... with fusible alloy such as Wood's metal and other alloys with similar compositions. The glass bulb ... Below the design temperature, it does not break, and above the design temperature, it takes less time for ... response time index (RTI), which typically has values between 35 and 250 m½s½, where a low value indicates ... Of course, if a ceiling has been painted, and some paint gets on a bulb, it will not ...