Model ACC-E(WHT)/SIL(HFP) is a Multi-Sensor, which which has been independently assessed and approved for use in a SIL2, low demand safety function with regards to random failure rates. The ACC-E(WHT)/SIL has three modes, which are controlled from the Control Panel, allowing either the optical element or thermal element or both elements to be active in making the fire decision. The sensor polling LEDs can be controlled via the Control Panel (pulsing/non-pulsing). The ACC-E(WHT)/SIL smoke chamber can easily be removed or replaced for easy maintenance.