Final answer:
The question pertains to the Engineering subject, relating to where shutoff valves should be installed. They should be accessibly located to allow for easy operation during maintenance or emergencies, following the norms set by relevant codes.
Step-by-step explanation:
The subject of the question appears to pertain to the field of Engineering, specifically relating to the installation and placement of shutoff valves. Shutoff valves are critical components in various systems, including plumbing, HVAC, and gas systems. They allow for the interruption of flow for maintenance, repair, or in the case of an emergency. The applicable building or safety codes will generally dictate where and how shutoff valves should be installed. They should be accessibly located to ensure that they can be easily reached when needed. This typically means in a location that can be reached without the need for removing obstacles, using ladders, or opening locked doors during an emergency.