3. RESPONSIBILITY
3.1 Vendor Responsibilities
- Design system as per URS and applicable standards
- Provide technical specifications and drawings (P&ID, layout)
- Ensure compliance of materials and components
- Submit documentation prior to installation
- Provide training to operating personnel
3.2 Client Responsibilities
- Review and approve submitted documents
- Provide site readiness and utilities
- Ensure inspection requirements are defined
- Provide storage, unloading, and permits
- Ensure EHS compliance during installation
4. BASIS OF DESIGN
4.1 Output Quality Parameters
| Parameter | Limit |
|---|---|
| Conductivity | < 1.3 µS/cm @ 25°C |
| Microbial Count | < 10 cfu/100 ml |
| TOC | < 500 ppb |
| Endotoxin | < 0.25 EU/ml |
Operational Limits
| Parameter | Design Limit | Alert Limit | Action Limit |
|---|---|---|---|
| Conductivity | < 1.3 | > 1.1 | > 1.2 |
| Microbial Count | < 10 | > 8.5 | > 9 |
| TOC | < 500 | > 350 | > 450 |
4.2 User Points
| Sr. No. | Point of Use | Location |
|---|---|---|
| 1 | Autoclave Chamber | Third Floor |
| 2 | Autoclave Jacket | Third Floor |
5. SYSTEM DESCRIPTION
The system distributes pure steam from the generator to designated user points.
Key Features:
- Fully drainable system with proper slope
- Installation of sanitary steam traps for condensate removal
- Hygienic design with SS316L piping
- Orbital TIG welding for high-quality joints
Design Specifications:
- Internal surface finish: < 0.5 Ra (electropolished)
- External finish: Mirror finish (180 grit)
- Use of diaphragm valves with PTFE/EPDM diaphragm
- Use of tri-clover fittings for hygienic connections
6. TECHNICAL SPECIFICATIONS
6.1 Valves & Instruments
Diaphragm Valves
- Type: Manual two-way
- MOC: SS316L
- Diaphragm: PTFE backed EPDM
- Quantity: 8
Sanitary Steam Traps
- Type: Thermostatic
- MOC: SS316L
- Quantity: 3
Pressure Gauges
- Range: 0–10 kg/cm²
- Accuracy: ±1% F.S.
- MOC: SS316L
- Quantity: 3
Pressure Regulating Valve
- Type: Pilot-operated diaphragm
- MOC: SS316L
- Quantity: 1
Actuated Diaphragm Valves
- Type: Pneumatic operated
- MOC: SS316L
- Quantity: 2
6.2 Tubes & Fittings
- Material: SS316L
- Sizes: ½”, ¾”, 2” OD
- Internal Finish: < 0.4 µm (Electropolished)
- External Finish: Mirror finish
- Insulation: Armaflex
Accessories include:
- Bends
- TC liners
- TC clamps (SS304)
- PTFE gaskets
- Pipe supports
7. WELDING AND CLEANING DETAILS
7.1 Welding
- Orbital TIG welding used
- Certified welders only
- 10% orbital welds and 100% manual welds inspected
- Argon gas (99.9%) used for purging
7.2 Inspection & Acceptance
- No cracks, pinholes, or overlap allowed
- Full penetration mandatory
- No rework on defective welds
7.3 Slope Requirement
- Minimum slope: 1:100 for drainability
7.4 Testing
- Hydro/Pneumatic pressure test for 30–60 minutes
- No pressure drop acceptable
7.5 Passivation
- As per ASTM A967
- Removes free iron and improves corrosion resistance
- Mandatory before commissioning
7.6 Rinsing
- Flushing with purified water
- Conductivity and pH to match inlet conditions
7.7 Identification
- All components tagged as per P&ID
8. DOCUMENTATION
Documents provided include:
- P&ID drawings
- Piping layout
- Design Qualification
- FAT documents
- IQ/OQ protocols
- Calibration certificates
- Welding qualification records
- Equipment manuals
9. UTILITY REQUIREMENT SPECIFICATION
- Pure steam supply up to inlet termination point
10. ENCLOSURES
| Sr. No. | Document | Document No. | Revision |
|---|---|---|---|
| 1 | P&ID | 00 |
11. REVISION HISTORY
12. ABBREVIATIONS
P&ID – Process & Instrumentation Diagram
PTFE – Poly Tetra Fluoro Ethylene
EPDM – Ethylene Propylene Diene Monomer
TOC – Total Organic Carbon
PSDS – Pure Steam Distribution System
13. SUMMARY AND CONCLUSION
Summary
The Pure Steam Distribution System has been designed in accordance with URS, cGMP, and pharmacopeial requirements. The system ensures hygienic distribution of pure steam with proper material selection, slope, and drainability.
Conclusion
The design complies with regulatory standards and is suitable for pharmaceutical applications. The system is expected to deliver reliable and consistent performance upon proper installation and validation.