The Wood Math Model Table

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

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)

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		Limited to a maximum concentration of 50 ppm for negative pressure APR
Benzene	71-43-2	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 compund
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
Vinyl chloride	75-01-4	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-norbornene
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 compund
Acrylonitrile	107-13-1		465	Limited to a maximum concentration of 100 ppm
Acrylonitrile	107-13-1	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

Return to Respiratory Advisor Homepage