Posted By FAH Hi Brian Would you mind sharing why you feel the need to ask about this? Given the plant concerned, what it does & how much noise they make, that any working area really should be an absolute "no go" for pedestrians especially, & that associated plant should always be directed by a banksman [from a suitable distance] or even the excavator operator to ensure an adequate safety distance; I'm not sure of the context of the query. Under the circumstances, a reversing alarm does seem rather superfluous. Frank Hallett

Posted By al wood segregate the working area so no pedestrians cannot enter, erect signage such as no entry. post signage on the machine - danger keep clear, do not approach machine etc etc. a reversing alarm in my opinion would not be practicable due to the 360 rotation of the machine.

Posted By FAH OK Brian If you're operating under OSHA Rules it changes the whole game! As you identify, it's rule, not risk, based or focussed. Additionally, the enforcers have almost no remit or ability to provide any amelioration or advice as to what may be considered acceptable - it's far worse than the UK on that score alone. I still see no possible value in an alarm on an item of plant such as you quote as to be sufficiently audible over the machine itself [& any other ambient noise] it would have to be similar to a flood or air-raid warning siren on the basis that if people can't hear the machine you must really up the DBs! If you're anywhere that automatically dives for cover when they hear these things it will be somewhat counter-productive to say the least!! If the enforcers won't accept your existing procedures [inc people exclusion]; then perhaps you could more usefully investigate the provision of cameras that have the ability to sense & warn of heat sources [like people] in the immediate vicinity? Good luck. Frank Hallett