A sample estimate for an overhead fiber optic communication line. executive documentation

Given the fact that fiber optic lines (FOCL) are the most complex mechanism for transmitting information in large volumes, estimate for the fiber compiled individually for each project.

Hair laying estimate is compiled by budget organizations with positive experience in the implementation of similar projects of different levels of complexity. No matter how difficult it is estimate for laying vols, the work on budgeting involves the initial definition of the tasks and goals of the FOCL.

The main features of budgeting FOCL

Therefore, before mark the wave, it is necessary to draw up technical documentation for the entire FOCL system, or in other words, the terms of reference for the FOCL. It is quite clear that only highly qualified highly qualified specialists with decent work experience can cope with a task of this level of complexity.

Before make an estimate for the wave, the customer must realize what level and type he needs a fiber optic network to solve certain problems. This way of asking the question will help later. make an estimate for the wave and control all previously planned expenditure items in it.

Competently and correctly compiled estimate for laying vols at the same time, it will help the contractor of the construction organization to imagine the very essence of the upcoming construction, to correctly plan its main tasks.

Estimate for laying vols for the contractor, in other words, it is a clear “sample” of the planned facility, based on which he will draw up an installation and commissioning plan during the construction of the entire FOCL system.

Hair laying estimate is equally important for both the customer and the contractor, since this is an official strictly regulated document, based on the sections of which all types of costs are determined, strict control and accounting is maintained over all types of work performed, the compliance of the ongoing activities with the previously planned project, the use of certain materials and equipment.

Today's customers understand that mark the wave it is extremely important, first of all, for them, since the high cost of estimates will be justified in the first years of operation of the FOCL system.

What you need to consider when drawing up an estimate for FOCL

Make an estimate for the Vols professional estimators will be able to - they will take into account the indexation of the cost of materials and equipment, the high productivity of the entire system. After all, the FOCL system is by far the most productive system for transmitting constant streams of information volumes over long distances at the highest possible speed.

Mark the Vols it is also necessary because the consumables themselves are not cheap, so the customer will initially know the estimated cost of the FOCL system project. At the same time, the high cost of FOCL is justified by the high quality, fire resistance, burglary resistance and security of the entire system. Even electromagnetic interference to the FOCL system is not terrible, so the flow of information reaches the addressee without hindrance.

At the same time, many experts, before make an estimate for the wave, try to study the construction project thoroughly, because subsequently the system should work "like clockwork". Therefore, saving on inexpensive components and equipment for the FOCL system is not worth it.

This consists of unwritten rules, on the basis of which, estimate vols laying- to equip the future trunk of the system, use only high-quality materials and components.

Before mark the wave, it is necessary to contact the contractor in advance, which will be engaged in the laying and installation of the entire system. After all, a copper cable (despite all its advantages) is easily damaged due to improper installation and installation. Therefore, it is necessary to involve highly qualified professionals with decent experience in this field for installation work.

It is quite clear that hair laying estimate should take into account the high cost of remuneration of experienced workers, as well as other important aspects:

• the cost of installing the entire system;
• the cost of selecting and supplying the necessary materials for creating a FOCL network;
• payment for the cost of materials and network equipment;
• payment for the cost of commissioning (up to certification of the entire system);
• remuneration of service personnel during the operation of the FOCL system.

Above in clause 2.6, the cost of laying and mounting the fiber optic cable was estimated taking into account the cost of the cable. For a complete calculation of economic costs, one should take into account: prices for POM and PROM; number of couplings used for laying; possible work on welding optical fiber; the cost of auxiliary equipment and tools; the cost of measuring and testing devices.

Tab. 4.1. Estimate for laying and installation of fiber optic cable

Prices are given as of 23.10.2001. For a more up-to-date price list, see http://www.optik.ru- regional representative office of "TKS" - "TKS-URAL".

Tab. 4.2. FOCL service

It should be noted that the above calculation is rough. For a more accurate estimate of costs, it is necessary to carefully analyze the market for fiber optic cables and cable laying and installation services.

