Tunnel type overpasses. Tunnel type dishwashers

Tunnel dishwashers , due to its high performance, are able to wash a huge amount of dishes in a limited period of time. The principle of their operation is simple: the dishes are placed on a continuously moving conveyor, and as they move inside the machine, they will pass through various zones sinks. Usually all technological process washing is divided into several stages:

• a washing zone where the dishes are intensively cleaned of dirt using jets of water and detergents;
• and a rinsing zone in which the dishes are washed hot water and rinsing agents.

During the washing of tableware, the water temperature is 50…60 °C. The task of the tunnel dishwasher at this stage is to remove dirt from the dishes as much as possible. This is achieved through a combination of the action of detergents and the high pressure of water coming from the washing nozzles. Water pressure is created due to the special arrangement of the washing nozzles. In tunnel machines, unlike other types of dishwashers, these nozzles are fixed and wash the dishes from four sides.

After washing, the dishes go to the rinsing zone. In this zone, the water temperature is approximately 80-90 °C. At this high water temperature, sanitization tableware, during which all the bacteria contained on its surface are destroyed. Thus, dishes washed in a conveyor tunnel dishwasher meet all sanitary and hygienic standards, unlike dishes washed by hand. The rinsing zone can be single, double or triple, depending on the rinsing levels. With the simplest, single rinse, the dishes are treated with hot water once.

In double rinsing, the dishes first pass through the wash arms that supply clean water at a temperature of 65 ... 70 ° C, which removes the dishes remaining on the surface detergents and sends them back to the washing area. Thus, both detergents and water are saved. Further, the dishes are supplied for rinsing with water at a temperature of 80 ... 90 ° C. This water already contains rinse aids. Triple rinse means dividing the rinse zone into three parts. In the first stage, the dishes are treated with clean water at a temperature of 65 ° C, removing the remnants of the washing solution, followed by rinsing with water at a temperature of 70 ° C, and at the final stage - rinsing at 85 ° C.

Depending on the designconveyor dishwasherand customer needs, such a machine can be equipped with additional modules. For example, a pre-wash section in which the dishes are rinsed clean cold water. The fact is that the remains of starch and proteins contained on dirty dishes under the influence of high temperature water begin to curl up and stick to the surface of the plates. To remove them, rinse the dishes with cold water before washing. In addition, additional washing sections can be installed in the machine to improve results, or a steam condenser that is able to trap water vapor generated during operation, reducing the cost of ventilation of the room. Also a very useful option is the energy recovery and saving system, which uses the generated steam to heat the water supplied to the machine from the main, thereby saving energy for its heating.

1. The dimensions of tunnel stairs are calculated separately. Only high quality metal products are allowed. The minimum width is 60 cm. 35-40 cm is the radius for safety arches, they must be present in any design. Between themselves, these arcs are fastened with the help of special strips. One arc is at a distance of at least 80 cm from the other.
2. Instead of mid-flight evacuation tunnel ladders can be used on some types of towers if they are equipped with a special device with its own mechanism so that workers can easily climb to the decks. This option is also valid for cases where there is a so-called ASP mechanism.
3. To the top of the panels, built-in tunnel-type stairs are arranged along the edges of the end panels. A special portable step-ladder is used to get inside this structure. Sheds are arranged above the driller's post. End panels are connected to each other with beams.
4. Intermediate platforms are often installed along the entire height of this product. They must be at least 6 meters apart.
5. Tunnel-type stairs are mounted if the rise to a height has a slope of more than 60 degrees.

Tunnel water intake. With pressure derivation, the tunnel water intake is placed as deep as possible, but slightly higher than the bottom of the reservoir so that the water intake inlet is above the calculated level of pump deposition.

Water intake (Fig. 559) consists of a socket water intake 3, smoothly passing to the normal section of the supply conduit; water intake, fenced with shandors 1 and lattice 2, and shutter cameras 7 . In order to use conventional butterfly valves, the conduit in front of the chamber is divided into two sleeves 8 smaller section. The shutter chamber unites the assembly, to which the mine shaft adjoins from above 4, used in the construction and operation of the node. An air duct is located in the mine shaft 5, which runs in the upper part of the pressure supply tunnel and serves to prevent the formation of a vacuum in the conduit when the water is drained and air locks when filling it. From the side opposite to the water intake, a supply tunnel adjoins the chamber 6 .

Rice. 559.

The dimensions of the water intake are determined based on the passage of water through it at a low flow rate (0.8-1.6 m/s), which leads to a minimum pressure loss in the water intake. The structural shape of the head unit and its location are set experimentally on models. This allows you to take the best hydraulic modes and optimal design forms.

The material for the building structures of the water intake is monolithic concrete and reinforced concrete. For the construction of the shaft, in addition to the listed materials, precast concrete can be used.

Free-flow tunnels are usually used for the outlet conduit and less often for the inlet. The capacity of such tunnels is mainly determined by their cross-sectional area and longitudinal slope, which determines the flow velocity. The forms of the internal outline recommended for non-pressure tunnels by the instructions of SN 238-63 (Fig. 560) are mainly outlined by box curves. Form I - for strong, non-fractured rocks in which rock pressure does not appear. Form II - for rocks of medium strength with a strength coefficient f> 3 in the absence of lateral pressure. Form III - for breeds with a strength coefficient f= 1.5÷3 with high vertical and low horizontal rock pressure. Form IV - for weak breeds (with f < 1,5) с большим всесторонним горным давлением.

Rice. 560.

The practice of designing and building non-pressure hydrotechnical tunnels has developed certain relationships between the dimensions of their cross sections. So, regardless of the cross-sectional shape, with slight fluctuations in the water level, it is recommended to design them with the same clear dimensions in height. H and width IN. If fluctuations in the water level in the tunnel are significant, then the ratio is recommended H = 1,5IN. The same ratio is taken for sections of tunnels that have a variable height.

The cross section of a non-pressure tunnel with its maximum filling with water in the upper part must remain free; the minimum height of the airspace above the water surface should be 0.15 H and not less than 40 cm.

For other geometric parameters indicated in fig. 560, the following ratios are recommended:

form I	r 1 = 0,75B ;	r 2 = (0,1-0,15)IN ;
form II	r 1 = 0,5IN ;	r 2 = (0,1-0,15)IN ;
form III	r 1 = 0,25B ;	r 2 = (0,2-0,25)IN ;	r 3 = (1-2)B ;
form IV	r 1 = 0,5B ;	r 2 = (0,1-0,15)IN ;	r 3 = (1-2)IN ;	r 4 = (1-1,5)B

The cross-sectional dimensions of a non-pressure tunnel are determined by a feasibility study (see SN 238-63, appendix). Pre-select the shape of the cross section (see Fig. 560). Then calculate the hydraulic radius R the most advantageous section depending on various water flow rates and factors of resistance to its movement, the length of the tunnel, the performance of the hydraulic unit, turbine and generator, estimated costs and depreciation.

