concealed work inspection report(e.g. "In accordance with current construction standards and rules in the USSR, concealed work must be inspected by the proper construction organization before being concealed by subsequent work." thefreedictionary.comAiduza)
Concealed works acceptance act(освидетельствования – examination, inspection – но в этом случае принимающая сторона согласовывает скрытые работы. nurseit)