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Specific Questions about Testing Paint, Dust, and Soil for Lead

Are All Painted Surfaces In the Home Tested? Not every single painted surface in the home will be tested in an inspection, but all types of painted surfaces are tested. For example, a room may have three windows, all painted the same color and all made out of wood. The certified Inspector may not test all three windows, because they appear to be the same.

In a similar fashion, the certified Inspector will go through every room and test the different types of painted surfaces in the rooms. Painted surfaces on the outside of the home, detached structures (such as garages), and items like painted fences and swing sets should also be tested.

Inspections differ from risk assessments and lead hazard screens. In a risk assessment, only deteriorated paint and paint that has been mouthed or chewed by a child will be tested. In a lead hazard screen, only deteriorated paint is tested.

How Are Painted Surfaces Tested? There are currently two methods recognized by EPA for testing paint: Portable X-Ray Fluorescence (XRF) analyzers and paint chip sampling followed by analysis by a laboratory recognized by EPA's National Lead Laboratory Accreditation Program (NLLAP).

  • I. Portable X-Ray Fluorescence Analyzers (XRFs). A portable XRF measures lead in paint, generally without damaging the paint. However, readings from some XRFs are affected by the base material (known as the "substrate") underneath the paint, such as wood, plaster, or metal. For these cases, the certified Inspector removes paint from a few surfaces of each type and takes a measurement on the unpainted surface. These measurements provide a baseline to adjust the lead in paint value. This procedure may do some paint damage. Also, for curved surfaces or very deteriorated paint, XRF analyzers may not read accurately and a paint chip sample may be required.

When a certified lead-based paint professional follows good testing practices, XRF analyzers provide a fast and reliable method for classifying many painted surfaces. However, some XRF test results may be inconclusive (neither positive nor negative). Then laboratory testing of a paint chip sample may be necessary. Because the XRF analyzer uses a radiation source to detect lead, occupants in the household should be asked to stay out of rooms behind the surfaces being tested.

  • II. Paint Chip Sampling And Laboratory Analysis. Paint chip samples are collected for laboratory analysis by removing one to four square inches of paint from the surface. All layers of paint in the sampled area are included in the sample. Usually samples will contain some of the material beneath the paint, such as wood, plaster, or concrete particles. The amount of this material will be kept to a minimum.

Tools such as chisels and scrapers are used to remove the paint. Sometimes a heat gun is used to soften the paint and make the removal easier. If so, a respirator should be worn by the person operating the heat gun for protection from lead and other fumes. In addition, the room or area should be well ventilated to protect occupants. After collecting the paint chip sample, the certified lead-based paint professional will repair the scraped area so that adjacent paint will not peel or flake off. Any paint chips or dust from the sampling should be cleaned up by the certified lead-based paint professional to ensure no lead dust is left behind.

Paint chip samples should be analyzed for lead by a laboratory recognized by EPA's NLLAP as proficient for testing lead in paint. EPA has established the NLLAP to ensure that laboratory analyses are done accurately. A laboratory on the list is recognized as proficient for testing for lead in whichever of the three sample types (paint, dust, or soil) the laboratory has qualified. The certified Inspector and certified Risk Assessor must ensure that any paint chip samples from your home are analyzed by a laboratory on the NLLAP list for paint. Your State may have its own lead program and different regulations. For more information, contact NLIC at 1-800-424-LEAD or visit www.epa.gov/lead.

While paint chip sampling followed by laboratory analysis is generally more accurate than XRF testing, sampling and analysis take longer to complete and paint chips must be scraped from many surfaces in the home. In some cases, a surface may be curved or so deteriorated that an XRF cannot be used properly and sampling may be the only way to test the paint.

What Do The Results Of Paint Testing Mean? A certified lead-based paint professional will use guidance specific for each type of XRF analyzer to determine whether a measurement indicates that:

  • Lead-based paint is present,

  • Lead-based paint is not present, or

  • The measurement is inconclusive and a laboratory test is necessary.

The guidance ensures the XRF measurement classifies paint as lead-based when there is 1.0 milligram of lead per square centimeter of painted surface or greater (1.0 mg/cm2). An XRF analyzer typically reads in mg/cm2, meaning milligrams per square centimeter.

Figure 150: Federal Definition Of Lead-Based Paint Depends On How Test Results Are Reported

How Test Results Are Reported

Federal Definition Of Lead-Based Paint

If results are reported as percent (or equivalent)

Then, in order for it to be considered lead-based paint, the paint must have greater than or equal to 0.5% (which is the same as 5,000 ug/g or 5,000 mg/kg or 5,000 ppm) lead

If results are reported as milligrams per square centimeter

Then, in order for it to be considered lead-based paint, the paint must have greater than or equal to 1 mg/cm2 lead

When the paint chip sampling followed by laboratory analysis method is used, the Federal definition of lead-based paint is dependent on how the results are reported:

If the laboratory report is expressed as weight of lead per weight of paint chip, the Federal definition of lead-based paint is 0.5 percent lead (0.5%). This is mathematically the same as 5,000 milligrams of lead per kilogram of paint chip (5,000 mg/kg), or 5,000 micrograms of lead per gram of paint chip (5,000 ug/g), or 5,000 parts per million lead (5,000 ppm).

If the laboratory report is expressed as a weight of lead per unit area of painted surface, the Federal definition of lead-based paint is 1.0 mg/cm2 (the same as for XRF analysis).

It is possible to report laboratory results in both types of units, but this is rarely done because of the additional time and work required. Unfortunately, there is no universal definition of lead-based paint. Some State and local governments have definitions of lead-based paint which differ from those in Federal law. It is recommended that when there is a conflict between the Federal definition and a State or local definition, the more stringent standard (that is, the lower number) be used to define lead-based paint. A certified lead-based paint professional (certified Inspector or certified Risk Assessor) should be aware of and should follow the appropriate standard.

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