Clear cross-sectional dimensions are determined by:

a) for the trough-shaped form II according to the formula B = H = 3,28 R ;

b) for box form IV according to the formula B = H = 3,26 R . The minimum cross-sectional dimensions of non-pressure tunnels are limited by the conditions of safety and convenience of work. For unlined tunnels, the smallest height H= 2.5 m and width with form I IN= 2 m, and with form II IN= 2.5 m. For tunnels with lining - H= 2.1 m, width with form I B= 1.9 m, and with form II IN\u003d 2.1 m. The smallest diameter of the tunnel of a circular shape without lining D= 2.7 m, lined D= 2.3 m. For maximum dimensions there are no tunnel restrictions.

The circular outline of the cross sections of non-pressure tunnels is used much less frequently than the shapes shown in Fig. 560. It is rational when driving in soft rocks and in case of significant external hydrostatic pressure on the tunnel lining.

In strong, non-eroded and non-weathered rocks, it is allowed to leave non-pressure tunnels without linings. However, to reduce roughness and reduce hydraulic friction losses, it is recommended to cover the inner surface of workings in such tunnels with a leveling layer of concrete using gunning or spraying. Monolithic concrete is usually used as the material for structures of non-pressure tunnels.

Tunnel lining structures monolithic concrete in relation to the considered forms are shown in Fig.561. Structures I and II act as a leveling lining. Therefore, in hard rocks, lining I is not closed in the upper part, walls 20-30 cm thick are only brought up to the maximum design water level in the tunnel.

Rice. 561.

Linings III and IV are load-bearing, designed to withstand both vertical and horizontal rock pressure. The thickness of the elements of such structures is determined by static and strength calculations. It depends on the size of the working and the physical and mechanical properties of the rocks in which the tunnel passes.

These ovens are the most advanced and are installed in bakeries located in areas rich in cheap electricity. The use of electrically heated ovens improves sanitary and hygienic conditions and improves the culture of the enterprise.

Furnaces BN-25e and BN-50e. Tunnel ovens are made from metal frame lined with sheets. The oven consists of a baking chamber, a device for humidifying the environment of the baking chamber, a drive and tension station, a mesh conveyor, heating elements, ventilation system for removing the vapor-air mixture, systems of instrumentation and automation.

The BN-25e furnace (Fig. 1) includes eight sections 1.5 m long each. The baking chamber of the oven is divided into four thermal zones. Products are heated using tubular electric heaters (TEHs) with a capacity of 1.8 kW each. The power of electric heaters located above the conveyor is 91.8 kW, and below the conveyor - 59.4 kW.

The first thermal zone with a total capacity of 54 kW is heated by 18 upper and 12 lower electric heaters; the second with a total capacity of 43.2 kW-15 top and 9 bottom electric heaters, the third with a total capacity of 32.4 kW - 12 top and 6 bottom electric heaters and the fourth zone with a total capacity of 21.6 kW - 6 top and 6 bottom electric heaters. For rational control of the operation of the oven, all elements by zones are combined into "automatic and manual groups. The device for moisturizing products, located at the beginning of the oven and occupying about 5% of the total length of the baking chamber, consists of four perforated pipes with a diameter of 1" with holes for steam outlet with a diameter of 2 .5 mm. The pipes are installed above the mesh conveyor with a pitch of 130 mm and a distance to the furnace hearth of 126 mm. To reduce steam leakage, a cap 2670 mm wide and 560 mm long is arranged above the pipes. The steam humidifier is separated from the baking chamber by a rotary damper.

To remove the steam-air mixture from the baking chamber, a ventilation system is installed above the oven. Along the entire length of the furnace in its upper

part, a metal ventilation duct with a diameter of 160 mm is mounted. It is connected to the hoods of the hoods from the landing and unloading zones, the third and fifth sections of the furnace. The ventilation of the baking chamber is controlled by throttle valves.

Rice. 1. Furnace BN-25e:

1- tension device; 2 - preheating of the conveyor; 3 - fan to remove the vapor-air mixture; 4 - electric heaters; 5 - drive; 6-steam supply

On the left side of the oven in sections II and IV there are inspection hatches to control the baking process. The hatches are equipped with low-voltage electric lighting, which automatically turns on when the outer door of the hatch is opened.

The drive of the furnace is carried out from a three-speed electric motor with a power of 1.4; 1.8; 2.2 kW with a speed of 750, respectively; 1500 and 3000 rpm.

The duration of baking in the interval of each range is smoothly regulated by the speed variator.

The conveyor mesh consists of individual spirals connected to each other by ramrods. It is cleaned while driving with the brush drive motor turned on, which can be pressed against the drive drum with a special handwheel. After cleaning is completed, the brush is retracted from the drum and only then its electric motor is turned off. The mesh is stretched by the driven drum, and when it is shifted to the side, the adjustment is made by tensioning one of the sides of the driven drum.

The upper electric heaters transfer the main part of the heat to the baked products by radiation, the lower ones - by thermal conductivity through the metal sheet and under the ovens.

The side walls of the baking oven are not heated, but only reflect the radiation received from the upper and lower heaters. The total amount of heat transferred by the lower elements in the first zone is somewhat higher than by the upper elements, due to the location of the steam humidifier in this zone. The relative humidity of the baking chamber environment in the humidification zone is 75-80%.

The device for planting bread on the hearth of the oven is a carriage mounted by rollers on attached guides, along which it performs a reciprocating motion. A conveyor for dough pieces with a width of 2000 mm is mounted on the carriage from a belting tape moving along the guides of the carriage.

Landing can be done both at the landing mouth of the furnace, and directly into the baking chamber. The speed of the planter conveyor is selected independently of the mesh hearth speed.

The BN-50e furnace includes 16 interconnected sections 1.5 m long each. The frame of the furnace bears all structural elements and the outer metal cladding. FROM right sides s furnace along the entire length of the attachment is mounted from the corner St. 3 with a height of 1308 and a width of 300 mm for the installation of current-carrying wires. For free air circulation in the lower and upper parts of the casing there are louvered grilles.

The outer skin is made of metal sheets 1.25 mm thick, which are connected to the frame by clamping metal strips, fixed with screws. In the places of installation of devices and hatches, metal sheets have corresponding cutouts, and removable shields are made for units that require periodic inspection (electric heaters, drive elements).

