Figure 4-9. Extension planking
Table 4-1. Sizes of extension planking
b. Extension Ladder. An extension ladder (Figure 4-10) consists of two or more sections that
are adjustable to various lengths. The ladder sections are adjusted by pulling on a rope that is reeved
(threaded) through a pulley. The pulley is mounted on the ladder's stationary section, and a rope is
attached to the ladder's extension section. The extension ladder overlaps to hold the sections together.
The sections will overlap at least 3 feet for ladders up to 38 feet long, 4 feet for ladders up to 45 feet
long, and 5 feet for any extension ladders over 45 feet long. Lock the rungs of one ladder section to
another section with a secure locking device. Ensure that the ladder sections are in the down position,
then erect the extension ladder in the same manner as a straight ladder. After the ladder is erected, lean
the top away from the building and raise it to the desired height with the pulley and rope arrangement.
Ensure that the ladder sections are locked in place before ascending the ladder.