Quick answer: in water service the pressure is rarely the problem — corrosion is. Seawater and brine attack carbon steel quickly, and even stainless steel 316 has limits once the temperature and chloride level rise. The right answer for hot seawater or brine is usually a higher alloy or a different material family, decided by chloride level and temperature.
Recommended valve matrix
| Service | Valve type | Body material | Notes |
|---|---|---|---|
| Seawater intake and outfall | Butterfly valve, gate valve | CF8M or higher grade | Confirm chloride level and temperature |
| Brine and concentrate lines | Butterfly valve, ball valve | Higher alloy or duplex grade | Soft seats must suit the medium |
| Treated water distribution | Gate valve, butterfly valve | WCB or CF8 | Coating system matters as much as the body |
| Pump discharge | Dual plate check valve | CF8M | Short face-to-face suits header layouts |
| Chemical dosing | Globe valve, ball valve | CF8M or PTFE-lined | Match seat and gasket to the chemical |
Why seawater is the hardest case in water service
- Chlorides break down the passive layer of standard stainless steel, causing pitting and crevice corrosion
- The risk rises with temperature — warm seawater is far more aggressive than cold
- Stagnant zones and crevices corrode first, so gasket and seat geometry matter
- Carbon steel needs both internal and external protection in a coastal plant
What to send us with the inquiry
- Chloride level, temperature and whether the line is continuous or intermittent
- Whether the valve is in the intake, process or outfall section
- Coating and painting requirement for the plant atmosphere
- Required documentation and inspection level
待补内容位：待补：中东水项目实际案例（如阿联酋、沙特项目，客户名可脱敏）、可提供的海水工况材质方案清单、涂层体系说明。