A building owner recently requested proof of impact sound insulation for installed soundproof doors.
Due to the structural situation, the wooden surround frame bridged an acoustically planned joint, so that sound transmission could be proven here.
Even if sound is actually transmitted via this "bridging", this is not a defect. In the relevant standard, DIN 4109-1, there is a - (dash) in Table 1, line 4 for doors in the impact sound insulation. No values are to be specified/declared here. In this respect, "only" the standard sound insulation value for the door element applies.