We put a thermal camera over the pool because a drowning is silent and a body under the water is warm for longer than it is visible. It sees heat, not light. After close the pool hall is dark and empty and the camera shows one warm shape, in the lifeguard chair, facing the water, at body temperature, until the first lifeguard climbs into it at six.
I am the pool manager at a leisure centre and I bought the thermal camera.
Why.
A person in trouble in water does not shout. They go under quietly and they are hard to see from the chair through the glare, and the thermal camera sees a warm body against cool water from any angle in any light, and it alarms if a warm shape stops moving under the surface. It is a good piece of kit and I would buy it again.
It records all night, because it is cheaper to leave it on than to have somebody turn it off.
After close, the pool hall is empty. The lifeguards clock off, the lights go off, the doors are locked. On the thermal camera the water is a flat blue, the tiles are a darker blue, and the lifeguard chair, which is the high chair at the deep end, has a shape in it.
The shape is body temperature. It is the size of a person sitting. It faces the water. It does not move except that, about every twenty minutes, the head turns to the shallow end and back, which is the scan a lifeguard does.
It is there from about half an hour after the last lifeguard leaves until the first one arrives, and when she climbs the chair in the morning the shape is not there for her to sit on, and the chair, she says, is warm.
What has been checked.
The camera. Replaced. The shape is on the second camera.
The chair. Nothing on it, nothing in it, no heater, no wiring. Cold to a hand at midnight, when I have gone in and put my hand on it, and warm on the camera at the same moment, with my own shape standing beside it, two warm shapes, one of which I could account for.
The pool hall on the ordinary camera. Empty. A chair with nobody in it.
The scan.
Every twenty minutes, the head turns. Shallow end, hold, deep end, hold. It is the scan pattern that is taught on the course, and it is done well, and I have watched a lot of lifeguards do it badly.
At about three in the morning, most nights, it does something else. The shape stands up in the chair and leans forward, towards the deep end, the way a lifeguard does when they have seen something, and holds, and sits.
I have gone through the water at the deep end on the thermal recording at those moments. There is nothing warm in the water. Whatever it is looking at is not warm.
What is done about it.
The night recording is not part of the safety file, because nothing happens in the pool at night. I have not shown it to anybody except the head lifeguard, who watched it, and said the scan was better than half her staff's, and asked me not to show it to them.
What I do.
I manage the pool.
We had a near miss in July, a boy of nine, in the deep end, under, about ten seconds, the sort that is over before the whistle if the lifeguard on the chair is looking the right way, and she was, and she was in the water and had him and it was nothing.
I asked her afterwards what made her look. She said she did not know. She said she had been scanning the shallow end and something made her turn, early, before the twenty minutes, and she looked at the deep end and he was under.
I went to the thermal recording of that afternoon. She is in the chair. At the moment she turns, there is a second shape in the chair with her, behind her, at body temperature, for about four seconds, leaning towards the deep end, and then it is gone, and she is in the water, and he is fine.
I have not told her. She would not sit in the chair. And I want it in the chair.