Payback period of the project (approximate calculation):

To calculate the payback period of the project, one should take into account the cost of communication services in the given region (telephone communication, data transmission and cable television). Let all PD channels be distributed, and for cable television the number of users is 20,000 per channel in Seversk and 20,000 per channel in Tomsk. Next, we calculate the monthly profit from communication services, data transmission and cable television.

Cost of 1 minute of telephone conversation between cities: 2 rubles/min.

Average talk time per user: 10 min.

The cost of 1 megabyte of information downloaded from the 1st PD channel: 3 rubles.

The cost of using 1 TV channel per month per user: 50 rubles / month

Tab. 4.3. Net profit from FOCL per month

As can be seen from Table. 4.3 profit per month is 2 times (!) Exceeds the cost of laying and installing the FOC. But not everything is so simple, along with such a huge profit, the costs that appear in the process of servicing the line also pop up.

Tab. 4.6. Cost per month

Payment for external traffic, phone calls outside the region, etc.

Most of the income was "eaten" by taxes. Now let's sum up and calculate the payback period of our project:

Static costs: $123,810.49

Dynamic spending per month: $103,798.65

Net revenue per month: $155,139.

Profit per month: $51,340.35.

Payback period: 2.5 months.

It should be remembered that the payback period is calculated after the project is put into operation! The calculation was carried out roughly, for a more accurate one, it is necessary to conduct a detailed analysis of the market related to our project, etc.

In electrical work, a huge amount of cable products is used: wires and cables, as well as cable channels, corrugated pipes, trays and boxes used to protect them. Of course, the cable products themselves have the largest assortment: there are thousands of nomenclature items that differ in type, brand, cross section and purpose of the cable. In this essay, we, of course, will not be able to find prices for all types of cables and wires. Let's try to better consider the most popular types of cables most commonly used in cost estimates:

UTP twisted pair;

Fiber optic cable;

Optical cable (FOCL);

SIP wiring;

Overhead line wires and lightning protection cables;

Power cable type VVG (ng) (LS);

Control KSSP, KVVG;

Wire PV3 yellow-green for grounding.

The listed cables, especially power VVG, have many modifications that differ in cross section, number of cores, incombustibility, power, etc. Almost each of them can be laid in different ways: openly and hidden under wallpaper, in ceilings, trays, corrugated pipes, cable channels. To protect cables in places where they pass through walls, steel sleeves are often used, which are cut from pipes with a diameter of 20-50 mm. Many power cables adapted to environmental conditions can be laid in a trench on a sandy base or without it. The places where cables pass on the ground are often marked with signal tape. Consider the option estimating the installation of cables using the example of UTP and fiber optic cable (FOCL):

An example of an estimate for the installation of optical cables FOCL and computer UTP

Please note that in our example, the optical cable is laid along a cable, which is very typical for outdoor installation. Thus, we came across another type of cable laying, which can also be used in the preparation of estimates - this is cable wiring. Note that the work on setting up the laid lines of a fiber-optic cable is placed in the section of installation, and not commissioning, which, however, is very typical for part 10 "Communication networks". Here, installation prices often coexist with commissioning and configuration of devices, low-voltage networks, communication and telephony devices.

Another typical option that can be found in almost any estimate for electrical work is the laying of power wires in corrugated pipes.

Drawing up an estimate for laying power wires in a corrugated pipe

Often the cable needs to be laid not in flexible corrugated pipes, but in stronger protective devices, such as trays or cable channels. For this, the TER territorial base has other rates. Laying cables and wires in trays is especially relevant for outdoor wiring. The following example of an estimate calculation just demonstrates the laying of cable products not inside the room, but from the outside (more precisely, at the point where the cables enter the building).

