Each type of heat detector has its advantages, and it cannot be said that one type of heat detector should always be used instead of another. If one were to place a rate-of-rise heat detector above a large, closed oven, then every time the door is opened a nuisance alarm could be generated due to the sudden heat transient. In this circumstance the fixed threshold detector would probably be best. If a room filled with highly combustible materials is protected with a fixed heat detector, then a fast-flaming fire could exceed the alarm threshold due to thermal lag. In that case the rate-of-rise heat detector may be preferred.