How close to a sidewall may a heat detector be installed?

The correct choice indicates that a heat detector should be installed no closer than 4 inches to a sidewall. This distance is based on industry standards ensuring that the detector can accurately sense changes in temperature without interference from adjacent surfaces. Proximity to a wall can cause issues such as obstructed airflow or heat transfer, which may prevent the detector from functioning optimally.

By maintaining a minimum distance of 4 inches, you help ensure that the detector can detect heat rising in the room, which is essential for its responsiveness and reliability in an emergency situation. Adhering to this guideline is important for safety purposes, as it helps to ensure that the detection of potential fire conditions is both prompt and effective.

Other options suggest either too little or too great a distance, which could impair the heat detector's function. Keeping the right distance allows for the manufacturer's intended performance and aligns with safety regulations for fire detection systems.