An example of drawing up an estimate for external cable laying along trays with sealing and wiring and connection by device

In the previous budgeting example, we installed an outdoor cable in a tray and brought it into the building, sealed it and connected it to devices in the right places. Now consider the option when the UTP cable, power VVG or control KVVG must be laid in the cable channel indoors. For this case, there are direct prices, both for laying the cable channel and for installing the wire itself. Let's look at an example below:

An example of drawing up an estimate for installing a cable in a cable channel in a room

We looked at several examples of wiring, incl. in trays, boxes, corrugated pipes, on a cable, in a cable channel, as well as an external mounting method. I would like to dwell on the method of laying wires in a trench on a ready-made sand base. For these types of work there are direct prices from part 8 of the collection for the installation of electrical devices - they are easy to find in the collection. The only point is that these prices for laying wires in a trench are for power cables designed for higher voltage than most control and management cables. Therefore, it is not recommended to lay low-voltage cables along them, and for power ones, these prices will be just right. On this slightly optimistic note, I would like to end our short excursion into the estimated pricing industry in terms of laying cables VVG, UTP, SIP, PV3, KVVG and many of their analogues. By no means claiming to be the ultimate truth, we just tried to describe some of the most popular solutions when searching for prices on this topic. In general, as we have noticed, one of the features of using the TER, FER, GESN bases is the multivariance in the selection of prices for the same work (of course, in the absence of a direct price), so nothing prevents you from choosing one or another standard from the base yourself , and, perhaps, it will turn out to be more accurate and more appropriate than what we proposed. Thank you for your attention.

Is fiber optic communication lines (FOCL) - a system based on a fiber optic cable, designed to transmit information in the optical (light) range. In accordance with GOST 26599-85, the term FOCL has been replaced by FOCL (fiber-optic transmission line), but in everyday practice the term FOCL is still used, so in this article we will stick to it.

FOCL communication lines (if they are correctly carried out) in comparison with all cable systems are distinguished by very high reliability, excellent communication quality, wide bandwidth, much longer length without amplification and almost 100% immunity from electromagnetic interference. The system is based on fiber optic technology– light is used as a carrier of information, the type of transmitted information (analogue or digital) does not matter. The work mainly uses infrared light, the transmission medium is fiberglass.

Scope of FOCL

Fiber optic cable has been used to provide communication and information transmission for more than 40 years, but due to its high cost, it has become widely used relatively recently. The development of technologies has made it possible to make production more economical and the cost of the cable more affordable, and its technical characteristics and advantages over other materials quickly pay off all the costs incurred.

At present, when a complex of low-voltage systems (computer network, access control system, video surveillance, security and fire alarms, perimeter security, television, etc.) is used at once at one facility, it is not possible to do without the use of fiber-optic communication lines. Only the use of fiber optic cable makes it possible to use all these systems simultaneously, ensuring correct stable operation and performance of their functions.

FOCL is increasingly used as a fundamental system in the development and installation, especially for multi-storey buildings, long buildings and when combining a group of objects. Only fiber optic cables can provide the appropriate amount and speed of information transfer. All three subsystems can be implemented on the basis of fiber, in the internal trunk subsystem optical cables are used equally often with twisted pair cables, and in the external trunk subsystem they play a dominant role. A distinction is made between fiber optic cables for external (outdoor cables) and internal (indoor cables) laying, as well as connecting cords for horizontal wiring communications, equipping individual workplaces, and combining buildings.

Despite the relatively high cost, the use of optical fiber is becoming more and more justified and is becoming more and more widely used.

Advantages fiber-optic communication lines (FOCL) before traditional "metal" transmission media:

• Wide bandwidth;
• Slight signal attenuation, for example for a 10 MHz signal, it will be 1.5 dB / km compared to 30 dB / km for RG6 coaxial cable;
• The possibility of "ground loops" is excluded, since the optical fiber is a dielectric and creates electrical (galvanic) isolation between the transmitting and receiving ends of the line;
• High reliability of the optical environment: optical fibers do not oxidize, do not get wet, are not subject to electromagnetic influence
• Does not cause interference in adjacent cables or in other fiber optic cables, since the signal carrier is light and it remains completely inside the fiber optic cable;
• Fiberglass is absolutely insensitive to external signals and electromagnetic interference (EMI), no matter which power supply the cable runs next to (110 V, 240 V, 10,000 V AC) or very close to a megawatt transmitter. A lightning strike at a distance of 1 cm from the cable will not give any interference and will not affect the operation of the system;
• Information security - information is transmitted via optical fiber "from point to point" and it can be eavesdropped or changed only by physical intervention in the transmission line
• Fiber optic cable is lighter and smaller - it is more convenient and easier to lay than an electric cable of the same diameter;
• It is not possible to branch off the cable without damaging the signal quality. Any interference in the system is immediately detected at the receiving end of the line, this is especially important for security and video surveillance systems;
• Fire and explosion safety when changing physical and chemical parameters

