Engineering bricks are a type of brick used where strength, low water porosity or acid (flue gas) resistance are needed. Engineering bricks can be used for damp-proof courses. Clay engineering bricks are defined in § 6.4.51 of British Standard BS ISO 6707-1;2014 (buildings & civil engineering works - vocabulary - general terms) as "fire-clay brick that has a dense and strong semi-vitreous body and which conforms to defined limits for water absorption and compressive strength"