Research ArticleArticles

Residual Strength of Carabiners Used by Tree Climbers

Brian Kane and H. Dennis Ryan
Arboriculture & Urban Forestry (AUF) March 2009, 35 (2) 75-79; DOI: https://doi.org/10.48044/jauf.2009.014

Article Figures & Data

Figures

  • Figure 1.
    Figure 1.

    Types of failure of carabiners (clockwise from upper left): key, body, hinge, barrel.

  • Figure 2.
    Figure 2.

    Scatter plot and best-fit line for the relationship between breaking strength (PMAX) and surface roughness (ρ) of new (•) and used (▪) carabiners. The prediction equation, PMAX = 32.33 − 2.49ρ, was weak (r2 = 0.15) but the intercept (P < 0.0001) and regression coefficient (P = 0.0185) were both significant. The minimum value of the ordinate corresponds to the minimum breaking strength of hardware (22.24 kN) set forth in the Z.133 (Anonymous 2006).

Tables

  • Table 1.

    Means (SE’s in parentheses) for relative breaking strengthz, breaking strength, and surface roughness of carabiners. For each comparison, read down a column, means followed by the same letter are not different (P > 0.05).

    ShapeGateConditionNRelative Breaking Strength (%)Breaking Strength (kN)Surface Roughness (mm)
    Am’DBall-LockNew413.8 (1.79) a31.88 (0.50) a0.73 (0.04) a
    Am’DBall-LockUsed49.40 (3.54) a30.63 (0.99) a0.84 (0.25) a
    Am’DTri-ActNew415.8 (2.61) a32.43 (0.73) a0.64 (0.05) a
    Am’DTri-ActUsed613.7 (1.45) a31.83 (0.40) a0.52 (0.10) a
    WilliamBall-LockNew317.7 (1.73) a29.43 (0.43) a0.85 (0.07) a
    WilliamBall-LockUsed612.1 (1.56) by28.02 (0.39) by0.86 (0.13) a
    WilliamTri-ActNew521.8 (1.72) a30.46 (0.43) a0.69 (0.05) a
    WilliamTri-ActUsed519.3 (2.01) a29.82 (0.50) a0.83 (0.17) a
    Am’D—New814.8 (1.51) a32.15 (0.42) a0.68 (0.03) a
    William—New820.3 (1.39) b30.08 (0.35) b0.75 (0.05) a
    Am’D—Used1012.0 (1.69) a31.35 (0.47) a0.65 (0.12) a
    William—Used1115.3 (1.64) bx28.84 (0.41) b0.84 (0.10) a
    —Ball-LockNew715.5 (1.40) a30.83 (0.59) a0.78 (0.04) a
    —Tri-ActNew919.2 (1.76) a31.33 (0.51) a0.67 (0.04) b
    —Ball-LockUsed1011.0 (1.63) a29.06 (0.60) a0.85 (0.12) a
    —Tri-ActUsed1116.2 (1.44) b30.92 (0.44) b0.66 (0.10) a

    • ↵zsee equation 1.

    • ↵yP = 0.0614

    • ↵xP = 0.0599

  • Table 2.

    Means (SE’s in parentheses) for relative breaking strengthz, breaking strength, and surface roughness. Read down a column, means followed by the same letter are not different (P > 0.05).

    Failure TipeNRelative Breaking Strength (%)Breaking Strength (kN)Surface Roughness (mm)
    Barrel1115.9 (1.58) a31.46 (0.41) a0.57 (0.05) a
    Body613.7 (1.07) a29.57 (0.76) ab0.89 (0.09) b
    Hinge611.3 (2.68) a31.15 (0.75) ab0.83 (0.15) ab
    Key1417.5 (1.48) a29.86 (0.47) by0.76 (0.08) ab

    • ↵zsee equation 1.

    • ↵yP = 0.0551

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Residual Strength of Carabiners Used by Tree Climbers
Brian Kane, H. Dennis Ryan
Arboriculture & Urban Forestry (AUF) Mar 2009, 35 (2) 75-79; DOI: 10.48044/jauf.2009.014
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