• The cost of the cable is decreasing every day, its quality and capabilities begin to prevail over the cost of building low-current based on FOCL

There are no ideal and perfect solutions, like any system, FOCL has its drawbacks:

• The fragility of fiberglass - with a strong bending of the cable, the fibers may break or become cloudy due to the occurrence of microcracks. To eliminate and minimize these risks, cable reinforcing structures and braids are used. When installing the cable, it is necessary to follow the manufacturer's recommendations (where, in particular, the minimum allowable bending radius is standardized);
• The complexity of the connection in the event of a break - a special tool and qualification of the performer are required;
• Sophisticated manufacturing technology, both the fiber itself and the FOCL components;
• Complexity of signal conversion (in interface equipment);
• Relative high cost of optical terminal equipment. However, the equipment is expensive in absolute terms. The cost-to-capacity ratio for FOCL is better than for other systems;
• Clouding of the fiber due to radiation exposure (however, there are doped fibers with high radiation resistance).

The installation of FOCL systems requires the contractor to have an appropriate level of qualification, since the termination of the cable is carried out with special tools, with special precision and skill, unlike other transmission media. Routing and signal switching settings require special qualifications and skills, so in this area you should not save and be afraid to overpay professionals, eliminating system malfunctions and the consequences of improper cable installation will cost more.

The principle of operation of a fiber optic cable.

The very idea of ​​transmitting information using light, not to mention the physical principle of operation, is not entirely clear to most ordinary people. We will not go deep into this topic, but we will try to explain the main mechanism of fiber optics and justify such high performance.

The concept of fiber optics is based on the fundamental laws of reflection and refraction of light. Due to its design, fiberglass can keep light rays inside the fiber and prevent them from "passing through walls" when transmitting a signal for many kilometers. In addition, it is no secret that the speed of light is higher.

Fiber optics is based on the effect of refraction at the maximum angle of incidence when total reflection takes place. This phenomenon occurs when a beam of light leaves a dense medium and enters a less dense medium at a certain angle. For example, imagine an absolutely motionless expanse of water. The observer looks from under the water and changes the viewing angle. At a certain moment, the viewing angle becomes such that the observer will not be able to see objects that are above the surface of the water. This angle is called the angle of total reflection. At this angle, the observer will see only objects that are under water, it will seem that you are looking into a mirror.

The inner core of the FOCL cable has a higher refractive index than the sheath and the effect of total reflection occurs. For this reason, a beam of light, passing through the inner core, cannot go beyond its limits.

There are several types of fiber optic cables:

• With a stepped profile - a typical, cheapest option, the distribution of light goes in "steps" and the input pulse is deformed due to the different lengths of the trajectories of the light rays
• With a smooth profile "multimode" - the rays of light propagate at approximately the same speed in "waves", the length of their paths is balanced, this improves the characteristics of the pulse;
• Single-mode glass fiber is the most expensive option, it allows you to stretch the rays in a straight line, the momentum transmission characteristics become almost perfect.

Fiber optic cable is still more expensive than other materials, its installation and termination is more difficult, it requires qualified performers, but the future of information transmission is undoubtedly in the development of these technologies and this process is irreversible.

FOCL consists of active and passive components. At the transmitting end of the fiber optic cable there is an LED or a laser diode, their radiation is modulated by the transmitting signal. With regard to video surveillance, this will be a video signal; for the transmission of digital signals, the logic is preserved. When transmitting, the infrared diode is modulated in brightness and pulses according to signal variations. To receive and convert an optical signal into an electrical signal, a photodetector is usually located at the receiving end.

