It depends on what you are scanning, conventional channels should here static when squelch is at 0. Trunked systems usually won't hear static because the scanner is monitoring the active control channel.
The normal squelch setting on the 996P2 is 2. For a digital trunked system, you will not hear noise. For conventional analog frequencies, you will hear noise only if using carrier squelch (no CTCSS or DCS tone programmed). If tone is programmed, you will not hear noise.