In Indonesia, the term “tangga monyet” refers to a type of vertical ladder installed attached to building structures or facilities such as tanks, silos, towers, and chimneys. The distinctive feature of this ladder is the presence of a safety cage that encloses the back of the ladder to prevent the risk of falling when used, also known as a cage ladder.

Used in Various Sectors

Cage ladders are commonly found in sectors such as:

• Manufacturing plants

• Power plants

• Water treatment facilities

• Watchtowers

• Multi-level warehouses

• Civil and high-rise construction projects

• Tank maintenance access

Access to service areas, roofs, or inspection rooms in tall structures is generally impossible without this type of ladder. Because of its wall-mounted design and space efficiency, the cage ladder has become the main choice compared to conventional ladders or spiral stairs.

Safety Standards in the Field

Although widely used, the installation and selection of cage ladders must still comply with occupational safety principles. Some important points of concern in Indonesian projects include:

• The distance between rungs must be consistent and follow ergonomic standards

• The cage is usually mandatory if the ladder height exceeds a certain limit

• A rest platform is required at certain heights for safer access

• The ladder must be firmly attached to the main structure through a precise mounting system

However, in practice, many projects in the field use cage ladders made from ordinary metal without corrosion protection, or even installed without a safety cage, which can increase the risk of workplace accidents.

Shift to Safer Materials

While cage ladders were previously generally made from galvanized steel or iron, more projects in Indonesia are now considering Fiberglass Reinforced Plastic (FRP) ladders due to their weather resistance and non-conductive properties, especially in areas prone to high voltage electricity.

Cage ladders remain an important component in supporting vertical mobility in multi-story buildings or tall structures in Indonesia’s industrial world. In addition to their vital function, the installation and selection of ladder types must also consider long term safety, material quality, and resistance to working environment conditions. Along with the development of construction technology, cage ladders continue to adapt, from being merely an auxiliary tool to becoming part of an integrated workplace safety system.