The baking chamber is insulated with glass wool on all sides. The thickness of the layer on the left and right sides is 350, below - 245 and above - 450 mm. The baking chamber is heated by tubular electric heaters with a power of 2 kW each. In its upper part above the conveyor there are 87 electric heaters, in the lower part - 72.

The furnace is divided into four thermal zones with independent upper and lower heating. The first, second and third overhead heating zones consist of 24 electric heaters with a capacity of 48 kW each. The fourth upper heating zone has 15 electric heaters with a capacity of 30 kW.

The first zone of the lower heating consists of 21 electric heaters with a power of 42 kW, the second and third - of 18 with a power of 36 kW and the fourth - of 15 with a power of 30 kW. On the landing side of the furnace, six heating elements with a power of 3 kW are built in. The elements are divided into two groups and serve to heat the landing part. For automatic temperature control in the baking chamber, a thermocouple is installed in each zone.

All other elements of the furnace are similar to the BN-25e furnace.

Technical characteristics of BN-25z and BN-50e furnaces

Productivity, kg/h 450-650 900-1300

Hearth area within the baking chamber, m 2 25 50

Hearth width, m 2.1 2.1

Baking chamber length, m 12 24

Specific electricity consumption, kWh/kg 0.22-0.26 0.20-0.22

Total power of heating elements, kW 169 326

conveyor drive 0.8; 1.0; 1.2 1.4; 1.8; 2.2

» brushes 1.0 1.0

» suction fan 1.0 1.0

Overall dimensions, mm 14500 x 3200 x 2200 26500 x 3200 x 2200

Weight of metal structure, t 26 35

Furnaces PIK-8 and PIK-16. The PIK-8 furnace (Fig. 2) with quartz infrared emitters was created by employees of the Industry Research Laboratory of KTIPP, MTIPP and employees of the republican association "Moldkhlebprom". In 1972, the Shebekinsky Machine-Building Plant of the Minlegpishchemash began their mass production.

The oven can be produced both for the production of gingerbread and cookies, and for straws and lamb products - with a separate section for hygro-thermal treatment and a transfer device on the hearth of the oven.

The PIK-8 oven has a mesh under the width of 850 mm and is designed for the production of salty and sweet sticks (straws) and drying.

The baking chamber is heated by heating elements located at the bottom

Rice. 2. Furnace PIK-8:

1 - drive station; 2 - main mesh under; 3 - baking chamber; 4 - second section; 5 - first section; 6 - block of heating elements; 7 - block of quartz emitters; 8 - tension station; 9 - system for extracting vapors of baked goods; 10 - steam pipes; 11 - humidifying section; 12 - mesh under humidifier

part of the chamber under the grid, and KG-220-1000 quartz emitters (i.e., voltage 220 V and power of one heater 1000 W) located in the upper part across the chamber. There are three emitters across the width of the baking chamber. They are tubes 350 mm long and 10 mm in diameter, made of heat-resistant quartz glass. Inside the tube there is a tungsten filament attached to metal bases located at the edges of the radiator. The temperature of a hot tungsten filament reaches about 2000°C.

The use of such emitters, due to the special properties of the thermal radiation generated by them, which penetrates to a certain depth into the baked products, can significantly reduce the baking time.

There are four thermocouples on the service front side of the oven, corresponding to the four heating zones of the oven and used to measure and control the temperature of the baking chamber, and hatches for access to the emitters.

The baking chamber of the oven is a horizontal rectangular tunnel with a width of 1050, a height of 200 and a length of 10,000 mm. The metal mesh of the conveyor - the hearth of the oven moves along the metal guides located across the baking chamber. Under the grid, heating elements are also installed across the chamber.

The steam humidification devices of the PIK-8 and PKhK furnaces are similar. The difference lies in the design of the conveyor. In the PIK-8 oven, in the steam humidification zone and in the baking chamber, there are two mesh conveyors (hearths) 2 and 12. Each conveyor has an individual drive. In the PIK 8 oven, mesh hearths are attached to the driving chains and moved with the help of driving drums with sprockets, as in the PKhK ovens.

The speed of movement of mesh hearths in the humidification zone and in the baking chamber is the same. At the end of the working branch of the humidification zone conveyor, the products are transferred to the baking chamber conveyor.

The temperature in all heating zones of the baking chamber is automatically maintained at the set level. To do this, in each of the four zones

Rice. 3. Furnace HPS-25

the furnace has a control device that turns off or turns on quartz emitters and heating elements included in automatic scheme. Their capacity is about 50% of the total installed capacity. The PIK-8 furnace is all-metal. The inner sheets that form the baking chamber and the outer casing of the oven are painted in light colors. A layer of mineral wool insulation is laid between the baking chamber and the casing.

The productivity of the oven when baking bread sticks is 150 kg/h, the duration of baking sticks is 6-7 minutes.

In this furnace, approximately 50% of the installed power falls on quartz emitters and half on heating elements.

The Riga Electric Lamp Plant has now improved the socles of quartz emitters, which was caused by the need to increase the durability of the lamps in the baking chamber environment.

When baking straws, the energy consumption is 500 kWh per 1 ton of products.

Overall dimensions of the furnace PIK-8 13 650X1850X1550 mm. Based on the PIK-8 and PKhK-16 furnaces and further research, a PIK-16 furnace with infrared heating and a hearth area of ​​16 m2 is currently being developed.

Furnaces HPS-25 and HPS-40. Through-type baking ovens of the HPS-25 and HPS-40 brands with electric heating are designed for baking a wide range of bakery products in areas with sufficient resources of cheap electricity.

Furnaces KhPS-25 and KhPS-40 are designed and manufactured on the basis of furnaces PHS-25m and PHS-40m. On fig. 3 shows the KhPS-25 furnace.

The electrical circuit of the furnace is designed for connection to a three-phase alternating current network with a voltage of 380/220 V. The total installed power for the KhPS-25 furnace is 263 kW, KhPS-40 is 319.1 kW.

Control, protection, signaling and automatic temperature control equipment is installed in the power board and control board.

Electric circuit. To heat the furnace, typical tubular electric heaters are used, which are protected from short circuits by automatic switches of the A 3114 and AP50-ZMT types. To turn on and off the electric heaters, magnetic starters of the PA type of the fifth, fourth and third sizes are provided.

Start-up equipment is mounted in shields. The power shield has an introductory knife switch RB-36 for a working current of 600 A.

principled circuit diagram oven provides three control circuits: control circuit temperature regime oven, oven conveyor control circuit and fan control circuit.

