The fire pump in a small DC condo building: churn tests, the annual flow test, and what the board owes

Somewhere in the cellar of a lot of four and five story condo buildings in Northwest and on the Hill there is a green or red pump on a concrete pad, a controller cabinet beside it, and a log sheet that stopped getting filled in a few managers ago. The pump is there because DC street pressure on the high ground, Mount Pleasant, Petworth, the upper blocks of Georgetown, could not reach the top floor heads with enough left over. This article covers what the pump does, the two tests it needs, what the log is for, and what a board that inherited one owes.

Why a small building has a pump

A sprinkler system is a hydraulic calculation. The designer picks the most remote heads, figures the pressure needed to flow them, adds the pipe losses down to the street, and compares that with what a flow test showed the main could give. Where the street comes up short, the design adds a pump. In a two unit rowhouse that is usually a small booster, and the low pressure article covers that case. In a condo building of thirty or forty units with heads six stories above the main, it is a listed fire pump with its own controller and, in most District buildings, an electric motor.

Beside it sits a jockey pump. The jockey is small and runs often. It holds the system at pressure against the small leaks and the overnight temperature drops that every system has, so the big pump does not start for nothing. When the main pump starts on its own, it is because pressure fell past what the jockey could hold, and that is the sound of either a flowing head or a problem.

The no flow test

The short test is called a churn test or a no flow test. Someone starts the pump, lets it run against closed valves, watches the suction and discharge gauges, checks the packing drips, listens, and shuts it down. Ten minutes for an electric pump. The point is to prove the controller still starts it and the motor still turns.

How often depends on the edition of NFPA 25 the District is enforcing and on the pump. Diesel pumps run weekly. Electric pumps ran weekly under older editions and monthly under the newer ones for most buildings. Ask your contractor which frequency your building is held to and write it on the log sheet. A log that shows the pump started every month for three years is worth more to a fire inspector than any invoice.

Most buildings this size have no engineer on staff, so the churn test lands on the manager, a board member, or the sprinkler contractor on a service contract. Any of those works. What does not work is nobody. A pump that has not turned in a year has a fair chance of not turning when a head opens, and the first anyone learns of it is the notice of violation or the fire.

The annual flow test

Once a year the pump is run under real load. The contractor opens the test header outside, or a flow meter in the pump room, flows water at three points, no flow, the rated flow, and one and a half times the rated flow, and reads pressure, current and voltage at each. Those readings are plotted against the curve the pump shipped with and against last year's test. A pump that is losing ground shows it here before it shows it anywhere else.

The flow test needs planning in a rowhouse block. The test header puts a lot of water into the alley or the street for ten minutes. Neighbors should hear about it the day before, the drain should be checked for leaves, and nobody should park in front of the outlets. The contractor files the result with the annual sprinkler report, and the inspection report article explains how to read the findings that come with it.

The findings that come up

Packing that drips too much or not at all, which is an adjustment. A controller with a pressure switch set wrong so the pump starts late. Batteries, on the rare diesel. A suction gauge that reads low because the backflow upstream is fouling. A pump room with the heat turned off, which in a cellar on a January night is a frozen test line. And the one that matters most, a flow test that comes in under the curve, which can be worn impeller, a suction problem, or a street supply that is weaker than it was when the building was built. The main break article covers the street side of that.

What the board owes

The pump is a common element. The association inspects it, tests it, logs it, and keeps the reports, the same as the rest of the system. When Fire Prevention walks the building, the pump log and the last flow test are the first two things they ask to see in the cellar.

Budget for it. A fire pump is the one part of a residential sprinkler system with a motor, a controller and moving parts, and it is the line in the reserve study most often missing. The reserve study article explains how to get the pump onto the schedule so its replacement is a line item and not a special assessment.

And keep the power on. An electric fire pump that loses its feed is an impairment, and a building that shuts off the pump breaker to stop the jockey from cycling at night has disabled its own protection. The power outage article covers what happens when the feed goes down for reasons nobody chose.

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