Thank you for the response Dr. Dubbeldam. You are right, with blocking, the He void fraction is 0.43, as opposed to 0.49 without blocking. The way I obtained this was installing the latest version of RASPA (2.0.45), as opposed to the earlier version that I was using (RASPA 2.0). In RASPA 2.0, there is no difference in He void fraction computed with and without blocking as can be seen below from the output files. RASPA 2.0 does not read the block file, as opposed to RASPA 2.0.45.
RASPA 2.0 :
Number of pockets blocked in a unitcell: 0
Pockets are blocked for this component
Block-pockets Filename: FAU.block
RASPA 2.0.45 :
Number of pockets blocked in a unitcell: 56
Pockets are blocked for this component
Block-pockets Filename: FAU.block
Block center: 9.412125 21.961625 9.412125 distance: 3.000000
Block center: 21.961625 21.961625 21.961625 distance: 3.000000
Block center: 9.412125 9.412125 21.961625 distance: 3.000000
Block center: 21.961625 9.412125 9.412125 distance: 3.000000
Block center: 15.686875 3.137375 15.686875 distance: 3.000000
Block center: 3.137375 3.137375 3.137375 distance: 3.000000
Block center: 15.686875 15.686875 3.137375 distance: 3.000000
Block center: 3.137375 15.686875 15.686875 distance: 3.000000
Block center: 0.000000 0.000000 0.000000 distance: 1.000000
Block center: 6.274750 6.274750 0.000000 distance: 1.000000
Block center: 12.549500 12.549500 0.000000 distance: 1.000000
Block center: 18.824250 18.824250 0.000000 distance: 1.000000
Block center: 6.274750 0.000000 6.274750 distance: 1.000000
Block center: 12.549500 0.000000 12.549500 distance: 1.000000
Block center: 18.824250 0.000000 18.824250 distance: 1.000000
Block center: 0.000000 6.274750 6.274750 distance: 1.000000
Block center: 0.000000 12.549500 12.549500 distance: 1.000000
Block center: 0.000000 18.824250 18.824250 distance: 1.000000
Block center: 12.549500 6.274750 18.824250 distance: 1.000000
Block center: 12.549500 18.824250 6.274750 distance: 1.000000
Block center: 18.824250 12.549500 6.274750 distance: 1.000000
Block center: 6.274750 12.549500 18.824250 distance: 1.000000
Block center: 6.274750 18.824250 12.549500 distance: 1.000000
Block center: 18.824250 6.274750 12.549500 distance: 1.000000
Block center: 23.791760 23.791760 20.131489 distance: 0.500000
Block center: 20.131489 20.131489 20.131489 distance: 0.500000
Block center: 20.131489 23.791760 23.791760 distance: 0.500000
Block center: 23.791760 20.131489 23.791760 distance: 0.500000
Block center: 11.242260 11.242260 20.131489 distance: 0.500000
Block center: 7.581989 7.581989 20.131489 distance: 0.500000
Block center: 7.581989 11.242260 23.791760 distance: 0.500000
Block center: 11.242260 7.581989 23.791760 distance: 0.500000
Block center: 4.967510 1.307239 1.307239 distance: 0.500000
Block center: 4.967510 4.967510 4.967510 distance: 0.500000
Block center: 1.307239 1.307239 4.967510 distance: 0.500000
Block center: 1.307239 4.967510 1.307239 distance: 0.500000
Block center: 4.967510 13.856739 13.856739 distance: 0.500000
Block center: 4.967510 17.517010 17.517010 distance: 0.500000
Block center: 1.307239 13.856739 17.517010 distance: 0.500000
Block center: 1.307239 17.517010 13.856739 distance: 0.500000
Block center: 20.131489 7.581989 7.581989 distance: 0.500000
Block center: 20.131489 11.242260 11.242260 distance: 0.500000
Block center: 23.791760 7.581989 11.242260 distance: 0.500000
Block center: 23.791760 11.242260 7.581989 distance: 0.500000
Block center: 13.856739 13.856739 4.967510 distance: 0.500000
Block center: 17.517010 17.517010 4.967510 distance: 0.500000
Block center: 13.856739 17.517010 1.307239 distance: 0.500000
Block center: 17.517010 13.856739 1.307239 distance: 0.500000
Block center: 17.517010 4.967510 17.517010 distance: 0.500000
Block center: 13.856739 4.967510 13.856739 distance: 0.500000
Block center: 13.856739 1.307239 17.517010 distance: 0.500000
Block center: 17.517010 1.307239 13.856739 distance: 0.500000
Block center: 7.581989 20.131489 7.581989 distance: 0.500000
Block center: 11.242260 20.131489 11.242260 distance: 0.500000
Block center: 7.581989 23.791760 11.242260 distance: 0.500000
Block center: 11.242260 23.791760 7.581989 distance: 0.500000