I need some help with this one......a super on a Job site informed me today that I will not be allowed back on his site unless my pump is fitted with a safety beeper that will sound when we are moving the boom. He says that this is an OSHA requiremt???????? is he mixing up a crane and a concrete pump????  

He's wrong. Cranes aren't even required to have them. Although many have them or strobe lights for swing function

sound like that bloke is talking out of his arse,if we had to have horns on the boom every time it moved then you would need one on every moving machine like 360 excavator ,fork lifts . the only machine that has a horn when moving is mobile platform (cherry picker), and unless you have a man  basket on the end of your boom ,tell the bloke to double check where he heard the crap 

is it possible he's simply referring to "the boom" in reference to the whole truck, and talking about a backup alarm.

im running into this more and more. we have 4 or 5 jobs like this

I would put the loudest (train horn) siren on and make it work with every function and when the pump is pumping. Put in some good earplugs and earmuffs and let em listen to that all day.

I was told to leave site a few years back because i had no crane safe sticker, i pointed out the sticker that says the boom sould never be used as a crane, and he shut up.

Wonder where these guys come from you have to wonder about their saftey training program, a backup beeper it a must have, as far as the boom put a red beacon on the last 90 that do the trick.

Makes you think... If such complete retards are responsible for our safety.... Should we start worrying???

REGARDLESS of the safety requirements in your area. It sounds like you need to fix the problem to get back on your job. Most likely someone has disconnected the horn off of the turret. Depending on the brand/year of pump you're running there should be a horn located on the turret somewhere close to the limiting switch, if it's connected and not working you can run a jumper wire from the horn on the turret to the electric horn under your cab so it can be sounded by the switch on the remote box.