Gas or Vapour to be Measured Chemical Formula	Réf tube	Gastec Tube No. & Name	Measuring Range (ppm)	No.of Pump Strokes	Shelf Life (year)	Note		TLV- TWA,C (ACGIH) (ppm)
Iodine I2	9L	Nitrogen dioxide	0.2-12	2	3	-		C 0.1
	80	Acid gases	0.12-2.4	2	2	-
Isoamyl acetate CH3CO2(CH2)2CH(CH3)2	148	Isoamyl acetate	10-200	2	2	T		100
Isoamyl alcohol (CH3)2CH(CH2)2OH	117	Isoamyl alcohol	5-300	2	3	T		100
Isobutane (CH3)3CH	103	Hydrocarbons (LowerClass)	0.84-1.68%	1/2	2	++		-
			0.07-0.84%	1
			0.035-0.07%	2
	104	Butane	55-3080	1	3	-
Isobutene (CH3)2C:CH2	101L	Gasoline(Petrol)	0.07-2.2%	1	3	-		-
Isobutyl acetate CH3CO2CH2CH(CH3)2	144	Isobutyl acetate	10-300	2	2	T		150
Isobutyl acrylate CH2:CHCO2CH2CH(CH3)2	142L	Butylacetate	2.6-78	2	2	T		-
Isobutyl alcohol (CH3)2CHCH2OH	116	Isobutyl alcohol	10-150	2	3	T		50
Isooctane (CH3)3CCH2CH(CH3)2	101	Gasoline(Petrol)	0.027-0.54%	1	3	-		-
Isopentane (CH3)2CHCH2CH3	103	Hydrocarbons (LowerClass)	1.08-2.16%	1/2	2	++		-
			0.09-1.08%	1
			0.045-0.09%	2
Isopentyl acetate	See Isoamyl acetate
Isopentyl alcohol	See Isoamyl alcohol
Isophorone C9H14O	154	Cyclohexanone	2-30	8	2*	T		C 5
Isopropyl acetate CH3CO2CH(CH3)2	146	Isopropyl acetate	20-500	2	2	T		250
Isopropyl alcohol CH3CH(OH)CH3(i-C3H7OH)	113	Isopropyl alcohol	2.5-5%	1/2	3	T		400
			0.04-2.5%	1
			0.02-0.04%	2
	113L	Isopropyl alcohol	50-800	1	3	T
			25-50	2
Isopropyl amine (CH3)2CHNH2	180	Amines	5.5-110	1	3	T		5
	180L	Amines	0.45-9	1	2	T
Isopropyl ether m(CH3)2(CH)n2O	141L	Ethyl acetate	22.5-720	2	2	T		250
	161	Ethyl ether	0.018-0.45%	2	3	T
Isopropyl mercaptane (CH3)2CHSH	70	Mercaptans	10-240	1	3	T		-
Isovaleric Acid (CH3)2CHCH2CO2H	81	Acetic acid	2-50	1	3	H		-
	81L	Acetic acid	0.38-15	1	2*	T

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