Piping Systems

Caustic soda solution users are responsible for building and maintaining a properly designed storage and handling system which meets applicable safety and regulatory requirements. Each caustic soda solution user is responsible for determining which piping is suitable for its individual facility.

Seamless carbon steel butt-welded Schedule 40 pipe is recommended. Lined, flanged pipe has also been used successfully. All piping should be installed above ground.

All process pipes should be heat traced and insulated if temperatures below 65°F (18°C) are anticipated for even short periods. Self-regulating electric heating tape is recommended. Other heating tapes or cables with thermostatic control may also be used. Steam tracing is not recommended since the temperature of caustic soda solution can readily exceed 120°F (60°C) under static conditions, causing eventual stress corrosion cracking. Reference the Caustic Soda Service Graph (33KB PDF) to understand the issue. Insulation and weatherproofing are also required, if the piping must be heated.

If maintaining low iron concentration in the caustic soda solution is important, use a flanged steel pipe with a polypropylene lining. Because of the hazardous properties of caustic soda solution, unsupported plastic pipe should not be used, and fiberglass reinforced plastic (FRP) pipe should not be used.

If possible, the entire piping system should be free-draining to facilitate maintenance. Otherwise, capped drain valves should be installed at the lowest point in the system.

All piping systems should preferably be color coded and stenciled with "Caustic Soda" every ten feet (3 meters).

For additional information on caustic soda solution piping systems, review The Chlorine Institute, Inc. Pamphlet 094 "Sodium Hydroxide Solution and Potassium Hydroxide Solution (Caustic): Storage Equipment and Piping Systems." This pamphlet and additional resource materials can be purchased through the Chlorine Institute web site or send your request via fax to (703) 741-6068.

The information contained above is supplemental to the Internet Disclaimer and is not intended to be all-inclusive as it relates to use, handling, storage, disposal and all other described activities. Recipients must make their own determination of suitability and are responsible for compliance with all applicable federal, state, provincial, municipal laws and/or other regulations. This information is offered solely for your consideration and verification and in no event will The Dow Chemical Company be responsible for damages of any nature whatsoever resulting from the use or reliance upon this information or the product to which this information pertains.