Understanding of the behaviour of laminated glass under blast loading is fundamental to the successful design of curtain walling against explosions. Several engineering model are available which describe the pre- and post-crack capacity of laminated glass suitable for formulation in a Single Degree of Freedom analysis, but each suffers from limiting underlying assumptions and the lack of systematic examination of the behaviour of laminated glass under blast loading means there is no general agreement about the analysis methods for design. This paper reports the development of a validated engineering model of laminated glass under blast loading, which is an evolution of those currently adopted in the UK and the US and have their foundation in UK and US full-scale blast tests undertaken since the mid-1980s. The model defines the pre- and post-cracked phases of the material response. The energy absorption in the pre-crack phase relative to the post-crack phase is small; therefore this paper focuses on the post-crack behaviour. The model is based on smeared material properties representing the nonlinear behaviour of the laminated pane in the post-crack phase, which avoids the need for explicit assumptions about the crack patterns and densities or the development of bond stresses in the pvb-glass interface. The reaction forces applied by the pane are calculated from measured stresses/strains using digital image correlation and strain gauge data, and are employed as an indirect means of deriving the internal resistance of the system. A generalised SDOF algorithm is used to develop a revised resistance function fitted to the experimental test data and the findings of these SDOF assessments reported. Investigation is made of the time-varying nature of the load- and mass-transformation factors for incorporation into the ongoing development of the model, and the next steps in the development of the glazing model are outlined.