Dummy mullions and transoms, which are used to simulate small pane glazing frames while using large panes of glass, both to the inside and outside of double glazing units, will have no effect on thermal safety, if Pilkington Optifloat™ Clear is combined with Pilkington K Glass™ , Pilkington K Glass™ S or Pilkington Optitherm™ S1 Plus are specified.  There is no need to submit requests for thermal stress calculations for these products where dummy frame members are used unless there are other aspects present that are detrimental to thermal safety, e.g. backups (including blinds/curtains), shadows, heaters, etc.

Where solar control glass is specified, the effects from the dummy frame members will be only marginal and will be taken into account when carrying out the standard thermal stress calculations. There is still no need to submit requests for thermal stress calculations for these products where dummy frame members are used unless there are other aspects present that are detrimental to thermal safety, e.g. backups (including blinds/curtains), shadows, heaters, etc.