12
Using Chart 2 to Calculate Minimum
Required Fall Clearance for the 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 (3.1 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 (6.0 m) 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 (1.3 m) away from the SRD. Minimum required fall clearance is 20.5 feet (6.3 m) 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
5.2.2 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
