Sample collection

When investigating hazardous substances, it is often required to take samples for further laboratory analysis.

This is the only way to confirm or discard with certainty the suspicion of the presence of a particular hazardous substance.

However, to ensure that the results obtained from laboratory tests are valid and representative, the samples obtained must be properly collected.

Furthermore, when working with hazardous substances, it must always be borne in mind that in order not to run risks or put third parties at risk, the appropriate safety measures must always be taken, both when taking the samples and in the laboratory itself, both when handling and testing them.

What is the sample collection process?

To verify that an area is hazardous-free, it is typically necessary to collect samples and send the samples to a laboratory to test for the presence of hazardous substances.

Sampling may be required at different stages of a construction’s life span, as well as for different types of inspections carried out on it.

When an initial inspection is conducted during the service life of the construction to elaborate an inventory of the hazardous substances present in it. In these cases, just a few samples are collected.
When the initial assessment indicates problems, an inspector visits each potentially affected area and collects samples.
Before a rehabilitation or demolition project, know exactly the hazardous substances present on the site before the beginning of the works to be able to handle them correctly.
After a decontamination project is complete, an inspector collects and tests samples to verify there are no hazardous substances left in the area.

Therefore, a particular area to assess during the lifetime of a construction and at the end of it may have several samples associated with it. Thus, for each separate sample, it is important to identify the collection date, who collected the sample, where it was sent for testing and any other relevant information.

Nevertheless, these samples must always be taken following the required safety measures for the handling of the suspected hazardous substance. It is necessary to use all the appropriate PPEs: gloves, masks, protective garments, etc. Depending on the type of sample that is being collected and the hazardous substance that it is suspected of containing, it may be required to follow specific measures when collecting the sample. The appropriate government regulatory agency should be consulted for information on these requirements.

Furthermore, it must be noted that it is not necessary to collect samples for each area. An experienced inspector should inspect the areas defined to determine where actual sampling is necessary. The inspector can indicate these areas on floor plan drawings. They will also note which areas were not sampled but are presumed to contain the hazard. The inspector’s sampling methods vary by substance.

How should sample collection be documented?

To ensure that the results obtained from the tests carried out in the laboratory are reliable and to avoid unnecessary risks, it is essential that the entire sampling process is well documented and that all relevant information is compiled for each sample.

Each inspector and each laboratory will have its way of proceeding in this respect, but in general, it is recommended to create, for each sample, a form or similar containing the following data:

Sample code	A value that uniquely identifies each sample. When the sample is to be sent to the laboratory, it should be labelled with this value.
Date collected	he date on which the sample was collected.
Analysis requested	It should be indicated the type of analysis that the inspector requests the laboratory to perform.
Sample type	Sample taken from the surface of a material, air, etc.
Sample description	Description of the type of material collected, such as “dust” or “paint chip”, etc.
Sample location	Description of the area from which the sample was collected. Plans and other graphic documents can be used to support this description.