Impact Noise

Impact noise is noise generated due to impacts in other locations, than in the actual room where disturbance is experienced. A typical example is the noise in a cabin caused by people walking on the deck above.

The impact noise properties are characterised by the measured sound pressure level in a receiving room, when a standardised source (tapping machine) generates a well defi ned impact on the fl oor of the source room. The source room and the receiving room must not necessarily have a common wall or floor, but the noise can be transmitted as flanking transmission through the structure of the ship. It is obvious that the kind of connection between the different construction elements has a big influence on the noise transmission.

Here, a floating/resilient floor in the sending room and/or an optimised ceiling construction in the receiving room can have a very effi cient noise reducing effect.

Typically, sources of impact noise are human activities, such as sports activities, dancing and walking. Another source of impact noise is the use of transport trolleys in the galley or service corridors.

The sports activities, such as ball games, jogging paths and running bands, present a particularly severe problem. The frequency content of the impact arising from a fl exible ball or from footsteps has a high content of low frequency energy. As earlier described, it presents a challenge to reduce low frequency noise.