Thermal insulation of flange connections, fittings, sections of pipelines subject to periodic inspection, and expansion joints must be removable.
3.24. The outer surface of pipelines and metal structures heating networks must be protected with reliable anti-corrosion coatings. Work to protect heating networks from corrosion, corrosion measurements, and operation of corrosion protection equipment must be carried out in accordance with Standard instructions on the protection of heating networks from external corrosion and Rules and regulations on the protection of heating networks from electrochemical corrosion. Commissioning of heating networks after completion of construction or major repairs without external anti-corrosion coating is not allowed.
When using heat-insulating materials or pipeline structures that exclude the possibility of pipe surface corrosion, protective covering protection against corrosion may not be provided.
3.25. Discharge of water from associated drainage systems onto the ground surface and into absorption wells is not permitted. Water drainage must be carried out in storm sewer, reservoirs or ravines by gravity or by pumping after approval in the prescribed manner.
3.26. In the passage channels it should be carried out supply and exhaust ventilation, ensuring both the heating and inter-heating periods the air temperature does not exceed 50 degrees. C, and during production repair work and inspections - no higher than 32 degrees. C. Decrease in air temperature to 32 degrees. C is allowed to be produced by mobile ventilation units.
3.27. The control equipment for electrical installations in underground chambers must be located outside the chambers.
3.28. Electric lighting should be provided in pumping stations, heating points, pavilions, tunnels and siphons, chambers equipped with electrical equipment, as well as on platforms of overpasses and free-standing high supports in places where electric drive fittings, regulators, and instrumentation are installed.
3.29. For centralized control and management of equipment of heating networks, heating points and pumping stations, telemechanization technical means must be used.
3.30. The following must be provided at the outlets of heating networks from heat sources:
Measurement of pressure, temperature and coolant flow in the supply and return pipelines of network water, steam, condensate, make-up water pipelines;
Alarm and warning signaling of limit values of make-up water flow, pressure difference between the supply and return lines;
Heat energy and coolant metering unit.
Rules technical operation thermal power plants Team of authors
6. HEATING NETWORKS
6. HEATING NETWORKS
6.1. Technical requirements
6.1.1. The method of laying new heating networks, building structures, and thermal insulation must comply with the requirements of current building codes and regulations and other regulatory and technical documents. The selection of pipeline diameters is carried out in accordance with the feasibility study.
6.1.2. Pipelines for heating networks and hot water supply with a 4-pipe installation should, as a rule, be placed in one channel with separate thermal insulation of each pipeline.
6.1.3. The slope of heating network pipelines should be at least 0.002, regardless of the direction of movement of the coolant and the method of laying the heating pipelines. The routing of pipelines should exclude the formation of stagnant zones and ensure the possibility of complete drainage.
Slope of heating networks to individual buildings at underground installation is received from the building to the nearest camera. In certain areas (when crossing communications, laying over bridges, etc.) it is allowed to lay heating networks without a slope.
6.1.4. At the intersection of heating networks when they are laid underground in channels or tunnels with gas pipelines, leak sampling devices are provided on the heating networks at a distance of no more than 15 m on both sides of the gas pipeline.
The passage of gas pipelines through the building structures of chambers, impassable channels and niches of heating networks is not allowed.
6.1.5. When heating networks cross existing water supply and sewerage networks located above the pipelines of heating networks, as well as when crossing gas pipelines, casings should be installed on the water supply, sewerage and gas pipelines at a length of 2 m on both sides of the intersection (in the clear).
6.1.6. At the inputs of heating network pipelines into buildings, it is necessary to provide devices that prevent the penetration of water and gas into the buildings.
6.1.7. At the intersection of above-ground heating networks with high voltage lines power transmission, it is necessary to ground (with a resistance of grounding devices of no more than 10 Ohms) all electrically conductive elements of heating networks located at a distance of 5 m in each direction from the projection axis of the edge of the structure overhead line power transmission to the surface of the earth.
6.1.8. In areas where heat pipelines are laid, the construction of buildings, storage, and planting of trees and perennial shrubs are not allowed. The distance from the projection on the surface of the earth of the edge of the building structure of the heating network to the structures is determined in accordance with building codes and regulations.
