I thought this image was a good way to show why Codes and standards for hazardous materials such as NH3 REQUIRE REMOTE Emergency Shutdown Systems. For example, CGA 2.1 states the following:
If an emergency shutoff valve is installed, the following requirements shall be met:
- Approved emergency shutoff valves or internal valves shall incorporate a reliable actuation system (for example, electrical, pressure, or cable) that closes all of the emergency shutoff valves or internal valves of the piping system on the first attempt in the event of an emergency or of testing from a remote location. There shall be a minimum of two remote actuation locations reasonably opposite to each other; and
- If using a pressure source for activation of the emergency shutoff valves or internal valves, nitrogen, compressed air, or carbon dioxide is deemed acceptable. If using compressed air as a pressure source, the air shall be clean and kept at a moisture level that does not prevent the system from operating . Propane or other flammable materials shall be prohibited for use to activate an emergency shutoff valve or an Internal valve.
