About: http://webisa.webdatacommons.org/403097023

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	above a ceiling by which air is passed through the ceiling into a room is a generally planar integral circular structure formed of a rigid material, such as sheet metal.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com