4.2 Tools and Gauges to Identify Protrusions

Tools and gauges to identify protrusions

Domain 1I tests the method. CPSC 2025 §3.2.2 tells you that projections should meet Figures 2 and 3 and then sends you to Appendix B for the test. ASTM F1487-21 Figure A1.10 is the matching performance figure for the three projection gauges. The NRPA Table of Dimensions, Rev 1/2024, is the dimensional crib sheet you will have in the exam room. Bring the gauges, use them in the order the figures describe, and write down which gauge failed at which orientation. A narrative that says “possible protrusion on the climber” without a gauge, a station, and a citation is not an inspection finding.

The three projection gauges (NRPA Table of Dimensions, Rev 1/2024)

These are the only three general discs. Do not invent a fourth outside diameter. The vertical 0.12 in tool is a thickness gauge for the special swing and slide tests, not a fourth disc.

Why three discs instead of a tape? A projection that is short and thin fails the small gauge (0.25 in face, 0.50 in hole) even though it would pass the middle gauge’s 0.75 in height. A projection that is thicker may not enter the small hole at all, so the small disc never “sees” it; the middle or large disc, with a bigger ID, is the one that can drop over it and hang. You run all three because a pass on one is not a pass on the family.

General test method — do not invent a sequence

CPSC Appendix B.2.1 Determining whether a projection is a protrusion and F1487 Figure A1.10 describe the same idea. Follow that sequence; do not substitute a homemade “if it looks sharp” rule.

1. Identify every accessible projection — anything that extends outward from a surface in the use zone or on the equipment.
2. Successively place each of the three projection gauges (CPSC Figure B1) over the projection.
3. Visually determine whether the projection penetrates through the hole and beyond the face of the gauge (CPSC Figure B11).
4. Pass: the projection does not extend beyond the face of that gauge.
5. Fail: a projection that extends beyond the face of any one of the three gauges is a hazardous protrusion and should be eliminated.

The field image of a fail is a gauge that hangs on the projection: the shank fit through the ID, and the proud length is greater than the gauge height, so the disc does not sit down on the surrounding surface. “Hangs” and “extends beyond the face” are the same fail. A gauge that sits flush on the surrounding surface, with the projection remaining inside the hole and short of the face, passes that disc.

Orientation matters. Test the projection along the direction it actually stands proud of the surrounding surface. A bolt that is harmless when the gauge is held flat against a post may fail when the gauge is held perpendicular to the end of the bolt. On irregular castings, rotate to the most adverse accessible orientation that still matches the figure — you are not allowed to tilt the gauge into a position the figures do not show just to force a pass.

Figures 2 and 3 still apply before you put the disc away. If the diameter increases toward the exposed end, or if more than two threads stand beyond the nut, you already have a §3.2 / §3.2.2 design fail even while you finish the gauge sequence.

Special test: suspended members of swing assemblies (B.2.2)

CPSC Appendix B.2.2 exists because “given the potential for impact incidents, projections on swings can be extremely hazardous.” A special test gauge (Figure B2 — the same family as the 0.12 in vertical tool) and a special procedure are recommended. When tested, no bolts or components in the potential impact region on suspended members should extend through the hole beyond the face of the gauge.

The handbook’s field sequence is:

• Hold the gauge vertically with the axis through the hole parallel to the swing’s path of travel.
• Place the gauge over any projections that are exposed during the swing’s path of travel — seat hardware, the underside, and the lower suspending connections, not only the pretty face of the hanger.
• Visually determine whether the projection penetrates through the hole and beyond the face.
• Pass if it does not extend beyond the face; fail if it does. A fail is a hazardous protrusion and should be eliminated.

CPSC §5.3.8.5 restates the same idea in equipment language: nothing, including bolts or other parts, on the front, back, or underside of a swing should stick out more than 1/8 in. Do not substitute a casual glance or a single general disc for B.2.2. A 1/2-inch proud hanger bolt that somehow argued its way past a misapplied large disc still fails the 1/8 in swing rule.

Special test: projections on slides (B.2.3)

CPSC Appendix B.2.3 is the clothing-entanglement height check that matches §5.3.6.7. To minimize clothing entanglement, a projection that (1) fits within any one of the three Figure B1 gauges and (2) has a major axis that projects away from the slide bed should not stand more than 1/8 in (0.12 in) perpendicular to the plane of the surrounding surface.

The handbook’s field sequence is:

1. Identify every projection in the shaded slide-path area shown in CPSC Figure B13 — the bedway the body travels, both sidewalls, and the platform-to-chute entrance.
2. Determine which of those projections fit inside the three projection gauges.
3. Place the swing-and-slide projection gauge (0.12 in face) next to the projection and check height.
4. Fail any projection that extends beyond the face of that 0.12 in gauge.

Two limits stop you from inventing extra steps. First, B.2.3 is not the test for the underside of a slide chute. For a circular chute, the portion of the underside outside the shaded path returns to the general B.2.1 gauges. Second, §5.3.6.7 also fails gaps at the top of the chute where it meets the platform; a drawstring-sized joint does not need a failed disc to be written as an entanglement cause.

Walk the slide as a child would travel. Sit or kneel at the platform, face the chute, and move the gauge down the bedway and along each sidewall to the exit region. Hardware that is harmless on the outside of a tube can be a hood-catch on the inside corner of the entrance hood.

Where to test, and what to write down

Test projections in the use zone, on accessible equipment surfaces, on swing seats and suspending members, and along slide paths. CPSC §3.2 also sends you to §5.3 for the extra swing and slide rules. User-tied objects do not need a protrusion gauge: they are entanglement removals (Domain 1F/1G).

Document, at minimum:

• Equipment name and identifier, bay, and age group.
• Exact location (for example, “south belt swing, seat-end underside bolt, east chain” or “north slide, left sidewall, 18 in below the platform nosing”).
• Which gauge failed and the orientation (“small projection gauge, axis perpendicular to the panel, projection extended beyond the face”; “B.2.2 swing gauge held vertically, hole axis parallel to travel, hanger bolt beyond the face”; “B.2.3 vertical 0.12 in gauge failed on bedway rivet”).
• Measured proud length when you have it (the 1/2 in hanger bolt), plus whether more than two threads are exposed.
• Cited criterion (CPSC Appendix B.2.1 / B.2.2 / B.2.3, §3.2.2, §5.3.6.7, §5.3.8.5, or F1487 Figure A1.10).
• Priority and interim control (bay bagged, chute blocked, fastener capped or removed).

The owner still decides repair versus removal. Your job in Domain 1I is to prove, with a named gauge and an orientation, that the protrusion cause from 4.1 is present.