The use of personal protection should always be the last resort when looking for ways to control health and safety risks. Although this principle applies to ear defenders as much as any other type of PPE, it’s difficult to avoid their use in many industries where exposure to noise can be difficult to control, at least in the short term, by engineering measures.
If ear defenders have to be used, it’s important that they are suitable and will provide adequate protection. Their performance is frequency dependant – like most noise control measures they are more effective against higher frequencies. So when selecting ear defenders for a particular application it’s important that this is taken into consideration. There are three methods that can be used to achieve this, which are described in Appendix 3 of the Health and Safety Executive’s publication L108 Controlling noise at work.
I’ve recently uploaded a presentation to Slideshare which describes these methods and which illustrates them with some worked examples. It also briefly covers some of the other factors that need to be considered when selecting ear defenders.