Read this link, and I think it will help you understand what sprinklers is all about and enhance what Jack is saying.
In reading this post, it sounds like the sprinkler system was installed under 13R because it was a bussiness. If that is the case, chances are it was connected to a central fire alarm panel also and a dialer to call out a general alarm to a security monitoting company.
Now that it is a one unit residential, it would only need to meet the NFPA 13D requirements. A lot mor lenient on coverage, (200 sq. ft. per head at 15 gals. per minute.)
Depending on your local, it does need to be inspected by a licensed Sprinkler System Contractor at least ounce a year.
On a wet system, with water coming from the City ex. , it would be a separte water line in most cases and have a shut off on the exterior, and one on the inside. Then it would be an RPZ valve or backflow preventer, another valve and then up to the main sprinkler valve equiped with a tamper alarm switch.
Then it would be the alarm valve which sets off the fire alarm upon flow, indicating a fire or broken head.
A dry system is just air and used mostly for sprinkler pipes in a remote region of the dwelling or establishment that are prone to freezing.
A small air compressor would be the indicator of this type of system.
You can also have a wet system with a glycol loop.
This is where no air is required, the system is wet, and a portion of the system, lets say in the attic area, needs to be protected from freezing, so glycol is added to that portion of the rest of the system with a loop and backcheck valve to hold the glycol contained.
Either system would have a drain valve on what I call the Main tree to empty the system to the outside.
Hope this helps a little.