Cable routes in open-plan facilities

With the development of technology and technology from the middle of the XX century. there is a tendency to use electromagnetic waves of a higher frequency in communication systems and, accordingly, to increase the data transfer rate, at the same time, stereotypes in the field of design and architecture of premises are crumbling. In the projects of modern office-type buildings, a combination of open spacious rooms and a number of auxiliary rooms, separated by light walls or partitions, is envisaged. Of course, such changes in architecture also affect the components of the interior, including engineering systems.

Examples of open-plan premises, or "open" offices (open space), are various showrooms, car dealerships, shopping areas, corridors and halls of exhibition centers, airport halls, checkout areas of shopping centers and malls, medical chambers, museum galleries, sports grounds indoor pavilions and centers. During the design, deployment and subsequent operation of cable systems in such premises, the question is invariably acute: how to optimally organize a network of workplaces away from walls and ceilings, without violating the architecture of the above premises? To solve this problem in such projects, when the only possible place for laying cables is only the space under the floor and / or directly in the embedded floor (in the case of a monolithic concrete floor), systems of cable traps and mini-columns are used.

Raised floor systems

Let us consider in more detail the existing structures of raised floors and monolithic cast concrete floors. The former include high raised floors on adjustable (from 5 to 30 cm) racks, traditionally used in server rooms and data processing centers (DC), as well as low-profile raised floors with a height adjustment level of 5-7 cm, usually used for arranging floors in large open rooms. The corresponding technical solutions have a similar design and may differ in overall dimensions and thickness of the plates, decorative finishes, materials, and the texture of the plate itself. In most countries in Europe and developed countries in Asia, when using a system of floor hatches and trays, cables pass along the shortest path from the cross-floor to the intermediate connection points serving the working areas,and then - again along the shortest path to the terminal devices of the workplace.

Installation of cable systems under a raised floor is possible not only in new office complexes, but also in buildings under reconstruction. At the same time, it is not necessary to build an expensive (high) raised floor, as in modern data centers, where it serves not only for laying cable bundles, but also for distributing cooling air flows, as well as for installing other engineering subsystems. Nowadays, a simplified type of raised floor is often used - the already mentioned low-profile (or double) floor. In this case, the raised floor height (5–7 cm) is sufficient for laying the SCS elements.

Information cables are routed under the raised floor (in trays and flexible corrugated pipes) directly to floor hatches or mini-columns for each desktop or user group.

Installation components (information sockets of various types) are placed in hatches or columns or are led out into furniture distribution boxes. The wiring of power cables is done according to the same principle. It should be noted that when using a raised floor in combination with floor hatches or mini-columns, the overall cable routing system becomes much more flexible: in a short time, you can move the cable bundle to another part of the hall and install a slab with a hatch or mini-column.

Raised floor systems can easily integrate cable hatches made of different materials (ABS plastic, polyamide compositions, aluminum, brass, steel) and having different degrees of protection (from IP20 to IP44, and in some cases to IP54) and a different number of modules for the installation of wiring accessories and information connectors. When choosing hatches, special attention should be paid to the intensity of people visiting these premises. The material of the hatch should be selected based on the direct load on it and the necessary protection against mechanical damage (anti-vandal designs). It should be clarified that a hatch made of ABS plastic or polyamide compositions and perfectly suitable for servicing a workplace in a small office or hospital room cannot be used, say, in a floor structure,intended for the showroom of a car dealership or hall-corridor of the airport, through which electric cars or cleaning electric vehicles ply. In this case, you cannot do without the use of construction materials such as aluminum or brass. Improved protection against deformation and damage should also be provided when equipping the checkout area of ​​a large hypermarket, since a large flow of customers passes along the checkout.
  
Structurally, hatches can be different and contain several options for places for installing sockets and modules - as a rule, from 1 to 6, in extended versions up to 8 or 12. When installing in a raised floor, it is not necessary to additionally adjust its level, since the hatches have a protective installation case and when placed in the raised floor slabs, sufficient space is created for mounting the landing box and supplying cable bundles in corrugated or rigid pipes or on trays with supports on the base floor. Thus, the hatches are easily integrated into the existing floor structure by inserting exactly in the place where the customer or consumer needs it. To connect to the power supply or data cables, you just need to install the corresponding power outlet module or information module in them. In the hatch cover, as a rule,there are special cable outlets, and the cover itself can have a removable false cover for installation in the resulting field of the main cover of the decorative floor covering (carpet, laminate, linoleum or parquet).

Thus, the hatch matches the color and texture of the raised floor. Hatches are also available without false covers, usually they are made of metals - aluminum or brass, less often of steel. These materials are well combined with the main colors and textures of the floor and look in the "high-tech" style, while, due to the high degree of protection, such hatches can withstand several times more load than plastic ones.

