The panel has eight zones. Seven of them are wards. Zone seven is a corridor of ground that has been a car park for twenty years, and twice a year it tells me the oxygen pressure there is falling.
I am an authorised person for medical gases at a district general. That is a formal role with a certificate behind it and it means that when the oxygen does something, I am the one who goes.
I want to explain the panel because everything here is on it.
Piped medical gases run through a hospital the way water does: oxygen, nitrous, medical air, and vacuum, from a manifold or a VIE outside, through valves and pipework, to terminal units at every bed head.
Every zone has an area valve service unit, a box on the wall with a valve and a pressure sensor. If the pressure in that zone goes outside its window, the sensor tells the panel, and the panel goes off at switchboard, at estates, and at the nurses' station in that zone.
It is a two-tone alarm and there is no snooze on it. You go, and you keep going until you know why.
Our panel has eight zones.
Zone seven is labelled, in the original engraved plastic from the 1988 install, EAST WING GROUND.
The east wing came down in 2004. I was not here then; I came in 2009. There is a photograph of it in the corridor by the league of friends shop and it was a two storey brick thing with a flat roof and it looks like every hospital building of its year.
Where it stood is a car park with fourteen spaces and a smoking shelter nobody is supposed to use.
Twice a year, roughly, zone seven alarms.
Low pressure, oxygen.
The first time was in the October of 2010 and I did exactly what I was trained to do, which is go. I went to where the panel says zone seven is, which the drawings put at the east end of the ground floor link corridor, and I stood at a fire door looking out at a car park in the rain at twenty past three in the morning.
Then I went and found the AVSU for zone seven, which is still on the wall in the link corridor because you do not rip out a gas box for the sake of tidiness, and the gauge on it read what a capped and drained leg should read, which is nothing.
And the panel was showing low pressure.
Not no pressure. Not a fault. A falling pressure in a line that has been cut, capped, purged and certified dead for twenty years.
Here is what has been done about it, over fifteen years, by people other than me.
2011: the panel was replaced. New panel, new head end, same field wiring. It alarmed again in 2012.
2014: the field wiring for zone seven was disconnected at the panel and the zone was configured out. Physically disconnected, terminals empty, and the configuration set to seven active zones.
It alarmed in the November of 2015, on a panel where that zone did not exist in software and had no wire in it. The engineer who came out from the manufacturer wrote in his report that the alarm was not reproducible and that he had found no fault, and that is a completely honest thing for him to have written.
2017: the whole leg was traced with the intent of removing it. That is when we found that it is not capped where the drawings say.
The drawings say the east wing leg was cut and capped at the link corridor when the wing came down.
It was not. It was capped about eleven metres further east, which is under the car park, and the eleven metres between is live pipe with a valve on it that is shut.
Nobody could tell me why. The demolition was done by a contractor who no longer exists and the as-builts were never updated, which is depressingly normal.
We proposed removing it. It got as far as a quote and then it did not happen, because taking up eleven metres of car park to remove a dead pipe is forty thousand pounds and there is always something more urgent, and I have watched that decision get made four times now and I would make it the same way.
So there are eleven metres of oxygen pipe under a car park with a shut valve at one end and a cap at the other.
And twice a year something tells a panel it is not connected to that the pressure in it is falling.
I have done one thing that is not in any report.
In 2021 I put a gauge on the test point at the AVSU and left it there, with a data logger, for fourteen months. It is not a difficult thing to do and it did not cost anything and nobody asked.
The line holds nothing. Flat, at atmospheric, for fourteen months, which is what a dead leg does.
Except on the two nights it alarmed.
On both of those nights the logger shows the line at three point nine bar for about forty minutes, and then falling, over about six minutes, to nothing.
Three point nine bar is not a random number. Piped oxygen at a terminal unit runs at four bar nominal, and a line at the bottom of its tolerance, being drawn from, reads three point nine and falling.
Something was in that pipe, at working pressure, and then it was used.
I have not shown anybody the logger data and I am not going to, and I know how that sounds coming from a man with a certificate that exists precisely so that somebody is accountable.
Here is why.
If I take that to my head of estates, the outcome is not an investigation. The outcome is that eleven metres of pipe under a car park becomes a live gas asset again, on a register, requiring a permit, an annual certification and a testing regime, and the first thing anybody will do is open the valve to test it properly.
And I have been doing this for a long time and I have never once been able to think of a good answer to the question of where the oxygen in that pipe was going.
So the valve stays shut. I sign what I can honestly sign, which is that zone seven is isolated, which it is. And twice a year, at some point in the night, a panel with no wire in it tells me that somewhere under a car park with fourteen spaces, something is breathing.