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The Wood Math Model Table

The table below provides breakthrough times for 120 chemicals at various concentrations.  OSHA derived these breakthrough times from the Gerry O. Wood math model (Wood, G.O., Estimating Service Lives of Organic Vapor Cartridges, American Industrial Hygiene Association Journal, 55:11-15, 1994).

Keep in Mind Keep In Mind
  • OSHA used the following standard conditions:
Number of respirator cartridges: 2
                                                     
Temperature: 72 degrees Fahrenheit (22 degrees Celsius)
Sorbent: Activated charcoal Relative humidity: less than or equal to 50%
Sorbent mass per cartridge: 26 g Breakthrough: 10%
Flow rate: 53.3 liters per minute                                                     
  • If the conditions in your case are significantly different from these, in particular relative humidities greater than 65%, you will need to make the appropriate corrections to the time given by the table. Another section of this advisor provides a discussion of these factors.
How to use this Table

Look down the left column to find the chemical and across the row to the column with the identified concentration, and there you will find the service life time in minutes.

Breakthrough Times (min)
 
Work
Shift
Indicates that the service life for this contaminant is limited to a single workshift by the OSHA Standard.
Name CAS # Contaminant Concentration (ppm)
50 100 200 500 1000
Aromatics
Benzene 71-43-2 Work
Shift
Limited to a maximum concentration of 50 ppm for negative pressure APR
See the Benzene Standard
1910.1028(g)
Toluene 108-88-3 1018 562 307 135 72
Ethylbenzene 100-41-4 1133 604 319 135 70
m-Xylene 108-38-3 1143 608 321 136 70
Cumene 98-82-8 1122 586 304 126 64
Mesitylene 108-67-8 1159 603 311 128 65
p-Cymene 99-87-6 1104 566 289 117 59
Alcohols
Methanol 67-56-1 This calculation is not applicable to this compound
Ethanol 64-17-5 123 105 85 60 43
Isopropanol 67-63-0 425 286 186 101 61
Allyl alcohol 107-18-6 789 495 303 152 87
Propanol 71-23-8 551 364 233 123 73
sec-Butanol 78-92-2 773 464 272 130 72
Butanol 71-36-3 1073 615 345 156 84
2-Pentanol 6032-29-7 1091 601 327 143 75
3-Methyl-1-butanol 123-41-3 1242 672 358 152 78
4-Methyl-2-pentanol 108-11-2 1076 578 307 130 67
Pentanol 71-41-0 1281 690 366 155 79
2-Ethyl-1-butanol 97-95-0 1246 657 342 142 72
Monochlorides
Methyl chloride 74-87-3 Not applicable, boiling point below ambient temperatures
Vinyl chloride 75-01-4 Not applicable, boiling point below ambient temperatures
See the Vinyl Chloride Standard
1910.1017(g)
Ethyl chloride 75-00-3 Not applicable, boiling point below ambient temperatures
2-Chloropropane 75-29-6 224 150 99 54 34
Allyl chloride 107-05-1 264 177 116 64 40
1-Chloropropane 540-54-5 492 301 181 90 52
2-Chloro-2-methylpropane 507-20-0 655 374 212 98 54
1-Chlorobutane 109-69-3 733 422 239 111 61
2-Chloro-2-methylbutane 594-36-5 705 398 222 101 55
1-Chloropentane 543-59-9 852 474 260 116 62
Chlorocyclopentane 930-28-9          
Chlorobenzene 108-90-7 1327 709 376 160 83
1-Chlorohexane 544-10-5 993 530 281 119 62
o-Chlorotoluene 95-49-8 1297 682 356 148 76
1-Chloroheptane 629-06-1 930 492 258 109 56
3-(Chloromethyl) heptane 123-04-6 771 410 216 92 48
Dichlorides
Dichloromethane 75-09-2 See the Methylene Chloride Standard
1910.1052(g)
trans-1,2-Dichloroethylene 156-60-5 296 198 129 71 44
1,1-Dichloroethane 75-35-4 234 157 103 57 35
cis-1,2-Dichloroethylene 156-59-2 356 236 152 82 50
1,2-Dichloroethane 107-06-2 482 310 194 101 60
1,2-Dichloropropane 78-87-5 776 452 259 121 67
cis-1,2-Dichloropropene 6923-20-2          
