Why are fire alarm cables considered special cables?

Fire alarm cables often carry low voltage signals, but the circuit function is safety-critical.
They may require controlled capacitance, stable impedance, twisted pairs, screening, LSZH sheath, or fire resistant construction.
In long alarm loops, poor cable selection can cause signal instability, false alarms, or communication failure.
For this reason, fire alarm cable selection should consider both electrical signal quality and fire performance.