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)
Water vapour H2O	6	Water vapour	18-32mg/l	1/2	3	T		-
			1-18mg/l	1
			0.5-1mg/l	2
	6L	Water vapour	1-2mg/l	1/2	3	T
			0.05-1mg/l	1
	6LP	Pipeline Dew Point Tube	3-40 LB/MMCF	1	3	T
	6LLP	Pipeline Dew Point Tube	2-10 LB/MMCF	2	3	T

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