Security and Access Control Systems
Security and Access Control Systems tests intrusion detection, door hardware, credentials, power, and code-compliant egress. Expect questions on PIR and dual-technology detectors, door contacts, request-to-exit devices, fail-safe and fail-secure locks, battery backup, and PoE budgets.
Core rules
- Fail-safe locks unlock on power loss and are used where life safety requires free egress. Fail-secure locks remain locked on power loss and are not a substitute for a compliant exit.
- Electrified locks on egress doors generally require a request-to-exit device and release by the fire alarm system. Check the adopted building code and NFPA 101.
- Intrusion zones should be supervised. Dual-technology detectors combine passive infrared and microwave to reduce false alarms.
- Calculate standby battery capacity with a derating factor, and calculate PoE load against the switch budget, including cable loss and startup current.
- Change default passwords, encrypt network links, and protect controllers in locked enclosures.
Worked example
A 24-port PoE switch is rated 370 W. Sixteen cameras draw 12 W each, or 192 W. Eight access controllers draw 10 W each, or 80 W. Total load is 272 W. At an 80 percent design limit, usable power is 296 W, so the design fits but has only 24 W margin. The technician checks startup current and cable length before accepting the design.
Traps
Reversing fail-safe and fail-secure; omitting a request-to-exit device; assuming a mag lock alone is code-compliant; ignoring battery aging; and accepting a PoE total without headroom.