You enter the elevator - as responsible user or you simply have the project under your control as part of a construction - and just before marking the floor you want to get you look at the small plate that indicates the maximum lift load: "4 people , 300 kilograms ", for example.
How is that limit determined? Obviously, you are not at a whim, a standard by dimensions or a random decision. There are technical criteria, subject in this case to physical laws, that forced to determine that specific weight.
Technical requirements
We must insist that they are physical laws that do not depend only on the size of the cabin. In fact, surely you know that there are technical requirements - set by every nation, region and regulatory body of construction - that force manufacturers, distributors and marketers to ensure the safety of users.
The weight or load to be transported depends on the lifting system, the maximum speed allowed for the operation, the number of floors of the building as well as its use, the materials used, the energy that feeds it and, finally, the available space. For this reason, the calculation is not obvious even for experts and it is a branch of specialized knowledge.
Normative
Regarding regulations, the Spanish regulations, for example - adapted in 2016 to a regulation of the European Union - is obliged to design and manufacture the cabin with space and resistance according to the maximum number of people and the nominal weight fixed by the Installer.
Precisely, the selection of suspension and lift components is related to the materials used in the cabin. So when you want to incorporate an elevator into a new or existing constriction you have to think about several factors: the functionality, the capacity you need according to the type of building and the materials of the elevator according to the finish you want to give the space.
Other elements
As we mentioned, the subject of the maximum weight or load of the elevator is framed in physics. That is why in Astarlifts we understand that this is a complex issue and that the decision can not be random or capricious. As an additional determinant - in addition to space, lifting system and materials - you should consider lifting speed.
For more than a decade in Europe, cabins are required to have a visible plate with the nominal load (kilograms) and maximum number of people they can carry. However, many times, users focus on their own time pressures and set aside general security. For this reason, modern regulations require the incorporation of systems that block the operation of the lift when the permissible load is exceeded.
Another consideration that determines the maximum weight in the elevator is the number of floors that the building has. Needs differ between a modest five-level residential building, a shopping center, a hospital and a skyscraper.
The Importance of Use
The use also often determines the estimated number of elevator users. We refer to the difference in use in a residential building and in an office where the population density is highest.
The suspension of the cab can be made through cables or chains in combination with coupling systems or friction pulleys and counterweights; And the energy that powers the systems influences both the maximum load and speed of the equipment.
Tests
A new installation of an elevator does not only happen in the case of a construction. In fact, it is increasingly common to introduce equipment in buildings that did not have them. Such a project puts you in the face of the challenge of introducing a cabin into a space that was not designed for it.
Users want more comfort and even a revaluation of their property. But your consideration is to take advantage of any available space. The maximum load is an important issue. For this reason, installation trials of a new lift include tests with an empty cabin and a static test mobilizing 1.25 times the nominal load allowed. All this corroborates the limit set by manufacturer and installer and the result should indicate that in no case deformity, another guarantee of safety in the elevators.
Safety
It is important that you take into account other current safety requirements in lifts, such as door lock and two-way communication services or tele-assistance in case of emergency.
The elevator, although it has more than 2000 years of history, is a symbol of the modern life and eliminates barriers of mobility for people with disabilities, with reduced mobility or senior citizens. But the intention is that they do so while providing their users with maximum security.
Verification
One of the concerns of the sector is that the most modern regulations aim to verify the new facilities while the existing ones can remain stagnant with their previous characteristics.
However, in Astarlifts we recommend to take into account this new regulation when you are in charge of a rehabilitation or reform of any type of building.
You can make a list with some verification items. Surely, you will already find the plate with the maximum load allowed. Then you should check the lift system, the maximum speed and the materials used. You can then check the security elements: block when the load is exceeded, opening and closing doors, in addition to the communication system. A simple analysis will lead you to get a successful project.
The data
You may be surprised to know that the elevator is the most widely used means of transportation in the world. Remember that it serves for the vertical transfer of people. At the same time, it is the safest means of transport that exists thanks to security requirements such as those mentioned.
The latest data from the Feeda (Spanish Business Federation of Elevators) indicate that the country is the world leader in lifts with 19.8 equipment per 1,000 inhabitants. That allows to move five times in a day to all the national population.
directive Europe
Safety measures, including verification of the combination that allows the maximum load of each unit. In fact, this line is regulated in a security directive in the European territory established in the year 2014.
Precisely that document also establishes the need to place the plate with the maximum weight allowed in the unit in number of people and in kilograms (the frequent legend: maximum capacity 4 people, 300 kilograms); As well as the factors that are taken into account to determine them and the tests to verify that cap.
As part of the safety guarantees there is one specifically related to the loading and acceleration of the elevator in case of emergency. This is an indication that a safety device is included that prevents the fall or uncontrolled movement of the cab when there is an interruption of power or a failure of one of the components.
The requirement is that the device operates independently of the suspension elements, but is capable of operating for the nominal load and maximum speed provided by the installer.
This is another important fact regarding the need to establish and respect this maximum load: how does the emergency system work when that weight is exceeded? If we look at the standard as a whole, which also requires the blocking of operation when the weight limit is exceeded, this line takes on an additional meaning.
The maintenance
The electrical, electronic and mechanical systems of the elevator, as well as its parts and components wear out with the use and passage of time. That is why preventive maintenance plans are made.
A device subjected to a constant over use because it constantly exceeds the maximum permissible load undergoes a greater wear and tear than that anticipated by its manufacturer and installer. Think, for example, of the metals and pulleys that may be present in the equipment.
That can lead to cabin leveling problems, which are the most frequent cause of accidents in elevators, according to Feeda. The usual thing is that the consequences of the overloads begin to appear little by little. That means that a single excess will probably have no serious or fatal consequences, but that its insistent occurrence will begin to damage the facility.
Quality devices
Hence the importance of installing devices that verify weight and block usage. The first element is the balance that meets the requirement of load check. Next, and as a consequence, there must be a good alarm or door lock system when it has been found that, in fact, the limit previously established by those responsible has been exceeded.
Keep in mind that it can be difficult to control the number of users hurrying to quickly board the cabin. Especially, when the clock brushes the hour of entry to the office or, on the contrary, when it marks the time of departure the day before a holiday while family, friends or holidays are tempted with promises of rest and relaxation.
