Final answer:
Heat detectors must be spaced properly in relation with open web bar joists. Specific depths of the top chord of the joist defined by fire codes dictate when the joist affects detector spacing. Knowing these specifics is crucial for the effective operation of fire protection systems.
Step-by-step explanation:
The question pertains to the installation of heat detectors and their spacing in relation to the construction features of a building, particularly in regards to open web bar joists. When dealing with fire protection systems and heat detector installation, it is important to consider the depth of the top chord of the bar joist. According to the National Fire Protection Association (NFPA), open web bar joists are not a factor in heat detector spacing unless the top chord is a certain depth which is typically defined in specific fire codes or standards. Details such as these are critical to ensure that the detectors operate effectively during a fire, detecting the rise in temperature and triggering the appropriate alarm and response systems.