All equipment of control circuits and start-up protection equipment of electric motors are mounted in the control panel.

The temperature control circuit of the furnace consists of eight identical control circuits, consisting of thermocouple sensors of the TKhK-0515 brand and T = 0 - 600°C (for the KhPS-25 furnace), thermocouples of the TKhK-KhSh brand and T = 0 - 600°C ( for the KhPS-40 furnace), secondary devices (EPV2-11A brand potentiometers) and actuators (magnetic starters of the PA series).

The electronic potentiometers are powered by a voltage of 127 V from two isolating transformers type TBS 2-0.4. Thermocouples are mounted on the furnace in four zones and connected to electronic potentiometers using a compensating drive of the HK-KPO brand. Automatic and manual temperature control is carried out using universal switches of the type UP 5311-S23 and UP 5312-F105 installed on the control panel.

For control circuits, a voltage of 220 V is used. The connection of the power panel and the control panel is carried out with a wire of the appropriate section in gas pipes. The connection between the furnace heaters is made with copper wires of appropriate cross sections.

In case of a lack of heat in the baking chamber of the oven (when baking certain types of bread), additional holes are provided into which electric heaters can be inserted, connecting to the corresponding groups evenly, eliminating the occurrence of phase imbalance.

Furnace heating and temperature control. The baking chamber of the oven is divided into four zones, each of which independently regulates and controls the temperature of the top and bottom.

In the first zone of the furnace (top), the heaters are divided into two groups: the heaters of the first zone and the heaters of the steam humidification zone, which can be switched on by the switch in the “Manual control” position of the handle or switched on in automatic mode through the switch from the EPV-1 electronic potentiometer.

At the bottom of the first zone, as well as in the remaining zones, the heaters are divided into two groups, which are automatically controlled from the EPV-2 - EPV-8 potentiometers when the switches are turned on to the "Automatic" position. When the temperature in the zone is below the set one, all heaters are automatically turned on, after which, when the lower limit of the set temperature is reached, one of the groups is turned off, and when the upper limit is reached, the second group is turned off and the temperature begins to fall.

Automatic control of the set temperature in the baking chamber of the oven is carried out by single-point automatic indicating potentiometers EPV2-11A, grading HK with a measurement limit of 0-400 ° C, operating in a set with thermocouples of the THC-0515 brand, with a measurement limit of 0-600 ° C (for KhPS- 25, HPS 40)-grade

The potentiometer has a regulating device consisting of three contact groups and three profile disks. The temperature measurement limits are regulated by the potentiometer profile disks, which are set to break the contacts. At the initial moment, when the furnace temperature is equal to the temperature environment, bottom and middle contacts must be closed. During commissioning, the potentiometers are adjusted.

After adjusting the potentiometers, the drives are connected to the coil terminals of the corresponding intermediate relays. By turning the switch handle to the right by "+ 45 °" (automatic control), the fixed contacts of the universal switches UP 5312 are closed, from which the coils of the magnetic starters operating in the "Min" and "Max" modes are powered.

Manual control provides for two modes of operation: weak heating - by turning the switch handle to "-45 °" the fixed contact closes, the heaters turn on and the furnace operates in the minimum heating mode; strong heating - by turning the switch handle to "-90 °", the fixed contacts are closed, all heaters are turned on and the oven operates in the maximum heating mode.

The temperature of the potentiometers is set by a fixed scale according to the technological cycle for the baking zones.

After heating the furnace to operating temperature, the furnace control system is transferred from manual to automatic mode. 6-10°C before the set temperature, the heaters operating in the "Max" mode are switched off. When the set temperature is reached, the remaining heaters operating in the "Min" mode are switched off.

When the temperature in the zone drops, the heaters turn on in reverse order.

Starting and setting up the furnace. Temperature and baking time are set according to the type of baked goods. The temperature is set on the upper scale of the potentiometers for each zone. The baking time of this type of product depends on the number of revolutions of the variator.

First you need to turn on the switch of the power shield (when the furnace is stopped, the switch must be turned off). On the control panel, the batch switch is turned on, the potentiometer lamps and the signal lamp light up, informing about the voltage supply to the devices.

Warming up the furnace from a cold state to operating temperature is recommended to be carried out carefully, increasing the temperature gradually. The heating time of the furnace to the operating temperature from a cold state should be at least 2.5 hours. It is not recommended to reduce the heating time of the furnace, as this can lead to a violation of the joints of the furnace units and unacceptable deformation of the parts. It is recommended to heat up the furnace with remote (manual) switching on of all groups of electric heaters (third position of the switch). After 15-20 minutes, the heaters are turned off and the temperature stabilizes in the entire furnace. After 3-5 minutes, the heaters are switched on again for 12-20 minutes. In this way

Rice. 4. Furnace HPS-100

the cycle is repeated until the temperature of the baking chamber approaches the set temperature.

After that, it is necessary to switch to the automatic heating mode of the furnace, i.e. put the switches of all zones in the first position. Simultaneously with the start of heating, it is necessary to turn on the furnace conveyor for its uniform heating, strictly following the recommendations for operating the furnace.

Technical characteristics of furnaces HPS-25 and HPS-40

Hearth area, m2 25 40

Installed capacity of electric heaters, 260 385 kW

Voltage, V 380/220 380/220

Productivity, t/day 10-15 15-25

Overall dimensions, m

length 15.5 22

width 3.27 3

height 1.5 1.51

Weight without thermal insulation, t 11.5 16.5

Furnaces of the HPS brand are mass-produced at the Shebekinsky Machine Plant.

The HPS-25 brand oven operates at a bakery in the town of Tapa, Estonian SSR, and the HPS-40 brand oven operates at the bakeries in Tartu and Belgorod.

The branch research laboratory for baking ovens of the Kiev Technological Institute of the Food Industry in collaboration with the Shebekinsky Machine-Building Plant created a new unified baking oven with a mesh hearth with electric heating with a hearth area of ​​50, 75 and 100 m2.

In 1974, such an oven with a hearth area of ​​100 m2 was made to work at one of the Chisinau bakeries.

The KhPS-100 oven (Fig. 4) is designed for baking bread and various bakery products. The design is based on the designs of modern tunnel furnaces. For the purposes of unification, units and separate elements of PHC and PHS furnaces (tension and drive station, etc.) are used in the HPS furnace.

Mesh under the furnace is attached to two leading chains. In the humidification zone, the pod has a rise at the beginning and end of the chamber. The angle of elevation is 15°, which ensures the passage of dough pieces inside the steam hood. Extraction of excess steam-air mixture was carried out inside the hood to reduce steam condensation on the walls.

