A very loud beeper is 100dB at 1m. But the little ones have their loudness measured when it is so close to your ears that you almost wear it.
Sound level is attenuated 6dB for each doubling of distance unless you are in a very reverberant room.
So 130dB at 5cm is 124dB at 10cm, 118dB at 20cm, 112dB at 40cm, 106dB at 80cm and about 105dB at 1m.
Sonalert make some very loud beepers. But they are pretty big.
Have you seen the huge "sound-cannon" used by police? It is very loud.