If they aren't needed, start stripping them down.
Use a formula like the following to get the total number of rows:
Code:
=ROW(OFFSET('FIRE ALARM DEVICES'!A1,COUNTA('FIRE ALARM DEVICES'!A:'FIRE ALARM DEVICES'!A)-1,0))
You can put this on the second and third sheet in say, C1. So then your formulas would be:
Code:
=COUNTIF('FIRE ALARM DEVICES'!$A$2:OFFSET('FIRE ALARM DEVICES'!$A$2,$C$1,0),"SIGA-PS")
Ax