Are Semi Rigid/ Radial duct systems as efficient as rigid ducting and is it SAP tested?
The semi-rigid ducting system has been classified as equally efficient in performance as the rigid duct work. See notes on the SAP Appendix Q website:
“A Semi-Rigid duct system is defined as a unique product supplied by a manufacturer or supplier comprising the components required for assembly of that system. Systems listed within the SAP Appendix Q database have demonstrated that their performance, when installed in a variety of configurations, is at least equal in terms of aerodynamic performance to SAP performance data for Rigid duct. It is therefore possible to select Rigid duct performance data when listed Semi-Rigid duct systems are specified for a dwelling. Refer to Specification Requirements for further details.”