Final answer:
A smoke or heat detector may be recessed in the mounting surface if it is designed to be mounted this way and meets the necessary safety standards.
Step-by-step explanation:
Recessed smoke detectors are typically designed to be flush with the ceiling or wall, providing a more aesthetically pleasing appearance. Additionally, recessed mounting can help protect the detector from accidental damage.
One example of a recessed smoke detector is the ceiling-mounted model, which fits snugly into a cutout in the ceiling. This type of detector usually has a trim ring that covers the gap between the detector and the ceiling, creating a seamless look.
Regardless of whether a smoke or heat detector is recessed or surface-mounted, it is important to follow the manufacturer's instructions for proper installation and placement to ensure optimal performance and reliable detection of smoke and heat.