Hi Habib,Here are a couple documents that will provide some good information regarding your initial question. Just copy the URLs straight into in the address bar of your web browser.1. www.emersonautomationexperts.com/.../ 2. www.emersonautomationexperts.com/.../Choosing-the-Proper-Pressure-Control-Device-for-your-Application.pdf Would you be willing to provide me with some information as to the process conditions, process fluid (MSDS), MAOPs, location of installation, and P&ID of the station so I can assist you further? There is a variety of information that pertains to regulators. Please use the following website for literature containing high pressure regulators (Type EZH and Type Fl) with natural gas.Hopefully, that will get you started in the right direction. Please don't hesitate in contacting me directly at Dennise.McDaniel@Emerson.com.Regards,Dennise