Contamination/Pollutants

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Contamination/Pollutants

Some gases and contaminants/pollutants can damage Rotronic humidity sensors.

The contaminants/pollutants can be divided into two categories:

Gases without influence and gases with an influence on the humidity sensors.

For contaminants/pollutants with an influence on the sensors and therefore with an influence

on the measurement result, the maximum constant concentration must be known (see table below).

Contaminants/Pollutants with an influence

Contaminant/Pollutant	Formula	MAC value		Permissible constant concentration
		MAC value		IN-1		HH-1		HT-1
		ppm	mg/m3	ppm	mg/m3	ppm	mg/m3	ppm	mg/m3
Acetone	CH3COCH3	1000	2400	3300	8000	3700	9000	3300	8000
Ammonia	NH3	25	18	5500	4000	5500	4000	5500	4000
Petrol		300	1200		150000		150000		150000
Chlorine	Cl2	0.5	1.5	0.7	2	1.5	4.5	0.7	2
Acetic acid	CH3COOH	10	25	800	2000	1000	2500	800	2000
Ethyl acetate	CH3COOC2H5	400	1400	4000	15000	4000	15000	4000	15000
Ethanol	C2H5OH	1000	1900	3500	6000	5800	10000	3500	6000
Ethylene glycol	HOCH2CH2OH	100	260	1200	3000	1200	3000	1200	3000
Formaldehyde	HCHO	1	1.2	2400	3000	2400	3000	2400	3000
Isopropanol	(CH3)2CHOH	400	980	4800	12000	6000	15000	4800	12000
Methanol	CH3OH	200	260	3500	6000	6000	8000	3500	6000
Methyl ethyl keton	C2H5COCH3	200	590	3300	8000	3300	8000	3300	8000
Ozone	O3	0.1	0.2	1	2	1.5	3	1	2
Hydrochloric acid	HCl	5	7	300	500	300	500	300	500
Sulfur dioxide	SO2	5	13	5	13	5	13	5	13
Hydrogen sulfide	H2S	10	15	350	500	350	500	350	500
Nitrous gases	NOx	5	9	5	9	5	9	5	9
Toluene	C6H5CH3	100	380	1300	5000	1800	7000	1300	5000
Hydrogen peroxide	H2O2	1	1.4	90	130	880	1200	90	130
Xylene	C6H5(CH3)2	100	440	1300	5000	1800	7000	1300	5000

Contaminants/Pollutants without influence

Note that the common sealing material silicone damages the sensor! When probes are installed

silicone must not be used!

Contaminant/Pollutant	Formula
Argon	Ar
Butane	C4H10
Natural gas
Ethane	C2H6
Helium	He
Methane	CH4
Neon	Ne
Propane	C3H8
Oxygen	O2
Nitrogen	N2
Hydrogen	H2