Heating of the baking chamber is carried out by "dark" heating electric resistance elements. For ease of regulation, the furnace heating system is divided into zones.

The oven uses a sectional assembly system that makes it possible to manufacture the baking chambers and the oven frame at the factory, which will greatly simplify the installation of the oven at bakeries.

Construction and work. The KhPS-100 tunnel oven with a mesh hearth 3 m wide. It uses electric heating of the baking chamber with dark resistance heating elements. The furnace is equipped with an automatic control and regulation system. It is assembled from separate sections, which are the furnace body, drive and tension device, automation system, external shields and insulation. All sections of the furnace are assembled at the factory and the installation of the furnace is reduced to the assembly of individual sections, the installation of external shields and the laying of thermal insulation.

The baking chamber consists of sections 4 m long each. Dimensions of the baking chamber: length 36 m, width 3.1 m, height 0.2 m. It slides under the oven along guides. Inspection hatches are placed in the baking chamber. Sections of the baking chamber are interconnected by expansion joints. Each section also has one rigid fastening: the front and end sections are at the ends, the middle one is in the middle.

Heating of the baking chamber is carried out by dark electric heaters - resistance elements. The heaters are located in the lower and upper parts of the baking chamber (above and below the grid).

The furnace heating system is divided into zones in which autonomous temperature control is carried out.

The device for hygrothermal treatment of dough pieces is a metal cap, inside of which there are perforated steam supply pipes. Mesh under has rise in a zone of humidification. This design allows you to create optimal conditions in the humidification zone, contributing to the intense sorption of steam by dough pieces.

To remove the steam-air medium from the baking chamber, the oven is equipped with a system of exhaust devices. At the beginning and at the end of the furnace, exhaust hoods are installed, which are connected by pipes to fans. The fans are connected to exhaust pipes.

Drive and tension stations are made of elements of drive and tension stations of PHC furnaces. The drive station is equipped with a manual drive and a locking device that turns off the electric motor when the hand drive is turned on.

Automation system. It consists of systems of automatic control and automatic regulation; blocking and protection systems.

The following parameters are controlled in the oven: temperature in the baking chamber, temperature of the steam supplied for humidification, pressure of the steam supplied for humidification, steam consumption, voltage and current, power consumption, baking duration.

Temperature control along the length of the baking chamber is carried out in each thermal zone and in the humidification zone. The parameters of the steam supplied for humidification are controlled by a thermometer and a manometer. Steam consumption is measured with a normal diaphragm.

Maintaining the set temperature in separate thermal zones of the baking chamber is carried out by turning on and off groups of heaters in separate zones included in the automatic furnace control circuit. The HPS furnace also provides for the regulation of the steam humidification mode.

The automation system of the KhPS-100 furnace includes a system of interlocks and protection:

when opening the hatches, through which it is possible to access the current-carrying parts, the voltage is automatically removed from them;

when the drive motor is overloaded, the safety pin is cut off and the transmission of rotation to the drive sprockets is stopped.

The furnace is equipped with light and sound alarm systems that inform about the operation of any of the protections.

Technical characteristics of the KhPS-100 furnace

Productivity on hearth bread weighing 1 kg, 2200 kg/h

Duration of baking, min 12-60

Hearth area, m 2 96

Hearth width, m 3

Baking chamber length, m 32

Baking chamber height, m ​​0.2

Specific electricity consumption (calculated), kWh/t 350

Specific steam consumption (calculated), kg/t 120

Installed power of electric motors, kW

including conveyor drive 4.5

rotation speed, rpm 1400

fan drives (two motors), kW 1.1

speed, rpm 2880

Overall dimensions, m

width 4.0

height 1.8

Weight, t 75

including metal structures 50

Approved and put into effect

Order of the Ministry of Emergency Situations of Russia

SET OF RULES

SP 166.1311500.2014

URBAN VEHICLE TUNNELS AND VIAWAYS

TUNNEL TYPE WITH LENGTH OF LOCKED PART NOT MORE THAN 300 M

REQUIREMENTSFIRESECURITY

City road tunnels and tunnel-tape flyovers

with length of covered part not more than 300 meters.

fire safety requirements

Introduction date - 2014-12-15

Foreword

Goals and principles of standardization in Russian Federation, the rules for the application of sets of rules are established by the Federal Law of December 27, 2002 N 184-FZ "On Technical Regulation".

The application of this set of rules ensures compliance with the requirements established by the Federal Law of July 22, 2008 N 123-FZ "Technical Regulations on Fire Safety Requirements".

About the set of rules

1. DEVELOPED AND INTRODUCED by the federal state budgetary institution "All-Russian Order of the Badge of Honor" Research Institute of Fire Defense of the Ministry of Emergency Situations of Russia"

(FGBU VNIIPO EMERCOM of Russia)

2. APPROVED AND PUT INTO EFFECT by order of the Ministry of the Russian Federation for Civil Defense, Emergencies and Disaster Relief (EMERCOM of Russia) dated December 8, 2014 N 684

3. REGISTERED by the Federal Agency for Technical Regulation and Metrology on December 29, 2014

4. INTRODUCED FOR THE FIRST TIME

This set of rules cannot be fully or partially reproduced, replicated and distributed as an official publication without the permission of the Russian Emergencies Ministry.

1 area of ​​use

1.1. This set of rules establishes requirements for ensuring fire safety of motor transport tunnels and tunnel-type overpasses with a covered part length of up to 300 m (hereinafter referred to as tunnels) and a slope of not more than 0.05 during their design and construction.

1.2. This set of rules applies to tunnels located in the city.

1.3. This set of rules does not apply to tunnels for mixed traffic of trackless and rail transport, tunnels for mixed traffic of vehicles, pedestrians and cyclists, as well as tunnels with skylights, as a result of which the length of each of the blocked parts does not exceed 300 m.