6.1.9. The materials of pipes, fittings, supports, compensators and other elements of pipelines of heating networks, as well as methods of their manufacture, repair and control must comply with the requirements established by the Gosgortekhnadzor of Russia.
6.1.10. For pipelines of heating networks and heating points at a water temperature of 115 °C and below, at a pressure up to 1.6 MPa inclusive, it is allowed to use non-metallic pipes if their quality meets sanitary requirements and corresponds to the parameters of the coolant.
6.1.11. Welded connections of pipelines are subjected to testing using non-destructive testing methods in accordance with the volumes and requirements established by the State Technical Supervision Authority of Russia.
6.1.12. Non-destructive testing methods should be applied to 100% of welded joints of heating network pipelines laid in non-passable channels under roadways, in cases, tunnels or technical corridors together with other engineering communications, as well as at intersections:
railways and tram tracks - at a distance of at least 4 m, electrified railways - at least 11 m from the axis of the outermost track;
railways of the general network - at a distance of at least 3 m from the nearest roadbed structure;
roads - at a distance of at least 2 m from the edge of the roadway, reinforced shoulder strip or the bottom of the embankment;
metro - at a distance of at least 8 m from structures;
power, control and communication cables - at a distance of at least 2 m;
gas pipelines - at a distance of at least 4 m;
main gas and oil pipelines - at a distance of at least 9 m;
buildings and structures - at a distance of at least 5 m from walls and foundations.
6.1.13. When monitoring the quality of the welding joint of a pipeline with an existing main (if there is only one shut-off valve between them, as well as when monitoring no more than two connections made during repairs), testing for strength and density can be replaced by checking the welded joint with two types of control - radiation and ultrasonic For pipelines that are not subject to the requirements established by the Gosgortekhnadzor of Russia, it is sufficient to check the continuity of welded joints using magnetic testing.
6.1.14. For all pipelines of heating networks, except for heating points and hot water supply networks, the following fittings are not allowed:
from gray cast iron - in areas with a design outside air temperature for heating design below minus 10 °C;
made of malleable cast iron - in areas with a design outside air temperature for heating design below minus 30 °C;
from high-strength cast iron in areas with a design outdoor temperature for heating design below minus 40 °C;
made of gray cast iron on drainage, blow-off and drainage devices in all climatic zones.
6.1.15. It is not allowed to use shut-off valves as control valves.
6.1.16. On pipelines of heating networks, it is allowed to use fittings made of brass and bronze at a coolant temperature not exceeding 250 °C.
6.1.17. Steel reinforcement is installed at the outlets of heating networks from heat sources.
6.1.18. Installation of shut-off valves is provided for:
on all pipelines of heating networks outlets from heat sources, regardless of the coolant parameters;
on pipelines of water networks D y 100 mm or more at a distance of no more than 1,000 m (sectional valves) with a jumper between the supply and return pipelines;
in water and steam heating networks in nodes on branch pipelines D y more than 100 mm, as well as in nodes on branch pipelines to individual buildings, regardless of the diameter of the pipeline;
on condensate lines at the inlet to the condensate collecting tank.
6.1.19. On water heating networks with a diameter of 500 mm or more at a nominal pressure of 1.6 MPa (16 kgf/cm 2) or more, with a diameter of 300 mm or more at a nominal pressure of 2.5 MPa (25 kgf/cm 2) or more, on steam networks with a diameter of 200 mm or more at a nominal pressure of 1.6 MPa (16 kgf/cm 2) or more, valves and shutters are provided with bypass pipelines (bypasses) with shut-off valves.
6.1.20. Gate valves and shutters with a diameter of 500 mm and more are equipped with an electric drive. When laying heating networks above ground, valves with electric drives are installed indoors or enclosed in casings that protect the valves and electric drive from precipitation and prevent access to them by unauthorized persons.
6.1.21. At the lowest points of pipelines of water heating networks and condensate pipelines, as well as sectioned sections, fittings with shut-off valves for draining water (drainage devices) are installed.
6.1.22. From the steam pipelines of heating networks at the lowest points and before vertical rises, condensate must be continuously removed through condensate drains.
