Falltech SRL Manuel De L'utilisateur page 7

5.4 Minimum Required Fall Clearance Calculation
Contractor SRD in an overhead condition, in which the SRD is installed anywhere in the allowable attachment area, which ranges from
directly above the user to level with the FBH D-ring, as shown in Figure 4. The overhead condition MRFC has six metrics, labeled A – F,
measured from the walking/working surface.
A = SRD Deceleration Distance
B = D-Ring Shift and Harness Stretch
C = Safety Factor
D = Sub Total- Minimum Required Fall Clearance
E = *Additional Fall Clearance Calculation Due To Swing Fall
F = Total Required Fall Clearance
The MRFC for an overhead anchorage, with no swing fall condition, is calculated as A+B+C=D. The user must be aware that if a swing fall
hazard exists, as shown in Figure 5, additional steps are required. Use Chart 1 on the following page to determine the amount of swing
fall, and place that value in E. Add the E value to the D value to determine the total MRFC.
Figure 4 - Calculating Required Fall Clearance: Overhead Anchorage
Deceleration Distance
Maximum allowable length of cable or web that
1.2 m may payout from the SRD once deceleration of the
A
(4 ft) user has begun and after a fall event occurs. For
work in low clearance areas, see Table 1B for Typical
Performance
Dorsal D-Ring Shift and FBH Stretch
0.5 m
B Combined amount of Dorsal D-ring up-shift and
(11/2 ft)
harness webbing elongation during entire fall event
Safety Factor
0.5 m Added length to account for other factors such as an
C
(11/2 ft) improperly adjusted harness, actual worker height
or worker weight
Sub Total- Minimum Required Fall Clearance
2.2 m
D for direct overhead use of SRD with No Swing Fall;
(7 ft)
sum of A, B and C only
*Additional Fall Clearance Calculation
E ____ m
due to Swing Fall (using Chart 1)
Total Required Fall Clearance
F ____ m
Including sub-total D and Swing Fall E (from Chart 1)
1. Overhead Anchorage 2. Walking/Working Surface
3. Nearest Lower Level or Obstruction
CMSRL01 Rev A
Figure 5 - Swing Fall Hazards: Overhead
A Anchorage
B Self-Retracting Lifeline
C Walking/Working Surface
D Swing Fall Impact after fall event
E Next Lower Level or Obstruction
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