Spot-Type Pneumatic Rate-of-Rise Detector 2 : A fire detector consisting of an air chamber, diaphragm, contacts, and compensating vent, in a single enclosure
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}