A combined fire suppression and detection system is described. The system comprises a fire panel 12 having a loop driver. A combined detection and suppression loop 18 is connected to the loop driver. A plurality of fire detection devices 14 and a plurality of fire suppression devices 19 are coupled to the detection and suppression loop 18. The fire suppression devices 19 comprise multiple sprinkler devices 19, each of the sprinkler devices 10 comprising a sprinkler bulb 100 and a circuit 120. The circuit 120 of the sprinkler device 10 is detectable via the fire panel 12 using the detection and suppression loop 18 in order to provide information from the sprinkler device 19 to the fire panel 12. A example method of use of the system includes testing of the system in order to ensure that the fire detection and/or fire suppression devices are correctly installed and/or are working correctly by using the fire panel 12 to obtain information from the circuits 120 of the sprinkler devices 19 in order to check that the sprinkler devices 19 are correctly installed, that installed sprinkler devices 19 are of the correct type and/or to identify sprinkler devices 19 that have been tampered with or otherwise damaged.