MSS SP-98-2020 covers the material, application, and performance requirements for liquid or powder interior coatings for valves, hydrants, and fittings. In addition, this Standard Practice covers equipment used to conduct holiday tests on coatings. These coatings are applied to interior ferrous surfaces of valves, hydrants, and fittings intended for use in water, drinking water, or reclaimed and wastewater systems where corrosion protection is specified. Where it is necessary, because of the application process or purchase requirements, the coating may also be specified for exterior use, with recognition that performance parameters may vary from those specified for interior use because of differences in exposure conditions. This Standard Practice does not cover the following: Special coatings agreed to by the purchaser and the manufacturer. Coatings for special service conditions such as salt water, acid, high temperature, etc. Internal areas of fire hydrants that are downstream of the main valve.