Fault Tree Analysis of a Paintball Gun

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Paintball Marker Initiated Injury - Fault Tree Analysis Thursday, April 02, 2009 Injury defined as those requiring emergency room treatment.

Paintball Marker Injures/Kills a Person

Paintball Impact Injury Occurs .012

Mechanical Based Marker Injury .0026

1.6e4 Compressed Air Injury Occurs (Pg 2)

.8836 Marker Fires (Pg 3)

Player in path of marker fire .90

1.0 Safety Equipment Fails (Pg 4)

Marker Bolt (17JA) backfires and hits player in face

Injury is severe enough to require hospitilization 0.015

.8836 Marker Fires (Pg 3)

Sight rail (47E) fails to stop marker bolt .111

Finger crushed between sight rail (47E) and Marker Bolt (17JA) .0026

9.5e7

Marker bolt not stopped by mechanical controls 13.4e7

Quick Disconnect Pin (23B) Fails to stop marker bolt Sight Rail (47E) Bolt Guard broken off of marker .05

Vibration loosens Screw-05B .01

.061 Screw-05B falls off gun releasing sight rail

Screw-05B head breaks off due to impact .001

Screw-05B not tightened properly after cleaning .05

Player’s face is behind marker .90 Player’s finger is between sight rail(47E) and bolt (17JA) .0029 .8836 Marker Fires (Pg 3)

Bolt Pin (21) fails to stop marker bolt .0011

.011

Disconnect Pin Breaks (23B) .001

Disconnect Pin Lock (23C) disengaged .01

Finger slip adjusting Velocity Screw (29C) .0025 Bolt Screw breaks (22) or not in place .0001

Finger in slot while manually setting bolt (17JA) .004

Bolt Pin (21) breaks due to impact or wear .001

Event probabilities were determined based on Conn et al. (2009), ASD Injury Report (2000) & Kee Action Sports Report (2009) or were determined by using best estimates based on experienced players giving opinions on estimated occurrence of bottom level events.

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Paintball Marker Initiated Injury - Fault Tree Analysis Thursday, April 02, 2009

Compressed Air Cylinder Explodes Injuring People

Compressed Air Injury Occurs

0.016009

People in explosion vicinity .80

1.6e4

Compressed Air Cylinder Breaks free of marker & becomes a projectile injuring a person 7.25e11

Cylinder explodes 0.02001125

Cylinder breaks free of marker and rapidly decompresses 2.9e10

.02 Cylinder suffers severe impact force .001 Cylinder burst disc fails to break

Cylinder is overpressurized .01125 Cylinder overfilled during refill .01025

Cylinder overheated causing compressed air to expand .001

.0025 Fill level gauge gives false reading (reads low, actual high)

False reading leads to explosion .00025

.10 Person filling tank does not stop at correct pressure

Cylinder breaks off marker 0.0029

True reading leads to explosion .01

Person filling tank does not check or understand fill .05 gauge

.25 Person filling tank does not stop at correct pressure

C/A Adaptor or Cylinder Threading Fails .0001 Cylinder mount screws fail (36D | 36E) .0001

Disconnect hose breaks (37J) .0001

Event probabilities were determined based on Conn et al. (2009), ASD Injury Report (2000) & Kee Action Sports Report (2009) or were determined by using best estimates based on experienced players giving opinions on estimated occurrence of bottom level events.

C/A Adaptor breaks (2235) .0025

Person in path of cylinder ‘rocket’ .25

.001 Cylinder burst disc fails to break

.0001 Pin in cylinder which releases air remains fixed on

C/A Male adaptor on cylinder breaks .0001

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Paintball Marker Initiated Injury - Fault Tree Analysis Thursday, April 02, 2009 *The marker firing could be viewed as a desired event in most situations. From that view this tree can be considered a success tree; however, in the case of the main initiating event of the marker causing injury, the firing of the gun can be considered a negative event contributing to the injury occurrence. So from that view this is a fault tree. Marker Fires* .8836

Compressed Air Flow Present .94

Trigger Activated .94

Touch Switch (JE27) Activated .9503

Trigger Pulled on Marker intentionally .95

Battery charged (JE1015) .99

Power turned on (E33A) .99

Power switch intentionally on (E33A) .98

Electrical short activates trigger switch (JE27)

Electrical short turns on power switch (E33A) .01

No blockages in air flow within gun .99

No air leaks in marker .95

Air Cylinder Attached with Air .99

.0003

Vibration loosens connecting wire leads to short .0001

Water enters dipswitch hole and shorts switch .0001

Compression chambers not leaking (44HJ, 08LJ) .90

Disconnect Hose not punctured (37J) .99

All O-Rings Functional (09, 19A, 20, 2135, 37A, 37C) .85

Normal wear and tear leads to broken wire short .0001

Event probabilities were determined based on Conn et al. (2009), ASD Injury Report (2000) & Kee Action Sports Report (2009) or were determined by using best estimates based on experienced players giving opinions on estimated occurrence of bottom level events.

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Paintball Marker Initiated Injury - Fault Tree Analysis Thursday, April 02, 2009

Safety Equipment Fails (PPE) 1.0

Mask not being worn 1.0

PPE being used/ worn fails 0.7712 Player removes Mask on field of play

Mask falls off during play .05

1.0

Player intentionally disregards rules of play 1.0

Barrel bag cords break due to impact .001 Player unaware of rules regarding mask

Barrel bag/ plug not on tight enough

.1872

Mask strap too loose or breaks .10

.01

Player needs to adjust mask .80

Player needs to clean mask due to fogging of lens .40

Player is feeling overheated .10

Player did not read posted field signage .80

Player did not read warnings posted on marker or paintball bags .7501

Player needs to breath without restriction .10 Signage not posted or visible .05

Player uninterested in reading and understanding warnings .75

Warnings not present .0001

.25 Mouth vents to large to prevent paint Lens Mask not shell/spray fractures due being worn entering to impact properly mouth .05 .0001 Lens fogs up Mask shell Face or ear due to play too soft or guards creating poor worn too fracture due visibility close to face to impact condition .0001 .01 .35

Player did not learn rule during field training session .312

Player did not listen during Player session Training uninterested in .30 session No training reading and covered session given understanding inadequate warnings .75 information .001 .001

Event probabilities were determined based on Conn et al. (2009), ASD Injury Report (2000) & Kee Action Sports Report (2009) or were determined by using best estimates based on experienced players giving opinions on estimated occurrence of bottom level events.

Training session moderator unqualified .01

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