trans-1,2-Dichloropropene 7069-38-7          
1,4-Dichlorobutane 110-56-5 846 475 263 118 64
o-Dichlorobenzene 95-50-1
Trichlorides
Chloroform 67-66-3 409 263 166 87 52
Methyl chloroform 71-55-6 618 366 214 102 57
Trichloroethylene 79-01-6 749 441 256 122 68
1,1,2-Trichloroethane 79-00-5 976 558 314 143 77
1,2,3-Trichloropropane 96-18-4          
Tetrachlorides
Carbon tetrachloride 56-23-5 677 398 231 109 61
Perchloroethylene 127-18-4 1106 609 331 145 77
1,1,2,2-Tetrachloroethane 79-34-5          
Pentachlorides
Pentachloroethane 76-01-7          
Acetates
Methyl acetate 79-20-9 182 131 92 55 36
Vinyl acetate 108-05-4 389 251 158 82 49
Ethyl acetate 141-78-6 483 299 182 91 53
Isopropyl acetate 108-21-4 668 386 219 102 56
Isopropenyl acetate 108-22-5          
Propyl acetate 109-60-4 768 438 246 112 61
Allyl acetate 591-87-7          
sec-Butyl acetate 105-46-4          
Butyl acetate 123-86-4 935 508 273 118 62
Isopentyl acetate 123-92-2 1007 530 277 116 59
1,3-Dimethylbutyl acetate 540-88-5          
Pentyl acetate 628-63-7 1023 537 280 117 59
Hexyl acetate 142-92-7          
Ketones
Acetone 67-64-1 118 92 69 44 30
2-Butanone 78-93-3 423 271 170 88 52
2-Pentanone 107-87-9 729 424 243 113 62
3-Pentanone 96-22-0 744 433 248 115 63
4-Methyl-2-pentanone 108-10-1 884 488 266 117 62
Mesityl oxide 141-79-7 1063 581 314 136 71
Cyclopentanone 120-92-3 1020 589 333 153 83
2,4-Pentanedione 123-54-6 1103 612 335 147 78
3-Heptanone 106-35-4 1061 561 294 123 63
2-Heptanone 110-43-0 791 432 234 102 54
Cyclohexanone 108-94-1 1257 683 366 157 81
5-Methyl-3-heptanone            
3-Methylcyclohexanone 625-96-7          
Diisobutyl ketone 108-83-8 963 496 254 103 52
4-Methylcyclohexanone 589-92-4          
Alkanes
Pentane 109-66-0 332 205 124 63 37
2,3-Dimethylbutane 79-29-8 533 307 175 82 45
Hexane 110-54-3 585 334 189 87 48
Methylcyclopentane 96-37-7 613 357 205 96 53
Cyclohexane 110-82-7          
2,2,4-Trimethylpentane 540-84-1 747 401 214 92 48
Heptane 142-82-5 769 420 227 99 52
Methylcyclohexane 108-87-2 842 463 252 111 59
1,3,5-Cycloheptatriene 544-25-2          
2,2,5-Trimethylhexane 3522-94-9 817 429 224 93 48
5-Ethylidene-2-orbornene            
Cyclooctane 292-64-8 747 410 224 99 53
Nonane 111-84-2 907 470 242 100 51
Decane 124-18-5 902 461 234 95 48
Amines
Methylamine 74-89-5 Not applicable, boiling point below ambient temperatures
Dimethylamine 124-40-3 Not applicable, boiling point below ambient temperatures
Ethylamine 75-04-7 Not applicable, boiling point below ambient temperatures
Isopropylamine 75-31-0 167 117 80 46 30
Propylamine 107-10-8 226 155 104 59 37
Diethylamine 109-89-7 498 299 177 86 49
Butylamine 109-73-9 580 349 207 100 57
Triethylamine 121-44-8 747 412 225 100 53
Dipropylamine 142-84-7 871 474 255 111 58
Diisopropylamine 108-18-9 716 395 216 96 51
Cyclohexylamine 108-91-8 1065 575 308 132 69
Dibutylamine 111-92-2 980 507 261 107 54
Miscellaneous
Methyl iodide 74-88-4 This calculation is not applicable to this compound
Acrylonitrile 107-13-1 Work
Shift
465 Limited to a maximum concentration of 100 ppm
See the Acrylonitrile Standard
1910.1045(h)
Dibromomethane 74-95-3 947 565 331 158 89
Pyridine 110-86-1 1031 599 342 158 87
Epichlorohydrin 106-89-8 866 525 310 150 84
2-Methoxyethanol 109-86-4          
1,2-Dibromoethane 106-93-4 1252 699 384 170 90
1-Nitropropane 108-03-2 933 548 315 147 80
2-Ethoxyethanol 110-80-5 1105 624 345 154 81
Acetic anhydride 108-24-7 1095 623 348 156 83
2-Methoxyethyl acetate 32718-56-2 1092 594 319 137 71
Bromobenzene 108-86-1 1448 761 397 165 84
2-Ethoxyethyl acetate 111-15-9 1143 600 312 129 65




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