In these same places, as well as on straight sections of steam pipelines, a device for starting steam pipeline drainage is installed every 400–500 m with a downward slope and 200–300 m with a counter slope.
6.1.23. To drain water from pipelines of water heating networks, discharge wells are provided with water drainage into sewerage systems by gravity or mobile pumps.
When draining water into a domestic sewer, a water seal is installed on the gravity pipeline, and if reverse flow of water is possible, an additional shut-off (check) valve is installed.
When laying pipelines above ground in an undeveloped area, concrete pits should be provided for draining water with water drainage from them using ditches, trays or pipelines.
6.1.24. To remove condensate from permanent steam pipeline drains, it is possible to discharge condensate into a condensate collection and return system. It is allowed to be discharged into the pressure condensate pipeline if the pressure in the drainage condensate pipeline is at least 0.1 MPa (1 kgf/cm2) higher than in the pressure pipeline.
6.1.25. At the highest points of heating network pipelines, including at each sectional section, fittings with shut-off valves for air release (air vents) must be installed.
6.1.26. In heating networks, reliable compensation for thermal expansion of pipelines must be ensured. To compensate for thermal elongation, the following are used:
flexible pipe expansion joints (U-shaped) with pre-stretching during installation;
turning angles from 90 to 130 degrees (self-compensation); bellows, lens, stuffing box and lip seals.
Stuffing box steel compensators can be used at P y no more than 2.5 MPa and a temperature of no more than 300 °C for pipelines with a diameter of 100 mm or more for underground installation and overhead installation on low supports.
6.1.27. Stretching of the U-shaped compensator should be performed after completing the installation of the pipeline, quality control of the welded joints (except for the closing joints used for tension) and securing the structure of the fixed supports.
The compensator is stretched by the amount specified in the project, taking into account the correction for the outside air temperature when welding the closing joints.
Stretching of the compensator must be carried out simultaneously on both sides at joints located at a distance of no less than 20 and no more than 40 pipeline diameters from the axis of symmetry of the compensator, using tension devices, unless other requirements are justified by the design.
A report should be drawn up regarding the expansion of expansion joints.
6.1.28. To control the parameters of the coolant, the heating network is equipped with select devices for measuring:
temperatures in the supply and return pipelines in front of the sectional valves and in the return pipeline of branches with a diameter of 300 mm or more in front of the valve along the water flow;
water pressure in the supply and return pipelines before and after sectional valves and control devices, in the forward and return pipelines of branches in front of the valve;
steam pressure in branch pipelines upstream of the valve.
6.1.29. At control points of heating networks, local indicating instruments are installed to measure temperature and pressure in pipelines.
6.1.30. The outer surfaces of pipelines and metal structures of heating networks (beams, supports, trusses, overpasses, etc.) must be protected with durable anti-corrosion coatings.
Commissioning of heating networks after completion of construction or major repairs without external anti-corrosion coating of pipes and metal structures is not allowed.
6.1.31. For all heating network pipelines, fittings, flange connections, expansion joints and pipe supports, regardless of the coolant temperature and installation methods, thermal insulation should be installed in accordance with building codes and regulations that define the requirements for thermal insulation of equipment and pipelines.
The materials and thickness of thermal insulation structures must be determined during design based on the conditions for ensuring standard heat loss.
6.1.32. It is allowed in places inaccessible to personnel, during a feasibility study, not to provide thermal insulation:
when laying return pipelines of heating networks in premises D< 200 мм, если тепловой поток через неизолированные стенки трубопроводов учтен в проекте систем отопления этих помещений;
condensate pipelines when discharging condensate into the sewer system; condensate networks with their joint laying with steam networks in non-passable channels.
6.1.33. Fittings, flange connections, hatches, expansion joints should be insulated if equipment or pipelines are insulated.
Thermal insulation of flange connections, fittings, sections of pipelines subject to periodic inspection, as well as stuffing box, lens and bellows expansion joints is provided for removable.
Heating network laid outdoors, regardless of the type of installation, must be protected from moisture.
6.1.34. The design of thermal insulation must prevent deformation and slipping of the thermal insulation layer during operation.
On vertical sections of pipelines and equipment, support structures must be installed every 1–2 m in height.
