The incomplete ironwork in this part-demolished building is the remains of a water-tube boiler, consisting of cylindrical drums which were linked by groups of pipes, most of them curved, passing through the firing area. This layout, with three drums above and two at the bottom, was known as a Stirling boiler. The firing door and ash removal doors are at the east end and the doors in the side were for maintenance access. Inside the firing area the pipes (water tubes) have been removed, their position shown by lines of holes in the drums.
W J Crompton, RCAHMW, 17 September 2009.

Part of Porth Wen brickworks (Nprn40736).