This code of practice uses normative references to the following standards and codes of practice:

GOST 19433-88 Dangerous goods. Classification and labeling

GOST 31565-2012 Cable products. fire safety requirements

GOST R 12.2.143-2009 Occupational safety standards system. Photoluminescent evacuation systems. Requirements and control methods

GOST R 12.4.026-2001 Occupational safety standards system. Signal colors, safety signs and signal markings. Purpose and rules of application. General technical requirements and characteristics. Test Methods

GOST R 50571.29-2009 Electrical installations of buildings. Part 5-55. Selection and installation of electrical equipment. Other equipment

GOST R 53300-2009 Smoke protection of buildings and structures. Acceptance and Periodic Test Methods

SP 1.13130.2009 Fire protection systems. Escape routes and exits

SP 2.13130.2012 Fire protection systems. Ensuring the fire resistance of protected objects

SP 3.13130.2009 Fire protection systems. Fire warning and evacuation control system. fire safety requirements

SP 4.13130.2013 Fire protection systems. Limiting the spread of fire at protected facilities. Requirements for space-planning and design solutions

SP 5.13130.2009 Fire protection systems. Fire alarm and fire extinguishing installations are automatic. Design norms and rules

SP 6.13130.2013 Fire protection systems. Electrical equipment. fire safety requirements

SP 7.13130.2013 Heating, ventilation and air conditioning. fire safety requirements

SP 8.13130.2009 Fire protection systems. Sources of external fire water supply. fire safety requirements

SP 10.13130.2009 Fire protection systems. Internal fire water supply. fire safety requirements

SP 12.13130.2009 Definition of categories of premises, buildings and outdoor installations for explosion and fire hazard

SP 52.13330.2011 Natural and artificial lighting. Updated edition of SNiP 23-05-95*

SP 60.13330.2012 Heating, ventilation and air conditioning. Updated edition of SNiP 41-01-2003

Note - When using this set of rules, it is advisable to check the effect of reference standards and classifiers in information system general use - on the official website of the national body of the Russian Federation for standardization on the Internet or according to the annually published information index "National Standards", which is published as of January 1 of the current year, and according to the issues of the monthly published information index "National Standards" for the current year . If an undated referenced referenced document has been replaced, it is recommended that the current version of that document be used, taking into account any changes made to that version. If the referenced document is replaced by a dated reference, it is recommended that the version of this document with the year of approval (acceptance) indicated above be used. If, after the approval of this International Standard, a change is made to the referenced document to which a dated reference is given, affecting the provision to which the reference is given, then this provision is recommended to be applied without taking into account this change. If the reference document is canceled without replacement, then the provision in which the link to it is given is recommended to be applied in the part that does not affect this link.

3. Terms and definitions

In this set of rules, the following terms are used with their respective definitions:

3.1. road tunnel: An urban underground (or underwater) linear structure for the passage of vehicles.

3.2. approach clearance: The limiting transverse outline of free space in a plane perpendicular to the longitudinal axis of the carriageway, inside which no elements of a structure or devices located on them should go.

3.3. pavement: Structural element highway, which perceives the load from vehicles and transfers it to the subgrade or tunnel structural element.

3.4. lining: The supporting structure of a tunnel that takes the load from the adjacent soil, enclosing the underground working and forming the inner surface of the underground structure.

3.5. tunnel portal: Enclosing load-bearing structure of the interface of the tunnel with the ground surface. Element of a road tunnel.

3.6. tunnel structure: An underground structure, an element of an auxiliary road tunnel, adjacent to the main tunnel or connected to it by an underpass.

3.7. tunnel carriageway: An element of a road tunnel intended for the movement of vehicles.

3.8. safety lane: The edge strip of the carriageway that limits the approach of vehicles to the service aisle located at the tunnel wall.

3.9. traffic lane: Part of the carriageway of a tunnel that is wide enough for vehicles to move in one lane.

3.10. tunnel-type overpass: An underground structure that is an element of a traffic interchange and is intended for the movement of vehicles.

3.11. ramp: Structure, element of a road tunnel that serves to allow vehicles to enter or exit a road tunnel.

3.12. service passage: A strip allocated at the wall of the tunnel with some elevation above the level of the carriageway, intended for the passage of service personnel through the tunnel.

4. General provisions

4.1. IN project documentation for each individual tunnel (an artificial structure with a unified life support system), a section "Measures to ensure fire safety" should be provided.

4.2. Along with this set of rules, the fire safety requirements set forth in the regulatory legal acts and regulatory documents on fire safety.

5. Fire safety requirements for the master plan

5.1. The mutual arrangement of aboveground and underground facilities and the tunnel during design and construction, their intersection or connection should not increase the fire hazard of each of them individually.

5.2. When crossing in terms of a tunnel gas pipelines of medium and high pressure, oil and product pipelines, special technical conditions must be developed in accordance with the current regulatory documents.

5.3. Fire-prevention distances from the ground structures of the tunnel (including from the portals) to the buildings and structures adjacent to them must be taken in accordance with the requirements of the current legislation, but not less than 15 m.

5.4. Evacuation exits from tunnel structures, access points for emergency services and places for connecting fire trucks to dry pipes should be marked with fire safety signs in accordance with the requirements of GOST R 12.4. 026.

5.5. Sources of external fire water supply should be provided in accordance with the requirements of SP 8.13130.

5.6. Water consumption for external fire extinguishing purposes should be at least 40 l / s.

6. Fire resistance of building structures

6.1. The fire hazard class of building structures of the tunnel, underground tunnel structures, evacuation stairs from tunnel structures should be taken as K0.

6.2. The fire resistance limits of tunnel structures should be provided according to Table 1.

Table 1

	Name	Fire resistance limit
	Bearing structures of tunnels: lining (walls, ceilings), columns
	Non-bearing walls and partitions of rooms with combustible materials, electrical equipment (tunnel ventilation chambers, dewatering installations, transformers, switchboards, etc.), partitions and floors of vestibules of rooms of category A and B
	The walls of the stairwells
	Marches and platforms of stairs
	Protection doorways in the stairwell
	Protection of doorways in service and technical and auxiliary premises

7. Fire safety requirements for space-planning solutions

7.1. The finishing of the tunnel structural elements must be made of non-combustible materials.

Fire hazard class building materials tunnel should take K0.

7.2. The load-bearing structures of the frames of noise barriers on the ramp sections of tunnels should be made with a fire resistance rating of at least R 45. The protection of noise barriers should be made of non-combustible materials.

7.3. The fire resistance of structures of ground service and technical and auxiliary structures should be determined in accordance with SP 2.13130.

7.4. The doorway connecting the volume of the tunnel with underground tunnel structures should be protected with fire doors with a fire resistance rating of EIS 90.

7.5. Cable collectors (if any) along the entire length every 150 m must be separated by fire partitions with a fire resistance rating of EI 45 with filling doorways with fire doors with a fire resistance rating of at least EIS 30.

7.6. For pavement it is not allowed to use materials with a higher fire hazard than G1.

7.7. In the blocked part of one-lane and two-lane tunnels with a length of more than 60 m, it is not allowed to provide slopes of more than 3%.

