5.2.2
30’ FT-R Non-Overhead Anchorage
The leading edge/below D-ring condition minimum required fall clearance
(MRFC) is calculated using five metrics, measured from the walking-
working surface: SRD Deceleration Distance, D-Ring Shift and Harness
Stretch [1 ft (0.3m)], Safety Factor [1.5 ft (0.5m)], Dorsal D-ring Height
[5 ft (1.5m)], and Swing Fall. Dorsal D-ring height is added to account
for the below D-ring tie-off compared to the overhead condition. Chart
2 below is calculated using the performance data of the SRD and includes
all five metrics listed previously to determine the MRFC.
X
-Set -Back
Distanc
e
Y
-Lateral O
ffset Dist
.
Z
- Minimum Required
Fall Clearance From
Working Surface
Figure 4 - MRFC Non-Overhead Anchorage
0 ft
(0 m)
2 ft
(0.6 m)
4 ft
(1.2 m)
6 ft
(1.8 m)
8 ft
(2.4 m)
10 ft
(3.0 m)
12 ft
(3.7 m)
14 ft
(4.3 m)
16 ft
(4.9 m)
18 ft
(5.5 m)
20 ft
(6.1 m)
22 ft
(6.7 m)
0 ft
(0 m)
16.5
(5.0)
18.5
(5.6)
20.5
(6.4)
22.5
(6.9)
24.5
(7.5)
26.5
(8.1)
28.5
(8.7)
30.5
(9.3)
32.5
(32.5)
34.5
(10.5)
36.5
(11.1)
38.5
(11.73)
5 ft
(1.5 m)
16.5
(5.0)
17.0
(5.2)
18.0
(5.5)
19.5
(6.0)
21.0
(6.4)
23.0
(7.0)
24.5
(7.5)
26.5
(8.1)
28.5
(8.7)
30.5
(9.3)
32.5
(32.5)
34.5
(10.5)
10 ft
(3.0 m)
16.5
(5.0)
17.0
(5.2)
17.5
(5.3)
18.5
(5.6)
19.5
(6.0)
21.0
(6.4)
22.5
(6.9)
24.0
(7.3)
25.5
(7.8)
27.5
(8.4)
29.0
(8.8)
31.0
(9.4)
15 ft
(4.6 m)
16.5
(5.0)
17.0
(5.2)
17.0
(5.2)
18.0
(5.5)
18.5
(5.6)
19.5
(6.0)
21.0
(6.4)
22.0
(6.7)
23.5
(7.2)
25.0
(7.6)
26.5
(8.1)
28.5
(8.7)
20 ft
(6.1 m)
16.5
(5.0)
17.0
(5.2)
17.0
(5.2)
17.5
(5.3)
18.0
(5.5)
19.0
(5.8)
20.0
(6.1)
21.0
(6.4)
22.5
(6.9)
23.5
(7.2)
25.0
(7.6)
26.5
(8.1)
25 ft
(7.6 m)
16.5
(5.0)
17.0
(5.2)
17.0
(5.2)
17.5
(5.3)
18.0
(5.5)
18.5
(5.6)
19.5
(6.0)
20.5
(6.2 m)
21.5
(6.6)
22.5
(6.9)
23.5
(7.2)
25.0
(7.6)
30 ft
(9.1 m)
16.5
(5.0)
17.0
(5.2)
17.0
(5.2)
17.5
(5.3)
17.5
(5.3)
18.5
(5.6)
19.0
(5.8)
20.0
(6.1)
20.5
(6.2)
21.5
(6.6)
23.0
(7.0)
24.0
(7.3)
SRD Se
tback Dis
tance fr
om E
dg
e (X)
Lateral Offset Distance (Y)
Chart 2
30’ FT-R
Using Chart 2 to Calculate Minimum Required Fall Clearance for the 30’ FT-R
2 foot (0.6 m) increments along the Y-Axis represent the
Lateral
Offset Distance
the user is working away from being directly
under the SRD
5 foot (1.5 m) increments up the X-Axis represent the
SRD Setback Distance from Edge
Example:
If the user needs to work 10 feet (3.0 m) away from the SRD along the edge, the SRD needs to be anchored back at least 15 feet (4.6 m)
from the edge. Minimum required fall clearance is 19.5 feet (6.0m) at maximum allowable swing fall.
Example:
If the only suitable Anchorage for the SRD is at the edge [0.0 feet (0.0 m)], the maximum allowable work zone is 4 feet (3.0 m) away
from the SRD. Minimum required fall clearance is 20.5 feet (6.4m) at maximum allowable swing fall.
Key to Work Zone Areas:
= Allowable Use Area = Not Allowed Use Area
WORKING IN THIS AREA MAY RESULT IN SERIOUS INJURY OR DEATH
MSRD20 Rev B
110421
10
