A close view of a number of penstock valves on lagged pipework outside a golden buff brick-built building, possibly a boilerhouse, in Chatham Dockyard.

A close view of a number of penstock valves on lagged pipework outside a golden buff brick-built building, possibly a boilerhouse, in Chatham Dockyard. There are eight valves on three levels of inter-connected pipework and the building has a steel casement window with a pivotted central opening frame.