Active components include multiplexers, regenerators, amplifiers, lasers, photodiodes, and modulators.

Multiplexer– combines several signals into one, so that a single fiber optic cable can be used to simultaneously transmit several real-time signals. These devices are indispensable in systems with an insufficient or limited number of cables.

There are several types of multiplexers, they differ in their technical characteristics, functions and scope:

• spectral separation (WDM) - the simplest and cheapest device, transmits optical signals from one or more sources operating at different wavelengths over a single cable;
• frequency modulation and frequency multiplexing (FM-FDM) - devices quite immune to noise and distortion, with good characteristics and circuits of medium complexity, have 4.8 and 16 channels, are optimal for video surveillance.
• Amplitude modulation with partially suppressed sideband (AVSB-FDM) - with high-quality optoelectronics, they can transmit up to 80 channels, they are optimal for subscriber television, but expensive for video surveillance;
• Pulse code modulation (PCM - FDM) - an expensive device, completely digital, used for the distribution of digital video and video surveillance;

In practice, combinations of these methods are often used. Regenerator - a device that restores the shape of an optical pulse, which, propagating through the fiber, undergoes distortion. Regenerators can be either purely optical or electrical, which convert an optical signal into an electrical one, restore it, and then convert it back into an optical one.

Amplifier- amplifies the signal power to the required voltage level, can be optical and electrical, performs opto-electronic and electro-optical signal conversion.

LEDs and Lasers- source of monochrome coherent optical radiation (light for cable). For systems with direct modulation, it simultaneously performs the functions of a modulator that converts an electrical signal into an optical one.

Photodetector(Photodiode) - a device that receives a signal at the other end of a fiber optic cable and performs optoelectronic signal conversion.

Modulator- a device that modulates an optical wave that carries information according to the law of an electrical signal. In most systems, this function is performed by a laser, but in systems with indirect modulation, separate devices are used for this.

Passive FOCL components include:

Fiber optic cable – acts as a medium for signal transmission. The outer sheath of the cable can be made of various materials: PVC, polyethylene, polypropylene, Teflon and other materials. An optical cable can have various types of armor and specific protective layers (for example, small glass needles to protect against rodents). The design may be:

Optical coupler- a device used to connect two or more optical cables.

Optical cross- a device designed to terminate an optical cable and connect active equipment to it.

spikes– designed for permanent or semi-permanent fiber splicing;

Connectors– for reconnection or disconnection of the cable;

Taps- devices that distribute the optical power of several fibers into one;

Switches– devices that redistribute optical signals under manual or electronic control

Installation of fiber-optic communication lines, its features and procedure.

Fiberglass is a very strong but brittle material, although thanks to its protective sheath it can be handled almost like electricity. However, when installing the cable, the manufacturer's requirements for:

• "Maximum Tension" and "Maximum Breaking Force", expressed in Newtons (about 1000 N or 1kN). In an optical cable, the main stress falls on the load-bearing structure (reinforced plastic, steel, Kevlar, or a combination of both). Each type of construction has its own individual performance and degree of protection, if the tension exceeds the prescribed level, then the fiber may be damaged.
• "Minimum bend radius" - make bends smoother, avoid sharp bends.
• "Mechanical strength", it is expressed in N / m (newtons / meters) - protection of the cable from physical stress (it can be stepped on or even run over by vehicles. You should be extremely careful and especially secure the intersections and connections, the load increases greatly due to small area of ​​contact.

Optical cable is usually supplied wound on wooden drums with a strong plastic protective layer or wooden planks around the circumference. The outer layers of the cable are the most vulnerable, therefore, during installation, it is necessary to remember the weight of the drum, protect it from bumps, falls, and take safety measures when storing. It is best to store the drums horizontally, but if they do lie vertically, then their edges (rims) should be in contact.