8. Fire safety requirements to ensure the evacuation of people in case of fire

8.1. On ramp walls with a length of more than 150 m, it is necessary to provide vertical fire escapes with a width of at least 0.9 m. The distance between fire escapes on each ramp wall should be no more than 150 m.

8.2. In the blocked part of the tunnel and on the ramp sections, at least one service passage should be provided, structurally made without breaks.

8.3. Elevation of the service passage above the level of the carriageway should be provided not less than 0.4 and not more than 0.6 m, and a width of not less than 0.75 m.

8.4. Escape routes and exits from tunnel structures should be provided in accordance with the requirements of SP 1.13130.

It is allowed to provide evacuation routes and exits from tunnel structures to the ramp.

8.5. In the blocked part of the tunnel, a photoluminescent evacuation system should be provided in accordance with the requirements of GOST R 12.2.143.

9. Fire safety requirements for engineering systems

9.1. Automatic fire alarm and fire warning systems

9.1.1. In the tunnel, automatic fire alarm and fire warning systems must comply with the requirements of SP 3.13130, SP 5.13130.

9.1.2. All premises and structures should be equipped with automatic fire alarm systems, except for the following premises:

ventilation chambers (supply, as well as exhaust, not serving industrial premises of category A or B) and other premises for the engineering equipment of the structure, in which there are no combustible materials;

stairwells;

blocked part of the tunnel.

9.1.3. The output of signals about the operation of fire alarm systems should be provided for in the control room of the operating organization. The fire signal should be additionally interlocked with an electrified sign installed before entering the tunnel about the prohibition of entering the tunnel.

9.1.4. Automatic system fire alarm should be provided with an integrated, address-analogue. The capacity of control and reception devices should be taken into account with a 20% reserve.

9.1.5. Manual fire detectors should be installed in tunnel structures, service and technical and auxiliary premises.

9.1.6. Places for installation of buttons for manual fire detectors must be marked with fire safety signs.

9.1.7. In tunnels with a length of the blocked part of more than 100 m, a video surveillance system with image output to the control room of the operating organization should be provided. The image from video cameras is recommended to be integrated into the citywide traffic control system.

9.1.8. Tunnel structures (including cable collectors), service and technical and auxiliary premises must be equipped with fire warning systems of the 2nd type in accordance with SP 3.13130.

9.1.9. In tunnels longer than 100 m, communication facilities (telephone sets) should be installed to transmit information about accidents, fires and other emergencies to the control room of the operating organization. Communication means should be installed near fire hydrants and marked with appropriate signs.

9.2. Internal fire water supply systems

9.2.1. In tunnels with a length of the blocked part of more than 100 m, it is necessary to provide for the laying of a dry pipe DN 100, laid on one side of each tunnel shaft with the installation of fire hydrants DN 65 on it. The distance between fire hydrants is determined by calculation. The dry pipe should be equipped with branch pipes with a diameter of 89 (77) mm, equipped with valves, check valves and connecting heads GM-80, designed to connect fire trucks.

9.2.2. The locations of the connection heads for connecting fire trucks should be marked with fire safety signs.

9.2.3. Dry pipes should be provided from seamless steel pipes.

9.2.4. Drain cocks DN15 should be provided for the lower sections of the dry pipe.

9.3. System for removing water spilled during fire fighting, flammable and combustible liquids

9.3.1. In tunnels, underground tunnel structures, service and technical and auxiliary premises, a system of gravity collection and forced drainage of water should be provided.

9.3.2. In the tunnel, inspection wells should be provided at least every 80 m, equipped with hydraulic seals with settling tanks with a volume of at least 0.2 m3.

9.3.3. When equipping the tunnel with a drainage installation at a point with a minimum mark (tray of the internal drain pipe), gravity drainage of water into the sump through a hydraulic seal must be provided.

9.3.4. The sump and pumps of the dewatering plant must be designed for receiving and pumping maximum number water in case of fire and rain. The control of pumping units and the control of the water level in the sump must be automated. In the room of the drainage installation, constant instrumental control of the gaseous medium must be provided.

9.3.5. The design of drainage devices, pressure pipelines, drainage devices and water collectors should exclude the possibility of water freezing in them.

9.4. Automatic gas fire extinguishing system

An automatic gas fire extinguishing system should be provided for the following tunnel structures: cable underground of underground transformer substations, hardware and server rooms located in tunnel structures, cable collectors. The system parameters must be provided in accordance with the requirements of SP 5.13130.

9.5. Ventilation, air conditioning and smoke protection systems

9.5.1. The transport zones of motor transport tunnels are not subject to protection by exhaust smoke ventilation systems when the necessary calculation justification is performed.

9.5.2. Systems of general exchange and exhaust smoke ventilation of tunnel structures must be designed in accordance with the requirements of SP 7.13130 ​​and SP 60.13330.

9.5.3. Placement of system fans is allowed supply and exhaust ventilation near-tunnel structures outside the structure when installing fences to protect against access by unauthorized persons. These fences should not contribute to the formation of snow cover that impedes the operation of systems.

9.5.4. An exhaust smoke ventilation system should be provided for:

a) for production or storage premises without natural ventilation of categories A, B, C1, C2, C3 with permanent workplaces of 50 m2 or more (in the absence of automatic water fire extinguishing installations in the room) or 200 m2 or more (if there are water automatic fire extinguishing installations);

b) for the upper and lower zones of premises (including cable collectors, etc.) equipped with gas automatic settings fire extinguishing (providing the removal of gas and smoke after a fire).

9.5.5. The supply of outdoor air by supply smoke ventilation systems should be provided for:

a) to the premises (to compensate for the volume removed by exhaust systems) specified in clause 9.5.4 of this set of rules;

b) in the vestibule locks at the entrances to the premises of categories A and B.

9.5.6. It is allowed to combine general exchange and exhaust smoke ventilation systems. At the same time, the design of general ventilation systems must meet the requirements for smoke ventilation systems.

9.5.7. The required fire resistance limits of ventilation ducts (shafts, collectors, air ducts) in exhaust smoke ventilation systems should be provided for at least:

EI 45 - for production or storage premises specified in subparagraph a) of paragraph 9.5.4 of this set of rules;

EI 15 - for the upper and lower zones of the premises provided for in subparagraph b) of paragraph 9.5.4 of this set of rules.

9.5.8. The required fire resistance limits of normally closed fire dampers, double-acting fire dampers of exhaust smoke ventilation systems must correspond to those established for ventilation ducts in accordance with clause 9.5.7 of this set of rules.

