Flooding-point data for packing materials are in reasonable agreement with the upper curve of the GPDC chart of Figure 6.35. Unfortunately, this is not always the case for pressure drop. Reasons for this are discussed by Kister [33]. As an example of the disparity, the predicted pressure drop of 0.88 inch H2O/ft in Example 6.13 for IMTP packing at 70% of flooding is in poor agreement with the 0.63 inch/ft determined from data supplied by the packing manufacturer.