How to calculate invert level of drain | height of instrument method | invert levels

How to calculate invert level of drain | height of instrument method | invert levels Friends, in this video I have given information about: Drain invert level how to calculate invert levels Reduced level calculation height of instrument method surveying Invert level of drain 🎥 Also visit ‪@TurvexCivil‬ for surveying and civil engineering tutorials.