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Sulfuric acid valves

Types of Sulfuric Acid Valves

Valve selection for Sulfuric Acid, Sulphuric acid H2SO4 can be daunting. First, determine function. If the service is for On/Off, fully open, or fully closed use, consider a Gate Valve, Rotary Valve, Ball Valve, Plug Valve, Diaphragm Valve, Butterfly Valve, Multi-port Valve or Stop Valve.                                                                                                                                                                                                                                                                                                                                         

Valve selection for control, metering, throttling or modulating situations requires a Globe Valve, Butterfly Valve, Control Valve, Relief Valve, Diaphragm Valve, Regulating Valve or Needle Valve. Backflow prevention is achieved with various types of check valves: Swing Check, Lift Check, Piston Check, Poppet Check, and Spring-loaded Ball Check. 

There are additional considerations in the process of selecting a Sulfuric Acid H2SO4 valve.  First, consider the size required by the application. What is the pipe size at the inlet and outlet of the valve? What is the flow capacity ( Cv)? Also, what is the maximum pressure of the process? Where does the fluid (process media) go upstream? Where does the process media go downstream? What is the maximum Sulfuric Acid H2SO4 fluid or gaseous temperature?

Materials of Sulfuric Acid Valves

Select the Valve body and trim materials based on their pressure/temperature rating in accordance with ANSI B16.34 AND chemical compatibility and resistance to Sulfuric Acid H2SO4 in various states and temperatures. Alloy 20 material ASTM A182 F20, Cast Alloy 20 A351 CN7M can be used for higher pressure applications and plastic or plastic-lined valves can be used in low-pressure systems.           

Sulfuric Acid H2SO4 Alloy 20, plastic and plastic-lined valve body end connections are chosen based on cost, maintenance, leak prevention, repair, and replacement. Threaded ends NPT are low initial cost, but subject to leak paths. Welded ends, socket welds, or butt welds provide leak-tight connections but are not easily replaced. Flanged ends are high cost but are preferred for maintenance and replacement.  

Finally, valve seals, gaskets, diaphragms, and O-rings must be compatible with Sulfuric Acid H2SO4. Select elastomeric seals, liners, and diaphragms based on their chemical compatibility and temperature resistance. Elastomers like Viton have better sealing characteristics, but plastics, for example, PTFE (polytetrafluoroethylene), and (perfluoroalkoxy) PFA have better resistance to Sulfuric Acid H2SO4. The most common materials used in H2SO4 chemical processing operations for corrosion resistance over a wide temperature range and extreme environmental conditions are Forged Alloy 20, ASTM A182 F20, Cast Alloy 20 A351 CN7M, plastic grades PVC, CPVC, Teflon, PTFE, and Kynar, PVDF. Elastomers include depending upon concentration and temperature: EPDM, Neoprene, SBR, Silicone, Butyl, Hypalon, Viton, and Kalrez, with Viton, and Kalrez generally accepted as most recommended for all Sulfuric Acid H2SO4 applications.  See our Chemical-resistance guide for proper selection at

Alloy 20 Valves 

Concentrated sulfuric acid at 93%, 96% and 98.5% H2SO4 ranges from 70% to 99%. Dilute acidities are in the range of 25-70%. Alloy 20, ASTM A182 F20, and A351 CN7M were developed for concentrated acid but also improved resistance to high temperatures, elevated pressures, and corrosion or abrasion resistance. Alloy 20 modern variants are alloy 20Cb-3 (N08020) and CN7M (N08807). Sulfuric Acid, Sulphuric acid H2SO4 piping systems include metal finishing, plating, Chlor-alkali, wastewater treatment, pulp and paper, food and beverage water sampling and injection, and metal finishing applications where safety and regard for human health are primary concerns. Full specifications are available in Authorized Parts Technical Library at:

Alloy 20 valves, known as Carpenter 20, and A20, are manufactured as a gate, globe, check, ball, butterfly, plug, needle, control, and safety relief valves in pressure classes 125, 150, 300, 600, 800, 900, 1500, 2500, and 4500 with a variety of trim options. Sizes range from ¼” to 24’. 

Corrosion-resistant valves feature stem packing arrangements that eliminate fugitive emissions leakage with packing designs utilizing Kalrez, Kynar, Viton, and Teflon seals, gaskets, and o-rings for protection.

Authorized Parts, Inc. offers a line of Alloy 20 Instrumentation or Miniature valves.: Needle Valve, 2-Way  Ball Valve, 3-Way Ball Valve, Lift Check Valve, and Inline Check Valve for tubing applications with compression ends.  Access catalog information for the following Alloy 20 valve manufacturers on our website: 

Plastic Lined Valves

Authorized Parts Inc. is a distributor of Plastic Lined Valves for Sulfuric Acid H2SO4 service. Our linings include Teflon, PFA, ETFE, and PTFE Valves. Plastic-lined valves are economical and corrosion resistant, optimal for high temperature, acidic, and corrosive environments. 

 Teflon PTFE Polytetrafluoroethylene, PFA Perfluoroalkoxy, PVDF Polyvinylidene Fluoride, Kynar, PP Polypropylene, ETFE Ethylenetetrafluoroethylene aka Tefzel, are all applied in accordance with manufacturers standards and procedures outlined by producers of CI, Cast Iron, DI Cast ductile iron, FS Forged steel, CS Cast steel, Alloy 20, Monel, Hastelloy C,  by ANSI American National Standards Institute, ASTM American Society for Testing and Materials F1545, and ASTM consolidated plastic lined piping standards.

Authorized Parts offers these valves in a wide range of value types and brands that include Rockwell, Nordstrom, Saunders, ITT Grinnell, McCanna, Stockham, Powell, Grove, Hill-McCanna, and Dezurik.  Available pressure classes are 150, 300, 600, 900, and 1500.  The body materials of these plastic-lined valves include cast steel, cast iron, ductile iron, polypropylene, PVC, 316SS, and alloy 20.

How to Order Sulfuric Acid Valves

To order please select the valve or fitting type, size, pressure class, body material, and end connections. Valve application parameters should be outlined when submitting a lining selection for verification of compatibility. Specify service media and service media temperature and include the type of lining desired. Pressure, Flow (i.e. GPM, SCFM, etc.), Trim, body end connection, Actuator, if actuated, Fail Open or Fail Close, Pneumatic or electric, actuation voltage, etc. Submit your RFQ on Authorized Parts website easy to use form at:



Yes. All valve testing requirements can be made available for Sulfuric Acid Valves Valves. MTR’s, NDE, Pressure Testing, Radiography Testing, Magnetic Particle, Dye Penetrant, PMI, Positive Material Identification, Hardness Testing, and Failure Analysis.

No. The rate of the valve is influenced by the diaphragm material. The hydrostatic test pressure must not exceed the maximum pressure rating of the diaphragm.

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