6.1.35. For above-ground pipelines when using thermal insulation structures made of combustible materials, 3 m long inserts made of non-combustible materials should be provided every 100 m of the pipeline length.
6.1.36. In places where electrical equipment is installed (pumping stations, heating points, tunnels, chambers), as well as in places where electrically driven fittings, regulators and instrumentation are installed, electric lighting is provided that complies with the rules for electrical installations.
The passage channels of heating networks are equipped with supply and exhaust ventilation.
6.2. Exploitation
6.2.1. When operating heating network systems, reliability of heat supply to consumers, supply of coolant (water and steam) with flow rate and parameters must be ensured in accordance with the temperature schedule and pressure drop at the inlet.
The connection of new consumers to the heating networks of the energy supplying organization is allowed only if the heat source has a power reserve and a reserve capacity of the heating network mains.
6.2.2. The organization operating the heating networks monitors the consumer's compliance with the specified heat consumption regimes.
6.2.3. When operating heating networks, access routes to network facilities are maintained in proper condition, as well as road surfaces and planning of surfaces above underground structures, ensuring the serviceability of enclosing structures that prevent unauthorized persons from accessing the equipment and shut-off and control valves.
6.2.4. Excavation of the pipeline route of the heating network or work near them by outside organizations is permitted only with the permission of the organization operating the heating network, under the supervision of a person specially appointed by it.
6.2.5. The organization draws up and permanently stores: a heating network plan (large-scale);
operational and operational (calculation) schemes;
profiles of heating mains along each main line with a static pressure line;
list of gas hazardous chambers and passage channels.
The heating network plan includes adjacent underground communications (gas pipeline, sewerage, cables), rail tracks of electrified transport and traction substations in an area of at least 15 m from the projection onto the ground surface of the edge of the building structure of the heating network or channelless pipeline on both sides of the route. On the plan of the heating network, the places and results of planned excavations, places of emergency damage, flooding of the route and shifted sections are systematically marked.
The plan, diagrams, profiles of heating mains and the list of gas-hazardous chambers and channels are adjusted annually in accordance with the actual state of heating networks.
All changes are made signed by the responsible person, indicating his position and the date of the change.
Information about changes in diagrams, drawings, lists and corresponding changes in instructions are brought to the attention of all employees (with an entry in the order log), for whom knowledge of these documents is mandatory.
6.2.6. On plans, diagrams and piezometric graphs the operational numbers of all heating mains, chambers (branch nodes), pumping stations, automatic control units, fixed supports, compensators and other heating network structures are indicated.
On operational (calculation) diagrams, all consumer systems connected to the network are subject to numbering, and on operational diagrams, in addition, sectioning and shut-off valves.
The fittings installed on the supply pipeline (steam pipeline) are designated by an odd number, and the corresponding fittings on the return pipeline (condensate pipeline) are designated by the next even number.
6.2.7. All gas-dangerous chambers and passage channels are marked on the operational diagram of the heating network.
Gas-dangerous chambers must have special signs, painted hatches and be kept securely locked.
Supervision of gas hazardous chambers is carried out in accordance with safety rules in the gas industry.
6.2.8. The organization operating heating networks (heat supply organization) participates in the acceptance after installation and repair of heating networks, heating points and heat-consuming installations owned by the consumer.
Participation in the technical acceptance of consumer facilities consists of the presence of a representative of the heat supply organization when testing the strength and density of pipelines and equipment of heating points connected to the heating networks of the heat supply organization, as well as heat consumption systems connected according to a dependent circuit. The organization operating heating networks stores copies of test reports, executive documentation indicating the main shut-off and control valves, air vents and drains.
6.2.9. After completion of construction and installation work (during new construction, modernization, reconstruction), major or current repairs with replacement of pipeline sections, heating network pipelines are tested for strength and density.
Pipelines laid in non-passing channels or channelless are also subject to preliminary tests for strength and density during the work process before installing gland (bellows) expansion joints, sectioning valves, closing channels and backfilling pipelines.
6.2.10. Preliminary and acceptance tests of pipelines are carried out with water. If necessary, in some cases it is possible to perform preliminary tests using a pneumatic method.
Performing pneumatic tests overhead pipelines, as well as pipelines laid in the same channel or in the same trench with existing utilities are not allowed.