The procedure and features of installing a fiber optic cable:

1. Before installation, it is necessary to inspect the cable drums for damage, dents, scratches. In case of any suspicion, it is better to immediately put the cable aside for further detailed study or rejection. Short pieces (less than 2 km) can be checked for fiber continuity with any flashlight. Fiber cable for infrared transmission transmits ordinary light just as well.
2. Next, study the route for potential problems (sharp corners, clogged cable channels, etc.), if any, make changes to the route to minimize risks.
3. Distribute the cable along the route in such a way that the connection points and connection of amplifiers are in accessible places, but protected from adverse factors. It is important that a sufficient supply of cable is left at the points of future connections. The exposed ends of the cable must be protected by waterproof caps. Pipes are used to minimize bending stress and damage from passing traffic. At both ends of the cable line, a part of the cable is left, its length depends on the planned configuration).
4. When laying the cable underground, it is additionally protected from damage at local load points, such as contact with heterogeneous backfill material, trench irregularities. To do this, the cable in the trench is laid on a layer of sand 50-150 cm and covered with the same layer of sand 50-150 cm from above. It should be noted that damage to the cable can occur both immediately and during operation (already after the backfilling of the cable), for example, from constant pressure, an unremoved stone can gradually push through the cable. Work on diagnosing and finding and eliminating violations of an already buried cable will cost much more than accuracy and compliance with installation precautions. The depth of the trench depends on the type of soil and the expected load on the surface. In hard rock, the depth will be 30 cm, in soft rock or under the road 1 m. The recommended depth is 40-60 cm, with a sand bed thickness of 10 to 30 cm.
5. Most often, cable laying in a trench or in a tray directly from the drum is used. When installing very long lines, the drum is placed on the vehicle, as the machine advances, the cable is laid in its place, while you should not rush, the pace and order of unwinding the drum is manually adjusted.
6. When laying the cable in the tray, the most important thing is not to exceed the critical bending radius and mechanical load. The cable should be laid in one plane, do not create points of concentrated loads, avoid sharp corners on the route, pressure and intersection with other cables and routes, do not bend the cable.
7. Pulling fiber optic cable through cable ducts is similar to pulling regular cable, but you should not use excessive physical effort and violate the manufacturer's specifications. When using clamp clamps, remember that the load should not fall on the outer sheath of the cable, but on the load-bearing structure. Talc or polystyrene granules can be used to reduce friction, other lubricants should be consulted with the manufacturer.
8. In cases where the cable is already terminated, special care must be taken when installing the cable so as not to damage the connectors, not to soil them and not to subject them to excessive stress in the connection area.
9. After laying the cable in the tray, it is fixed with nylon ties; it should not slip or sag. If the surface conditions do not allow the use of special cable fasteners, the use of clamps is acceptable, but with extreme care so as not to damage the cable. The use of clamps with a plastic protective layer is recommended, a separate clamp should be used for each cable and in no case should several cables be pulled together. It is better to leave a little slack between the end points of the cable attachment, and not to put the cable under tension, otherwise it will not respond well to temperature fluctuations and vibrations.
10. If the fiber is still damaged during installation, mark the area and leave enough cable for later splicing.

In principle, laying a fiber optic cable is not much different from installing a conventional cable. If you follow all the recommendations we have indicated, then there will be no problems during installation and operation, and your system will work for a long time, efficiently and reliably.

An example of a typical solution for laying a FOCL line

The task is to organize a FOCL system between two separate buildings of the production building and the administrative building. The distance between buildings is 500 m.

Explanations and comments:

1. The total length of the route is 500 m, including:
   • from the fence to the production building and the administrative building is 100 m each (200 m in total);
   • along the fence between buildings 300 m.
2. Cable installation is carried out in an open way, including:
   • from buildings to the fence (200 m) by air (constriction) using materials specialized for laying fiber optic lines;
   • between buildings (300 m) along a fence of reinforced concrete slabs, the cable is fixed in the middle of the fence canvas with metal clips.
3. For the organization of FOCL, a specialized self-supporting (built-in cable) armored cable is used.