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Safety Products for Machine Safeguarding - © 2002 - 2004 Honeywell International Inc. All rights reserved.
■ Safety Distance Calculations per EN 294 European standard
The dimensions of openings correspond to the narrowest dimension of a slot opening (for openings greater than 120 mm / 4.72 in, refer to the
EN 294 standard).
Safety distances
sr
for regular openings for persons of 14 years of age and above:
Part of body Illustration Opening size Safety distance
sr
Slot
Fingertip e ≤ 4 ≥ 2
4 < e ≤ 6 ≥ 10
Finger up to knuckle joint 6 < e ≤ 8 ≥ 20
8 < e ≤ 10 ≥ 80
Or 10 < e ≤ 12 ≥ 100
12 < e ≤ 20 ≥ 120
hand 20 < e ≤ 30 ≥ 850*
Arm up to junction with shoulder 30 < e ≤ 40 ≥ 850
40 < e ≤ 120 ≥ 850
■ Safety Distance Calculations per US ANSI / OSHA standard
Ds = K(Ts + Tc + Tr ) + Dpf
With
:
Ds = minimum safe distance between safeguarding device and hazard
K = speed constant: 1,6 m/sec (63 in/sec) minimum based on the movement being the hand/arm only and the body being stationary (a greater
value may be required in specific applications and when body motion must also be considered)
Ts = worst stopping time of the machine/equipment
Tc = worst stopping time of the control system
Tr = response time of the safeguarding device including its interface (Tr for interlocked barrier may include a delay due to actuation. This delay
may result in Tr being a deduct– negative value).
Dpf = the “Depth penetration factor” is the maximum travel towards the hazard if the guard can be opened a certain width or amount before a
stop is signaled.
Dpf values from OSHA O-10 Table:
If the maximum width or diameter Dpf equals (mm/in)
of the opening is less
than or equal to (mm/in)
6,4 / 0.25 12,7 / 0.5
9,5 / 0.375 38,1 / 1.5
12,7 / 0.5 63,5 / 2.5
15,9 / 0.625 88,9 / 3.5
19,1 / 0.75 139,7 / 5.5
22,2 / 0.875 165,1 / 6.5
31,8 / 1.25 190,5 / 7.5
38,1 / 1.5 317,5 / 12.5
47,6 / 1.875 393,7 / 15.5
54 / 2.125 444,5 / 17.5
Note: Over 54 mm / 2.125 in, the Dpf equals 800 mm / 31.5 in,
with a maximum allowable opening of 152,4 mm / 6 in.
Example: Dpf = 0 when the guard can be opened up to, but less than 6,4 mm / 0.25 in before issuing a stop command.
Dpf = 444,5 mm / 17.5 in if the guard can be opened 54,0 mm / 2.125 in.
At no time can the opening be greater than 152,4 mm / 6 in before issuing a stop command.
For more information, refer to the US regulations and standards (OSHA 29 CFR 1910.212 & 1910.217, ANSI B11.19 and ANSI/RIA R15.06).
*
If the length of the slot opening is
≤≤
≤≤
≤ 65 mm / 2.56 in, the thumb will act as a stop and the safety distance can be reduced to 200 mm / 7.88 in).
For more information on the guards installation, refer to the European standards: EN 811, EN 953, EN 294
