What Does
Duty Rating Mean?
The duty rating of a portable ladder is a classification that indicates its maximum weight capacity.
Duty ratings apply to all types of portable ladders, including step ladders, extension ladders, single ladders, articulating ladders, and platforming ladders. A duty sticker must be placed on each of these ladders as per safety standards.
Portable ladders are made for convenience and designed to safely hold a certain amount of weight. Exceeding this weight limit can cause the ladder or its components to fail, which could result in a serious or fatal injury.
Safeopedia Explains Duty Rating
Ladders are commonly used for everyday work, including at home and in offices. Since they are portable, they are frequently used in construction activities where the work is not carried out in a consistent, fixed location.
Ladders have different duty ratings depending on where and how they are intended to be used. Ladders intended for light duty use at home should never be used in industrial settings or on a construction site, where more robust, heavier duty equipment is required.
Categories of Ladder Duty Ratings
The American National Standards Institute (ANSI) has established five categories of ladder duty ratings:
- Type 1AA (Special Duty) – 375 lb load capacity for rugged use
- Type 1A (Extra Heavy Duty) – 300 lb load capacity for industrial use
- Type 1 (Heavy Duty) – 250 lb load capacity for industrial use
- Type 2 (Medium Duty) – 225 lb load capacity for commercial use
- Type 3 (Light Duty) – 200 lb load capacity for household use
Ladder Types and Duty Ratings
Common types of portable ladders include:
- Step ladders, which have a safe maximum reach of about 4 feet higher than the ladder’s height. Standing on the top rung of a step ladder is considered dangerous and can result in the user losing their balance and falling. Safely using a step ladder requires standing at least two steps down from the top rung, which limits the user’s reach.
- Extension ladders, which have adjustable lengths. These are non-supporting ladders, meaning they cannot stand on their own and must be leaning against a wall for the needed support.
- Articulated ladders, which have one or more pairs of articulated joints that can be locked in place. This allows them to be set up in different configurations, depending on the user’s needs.
Choosing the Right Portable Ladder
Whether in the workplace or in other settings, portable ladders must be chosen based on their duty ratings. The weight placed on the ladder when it is in use must not exceed the maximum safe load capacity indicated by its duty rating. When assessing the ladder’s capacity, it is important to take into account that that a person’s total weight also includes the weight of the clothes and personal protective equipment (PPE) they will be wearing, as well as any tools or materials they might be carrying.
The size of the ladder also matters. Using a ladder that is either too short or too long for the given application can be dangerous, even if its duty rating is correct.
The environment in which the ladder will be used is equally important. Metal ladders are unsafe for use when working near electrical sources, as they can conduct electricity. If the user comes into contact with a live wire while on the ladder, their body can complete the electrical circuit, causing electrocution which can lead to a fall due to the shock. In such cases, a wooden or fiberglass ladder with an appropriate duty rating is a more suitable choice.
Other safety considerations while choosing a ladder require evaluating the work environment and having knowledge of the type of ladders available.
Some questions to ask before using a ladder include:
- Will the ladder be resting on an even surface?
- Is there a lot of foot traffic in the area where the ladder will be used?
- Is the floor free of clutter and materials?
- Are there any obstructions on the way up the ladder?
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