Sven,
I think that the pipe there, is PB plumbing pipe, that's been painted over.
The person that installed this mess wasn't hanging around, I'd at least have fitted a few more saddles to the pipe, to make sure it was nice and straight!.(If my work standard WAS this rough!)
Are these fittings legal, for this type of use?, I note that you said that they are used as ceiling fixtures.(Indoors, I assume)
One more thing, them lamps are pointing pretty much up in the air, OK if you want to light the sky up.
