There is a surprising amount of gear suspended overhead in commercial environments, especially churches. Speakers, projectors, lights, displays and other gear compete for space on the ceiling. But hanging anything from a ceiling over people is a tricky business due to variables like static load, shock load, support capacity, hardware, safety backups among others.
Unsafe speaker rigging
Recently we replaced a poorly designed set of home made speakers from the ceiling of a church and noticed the following deficiencies. First, in the top-right corner of the photo, a simple piece of steel is held to beams using inadequate wood screws. While this might be sufficient for the weight if the speaker was hanging directly below, but the chain is on an angle, which encourages the screws to pull out.
Next, the hardware store grade chain links are connected to steel cable without the proper shields to keep from wearing through the cable. The cable is secured with bolt on clamps. Speakers are meant to vibrate, and bolts are not immune to loosening from vibration—bad combination.
But the weak link is that the steel cable runs through holes drilled in the speaker cabinets, so the whole extent of the weight is supported by about an inch of plywood. Meanwhile, the projector is suspended with a heavy iron pipe that is screwed into the ceiling beam using small wood screws through a flange that is not approved for overhead suspension since it has no locking method to prevent the pipe from unthreading from the flange.
Of course, there are no backup safety restraints in case the rigging fails. Liability insurance is not a solution! If you are not sure about the gear in your environment, you really need to call us!