Emtek R100, User Manual

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EMTEK, LLC - R100 USERS MANUAL / AUG2019.REV01 70
FELLER CALCULATION TABLE (1-100 CFU)
Applies to R100 300 Hole inlet Covers: R100.INLT.28 (28.3 LPM/1 CFM) & R100.INLT.100 (100 LPM)
Description
Feller conversions are calculations performed, per the formula below, to allow for potential coincidence capture events,
whereby more than one organism could potentially be drawn through the same inlet of the air sampler and be impacted, or
captured, on the same location on the test plate. Too note, the Feller Calculation is really intended for higher concentrations
of particles. As such, many sieve sampler producers don’t start applying the calculations until the “r” value of 15-30 CFU.
What is depicted below is the full calculation, starting with an “r” value of 1, or 1 CFU.
EMTEK, LLC Feller Calculations JAN.2014.v00
r Pr r Pr r Pr r Pr
1 2 51 57 101 124 151 211
2 3 52 57 102 125 152 213
3 4 53 57 103 127 153 215
4 5 54 60 104 128 154 217
5 6 55 62 105 130 155 219
6 7 56 63 106 131 156 221
7 8 57 64 107 133 157 223
8 9 58 65 108 135 158 225
9 10 59 67 109 136 159 227
10 11 60 68 110 138 160 230
11 12 61 69 111 139 161 232
12 13 62 70 112 141 162 234
13 14 63 72 113 142 163 236
14 15 64 73 114 144 164 238
15 16 65 74 115 146 165 241
16 17 66 76 116 147 166 243
17 19 67 77 117 149 167 245
18 20 68 78 118 151 168 247
19 21 69 79 119 152 169 250
20 22 70 81 120 154 170 252
21 23 71 82 121 156 171 254
22 24 72 83 122 157 172 257
23 25 73 85 123 159 173 259
24 26 74 86 124 161 174 261
25 27 75 87 125 162 175 264
26 28 76 89 126 164 176 266
27 29 77 90 127 166 177 269
28 30 78 91 128 168 178 271
29 32 79 93 129 169 179 274
30 33 80 94 130 171 180 276
31 34 81 95 131 173 181 279
32 35 82 97 132 175 182 281
33 36 83 98 133 177 183 284
34 37 84 100 134 178 184 286
35 38 85 101 135 180 185 289
36 39 86 102 136 182 186 291
37 41 87 104 137 184 187 294
38 42 88 105 138 186 188 297
39 43 89 107 139 188 189 299
40 44 90 108 140 189 190 302
41 45 91 109 141 191 191 305
42 46 92 111 142 193 192 308
43 47 93 112 143 195 193 311
44 49 94 113 144 197 194 313
45 50 95 115 145 199 195 316
46 51 96 116 146 201 196 319
47 52 97 118 147 203 197 322
48 53 98 119 148 205 198 325
49 54 99 121 149 207 199 328
50 56 100 122 150 209 200 331
Feller Conversion Table for RAS and P100 Inlet Covers with 300 Inlet Holes
RAS Inlet Covers: V100.RAS.28.A, V100.RAS.50.A, V100.RAS.100.A
P100 Inlet covers: P100.INLT.28, P100.INLT.100
r
=number of colony forming units counted on a 90mm petri dish
Pr
=Probable Statistical Total using Fellers Formula (Pr= N[1/N + 1/N-1 + 1/N-2 + … . 1/N-r+1)
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