Overview This standard provides requirements to (1) help utilities identify structures that may be at a high risk for below-grade corrosion; (2) excavate and inspect the selected structures; (3) categorize the condition of structures based on corrosion degradation; (4) prioritize structures requiring additional inspection based on those findings; and (5) help identify next steps as required. this NACE/IEEE joint standard is limited to the inspection and assessment of steel transmission towers@ poles@ and substation structures@ to include galvanized@ self-weathering@ and painted mild steel structures@ as well as other similar structures. It does not address the specific inspection of concrete foundations@ above-grade attachment points@ noncoated ground sleeves@ guy anchors@ or specific pass or fail criteria. In addition@ this standard does not provide procedures regarding repair and/or replacement of these same types of structures. This standard does not address localized corrosion@ which is corrosion that can take place in relatively small and limited steel surface areas as a result of unusual factors such as soil conditions@ electrical currents@ etc. For the purposes of this standard@ the area of inspection is composed of the transition zone and below-grade portion of the structure. The inspection area and depth of excavation is determined by the utility as appropriate to identify the extent of corrosion. This standard should not be used to address structures in continuous water immersion environments. The definitions of many of the corrosion-related terms used in this standard can be found in NACE/ASTM(1) G193. Purpose??The purpose of this standard is to provide procedures for the use of common inspection practices and technology on structures below grade. The standard includes: (a) Assessment of historical data to categorize inspection priority; (b) Below-grade inspection and assessment to categorize structures by level of condition; (c) Site-specific environmental factors and soil conditions; (d) Evaluation of existing repairs; (e) Assessment of foundation anchors and associated hardware; and (f) Detection of stray currents. NOTE:(2) While concrete foundations and guy anchors are not specifically addressed in this standard@ it is expected they will be addressed in separate standards.