Here's the Emergency Shower at Anglian Water's Newton on Trent Pumping Station, which is one of several water sources which supply the city of Lincoln.
If you spill some fluosilicic acid on yourself, this is where you run to try and save your skin, subcutaneous fat, underlying muscle, bone, heart rhythm, neurotransmitters, and anything else which might be interfered with by having a load of calcium suddenly sucked out of you.
The story goes that the Lincoln Division's Chief Chemist was showing some apprentices around one of the pumping stations where fluoride is added.
Dr Butterfield was giving a safety lecture. The group came to the Emergency Shower, to be told how to operate the high pressure water jet to avert possibly lethal acid burns.
"...And you pull this chain like so," he explained, and gave it a yank.
Unfortunately, the only thing to emerge was a brief and pathetic comedy dribble, immediately followed by much giggling from the assembled waterworks apprentices.