BTS Travaux Publics - Eduscol Retrotec test fans, blower door systems, duct testing systems and gauges ... EN13829, EN15004, FD E51-767, ISO 9972-2015, ISO 14520-2006, ... route cord under furniture or appliances. Arrange cord away from traffic area and where it will not be tripped ... Use simulator in Virtual Gauge, or the DM32 Flow Calculator?.