Fire Detection Devices offers the standard CR 135 detector specially designed to respond to a rate of temperature increase resulting from an attack on a vault or safe door. The units are calibrated to recognize a rate of increase of 4 Celsius degrees per minute. The Models 7050 and 7050-C comply with the requirements set out in UL 681. Both Models are UL and ULC listed under control number 97Y8.
Model 7050 is a combination Rate-of-Rise and Fixed Temperature detector. A set of normally open contacts will close when the surrounding air temperature increases...
The suffix "C" denotes Normally Closed, so "7050 C" describes a heat detector suitable for vault and safe protection, with normally closed contacts.