How XRF Testing Works: Lead Paint Detection in NYC
XRF (X-Ray Fluorescence) testing is the gold standard for detecting lead paint in NYC buildings. The device uses X-ray technology to instantly measure lead concentration in paint without cutting, scraping, or damaging surfaces. Here's how it works.
An XRF analyzer emits a beam of X-rays at the painted surface. Lead atoms in the paint fluoresce (emit their own X-rays) at a specific energy level. The device measures this fluorescence and calculates the lead concentration in milligrams per square centimeter (mg/cm²).
An EPA-certified inspector holds the XRF device against each painted surface for 2-5 seconds. The device displays the result immediately. Every component in the unit is tested: walls, windows (sill, jamb, frame, sash, apron), doors, baseboards, trim, and radiator covers.
Lead concentration above 1.0 mg/cm² is considered positive for lead paint under NYC and federal standards. Surfaces below this threshold are considered lead-free. Results are documented in a detailed report showing every tested surface.
Under Local Law 31: during apartment turnovers, as part of your Community District inspection cycle, and before renovation work in pre-1978 buildings. Proactive testing is recommended for any pre-1960 building.
According to DeLead NYC, XRF testing costs $150-$300 per unit. Results are instant — no lab wait times. The investment pays for itself by identifying exactly which surfaces need work, preventing unnecessary abatement. Schedule testing.
Modern XRF analyzers (Niton XL5+, Thermo Scientific) read lead concentration in mg/cm² with ±0.1 mg/cm² accuracy in 2-8 seconds per spot, non-destructive. Lab paint-chip testing is slightly more precise but destroys the surface and adds 5-7 days turnaround.
A studio takes 30-45 minutes, a 1-bedroom 45-75 minutes, a 2-bedroom 60-90 minutes. Inspectors test every paint component: walls, ceilings, trim, doors, windows, cabinets. A 20-unit building typically takes 2-4 days.