When you are fitting security devices, you must consider the risk of fire and not fit systems that will prevent escape from occupied buildings. For example, fitting and padlocking a steel bar gate over the face of a standard front door in a house will impede escape and misplacing the extra keys may prove fatal.
On the other hand, a BS: PAS24 door and frame provides better security and does not increase the fire risk. A window that may be used as a fire escape to a flat roof should not have a lock and key, but if fitted with laminated glass still provides security.
For your protection fit smoke detectors, at least one per floor level, and check batteries regularly.