I'm hoping someone might be able to advise on this. I work in a 130,000 sq foot open plan factory (designed to be a warehouse) we have about half a dozen forklifts running about all day which 2 of them are 7 ton LPG units (they are quite noisy but sound awesome), none of these are an issue. The problem we are facing is the Toyota Traigo 35, has an insanely loud reversing alarm, some of us engineers have open offices on the shop floor, the Toyota reversing alarm can be running for hours and its like working next to a domestic smoke alarm, its driving us insane and likely the reason we all have tinnitus, it can even be heard 2 streets away in a residential area, sadly the management are work-shy and arrogant so they are neither interested in our or any neighboring complaints.

I've surreptitiously measured the volume from about 10 metres away and seems to be about 90 - 95dB, the ambient noise level is a fairly constant 62dB.
This place has over 70 CCTV camera's constantly watching us for evidence so I can't stick tape over the sounder, actually I can't visibly see the alarm and anyway it would be seen as tampering with it if there was an incident.

The health and safety are only concerned with covering its legal liabilities and there is zero welfare here hence they have just set it at full bore to cover themselves, so, what I guess what I'm asking is

A. is there a rule of thumb for what the volume should be set to and

B. can the volume be adjusted, I'm guessing a modern unit like this can have a laptop plugged in during a service and the volume set to any desired level?

I've actually almost been hit by this forklift as the reversing alarm can be heard at pretty much the same volume wherever it is in the factory so its necessary for your own sanity to try to block it out, one day a blue light on the ground appeared from around a corner in front of me so I stopped just in time, I think this proves the alarm is too loud, a quieter alarm similar to all the other forklifts in use would have alerted me to the machine being in the near vicinity.

I did once send the management a link to a white noise reversing alarm and another unit that adjusts to the background noise level but there was no interest.