For construction monitoring, optical laser-based dust measurements offer a range of benefits when compared to reference grade instruments. In particular, their lower costs mean that more localised monitoring can take place by deploying more devices.
Undertaking a field calibration can in some instances increase the usefulness of optical sensors by allowing the values to be adjusted based on local conditions. For example, when the type of dust being measured varies across projects undertaking road works, tunnelling or cutting concrete. This process is often referred to as a K-Factor calibration.
The process for developing a K-Factor typically involves either co-locating your SiteHive Hexanode with a nearby reference grade monitor (either BAM [Beta Attenuation Monitor], TEOM [tapered element oscillating microbalances] or gravimetric-based) or deploying a near-reference device, such as a low-volume air sampler, on site at the actual deployment location.
Recently, for a major tunnel project in Victoria, a SiteHive Hexanode was co-located with a Victorian Government BAM monitoring station to undertake this calibration (see image above). Over a 2 week period the results were compared, and a K-Factor was developed.
Over the period, the PM10 values correlated well with the reference BAM monitor:
Based on these results a K-Factor specific to the project was developed and applied, with an R2 value of 0.868. The SiteHive Hexanode is already close to the BAM monitor in terms of accuracy, and with the K-Factor applied there is very little difference.
Comparisons like this provide confidence that lower cost, optical-based systems - such as the SiteHive Hexanode - can be relied on to provide valuable insight into project performance and impacts. As more of this technology is being used, projects are enabled to undertake proactive environmental management in real time.
Stay tuned for more developments in managing dust with SiteHive!