Every inspection is performed by a number of persons over a number of days. Most inspections are made by one man within one day, that’s 1 man-day. However, it is possible that some inspections require more people and/or more time. For example, we could send 2 inspectors to perform an inspection within 1 day, that’s 2 man-day.   Examples: 1 inspector on 1 day = 1 man-day 2 inspectors on 1 day = 2 man-day 1 inspector on 3 days = 3 man-day 2 inspectors on 2 days = 4 man-day