Combustion Byproducts on Surfaces:
Carbon black and combustion byproducts (carbonized material) depositing on surfaces can lead to permanent discoloration and “ghosting” effects. Sampling for carbon black on surfaces can be performed by the wipe method using a 1 square inch alcohol pad. These pads, used to clean an area prior to an injection, can be found at most pharmacies. Simply wipe as much area as necessary to darken the pad, place into a zip lock style plastic bag and submit for analysis. Results for this type of sampling are expressed in percent concentration. It is best to wipe hard surfaces such as TV screens and counter tops and avoid painted surfaces such as walls where possible.
Combustion Byproducts in the Air:
Two types of sampling are recommended depending upon your specific requirements. For personnel monitoring or OSHA compliant sampling a pre-weighted 5.0um PVC filter (Nuisance dust cassettes) is used to sample the air. The results will be reported in milligrams per unit volume for total dust. Additional analysis by Transmission Electron Microscopy (TEM) can confirm the presence of carbon black. Area sampling is commonly performed by 0.1um PC filter. This sampling technique is designed to capture all particles for analysis by electron microscopy. This is a definitive analysis for the presence of carbon black, not simply a total mass analysis like the NIOSH 5000. In addition to the analysis for Carbon Black LA Testing can identify incinerator ash, wood ash, coal/coke and partially burned organic dust (char). These are the dominant materials that are found when there are fires. Carbon black may be present but usually in very low concentrations compared to the partially ashed materials. If you have a situation where a point of origin is necessary then identification of the partially ashed particles can be the key. In the case of suspected arson testing for accelerants can also be performed. Analysis by Fourier Transform Infrared Spectrometry (FTIR), Gas Chromatography/ Mass Spectrometry (GC/MS) and High Performance Liquid Chromatography (HPLC) can reveal the identity of the accelerant used. LA Testing performs carbon black and combustion byproducts testing using a combination of techniques in culmination with Electron Microscopy (EM). Due to the size of many combustion byproducts, especially carbon black, analysis with light microscopes alone is inconclusive and generally not legally defensible. Don’t be fooled by laboratories that provide inexpensive testing by light microscopes. LA Testing provides expert analysis that frequently results in the dismissal of other less reliable techniques in court cases.