Acoustic doors

Both are single-number ratings, in decibels, of how much sound a construction blocks. Rw comes from laboratory tests to ISO 10140, rated under ISO 717-1, and is used in European and international specifications. STC comes from ASTM E90 tests, rated under ASTM E413, and is common in US specifications. The two are similar but not identical, so compare like with like when reviewing submittals.

Usually not in full. Laboratory tests are carried out in an ideal opening, while on site sound also travels through the wall, ceiling, floor and any gaps around the frame. Field results are therefore typically lower than the laboratory figure. Careful installation, a properly sealed frame-to-wall joint, correctly adjusted seals and a wall that matches the door all help close that difference.

Start from the acoustic target between the two rooms, which your acoustic consultant sets from the room use and background noise. The door should then match the wall: a high-performance door in a lightweight partition will not help, and a weak door will undo a heavy wall. For very demanding rooms, such as studios, a lobby with two acoustic doors in series is often the practical answer.

Yes. Acoustic and fire performance can be combined in one door set, which is common for plant rooms, auditoriums and corridors. The door must then be covered by evidence for both: fire test evidence and an acoustic test report for the same construction, including seals and hardware. Adding fire seals or changing hardware can affect acoustic performance, so state both requirements at the start.

Check seals regularly for damage, loss of compression and paint. Make sure the drop seal still meets the floor when the door is closed, because new floor finishes and wear change the gap; most drop seals can be adjusted. Closers and latches must pull the door fully onto its seals. A door left ajar, or a cable run through the frame, removes most of the insulation.