We had a wireless sytem installed in a Grade 1 listed building. The old wired system was well and truely out of date and in order to upgrade the whole system a wireless system seemed the best approach. There were initial concerns regarding the perceived effects of having very high voltage cables being close by and having very thick building walls, but these have proved not to be an issue. The system has been active for a couple of years and we have had no problems to date.    

Design & installation by a competent person is key as it can all go very wrong if left to cowboys.

A new PFI mental Health Unit was constructed in SE England and a wireless AFD system specified by the PFI Contractor. Installation costs would be far less for the profit making concern as of course, no power or data supplies/cabling are required. In addition, there was a closed protocol maintenance contract which meant that the NHS Trust had to buy batteries from the PFI company and nobody else. Watch those prices soar!

Come commisioning day, it appears  that the fire alarm designers & installation company didn't consider the design of the stud walling on the ward. It was plasterboard on galvanised steel studs reinforced by 2 layers of steel EMF mesh sheeting to stop clients kicking their way into their neighbours room. The mesh sheeting in practice created scores or Faraday cages which blocked all radio signals.

The NHS Trust had to install 40 to 50 booster aerials around the site, and even then there were routinely 40 faults showing. It took 5 years to iron out the issues

Lessons from this is dont just assess what is there now, but consider the design, materials and layout of the premises which is yet to be contructed