Jellied floor systems

Such a solution, as a rule, can be implemented during the construction of a new building or during its major reconstruction. In this case, the installation of the cable duct system is directly related to construction work, since it requires a concrete screed with a height of at least 55–65 mm over the entire area of ​​the room. The system of laying power and information cables directly into corrugated pipes made of polyolefins - HDPE (low pressure polyethylene) or polypropylene compositions - and / or into steel main trays of a closed type (a blind tray with a lid without perforation) allows you to create an extensive distribution network and operate it in the future as the main one. The network formed in this way can also be considered as a backup - to use it, for example,in the case of an increase in the number of users - or as a branched line. This way of placing workplaces and organizing cable routes is the most traditional and rational solution. It is practiced in the checkout areas of shopping centers, banking and industrial premises, airport and hotel lobbies, library and exhibition halls, and other similar premises.

As a rule, the systems for organizing wiring in concrete floors include, in addition to the hatches themselves, also highways in the form of steel blind trays, however, the simplest and most reliable solution is to lay cable bundles in corrugated pipes of "heavy type" of different diameters with a degree of protection IP55 and strength within 750 N per 5 sq. cm. Such an organization of cable routes allows, firstly, to easily change the laying trajectory when pouring into concrete at the stage of production or reconstruction of the floor itself, and secondly, to do without a set of different types of corners and fasteners (since the pipe is flexible). Finally, a very important argument in favor of using corrugated pipes is a significant reduction in the cost of the route; corrugated pipe "heavy type" designed specifically for pouring into concrete and is used in all buildings,where sliding formwork technology is used inside the walls, ceiling and floor.

Housings of protective boxes of covers, made of high-alloy steel or impact-resistant plastic, have a set of inlet holes. When joining the protective box with the corrugated pipe, couplings with a degree of protection from IP44 to IP66 are used - thus, the closed system is hermetically sealed and is able to withstand high loads under pressure on the future floor. The presence of several holes in the protective box of the hatch allows forcibly separating the bundles of power and low-current cables, thus eliminating possible negative pickups and interference. At the same time, using stationary steel broaches or special nylon broaches inside the corrugated line, you can stretch additional backup cables and wires after the concrete floor is ready. Undoubtedly,such a solution is less mobile than the organization of workplaces in hatches when using a raised floor, but it completely solves the issue of equipping connection points in rooms with a large flow of people or even cars where there is a heavy load on the floor.

More about hatches and minicolumns

Often during the operation of the system, the question of its tightness arises. As a rule, this is due to the cleaning of the office or the hall where the hatches are located. It was mentioned above that hatch systems can be different in degree of protection: from IP20 to IP44, therefore, when choosing a hatch system and underground highways, it is necessary to have information on how to clean the main room. So, hatches with a degree of protection from IP20 to IP40 are unlikely to be able to withstand wet cleaning, but for the most part they are an excellent, inexpensive and aesthetic solution for offices, hotel halls and halls, where, as a rule, carpet, parquet or polymer coating are used. and the main cleaning method is dry (vacuum cleaner or dry floor cleaning). In places where many people pass, and in special rooms (hospital wards, laboratories) where wet cleaning is recommended,it is reasonable to use hatches with a degree of protection of IP44 and higher.

At the design stage, it also makes sense to have an idea of ​​the possible load on the floor and the routes of movement of people in order to assess the necessary degree of protection against mechanical damage to the cover and hatch body. It is also important to plan the number of power outlets and information modules. Among European-made hatches, products of MK (England), Quintela (Spain), Thorsman (Sweden), Ackermann (Germany) are widely represented in Russia, and from domestic ones - the Ekoplast plant.

Another popular way to distribute power points and connect to communication and information networks of workplaces is the construction of an integrated system of mini-columns and associated cable routes located in the floor or under the raised floor. In the presence of a raised floor, as in the case with the use of a hatch system, cable bundles are laid in blind steel trays with supports on the main floor or routed through corrugated pipes from the power source (lead-in cabinet) or cross-section to the very foundations of the mini-columns. It is important to know how mini-columns differ from the columns connecting the ceiling and floor. In the system of mini-columns, only the base floor or raised floor is involved, such mini-columns have a height of 300 to 660 mm, that is, they do not exceed the height of the working table.They do not create additional boundaries in the open space and can be placed both under the desktop and in the immediate vicinity of it, while serving one or more workplaces. Columns with a height of 3 m and more are used when using a sub-ceiling space (in the case of suspended ceilings and organizing wiring above them) and, of course, negate the concept of an open room.
  
Unlike cable hatches, mini-columns are located directly on the raised floor slabs themselves or on the surface of the concrete floor. The support of the column is hidden by a pedestal framing frame, so that the place where the column itself is attached to the floor becomes invisible. As a rule, pedestal supports are in the form of steel brackets with holes for anchors and self-tapping screws (in the case of a raised floor) and a surface decorative frame. The mini-column itself is a rigid profile with a one-sided or two-sided cavity for placement inside groups of wiring devices and cable shelves-partitions in order to separate power lines from low-current ones. Since the columns rise above the floor level, the material of the columns is selected from the anti-vandal group - this is aluminum, less often steel. Among the possible options presented on the Russian market,it is worth noting the products of Legrand (France), Quintela (Spain), Tehalit (Germany), Nordic Aluminum (Finland), as well as the Russian plant "Ekoplast".

