Lead Hazard Evaluation, Risk Assessment, and Inspection Data Interpretation
A project designer must distinguish the evaluation tools and read their outputs correctly. An inspection determines the presence, location, and condition of lead-based paint, typically using an X-ray fluorescence (XRF) analyzer or laboratory paint-chip analysis; it answers "is lead paint here and where?" A risk assessment evaluates the likelihood of current and future lead hazards-deteriorated paint, dust, soil-and identifies the causes, often using dust wipe sampling and soil sampling with established clearance-type comparison values. A hazard screen is a limited evaluation. Clearance testing after work verifies that dust has been reduced below applicable standards.
Data interpretation matters: XRF readings can be affected by substrate interference (e.g., reading through to a substrate containing lead), so readings may need confirmation; results are reported in mg/cm² for XRF and by weight percent for chips. Dust and soil results are compared to applicable standards, and the designer must know which standard applies to the situation. Condition assessment (intact, fair, poor; deteriorated) drives whether the hazard is a "paint hazard" requiring stabilization. Friction and impact surfaces and chewable surfaces are evaluated even if paint is intact, because they can generate or expose dust.
Traps: confusing inspection (presence) with risk assessment (hazard likelihood and cause); assuming a negative XRF reading on one component means no lead anywhere; forgetting substrate interference; and misapplying a dust standard to soil or vice versa.
Rule of thumb: inspection = where is the lead; risk assessment = why is it a hazard and what should be done. Worked example: an inspector finds deteriorated paint on a window sash and dust above the comparison value on the sill; the risk assessment links the two-the friction surface is the cause of the dust-so the design must address the surface, not just clean the dust.