Hearing loop field strength and frequency response uniformity can be affected to a greater or lesser degree by building metal. Given that most loops are placed at the floor level, concrete floor reinforcement rod and metal floor pans may play a role in the loop design and installation. One option is to place the loop at the ceiling level, away from the floor metal. Ceilings with an interlocking suspended ceiling grids can also be a design issue. The effects of metal can usually be overcome, but they cannot be ignored.
Metal loss prevention is a better solution! Glass fibre reinforced polymer (GFRC) is an excellent alternative to metal reinforcement rod. Loop signal loss due to metal disappears. One recent installation of a loop system (Providence Free Reformed Church, St. George, ON) on a GFRC concrete floor, poured on grade, had the most uniform field strength and frequency response of any installation in the history of Better Hearing Solutions. GFRC is recommended anywhere a hearing loop might be used - and they can be used anywhere a hard of hearing person needs to hear.
For a more detailed description of metal loss issues, please go to the Ampetronic website.