1. A power-operated door that closes when subject to an abnormally highambient temperature, an unusual rate of temperature rise, or an abnormal smoke condition.
2.A power-operated door that opens when a person or automobile approaches.
1. A power-operated door that closes when subject to an abnormally highambient temperature, an unusual rate of temperature rise, or an abnormal smoke condition.
2.A power-operated door that opens when a person or automobile approaches.