climbing equipment standards -...
TRANSCRIPT
The Evolutionof
Climbing EquipmentStandards
finch images from Charles Darwin’s Voyage of the Beagle
Dave Custer
American Alpine Club/Alpine Club of Canada Delegate to theUIAA Safety Commission
CWA Engineering Standards Committee MemberMIT Lecturer
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are standards for the birds?
• climbers
• equipment manufacturers
• gym owners & operators
• safety folks
• regulation folks
• me
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a history of climbing equipment standards
the physics behind climbing standards
examples of radiative adaptation in climbing
a peek at where gym climbing standards might go
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• accidents• marketing• demographics• climbing developments• developments in related sports• research• assorted climbing organizations• government regulation
causes of equipment &/or standards evolution
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deep history
• not many climbers• not much standardization• no money to be made• it was a stupid sport anyhow
very similar to the aid climbingscene today.
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more climbers, accidents, & $$$, lead to more attention to standards
research and standards effectively reduce “equipment failure” to zero.
• mid 60s, rope testing• early 70s, UIAA safety commission• 70s and 80s, research & standards• 90s CEN, ASTM, etc.
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research
busted gear images from DAV Sicherheitskreis Taetigkeitsbericht 1980-1983
with research, inadequate equipmentbecomes extinct quickly.
0 1 2 3-1
time, s
0 1 2 3-1 0 1 2 3-1
time, s
-5
10152025
3035
-40 -30 -20 -10 0 10 20 30 40Placement Angle, Degrees
Failu
re L
oad,
kN
WI-S WI-FAI-S AI-FHarmston LuebbenDAV/OAV WI-S Long
(b)
best practices become apparent.
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standards organizations
UIAACEN PPE directive (CE)ASTM/ANSI/ISOCWA(REI)
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equipment standards(individual components of the safety system)
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systems theorymakes pin the blame onthe victimmore difficult
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image from American Alpine Club Journal, 1950
physics basis for standardsclimbers can tolerate ~10 G deceleration(18 G permitted on US Navy pilots duringparachute deployment)
the Earth’s gravitational field is 1 G (9.8 m/s2)
safe fall arrest distance lies between1/10 of fall distance (physics) and 1/5 fall distance (UIAA/CE dynamic rope standard)
( )mgMFmgT
kymgymgh
211
221
++=
=+
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where the energy goes during fall arrest
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Maegdefrau Datasqrt fall factor vs.
anchor load
0
2
4
6
8
0.00 0.50 1.00
sqrt fall factor
anch
or lo
ad (k
N)
Single Rope
Rope Pair
data from Helmut Maegdefrau’s PhD thesis
theory, experiment, and standards match well
95% of falls put less than 7 kN on the topanchor (minimum permitted open gate carabiner strength).
20 kN forces onanchors requireinappropriate useor a very, very badkarma (20 kN is the minimum closed gate carabiner strength).
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equipment still fails
Carabiner failure images from 2005
UIAA SafeCom meeting minutes
misusefatigueoveruseabusemodificationchemical abuse
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ice ax standards
current ice ax standardsare based on the demandsof mountaineering
B and T blades?shaft strength?
the remedy will be slow,probably by intended use.
image from Grivel web site.
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via ferrata
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via ferratastandards
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lessons from standards history
Standards evolve.Standards are based on research & “physics”.Standards prevent equipment failure accidents.The evolution is slower than the evolution of the sport.
Expect:Standards development to follow new climbing developments.Increased standardization of safety systems.Increased standardization of best practices for safety systems.
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wild prediction: belaying will become a sport
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best practice examples