What are the differences between continuous and impulse noise risks?

Noise exposure in the workplace can be continuous or intermittent, called ‘impulse’. The type of exposure affects the type and level of hearing protection required. 

Some hearing protectors are designed for impulse-type noise only. Passive hearing protectors can offer adequate attenuation for continuous and impulse noise exposure but may introduce additional risk by preventing the wearer hearing speech and warning signals. It is important to understand different types of noise exposure in order to select appropriate protection.

Continuous noise risks describe extended or constant high-level noise whereas impulse-type noise is characterised by short duration high-level peaks. Machinery, vehicles and power tools can be sources of continuous high-level noise. Sources of impulse-type noise risks include riveting, pile-driving, pneumatic nail guns and explosions.

Despite having a shorter exposure time than continuous noise, impulse noise can present a great degree of risk. The sound level is often higher than continuous noise and the short, spontaneous nature of exposure can mean the appropriate controls are overlooked.

Level-dependent hearing protectors can offer the ideal protective solution for impulse noise risks, attenuating harmful noise and amplifying low-level sounds such as speech and warning signals. This helps wearers to remain aware of their surroundings and in touch with other members of staff whilst being protected against harmful noise. 

If both continuous and impulse noise hazards are present, it is important to ensure hearing protectors are suitable. Some level-dependent hearing protectors are intended for protection against impulse noise only. 

Find out how level-dependent hearing protectors offer protection. 

Learn more about selecting ear defenders.