Why do I need an emergency light test system?

By law, emergency lighting is required within buildings that the public has access to (See What is Emergency Lighting?). It also applies to places of work. 

This is implemented through compliance to standards and codes of practice.  The standards are not just aimed at defining the design of emergency lighting, i.e. how much light and where, but it also covers the installation, commissioning and importantly, the testing of an emergency lighting installation. 

The codes of practice and testing requirements are outlined in BS 5266 and associate parts as well as EN50172.