1. Centre for Window and Cladding Technology, Univ. of Bath, Claverton Down, Bath BA2 7AY, U.K (corresponding author).
2. Centre for Window and Cladding Technology, Univ. of Bath, Claverton Down, Bath BA2 7AY, U.K.
3. Centre for Window and Cladding Technology, Univ. of Bath, Claverton Down, Bath BA2 7AY, UK.