Lead-based paint testing (Swabs vs XRF)
We often get the question from contractors and homeowners about the efficacy and usefulness of the EPA approved Lead-check swabs vs our XRF device. While the swabs can be useful for small home projects they carry some inherent risks and are simply not a good idea for construction projects of significant size. This includes whole house exterior painting and window replacement which seem to be the most common occurrence of swabs being utilized by contractors when they should consider hiring a lead-paint professional using an XRF device.
As quick information an XRF is a portable X-ray device with a nuclear source or X-ray tube that penetrates a material down to the substrate examining up to 34 layers of existing paint. It provides quick and very accurate results as well as has the ability to take many readings in a short period of time with no physical damage to the material during the survey.
Lead-check swabs are simply a cotton swab with a liquid glass pack inside; the user breaks the glass and uses the wet swab to wipe on the painted surface. If the swab turns red that is a positive indicator for lead-based paint. The major issues for the swabs are user error (i.e. not scoring the paint down to the original substrate and therefore not examining the oldest layers of paint which are the most likely to be lead containing, false positives associated with there being a red layer of paint which would turn the swab red whether or not lead is present as well as lack of incentive to take multiple samples as each swab used costs the examiner additional money which incentivizes the "inspector" to use fewer while expanding their more profitable RRP protocols for the project.
The perceived obstacle to having an XRF survey conducted vs swabs is the initial cost of the survey. Swabs are $6 apiece and are good for one sample while an XRF is a $16000.00 device with substantial maintenance costs but can take an infinite number of samples as during the half-life of the source. In general, an XRF survey on the exterior costs between $150.00 and $200.00 depending on the size of the dwelling and the number of architectural features. While this seems like a huge difference the major consideration is the quality and quantity of data obtained from these alternative forms of testing. What we have seen is many contractors using the swabs on the most likely components that will contain lead-
based paint on a dwelling and then declaring that EPA Renovation, Repair and Painting Program Protocols or RRP are required for the entire project. This can increase the overall cost by thousands of dollars as the required engineering controls and clean-up protocols take many more man hours and material to perform. We are contracted on a regular basis by insurance companies to follow-up a painting or window replacement bid that has been estimated using lead-based paint RRP protocols for the entire project based on a couple of strategic swab samples. In many cases, as we are able to take as many XRF shots as the project requires we are able to rule out large areas (often entire elevations) or groups of components (windows, soffits, fascia, doors) from RRP protocols. In turn this saves the homeowner substantial amounts of money.
As environmental scientists more data at higher quality is always a preferred scenario and in this case the extra $150.00-$175.00 is worth the chance of saving thousands and gives the peace of mind the entire area slated for impact has been properly examined. In summary while lead-check swabs can be useful for small do-it-yourself projects we do not recommend allowing projects especially associated with exterior materials (windows and painting) to have their lead-based paint protocols dictated by a swab test. There is simply too much potential for error or overestimation of the prevalence of lead-based paint to make this a smart choice. In addition, swab testing does not provide documentation you may want to present for a future real-estate transaction which is required during the disclosure process.
We are always happy to provide free consultation for individual project as everyone's situation is a little different and we enjoy helping property owners navigate these situations.