API MPMS 5.4 pdf download.Manual of Petroleum Measurement Standards Chapter 5—Metering 5.4.5 Selecting Accessory Equipment for Meters Accessory devices should be selected so that trouble will not arise from the following: a. Environment. Local climate extremes should be evaluated, and the installation should be protected accordingly. Electri- cal safety factors (including the hazardous area classification), electromagnetic and radio frequency interfer-...