Portable ladders are of different types, each of which has its own advantages and disadvantages. These types of portable ladder are self-supporting ladders, non-self-supporting ladders and special purpose ladders.
Portable self-supporting ladders can stand up on their own. Standard stepladders have a front section that has steps used for climbing up and a two legged back section to provide more stability. The latter require being set up on flat surfaces; floors, platforms, and slabs.
1. Self-supporting ladders: Standard step ladders cannot be adjusted and have flat steps on the front and a hinged back. The front and back sections are securely held together in an open position by a metal spreader or a locking device.
The back side is cross-braced and cannot be used for climbing. This type of portable ladder might also come with a bucket shelf that can support a 25 pounds load. If the shelf is present, it is fastened in such a manner that it can be folded up within the ladder as the ladder is closed. The shelf itself cannot support any weight so do not lean on it.
The standard step ladder is meant for use by only one person at a time. You need to check the manufacturer label to confirm if you can load it with more weight. In some cases, loading it with more weight could present dangers of the person falling. This is an important factor not just when buying ladders but also when setting horizontal lifeline and ladder safety gate.
On this type of ladder, the horizontal flat steps are placed at intervals to form the front section used for climbing. It might also have diagonals that join and stabilize the rear rails.
2. Non-self-supporting ladders: This is the type that gets leaned against a wall or other stable support structure that can support the ladder weight, user weight, tools and materials being used by the worker. The ladder is intended for use by one person at a time. The main types include single ladders and extension ladders.
3. Extension ladders: The offer the convenience and the greatest length in a general purpose ladder. They have two sections that travel over each other on guides or brackets so you can actually adjust the length of the ladder.
You can read more on how to set up or use portable ladders, horizontal lifeline and ladder safety gate elsewhere in this website.