The ladder is an indispensable tool for the implementation of a number of construction, installation and household work. That is why it should be in the arsenal of every home craftsman. Today, in addition to the usual ladder, there are several more models that are convenient and practical to use.
The topic of this article is both a retractable 3-knee fire ladder and a structure designed for domestic needs.
The main types of stairs
There are such stairs:
- Ordinary ladder, which can be either wooden or metal.
- Folding attached. This type also includes the three-knee retractable ladder l 60 used by firefighters.
- Stepladder (can be made of steel or aluminum).
- Transformer. Such designs are of several types:
- Three-knee.
- Four-knee.
- Stem or telescopic.
Fire escape
On duty, firefighters often have to enter high-rise buildings, and in some cases this must be done from the outside, since the interior rooms, engulfed in fire, do not allow for a full-fledged evacuation of people. In this case, several types of stairs are used, the longest of which is a three-knee fire escape.
This is an attached type structure, which consists of three segments approximately equal in length, which allows it to be expanded to a length of more than 10 meters.
Its main purposes are:
- Ascent of fire brigade personnel to attics and roofs of one-story buildings, as well as to the second and third floors of multi-storey buildings.
- Carrying out the evacuation of people from buildings engulfed in fire.
- Carrying out work inside large rooms (halls).
- Conducting training sessions.
Specifications
- Manufacturing material - steel. Thanks to the use of steel, not only the price of the product is reduced (in comparison with aluminum alloys), but also high strength is ensured, because as you know, steel is not characterized by fatigue of metals. High structural strength is necessary when carrying out mass evacuation work, when several people are on the stairs at the same time.
- Product weight is 46.5 kg, therefore, for the convenience of transportation, at least 2 people are required.
- Unfolded length - 10.7 meters.
- Assembled length approx. 4 and a half meters.
Three-knee construction for domestic use
Household 3 x knee ladder has significant structural differences from the fire. It refers to the type of transforming stairs, which can take various forms, having movable nodes.
The scope of the transformer is extremely wide. Such a product can be used in a variety of industries, from gardening fruit picking to the repair of facades and roofs of one-story buildings.
Such designs differ in the number of sections. One of the most popular and longest is a 3 by 10 staircase (3 sections of 10 steps). Typically, household options do not exceed 7 meters in height. If the working height of the product is more than 7 meters, then we are talking about a professional three-section transforming ladder used by builders.
Main characteristics
- A traverse is located in the lower part of the support section. This is a transverse bar by means of which the stability of the structure on the ground is ensured.At the ends of the traverse there are anti-slip interchangeable supports, called shoes.
- The extended sections are connected with ties. This is to prevent the ladder from collapsing at the most inopportune moment.
- On the second section, plugs are installed to ensure rigid fixation.
- The material of such products is anodized aluminum. This is a very light and durable material that significantly reduces the weight of the structure, allowing you to easily transport it yourself.
Advice! When buying a structure, pay attention to the steps, which should have a relief coating. The textured surface prevents slipping, making the product safer to use.
Folding options
This product is not called a transformer for nothing, because it can easily take on various positions, and therefore it is very popular both among professional builders and among home repair lovers. Such a three-knee ladder successfully embodies all the advantages of an attached and original two-section model, as well as a step-ladder.
Instructions for the use of such products provide for the following folding options:
- Attachable long universal design.
- The last section can be separated, which means that the structure can be used as a compact extension.
- Ladder. This option is obtained if the two lower sections are left folded together, while the upper one is set as a "house".
Conclusion
As you can see, two completely different designs can belong to three-knee ones, each of which has its own scope. The video in this article has prepared an overview on this topic (read also about the features of the Oman staircase for attic spaces).