Mini-columns can be of different designs and serve one or several consumers. So, in the case of a low (up to 350 mm) one-sided column, the working space inside its body can accommodate from 1 to 4 wiring devices, while a double-sided column with a height of 660 mm already accommodates up to 16 sockets or even 32 sockets, which means it is capable of serve from 3 to 6 full-fledged consumers. As for the selection of wiring and information sockets for mini-columns, there is a wide choice: various shapes, colors, decorative design. But it is necessary to study the design of the column in advance, since some manufacturers make profiles for modules of type 45 * 45 mm (Legrand), and others - for the so-called European standard with a diameter between the landing screws equal to 60 mm (Quintela, Nordic Aluminum).

The columns of the Ekoplast plant are an example of a universal solution, where both 45 * 45 mm modules and “Eurostandard” sockets are installed. The use of such a material as aluminum for the manufacture of mini-columns allows several times to increase their service life and create a reliable structure for the subsequent operation of the workplace. In addition, aluminum columns go well with different types of interior and flooring.

Other options

There are other ways of organizing jobs, ideologically similar to those described above. One of them differs in that, with the same principle of organizing the cable network under the floor, modular combined units are installed on the screed of the main floor under the raised floor, which function as consolidation points. On the one hand, horizontal cables of the SCS are connected to them, and on the other, zone cords. Special adapters are cut into the power bus near the consolidation point. The zone and power cords are brought out in the workplace area to the raised floor surface through special miniature cable hatches, and then they are placed in flexible cable channels, through which they are fed to the users' workplaces.

In a flexible conduit, data and power cables are routed separately along two separate paths. In particular, it provides a radius limiter that protects the data cable from the influence of power. On desktops, specially designed desktop boxes are mounted, which are equipped with different connectors (for connecting phones, computers and multimedia) and power outlets. However, a significant disadvantage of this method of surface wiring is the unreliability of the flexible channel in comparison with the rigid aluminum profile of the mini-column. These flexible ducts often bump into office workers when moving, which leads to deformations of both the duct and the cable bundle inside it. Special blocks can be installed on the work tables, resembling sections of a cable channel made of various materials:plastic, aluminum, steel. Inside such a profile, the same low-current or power outlets are installed as when using a system of hatches and mini-columns. The weak side of this solution is the rigid binding directly to the furniture and cluttering the desktop.

Combined solutions

In practice, in the design and construction of power supply and distribution systems for information cables, combinations of the above solutions are often used, namely: wiring hatch systems are combined with mini-column systems or traditional wall-mounted cable ducts. In closed rooms of such halls, cable ducts or corrugated pipes are often used, laid in the main walls.

If we consider any project of a room with a large hall, it becomes obvious that, in addition to the "open" space, there are all kinds of auxiliary premises. For a car dealership, this is, for example, an office of technical services, a secretariat, an accounting and sales department; for a shopping center - technical premises, management department, etc.

It is logical to use a system of cable channels (boxes) inside the auxiliary rooms. Firstly, it saves time during installation, and secondly, inside the cases of the cable channel, a place can be provided for connecting new workplaces in the event of expansion of departments. And of course, in such premises, cable channels made of PVC compositions can be used, which significantly reduces costs.

However, it is worthwhile in advance, preferably at the design stage, to choose the cross-section of the cable channels in such a way as to provide a margin of the internal channel capacity. The recommended cross-section of the cable channel is 40 * 100 or 55 * 100 mm or more when the number of users inside the auxiliary room is five to six or more. With this choice, you can always expand the working group of users by 30-50%.

Usually, a large number of installation sockets and modules can be installed in the cross-sections of such cable ducts, and such boxes have all the necessary accessories: corners, turns, plugs and supports. But, as in the case of mini-columns, it is necessary to initially plan a method for attaching sockets and modules. If it is assumed that sockets will be installed in the cable channels for a frame structure of the "Eurostandard" type, then the manufacturer must have special supports with a diameter of 60 mm between the seat screws of the support. If you plan to use modular wiring products, then you need modular installation supports. A number of manufacturers have universal solutions that allow both standards of sockets and modules to be mounted in one cable channel housing.

Returning to the problem of the equipment of "open" offices, we emphasize once again that, in our opinion, the most optimal from the point of view of installation and operation are the systems of zone distribution of the network with the use of floor hatches and mini-columns. Such systems make it possible to comprehensively solve the problems of power distribution, LAN channels and telephony in large rooms with a free layout, as well as equipping workplaces away from the main walls without violating the architecture of the ceiling and the walls of the room themselves.