a. Single-Rung Ladder. A single-rung ladder consists of two side rails that measure from 8 to
30 feet in length. Between the side rails, rungs (steps) are spaced 12 inches apart. Each rung is capable
of supporting weights up to 500 pounds. The size of a ladder is determined by its overall length.
Although single-rung ladders are available in lengths of up to 30 feet, it is better to avoid ladders that are
over 20 feet because of the difficulty in raising them. Figure 4-1 shows a typical single-rung wood
ladder. To help keep the bottom of the ladder from slipping, it is necessary to equip it with ladder safety
shoes or spikes (Figure 4-2).
Figure 4-1. Single-rung woodladder
Figure 4-2. Ladder safety shoes
(1) Selecting a ladder. Ladder selection depends on the height at which you must work. You
will work most efficiently in a space not higher than shoulder level nor lower than knee level. The
length of a ladder is critical because the area that you can safely reach is limited. Use a ladder that is
long enough for you to reach your work without climbing past the third rung from the top of the ladder.