Here's a short success story about the use of Trimod Besta float switches in the co-gen plants of wastewater authorities here in Australia.

 

This particular application utilised the IEC Ex rated ZKK5 01 04 model (SIL 3 capable) which operates in the same manner as the standard electric AA 01 04 side mount model shown below.

 

 

Function tested pneumatic models are also available for hazardous area applications.