At LCS Laboratory Inc., we specialize in Industrial Hygiene testing and emphasize the importance of collecting and analyzing blank samples for every project. Based on our extensive experience, we recommend submitting at least one blank sample to ensure accurate and unbiased results.
Why Are Blank Samples Essential?
Blank samples, also known as “field blanks,” are crucial for achieving reliable results. Without them, test quality may be compromised. Let’s examine the importance of blank samples from both compliance and practical perspectives.
Compliance with Method Requirements
Blank samples are often required for Indoor Air Quality testing to comply with regulations set by authorities like OSHA (USA) or the Ministry of Labour (Canada). Compliance with NIOSH, OSHA, or EPA methods necessitates specific sampling procedures, including blank samples.
Examples include:
- NIOSH 7400 (“Fibers in Air”): Requires 2-10 blank samples per batch.
- NIOSH 0500 (“Particulates in Air”): Recommends 2-10 blank samples for every project.
If your report will be reviewed by regulatory bodies, collecting and analyzing blank samples is essential to meet these standards. Without them, the project may be considered non-compliant, not because the sampling is incorrect, but due to method requirements being unmet.
Practical Aspects of Blank Samples
A “travel blank” is a sample provided by the laboratory, which is taken to the testing site, opened briefly, then closed and returned for analysis alongside the collected samples. This serves as a Quality Control sample. Ideally, the blank should return uncontaminated, but this is not always guaranteed.
Potential contaminants can occur during transit or in the field due to handling errors. If a travel blank shows traces of contamination, our laboratory adjusts results by accounting for any interference detected in the blank sample. Your report will state that the results are “blank corrected”
Typically, for small projects, one blank per batch is submitted. For extended sampling periods or projects spanning multiple days, 2-3 blanks may be submitted to account for varying conditions.
Learn More
For further details on air quality testing, visit our Industrial Hygiene Testing page or our Residential Air Quality page. To discuss your project, please feel free to email us.
