A fire appliance's pump has a pressure gauge and a flow meter that log every litre delivered, because the water put on a fire is evidence, and the tank has a level sensor. In the bay, most nights, with the engine off and the pump disengaged, the pump logs eight hundred litres a minute at seven bar for about twelve minutes, and the tank level drops by what that delivers, and the bay floor is dry.
I am the driver, which on my watch means the pump operator, and the pump's log is mine to read after every job.
How the pump is logged.
The pump is driven off the engine through a power take off, and it delivers water from the tank or from a hydrant to the hoses. A pressure transducer and a flow meter log the delivery every second, with the time, to the appliance's data recorder, and the tank has a level sensor that logs too. After a job I download the log for the report.
With the engine off the pump cannot turn, because there is nothing to turn it.
Most nights, between two and three, in the bay, the pump logs a delivery.
About eight hundred litres a minute at seven bar, which is two hoses working, for about twelve minutes, and the tank level drops from full to about half, which is what twelve minutes at that flow takes out of an eighteen hundred litre tank.
The engine is off. The bay is dry. The tank is full in the morning.
Full in the morning is the part I did not believe until I stood there. The level sensor logs it dropping to half and then, over the next hour, rising back to full, with the hydrant inlet closed and the bay's fill hose on its reel.
What has been checked.
The recorder, replaced. The transducers, replaced. The tank sensor, replaced, and the tank dipped by hand at the times the log says it is half: half, by the dipstick, in a bay with a dry floor.
The pump. Its shaft has a rotation sensor for the maintenance schedule, and the sensor logs the pump turning at the speed that gives seven bar, at the time the log says, with the engine off and the power take off disengaged and the appliance in the bay with its keys in the watch room.
The bay. Cameras front and rear, showing the appliance standing dark and still, with nothing coming off it, while nine thousand litres, by the log, go through its pump.
The water.
It is going somewhere, by the pump's account, and coming back, by the tank's, and the bay floor has a drain in it and I have put a bucket over the drain and it stays dry.
I have connected a hose to the delivery on a night I stayed down, and run it to the yard, and sat by it with a torch at two.
At the time the log says the pump ran, the hose stiffened, the way a charged hose stiffens, and water came out of the branch at the yard end at about the pressure the log says, and it was warm, and it smelled of smoke, and it ran for twelve minutes and stopped, and the tank was half, and by four it was full.
What is done about it.
The pump's log is downloaded and the night deliveries are marked as test runs, which is a category, and the brigade's fleet engineers have serviced the pump twice and found it in excellent condition, which it is.
I have not told them about the hose.
What I do.
I drive, and I pump.
The one thing I have changed is that I do not sleep in the dormitory that backs onto the bay.
The watch sleeps upstairs and the driver's bunk is by the pole, above the bay, and from the bunk you can hear the appliance, and I used to like that.
At two, most nights, from the bunk, you can hear the pump. Not the engine, which is off. The pump's own note, the whine it makes at seven bar, through the floor, for twelve minutes, and under it, on the nights I have listened, the sound of two branches working, the hiss and the beat of them, and men's voices, short, the way men talk on a job, and one of them is mine.