6.2 Friction, Impact, and Chewable Surface Hazards

Three named surfaces, three extra tests

Quick Answer: Friction, impact, and chewable surfaces have their own paint-lead hazard tests in 40 CFR 745.227(h)(2)(i)–(iii) (identical substance in 745.65(a)(1)–(3)). A friction hazard is LBP on a surface subject to abrasion where dust on the nearest horizontal surface underneath (window sill or floor) is at or above 745.65(b) — any reportable level on floors or interior sills on or after January 12, 2026. An impact hazard is damaged or deteriorated LBP on an impact surface caused by impact from a related building component. A chewable hazard is a chewable LBP surface with teeth marks. Everything else with deteriorated LBP falls under (h)(2)(iv) (Section 6.1).

Definitions for the three surfaces live in Subpart D, 745.63, and they apply across Part 745:

Interior window sill (745.63) is the portion of the horizontal window ledge that protrudes into the interior of the room — the stool, in carpenter language. That sill is often all three conversations at once: a horizontal dust surface under a friction sash, a chewable protruding edge, and a small component for the 10% poor-condition test.

Friction — windows, doors, floors, and the dust that proves it

Stand in a 1928 living room and open the double-hung window. The lower sash slides in the jambs. The meeting rail rubs. The sash edges grind against stops. Paint in those tracks turns to dust and drops onto the interior window sill and into the window trough (the well — Section 6.3). That is a friction surface subject to abrasion. 745.227(h)(2)(i) does not say "any painted window is a paint-lead hazard." It says the hazard is present on a friction surface that is subject to abrasion and where lead dust on the nearest horizontal surface underneath (examples: the window sill, or floor) is equal to or greater than the dust-lead hazard levels in 745.65(b).

On or after January 12, 2026, 745.65(b) is any reportable level of lead on floors or interior window sills from wipe samples analyzed by an NLLAP-recognized laboratory. Do not teach 40 / 250 / 400 µg/ft² as current, and do not use the old 10 / 100 floor/sill hazard numbers as if they still applied after that date. If the sash is grinding and the sill wipe is reportable, you have a friction paint-lead hazard even when the paint film on the sash still looks mostly intact.

Other friction pictures:

• Doors. A door that rubs the jamb or sweeps a painted threshold is friction. The nearest horizontal surface underneath is usually the floor. A bind you can hear on every close is abrasion you can explain to a crew.
• Floors. Painted wood floors under foot traffic are named in 745.63. The "nearest horizontal surface underneath" is often the floor itself — the dust sits where the abrasion happens.
• Stairs. 745.63 lists certain stair surfaces. Treads and painted nosings grind under shoes; dust falls to the tread and the landing.

Intact LBP on a friction surface is not automatically a Section 6.1 deteriorated-paint hazard. It becomes a friction paint-lead hazard when it is subject to abrasion and the underneath dust meets 745.65(b). If the window is painted shut, never moves, and is not being abraded, (h)(2)(i) does not fire. If that same stuck sash is peeling, (h)(2)(iv) may still fire as deteriorated LBP.

Why replacing a window beats stripping a friction surface

Paint removal — wet scraping, chemical strippers, heat guns below 1100°F — takes film off the sash and jamb. It does not take the sash out of the jamb. The two surfaces still slide. Any residue left in grooves, any LBP in an unstripped back-band, and any new coating you apply will be ground again the first time a child opens the window for air. Dust reloads the sill and the trough. Encapsulation on an operable friction pair is worse: the encapsulant is a film you have just asked a sash to sand off.

Component replacement (Chapter 12) removes the friction pair. New sash, new jamb liners with a new sash, or a full window unit means there is no LBP left to abrade. That is why supervisors and risk-assessment options so often prefer replacement of working windows over on-site paint removal. Jamb liners can reduce friction as a control, but they are a product decision on a remaining window; replacement is the clean abatement story when the report calls the window a friction hazard. Restricted practices (no torching, HEPA-only blasting, dry-scrape limits) still apply if you do remove paint — those are Chapter 13. The recognition point here is mechanical: a friction hazard is a moving pair plus dust, and stripping paint does not retire the pair.

Impact — the knob in the wall and the door in the frame

745.227(h)(2)(iii) is almost a photograph: a paint-lead hazard is present where there is any damaged or otherwise deteriorated lead-based paint on an impact surface that is caused by impact from a related building component (such as a door knob that knocks into a wall or a door that knocks against its door frame).

Two elements, both required:

1. The paint is damaged or deteriorated, and it is LBP.
2. That damage was caused by impact from a related building component, not by random aging, moisture, or a moving truck in the hallway.

Jobsite pictures:

• Walk a bedroom door. The knob has punched a crater in the plaster on the wall behind the swing. The crater's coating is cracked and flaking. That wall patch is an impact surface. The related component is the knob. If the coating is LBP, it is an impact paint-lead hazard. A door stop never installed is how this crater is born.
• The same door slams into the stop and frame. Paint on the stop is crushed, chipped, and bright where the door edge hits every day. That is the regulation's second example.
• Baseboards opposite knobs, painted door stops, and the strike-side jamb are the usual interior list. Exterior storm doors that slap a painted frame are the same physics outside.

A scuff on a wall with no related component doing the hitting is not this bullet. A peeling ceiling is not an impact hazard because a door hit it. Use (h)(2)(iv) for ordinary deteriorated LBP, and save (h)(2)(iii) for the paired-component hit.

Fixing the cause matters as much as fixing the film. Recoating the crater and leaving the knob to punch it again recreates the hazard. A proper stop, a wall protector, or replacing the damaged component is how you stop the repeated sudden force 745.63 is describing.

Chewable — teeth marks, not "a child might"

745.227(h)(2)(ii): a paint-lead hazard is present on any chewable lead-based paint surface on which there is evidence of teeth marks. Two pieces again: the surface is chewable LBP, and you can see teeth marks.

745.63 is strict about what is chewable. A young child must be able to mouth or chew it. Hard metal and other materials a young child's bite cannot dent are not chewable. A steel casement horn is not a chewable surface just because it is next to a toddler. A soft wood interior window sill with a scalloped bite pattern is the classic pass. A stair rail cap, newel, or other accessible protruding edge at child height is the same story.

Field height: young children mouth what they can reach. Supervisors treat about 5 feet and below — sills, railings, chair rails, protruding stools, the lower part of a balustrade — as the zone to inspect for teeth marks. The regulation does not write "5 feet" into 745.227(h)(2)(ii); Title X's accessible-surface idea and HUD field practice do. Do not invent a chewable hazard on an 8-foot crown molding because a report mentioned children. Do not ignore teeth marks on a 30-inch sill because the paint still looks "mostly intact" around the bites. The bites are the evidence.

An interior sill with no teeth marks is not a chewable paint-lead hazard. It may still be a dust-lead surface (wipe it), a friction dust catcher under a sash, or deteriorated LBP if it is peeling. Name the correct bullet.

Supervisor walkthrough, not a second risk assessment

You still do not take the wipes. You do put a hand on every window in the work area and feel whether it grinds. You look at the floor under painted doors and at the wall opposite every knob. You run a light along sills and rails below child height for teeth marks. When the risk-assessment report called a window a friction hazard, plan replacement (or another method that actually retires the abrasion) instead of a cosmetic strip-and-repaint that leaves the grinding pair in service. Chapter 7 is how that report is supposed to read. Chapter 12 is how replacement is specified. This section is how you recognize the three surfaces when the report is thin or the building has changed since the visit.