WFI Distribution Loop Pressure Control

Biopharmaceutical, pharmaceutical and other high purity industries utilize systems to produce ultra high purity and sterile water. These systems are known as WFI (Water for Injection) Systems or WFI Distribution Loop Systems. Typical uses for these systems can be found in Sterile Bulk API (Active Pharmaceutical Ingredient), BPC (Bulk Pharmaceutical Chemical) preparation, Parental Dosage Forms, and final cleaning for the applications listed previously.

WFI systems typically involve several sub systems or additional systems for the water production, storage and distribution. Many facilities may include a pre-treatment system that includes Pressure/Carbon Filters, Reverse Osmosis System, Ultra Filtration and a UV sterilizer might be the first stage. The next subsystem typically involves the creation of the WFI.WFI is typically created by one of the following methods, distillation (Vapour Compression or Multi-Effect), RO, or Ultra-Filtration.


Additional subsystems would include the WFI storage system which maintains the WFI at temperature and the WFI Distribution Loop which includes pumps and back pressure valves.

In these WFI Systems several parameters are measured to control certain negative outcomes. Here is a list of a few of the parameters measured:

  • Nitrates: Negative Health Impacts
  • Conductivity: Ionic Contaminants
  • Heavy Metals: Toxic to humans and animals
  • TOC: Food for microbes

WFI Distribution Loop Systems like other Biopharmaceutical systems have common problems and design recommendations to prevent these issues. Some issues include maintenance of physical, chemical and microbiological properties of the WFI, System Capacity, Dead Legs, Incomplete Sanitation and Poor Treatment. Designers use some of the following principles to help minimize issues: Sanitary diaphragm valves, Sloping lines for draining, SIP/CIP compatible and proper heating.

The Equilibar ® FD Series Back Pressure regulator offers precision pressure control across a wide range of flow rates and conditions. The FD Series is designed with the following features to help meet Biopharmaceutical WFI Distribution Loop design principles:

  • Drainability: Drainable and minimal hold up with air blow
  • CIP/SIP: Materials of construction capable of meeting cleaning requirements at elevated temperatures.
  • Sanitary/Hygienic Design: Mechanical and Electropolished Surfaces, Tri-clamp Connections
  • USP Class VI Diaphragms
  • Ultra wide flow windows
  • High Precision

Contact an application engineer to

WFI water distillation system (photo courtesy MECO, Multiple Effects Stills).

Product Details

FDO8 Sanitary Back Pressure Regulator

FDO8 Sanitary Back Pressure Regulator

Port Sizes:
Typical Pressure Ranges:
0 - 1 in WC
0 - 28 in WC
0 - 5 psi
0 - 10 psi
0 - 20 psi
0 - 30 psi
0 - 60 psi
0 - 100 psi
0 - 150 psi
Key Applications:
  • Liquid blending and dosing
  • Biopharma manufacturing
  • Sanitary Tank Blanketing
Technical Details

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