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OCR for page 49
49 For the Octagon MaxFlo 100/0 base case, the frequency of range distance. The results are given in Table 32. Because the tests generating a percentage difference greater than 20% lake-effect data was collected at an OAT lower than -3C increased from: (26.6F), fluid ABC-S at the 50/50 strength is not included in 2% at the shortest distance; to the analysis. 17% at mid-range distance; and The table shows that the frequency of cases where the 26% at the longest distance. between-site difference in HOT is 20% or more of the lower For the ABC-S 75/25 base case, the frequency of tests gen- site value is substantially greater for the lake-effect data. Much erating a percentage difference greater than 20% increased of the increase shows up in the above 50% difference category. from: 1% at the shortest distance; to Relationship Between Site-Separation-Distance 21% at mid-range distance; and and Between-Site HOT Differences Excluding 28% at the longest distance. Lake-Effect Data For the ABC-S 50/50 base case, the frequency of tests gen- erating a percentage difference greater than 20% increased Syracuse Hancock International Airport was selected for from: tests as it offered an opportunity to study lake-effect snowfall. 0% at the shortest distance; to Precipitation rates were recorded during one event, on Janu- 38% at mid-range distance; and ary 8, 2009. 42% at the longest distance. The lake-effect snowfall data was included in the previous analysis of between-site HOT differences versus distance sep- The mid-range distance showed a higher frequency of cases aration between sites. Because this data occurred only in the having between-site differences greater than 50%. mid-range distance, it would distort the true relationship of This examination shows that a relationship does exist be- between-site HOT differences versus distance. The base case tween site-separation distance and size of between-site hold- data was re-examined with the lake-effect snowfall data re- over time differences. moved. The results of the analysis with the lake-effect snow- fall data removed are given in Table 33. Examination of Lake-Effect Snowfall Removal of the lake-effect data produces a smoother rela- on HOT Differences tionship of HOT difference to distance, removing the bulge at the mid-range distance seen in the previous analysis (Table 31). The impact of lake-effect snowfall was examined by looking The final results by fluid type are: at the lake-effect snowfall data in isolation and comparing it to other data collected within the same site-separation range. For the Type I fluid base case, the frequency of tests generat- The lake-effect data was collected at a between-site distance ing a percentage difference greater than 20% increased from: of 8,300 ft, placing it in the mid-range for distance analysis. To 4% at the shortest distance to examine its influence on HOT at the two sites, the lake-effect 12% at mid-range distance and data was compared to the other data collected at the mid- 15% at the longest distance. Table 32. Effect of lake-effect snowfall on between-site HOT differences (20072008). Number of Tests where Difference Between Sites is Distance Range # (%) Fluid Type 7017 to 13390 ft 50% Total Type I no lake-effect 44 (88%) 2 (4%) 4 (8%) 0 (0%) 50 (100%) HOTs in Snow lake-effect 18 (56%) 2 (6%) 4 (13%) 8 (25%) 32 (100%) Clariant no lake-effect 45 (90% 3 (6%) 1 (2%) 1 (2%) 50 (100%) 2012 100/0 HOTs in Snow lake-effect 25 (78%) 3 (9%) 0 (0%) 4 (13%) 32 (100%) Octagon no lake-effect 44 (88%) 3 (6%) 2 (4%) 1 (2%) 50 (100%) MaxFlo 100/0 HOTs in Snow lake-effect 24 (75%) 5 (16%) 0 (0%) 3 (9%) 32 (100%) ABC-S 75/25 no lake-effect 43 (86%) 4 (8%) 2 (4%) 1 (2%) 50 (100%) HOTs in Snow lake-effect 22 (69%) 5 (16%) 1 (3%) 4 (13%) 32 (100%)

OCR for page 49
50 Table 33. Relationship of between-site differences and distance (excluding lake-effect data 20072009). Type I Holdover Times in Snow - Measured Rates (without lake-effect data) Number of tests where difference between Distance Range sites is (ft) 20% to 30% to 50% Total 29.9% 49.9 % 4167 5052 64 3 67 96% 4% 100% 7017 13390 44 2 4 50 88% 4% 8% 0% 100% 27800 28500 78 6 6 3 93 84% 6% 6% 3% 100% Total tests 186 11 10 3 210 analyzed 89% 5% 5% 1% 100% Clariant 2012 100/0 Holdover Times in Snow - Measured Rates Octagon MaxFlo 100/0 Holdover Times in Snow - Measured Rates (without lake-effect data) (without lake-effect data) Number of tests where difference between Number of tests where difference between Distance Range sites is Distance Range sites is (ft) 20% to 30% to (ft) 20% to 30% to 50% Total 50% Total 4167 5052 66 1 67 4167 5052 65 1 1 67 99% 1% 100% 97% 1% 1% 100% 7017 13390 45 3 1 1 50 7017 13390 44 3 2 1 50 90% 6% 2% 2% 100% 88% 6% 4% 2% 100% 27800 28500 73 14 6 93 27800 28500 68 16 6 3 93 78% 15% 6% 100% 73% 17% 6% 3% 100% Total tests 184 18 7 1 210 Total tests 177 20 9 4 210 analyzed analyzed 88% 9% 3% 0% 100% 84% 10% 4% 2% 100% ABC-S 75/25 Holdover Times in Snow - Measured Rates ABC-S 50/50 Holdover Times in Snow - Measured Rates (without lake-effect data) (no lake-effect data due temp restriction for 50/50) Number of tests where difference between Number of tests where difference between Distance Range sites is Distance Range sites is (ft) 20% to 30% to (ft) 20% to 30% to 50% Total 50% Total 4167 5052 66 1 67 4167 5052 12 12 99% 1% 100% 100% 100% 7017 13390 43 4 2 1 50 7017 13390 8 3 0 2 13 86% 8% 4% 2% 100% 62% 23% 0% 15% 100% 27800 28500 67 17 7 2 93 27800 28500 10 1 2 4 17 72% 18% 8% 2% 100% 59% 6% 12% 24% 100% Total tests 176 22 9 3 210 Total tests 30 4 2 6 42 analyzed analyzed 84% 10% 4% 1% 100% 71% 10% 5% 14% 100% For the Clariant 2012 100/0 base case, the frequency of tests For the Octagon MaxFlo 100/0 base case, the frequency of generating a percentage difference greater than 20% in- tests generating a percentage difference greater than 20% creased from: increased from: 1% at the shortest distance to 2% at the shortest distance to 10% at mid-range distance and 12% at mid-range distance and 21% at the longest distance. 26% at the longest distance.