Page 231 - Bài 1 ok_Neat

To maintain control during a lowering, always maintain an s-shaped
bend in the rope. Do not permit the entry angle of rope feeding into
the MPD to be less that 90° to the load end.

PARKING BRAKE

The MPD is designed with a Parking Brake locking feature, which prevents inadvertent
release of the rope through the device. Rope can be pulled in through the device
without having to unlock the Parking Brake. The Parking Brake function is intended to
temporarily secure the MPD when the operator needs to release their grip from the rope
entering the device. It is activated by turning the marked knob counterclockwise. When
a loaded MPD will be left unattended, the Parking Brake is locked and the secure
running end of the rope
with a tie-off at the device
(Half Hitch and Overhand
Knot) (Figure 93). When the
MPD is employed as a
ratchet or progress capture
device in a pulley system,
the Parking Brake is not
activated.

Figure 92- MPD secured with Parking Braked locked and tied off.
During an edge transition
with an abrupt transition and a sharp edge (as opposed to a gradual transition with no
sharp edges), the belay line tension should be kept hand tight. If the attendant
stumbles at the edge, both ropes are less likely to be damaged, if the belay line remains
untensioned during this action. Additionally, there is greater descent control during this
critical maneuver, if only one device and rope handles the lowering at this point. The
scenario of a main line failure while an attendant is negotiating the edge has the
potential to generate a one meter fall on three meters of rope. As stated previously the
MPD passes the British Columbia Council of Technical Rescue (BCCTR) Rescue Belay
Competency Drop Test.

100 | P age