vertical downstand face of an area of lower ceiling beyond. This usage presumably derives from experience on boats where to maintain the structural function personnel openings through bulkheads always retain a portion of the bulkhead crossing the head of the opening. Head strikes on these downstand elements are commonplace, hence in architecture any overhead downstand element comes to be referred to as a bulkhead. The term is also used to refer to large retroactively installed pressure barriers for temporary or permanent use, often during maintenance or construction activities. See also References External links Britannica definition Merriam-Webster definition WIPO Bulkhead for motor vehicle Canadian Armed Forces Glossary, see Fire Zone, page 5 of 14 Det Norske Veritas Type Approval for a fire damper inside and A60 bulkhead Subject-related patent by Free Patents Online An example treatise on the use of A60 bulkheads onboard tankers. Shipbuilding Nautical terminology Chinese inventions Ship compartments