This document covers the physical properties, potential contaminants and test procedures for heavy brine fluids manufactured for use in oil and gas well drilling, completion, and workover fluids. This document supplements API RP 13J, 5th edition (2014), the requirements of which are applicable with the exceptions specified in this document. This document provides more suitable method descriptions for determining the formate brines pH, carbonate/bicarbonate concentrations and crystallization temperature at ambient pressure compared to the methods provided by API RP 13J, 5th edition (2014). This document is intended for the use of manufacturers, service companies and end-users of heavy brines.