Lead Paint Testing 101

Jun 8, 2018

Are you concerned about lead paint in your home? Perhaps you are in the process of purchasing an older home or are contemplating a renovation. It is imperative to assess if a home has lead paint prior to disturbing it during renovation projects or if the paint is peeling and in poor condition. There are two types of lead paint methods that may be used to uncover lead paint problems: X-Ray Fluorescence (XRF) and Paint Chip Testing. In this blog post, we will discuss both methods and their advantages and disadvantages.


X-Ray Fluorescence (XRF) is the primary inspection method used in public housing inspections. XRF is highly coveted due to its portability, speed, and non-destructive methodology. This method of inspection utilizes an XRF handheld device which can evaluate painted surfaces and provide results within seconds. This device works by bombarding the area with gamma rays or high energy x-rays which interact with the paint. Once the radiation interacts with lead atoms, they knock off the outer electrons of the atom’s orbit. Once the electron is dislodged, another electron will come to fill its place which in turn emits an x-ray. The x-ray’s energy signature is then detected by the XRF handheld device which is programmed to detect only lead’s x-ray energy peaks. Once the data is analyzed, the XRF device will display a lead reading. This method’s quick turn-around-time allows it to be able to inspect an entire home for lead without the need to submit samples to a laboratory.

Paint Chip

Paint chip testing refers to the destructive method of lead sampling. This method involves collecting all the paint layers of a surface while leaving the substrate behind. It is imperative to collect as little of the substrate as possible as it may bias the laboratory result. The process is usually conducted using a utility knife or chisel sometimes in tandem with a heat gun to remove an area of paint usually no more than 4 square inches. After sampling is completed, the inspector will clean up any residual debris. It is recommended that the homeowner repair the sampled area after collection to stabilize the now damaged paint. The sample is then submitted to an accredited laboratory for analysis via the Flame Atomic Absorption Spectrometry method (Flame AAS). During this process, the sample is dissolved in nitric acid which is called the digestion process. The sample solution is then fed through a Flame AAS instrument which can accurately detect lead concentration based on the analysis of the light spectra of the flame.

Advantages & Disadvantages

While both methods can determine lead paint concentration with acceptable accuracy, they have their advantages and disadvantages. XRF is great for testing an entire home quickly and thoroughly, without anything destructive. However, the initial cost of the inspection is much higher than paint chip sampling if the area of concern is small. XRF testing is also not as accurate as Flame AAS, as XRF devices have a margin of error which makes borderline samples difficult to determine if lead paint is present. Sampling locations with borderline readings will often be paint chip sampled to determine the actual value of lead present. While paint chip sampling is more accurate than XRF, it damages any surface that is sampled which the owner must repair. The laboratory fees can make paint chip analysis more expensive than XRF testing if more than a small area is tested.

In conclusion, if you want to conduct a lead inspection of your property, you must determine which is the best method of testing to meet your needs. For complete home inspections for lead, it is more effective to utilize XRF lead testing because it is non-invasive and results are near instantaneous. For smaller scale inspections it is more effective to utilize paint chip sampling which can provide highly accurate results without the high initial cost of XRF testing. At Indoor Science, we offer lead paint chip analysis and can subcontract XRF testing. If you are concerned with lead paint in your property please contact us.