Max. load
The maximum weight a ladder is guaranteed to be able to support without breaking. When choosing an option for this parameter, it is worth considering not only the weight of the user himself, but also the additional weight — equipment, tools and other items that are planned to be used in the work. Also, it is necessary to make a margin for the maximum load. This is due not only to the fact that different people with different equipment can use the stairs. The fact is that this parameter can be measured by different methods, including with the help of a fixed load installed on the ladder; at the same time, a person, even during the most calm work, does not stand absolutely still. Accordingly, there are irregularities in the load, and it is quite possible that at some points it will exceed the calculated one even with a seemingly acceptable weight. This is fraught with breakdown at the most inopportune moment. Therefore, when buying, it is advisable to make sure that there is a weight margin of at least 10-15 kg — this will minimize the risk of such troubles.
Max. height
The maximum working height of the ladder. In models that do not have a footboard (see above), this parameter is usually indicated in the specifications for the total length of the stairs. It is worth noting here that the height of the upper step in such cases rarely corresponds to the working height to the nearest centimeter - firstly, the stairs are almost never strictly vertical, and secondly, the outermost steps are usually not on the very edge. However, in most cases this difference can be neglected. If the design provides for a footboard, then the height is measured along it.
When choosing a ladder by height, it should be taken into account that the longer the structure, the greater its weight and, usually, the higher the price. Therefore, buying a model with a long length makes sense only when there is a real need for it.
Dimensions (folded) (LxW)
Ladder dimensions in fully folded position. The smaller they are, the more convenient the ladder will be in storage and transportation. Usually, only the length and width are indicated in the characteristics, because. the thickness of modern stairs is very small and in most cases it can be neglected; and in some models, only the length may be indicated at all — for the same reasons.
Max working height
The maximum working height can be described as the highest height that can be reached using a given ladder. This parameter is determined as follows: the maximum height of the stairs is taken and the height of the person standing on it is added to it (or rather, the highest height that he can comfortably reach with his hands). Of course, this parameter is rather approximate, because taken into account for some average height; and in general the rules for counting will be different. So, for some manufacturers, to determine the maximum working height, they add 2 m to the height of the ladder, others — 2 m 10 cm, and if we are talking about a ladder (see "Design"), this increase can be even less — about 150 – 160 cm (in such models, the user rarely stands on the topmost crossbar). Nevertheless, this indicator makes it possible to estimate the height that you can reach, with an accuracy of a couple of tens of centimeters, which is most often quite enough.
Weight
The total weight of the ladder. On the one hand, the lighter the model you choose, the more convenient it will be to carry, the less effort will be expended. On the other hand, lighter weight means less material used in the construction of the stairs, and this can adversely affect reliability. Therefore, it is worth choosing an option for this parameter depending on the planned features of the application. If the expected load on the ladder is significantly lower than the maximum, then you can not pay close attention to the weight. But if you have doubts and/or plan to work in difficult conditions with a heavy load, you should choose the more massive one from two models with the same characteristics. It is unlikely that this will seriously affect the cost of forces, but the risk of breakage and a dangerous fall will decrease significantly.
