The placard on your sprinkler riser: reading the hydraulic nameplate, the head date stamp and the inspection tag on a Maryland home system.

A buyer walks a Clarksburg basement with her inspector, finds the sprinkler riser in the utility room, and sees a small metal plate riveted to the wall beside it with a dozen numbers on it. A paper tag hangs off the valve handle. A second tag hangs off the backflow preventer. Nobody on the walk can read any of it, so it goes in the report as present. Those three pieces of paper and metal, plus the stamp on every head in the ceiling, are the whole written record of what the system was built to do and whether anyone has checked it since. Here is what each one says.

The hydraulic nameplate

The metal plate is the hydraulic design placard. The contractor who designed the system fills it in at installation and it stays on the wall for the life of the house. On a residential 13D system it lists the design area, which is usually the two most demanding heads in the house and the room they sit in, the flow each of those heads needs in gallons per minute, the total demand for the system at the base of the riser in gallons per minute and pounds per square inch, and the contractor’s name and the date. Some plates add the pipe schedule or the water supply the design assumed: a street main at a stated pressure, or a well tank and pump at a stated flow.

The number that matters most to an owner is the pressure at the base of the riser. That is what the house has to deliver to the system when two heads open, and it is the number to hold up against the gauge on the riser on a quiet day. A gauge reading well above the placard demand is a system with margin. A gauge sitting at or under it is a system that needs a flow test before anyone trusts it, and our guides to reading the pressure gauge and low water pressure on a sprinkler system cover both halves of that comparison. On a well lot in Carroll or north Baltimore County the placard demand is also the number the pump and tank were sized to, and our guide to well tank and pump sizing explains what happens when a replacement pump does not meet it.

The sign at the control valve

Separate from the placard is a sign at the main shutoff. NFPA 13D asks for a permanent sign at the control valve that identifies it as the fire sprinkler valve and says that it stays open, because the most common way a home system gets disabled is a plumber or a new owner closing a valve they did not recognize. The sign should also point to the location of the valve if the valve is not in plain sight, and newer systems carry an owner information sheet near it with the contractor’s number and the maintenance the owner is expected to do. Our guide to the control valve walks through the handle and the drain, and our guide to residential sprinkler maintenance covers the owner checks that sheet describes.

The stamp on every head

Every sprinkler head carries its own record on the frame or the deflector: the manufacturer, a model number, a temperature rating, and the year it was made. The temperature rating is the one owners can use. Most heads in a Maryland house are the ordinary rating, around 155 degrees Fahrenheit, with a red bulb. Heads near a wood stove, over a range, in an attic or in a hot garage carry a higher rating, around 175 or 200, with a yellow or green bulb, and our guide to heads near a wood stove or fireplaceexplains why a swap to the wrong rating opens heads on a hot day. The year matters at resale and at the twenty year mark. Residential heads are fast response heads, and the national inspection standard calls for a sample of them to be tested or the heads replaced once they reach twenty years in service, then on a shorter cycle after that. A house built under Maryland’s statewide sprinkler requirement in 2011 or 2012 is coming up on that date, and our guide to how long a home sprinkler system lasts covers what the test involves. The model number is also what you check against a recall, which our guide to recalled sprinkler heads walks through.

The inspection tag

The paper or plastic tag on the valve handle is the annual inspection record. It carries the date of the last visit, the name and Maryland State Fire Marshal fire protection license number of the contractor, and usually a punch or a checkbox for what was done: gauges read, control valve exercised, main drain flowed, heads walked, alarm tested. A tag with a date inside the last twelve months is what an insurer, a buyer or a Prince George’s County rental license inspector is looking for. A tag that is three years old is a system nobody has looked at, and our guide to what an inspection costs covers the visit that replaces it with a current one and a written report. Our guide to sprinklers in a Maryland rental covers the license inspections where the tag is the first thing checked.

The backflow test tag

The second tag hangs on the backflow preventer, the assembly between the house water and the sprinkler pipe. It records the test date, the tester’s certification number and the result, and it is a different credential from the sprinkler license, which is why some houses have two contractors’ names in the utility room. Baltimore County mails a test notice on its cycle for houses on metro water, WSSC and Baltimore City have their own records, and the tag is what closes the notice. Our guides to backflow testing in Baltimore and the backflow testing page cover the test and what a failed one means.

When the placard is missing

A lot of the 2011 to 2015 systems in Maryland have no placard at all. The contractor hung the valve tag and skipped the plate, or the plate came off the wall during a basement finish. The design information is not lost. The permit file at Howard County, Montgomery DPS, Anne Arundel or whichever county issued the sprinkler permit holds the hydraulic calculations and the drawings, and a licensed contractor can pull them and make a new plate. We do that as part of an annual inspection when a house has none, because the placard is what the next inspector compares the gauge to. If you are buying, ask the seller for the placard information, the last inspection report and the last backflow test before closing, and our guides to buying a house with fire sprinklers and the new construction handover list the rest of the paperwork. The inspection that produces all of it is on our annual inspection page.