Dark brown square pipe with many branches
Yellow square pipe with branches beneath identical brown pipe
A very long round grey pipe on the ceiling.
Longest biggest around pipe on the ceiling.
A long grey and white tube on the ceiling.
a long thick pipe
large duct on a factory ceiling
yellow and grey overhead metal bars in a factory
the large duct hanging from the ceiling is made from metal.
the large duct hanging from the wall is gray in color.
a large pipe near the ceiling
a room filled with many pipes under construction in an industrial building