A movie, likely from 1950s or very early 1960s. I believe it was with aliens. When a couple of the characters were walking through what I remember looked like some factory/facility, blood was dripping onto the floor. It was coming from an overhead pipe. It was apparently from a group member that was placed in the pipe (pressurized?).
This is Quatermass 2 (1957).
Quatermass 2 (a.k.a. Enemy From Space in the United States and Canada) is a 1957 black-and-white British science fiction horror film drama from Hammer Film Productions, produced by Anthony Hinds, directed by Val Guest, that stars Brian Donlevy, and co-stars John Longden, Sidney James, Bryan Forbes, Vera Day, and William Franklyn. Quatermass 2 is a sequel to Hammer's earlier film The Quatermass Xperiment (1955). It was originally shown in the UK as Quatermass II. Like its predecessor, it is based on the BBC Television serial Quatermass II written by Nigel Kneale. Brian Donlevy reprises his role as the eponymous Professor Bernard Quatermass, making him the only actor to play the character twice in a film. It is considered as the first film sequel to use the ‘2’ / ‘II’ suffix within the title.
The film's storyline concerns Quatermass's investigation of reports of hundreds of meteorites landing only in the Winnerden Flats area of the UK. His inquiries lead him to a huge industrial complex, strikingly similar to his own plans for a Moon colony. This top-secret facility is in fact the centre of a conspiracy involving the alien infiltration of the highest echelons of the British Government. Quatermass and his allies must now do whatever is necessary to defeat the alien threat before it is too late.
This review mentions blood dripping from a pipe clogged with bodies.
An overhead pipe is cracked and blood drips on them from it. Oddly enough, some of the protestors have just been taken into one of the tanks. Putting two and two together, Quatermass exclaims, “That pipe has been blocked by human pulp!”
The scene in question can be viewed at the 2:25:43 mark in the video below.