23
Appendix 3 - Volatile Organic Compounds
The F8100 incorporates a photo ionisation detector (PID) sensor to detect volatile organic
compounds.
The European Union defines a VOC as "any organic compound having an initial boiling point less than
or equal to 250 °C (482 °F) measured at a standard atmospheric pressure of 101.3 kPa." Volatile
organic compounds are organic compounds with a high vapour pressure at room temperature. Their
high vapour pressure results from a low boiling point which causes large numbers of molecules to
evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air,
a trait known as volatility. Most scent or odours are of VOCs.
Example VOCs include petrol fumes, exhaust gases, paint solvents and dry cleaning products.
Harmful VOCs typically are not acutely toxic but have cumulative and often synergistic long-term
health effects causing damage to the liver, kidneys and central nervous system.
Using a method of ongoing verification, the PID sensor in the F8100 provides an effective method of
monitoring the performance of the activated carbon filter fitted in a breathing-air system.
Suggested Test Limits for VOCs
In EN12021:2014 it states compressed gas for breathing shall not contain contaminants at a
concentration which can cause toxic or harmful effects. In any event, all contaminants shall be kept to
as low as possible and shall be less than one tenth of a national 8 h exposure limit. For breathing air
only the limit shall be less than one sixth of a national 8 h exposure limit. For breathing at hyperbaric
pressures greater than 10 bar or exposure times greater than 8 h the levels shall be revised to take
into account the effects of pressure and exposure times.
As VOCs can indicate a range of potential contaminants it may be useful to use the limit stated of ≤30
ml/m
3
(PPM) for diving gas mixtures in tables 6, 7, 8 and 9 of EN12021:2014.
The other alternative reference is the technical specification ISO/TS 16975-1:2016 The International
Respiratory Protective Devices – Selection and Use Maintenance Document which has a stated VOC
limit of ≤25 ml/m
3
(PPM) for breathable air used to supply breathable gas RPD.
VOC Correction Factors
The PID sensor is calibrated against isobutylene gas, however if you can identify the compound being
sampled by the instrument a correction factor can be applied. The list of correction factors can be
downloaded from Factair’s website:
Summary of Contents for Safe-Air F8100
Page 1: ...0 F8100 SAFE AIR MONITOR OPERATING MANUAL FAC QAM 221 Issue B 02 19...
Page 2: ...1...
Page 35: ...34...
Page 36: ...35...
Page 37: ...36...
