I agree with Michael & Oleksiy:
one other thing to add is the type of facility (school, public building, private business, retail, etc.)
Much like the ASIS security audit (which includes Risk to Cost analysis) - we start with something we call a "needs analysis" where we meet / interview to gain input from different divisions (security, IT, facilities, site contractors/vendors, risk management, receptionist, kitchen, C-group, etc.)
The goal is to understand existing procedures, processes, use, risk and loss. Also, need to consider who will take ownership of the opening and alarm response.
Just as Oleksiy stated:
The classical rule states that any system that is protecting some asset should not be more expensive than that asset. And we now talking about not just buying costs but about Total Cost of Ownership including maintenance and other expenses.
BUT there is also - Safety, reputation and security come into play. harder to put numbers on personnel safety, but ASIS has some forms that assist with creating a risk to loss calculation.
Openings are moved into categories to create standards that can be utilized for operating procedures, new offices, changes in area functions, etc.
Here is an excerpt for categorization from a standards we created with a Corporate Headquarters:
Exterior Man Door Openings:
- Controlled and/or Employee entry / exit - Full access control (reader, REX, door position switch, lock)
- Emergency Exit only - door position switch and local sounder
- Roof Access doors – door position switch, sounder,
- Exit only door - door position switch, reader, local sounder. sounder wired into system so no local alarm with valid card read.
FYI - this is to allow personnel to exist certain doors, but to funnel them back to an entry/exit door for re-entry into the building.
- Public or main Entry / Exit Vestibule – Exterior Vestibule door - door position switch, lock. Controlled or time schedule opening. Interior Vestibule door - Reader / lock - Add door release to receptionist desk.
The same analysis is completed for interior doors. Some will have access, some monitoring, some keypad locksets, some with keys.