We picked up a new account where they want us to do what the other guys did.  Apparently to test all the high and low alarms facility wide (> 3,800 outlets/inlets) Company B would lower the house pressure to 40ish psi to trigger all the alarms, once confirmed each alarm functioned properly the house pressure would be restored.  I don't think they tested for high pressure.

 so to nip this in the bud, what publication/section can I refer to that will show that is a terrible method? 

Take it for what it is, Annex D in ASSE 6000

D.5.5 High/Low Pressure Alarms

a) If the pressure/vacuum sensors are installed

with gas-specific demand check fittings, they

can be removed from the piping system and

individually tested using a source of test gas or

vacuum.

b) For positive pressure gases:

1) Reduce the pressure to 20% below normal.

Verify that the appropriate alarm trips.

Silence the audible alarm. The visual alarm

should remain activated.

2) Raise the pressure to normal. The visual

alarm should be deactivated.

3) Raise the pressure to 20% above normal.

Verify that the appropriate alarm trips.

Silence the audible alarm. The visual alarm

should remain activated.

4) Reduce the pressure to normal. The visual

alarm should be deactivated.

c) For vacuum alarms:

1) Decrease the vacuum from normal to 300

mm (12 in) Hg. Verify that the appropriate

alarm activates. Silence the audible alarm.

The visual alarm should remain activated.

2) Increase the vacuum to normal. The visual

alarm should be deactivated.