An apparatus and method for detecting a pattern warning signal from a hazard alarm. In one embodiment, a buffer memory is used to store filtered, digitized information from an audio or optical detection device. A processor evaluates the information in the buffer memory to determine when a long lull time occurs between energy peaks present in a sampling of information from the analog-to-digital converter. The results are compared to at least one temporal pattern characteristic to determine if the hazard alarm has detected a hazardous condition.