I just got back from buying an alarm for my sump. The basement was flooded as part of hurricane Frances. The contractors are finally getting around to my house. The alarm I just bought was shrink wrapped and after opening it, I've discovered that it is useless (I was worried it might be when I bought it). At this point I'm assuming that the device is functional, but I can't hear it.
I have a hearing problem. At most normal pitches (i.e. conversation), my hearing is only moderately affected. But at the higher pitches, the loss is greater than 90dB. As a result I cannot hear watch beeps, most cell phones and most alarms. In my previous place of employment, I had to arrange for a co-worker to notify me if the fire alarm went off (The building had several false alarms while I worked there). It took me some time to find a fire and CO alarm that buzzed in the lower frequencies for my house. Needless to say, they were more expensive than the more common alarms. Fortunately the University where I work uses lower pitched fire alarms (with visual signals).
Most aquired hearing loss starts at higher frequencies. With the general increase in hearing problems in the general public, including that of Music or Noise Induced Hearing Loss, one would think that it would practical to make some adjustments in safety devices. Just because that 95dB piezo buzzer is cheaper doesn't make it safer if a significant portion of society can't hear it when it goes off.