9.5.9. The required fire resistance limits of ventilation ducts (shafts, collectors, air ducts) of supply smoke ventilation systems should be provided for at least:

EI 30 - for production or storage premises specified in subparagraph a) of paragraph 9.5.4 of this set of rules;

EI 15 - for vestibule locks at the entrances to rooms of categories A and B.

9.5.10. The required fire resistance limits of normally closed fire dampers, double-acting fire dampers of supply smoke ventilation systems must correspond to those established for ventilation ducts in accordance with paragraph 9.5.9 of this set of rules.

9.5.11. Fire damper drives should be provided with possible direct and reverse action in automatic and remote control modes in case of fire (thermal sensitive elements for these drives can only be used as redundant ones).

9.5.12. Emission of combustion products must be carried out with an outflow velocity of at least 20 m/s or at a lower velocity through shafts at least 5 m high from the ground.

9.5.13. Emission of combustion products should be provided at a distance of at least 15 m from adjacent buildings with windows and outdoor air intakes of general ventilation and air conditioning systems, as well as from air intakes of supply smoke ventilation systems of this building.

9.5.14. The distance from the exhaust devices of the exhaust smoke ventilation systems to the air intakes of the supply smoke ventilation systems located on the roof of the structure must be at least 5 m.

9.5.15. Grade technical condition smoke ventilation systems at new construction and reconstruction facilities, as well as at operated tunnels, should be carried out in accordance with GOST R 53300.

9.6. electrical installations

9.6.1. The electrical equipment of fire protection systems must comply with the requirements of SP 5.13130 ​​and SP 6.13130.

9.6.2. The reliability of power supply to consumers of security systems and fire protection systems must comply with reliability category I in accordance with the PUE.

9.6.3. Electrical equipment on underground transformer substations should not be oil-filled, dry cast resin transformers must be used.

9.6.4. Laid mutually redundant power supply lines, as well as emergency and working lighting wiring, must be isolated in fire protection by laying in different rooms, cable structures or in various molded electrical products (boxes, pipes, etc.) with a clear distance between them of at least 1 m.

9.6.5. For all electrical consumers, both manual control at the place of installation of the equipment and remote control with the control room of the operating organization.

9.6.6. The laying of cables of power and lighting networks along the route of the tunnels should be provided in the cable collector (with the exception of distribution networks suitable for equipment installed directly in the tunnels). Power and lighting cables should be laid on one side of the collector, signaling and security control cables on the other.

It is allowed to lay cables on one side of the cable collector in compliance with the requirements of the Electrical Installation Code for the distances between power cables and signaling and control cables, separating them with non-combustible horizontal partitions with a fire resistance rating of at least EI 45.

9.6.7. If it is not possible to lay cables in the cable collector, they may be laid in the volume of tunnels in special channels or niches protected by fire-resistant structures with a fire resistance rating of at least EI 120 or in fire-resistant cable boxes with a fire resistance limit of at least EI 120.

9.6.8. In rooms and common corridors of tunnel structures, cable lines can be laid directly along structures, under raised floors in boxes with a fire resistance rating of at least EI 60.

9.6.9. The structures of boxes and raised floors must be made of non-combustible materials belonging to the NG group.

For maintenance of cable products in raised floors, it is necessary to provide hatches.

It is allowed to design raised floors with removable ceilings.

9.6.10. On ramp sections near fire cabinets, it is necessary to provide sockets in a special design for connecting electrified equipment of emergency services with a distance between them along the tunnel length of not more than 100 m. The degree of protection of sockets is not lower than IP 66.

9.6.11. cable lines and electrical wiring must be made with cables that are flame retardant in group laying with low smoke and gas emission (version "ng-LS"), and for fire protection systems, an additional requirement is fire-resistant design (version "ng-FRLS") in accordance with GOST 31565.

9.6.12. Laying cables in ventilation ducts is prohibited.

9.6.13. The design, climatic version, protection class, degree of protection of the equipment must comply with the environmental conditions.

9.6.14. Electrical circuits must be protected against short circuit currents and overload.

9.6.15. The following indication should be displayed on the control post:

a) failure of the power supply to the switching and control equipment to which fire protection systems are connected;

b) the working condition of all switching devices of the system, the operation of which is critical for the functioning of the fire protection system;

c) the state of the emergency power supply.

9.7. Lighting

9.7.1. The device for working and emergency lighting must comply with the requirements of SP 52.13330, GOST R 50571.29, as well as PUE.

9.7.2. Lamps for lighting tunnels, evacuation lamps and light indicators in the blocked part of the tunnel must have a degree of protection against environmental influences of at least IP66.

9.7.3. In tunnels and near-tunnel structures, emergency lighting should be provided, providing an illumination level in a smoke-free environment of at least 10 lux.

9.7.4. Light indicators must be connected to the emergency lighting network:

locations of fire hydrants and sockets in accordance with clause 9.6.11 of this set of rules;

emergency exits;

places for installation of connecting heads for connecting fire equipment;

locations of sources of external fire-fighting water supply (on the facade of the building (structure)).

9.7.5. Switchgear and control equipment, emergency lighting controls must be clearly marked and accessible only to qualified and trained personnel.

9.7.6. Batteries built into emergency lighting fixtures are treated as a separate independent power source.

9.7.7. Emergency lighting circuits must be routed and marked in such a way that they cannot be switched off unintentionally.

9.7.8. In tunnels and tunnel structures, where constant and intermittent lighting modes are combined, each corresponding switching device must have its own independent control device and be able to switch separately.

9.7.9. Non-permanent emergency lighting fixtures should be switched on in the event of a power failure to the working lighting fixtures in the area where they are located.

9.7.10. In continuous operation mode, the power supply must be controlled at the main distribution board. The requirement does not apply to luminaires with built-in rechargeable batteries.

Note - For permanent emergency lighting fixtures, the emergency mode is determined in case of violation mains supply at the building's main switchboard.

9.7.11. Not more than 20 emergency lighting fixtures with a total load of 6 A can be supplied from one circuit protected by one overcurrent protection device.

Note - This requirement is not mandatory if stand-alone devices with built-in batteries are used.

9.8. Lightning protection

When installing lightning protection elements, it is necessary to follow the requirements in accordance with the Instruction.

10. Organizational and technical measures

At the approaches to the tunnel and at the ramps, a road sign should be provided prohibiting the passage of vehicles through the tunnel with dangerous goods of classes 1 (explosive materials), 2 (compressed liquefied gases), 3 (flammable liquids) and 4.3 (substances that emit flammable gases upon interaction with water) according to the classification in accordance with GOST 19433.