6.2.11. Hydraulic tests of pipelines of water heating networks in order to check strength and density should be carried out by test pressure and entered into the passport.
The minimum test pressure during hydraulic testing is 1.25 working pressure, but not less than 0.2 MPa (2 kgf/cm2).
The maximum value of the test pressure is established by strength calculations according to the normative and technical documentation agreed with the State Mining and Technical Supervision Authority of Russia.
The test pressure value is selected by the manufacturer (design organization) within the range between the minimum and maximum values.
All newly installed pipelines of heating networks controlled by Gosgortekhnadzor of Russia must be subjected to hydraulic testing for strength and density in accordance with the requirements established by Gosgortekhnadzor of Russia.
6.2.12. When conducting hydraulic tests for the strength and density of heating networks, it is necessary to disconnect the equipment of the heating networks (stuffing box, bellows compensators, etc.), as well as sections of pipelines and connected heat-consuming power plants not involved in the tests.
6.2.13. During operation, all heating networks must be tested for strength and density to identify defects no later than two weeks after the end of the heating season.
6.2.14. Strength and density tests are carried out in the following order:
disconnect the tested section of the pipeline from existing networks;
at the highest point of the section of the pipeline being tested (after filling it with water and bleeding air), set the test pressure;
the pressure in the pipeline should be increased gradually;
the rate of pressure rise must be indicated in the regulatory and technical documentation (hereinafter referred to as NTD) for the pipeline.
If there is a significant difference in geodetic elevations in the test area, the value of the maximum permissible pressure at its lowest point is agreed upon with the design organization to ensure the strength of the pipelines and the stability of the fixed supports. Otherwise, the site must be tested in parts.
6.2.15. Tests for strength and density should be carried out in compliance with the following basic requirements:
When performing tests, pressure measurements should be made using two certified spring pressure gauges (one is a control one) of class no lower than 1.5 with a body diameter of at least 160 mm. The pressure gauge must be selected from the condition that the measured pressure value is 2/3 of the scale of the device;
test pressure must be provided at the top point (mark) of the pipelines;
the water temperature must be no lower than 5 °C and no higher than 40 °C;
when filling with water, air must be completely removed from the pipelines;
the test pressure must be maintained for at least 10 minutes and then reduced to working pressure;
at operating pressure, a thorough inspection of pipelines is carried out along their entire length.
6.2.16. The test results are considered satisfactory if during the test there was no drop in pressure and no signs of rupture, leakage or fogging were found in the welds, as well as leaks in the base metal, in valve bodies and seals, in flange connections and other pipeline elements. In addition, there should be no signs of movement or deformation of pipelines and fixed supports.
It is necessary to draw up a report in the established form regarding the results of testing pipelines for strength and density.
6.2.17. Pipelines of heating networks, before they are put into operation after installation, major or routine repairs with the replacement of pipeline sections, are subject to cleaning:
steam pipelines – purging with steam discharge into the atmosphere;
water networks in closed systems ah heat supply and condensate pipelines - hydropneumatic flushing;
water networks in open heat supply systems and hot water supply networks - hydropneumatic washing and disinfection (in accordance with sanitary rules) followed by repeated rinsing with drinking water. Repeated flushing after disinfection is carried out until the quality of the discharged water reaches the level that meets the sanitary standards for drinking water.
It is necessary to draw up a report on the flushing (purging) of pipelines.
6.2.18. To flush closed heating systems, it is allowed to use water from drinking or technical water supply, after flushing, water is removed from the pipelines.
6.2.19. Connection of heating networks and heat consumption systems after installation and reconstruction is carried out on the basis of a permit issued by state energy supervision authorities.
6.2.20. Filling pipelines of heating networks, their flushing, disinfection, turning on circulation, purging, warming up steam pipelines and other operations for starting up water and steam heating networks, as well as any testing of heating networks or their individual elements and structures are carried out according to a program approved by the technical manager of the organization and agreed upon with a heat source, and, if necessary, with environmental authorities.
6.2.21. The start-up of water heating networks consists of the following operations:
filling pipelines with network water; establishing circulation; network density checks;
switching on consumers and starting adjustment of the network.
The pipelines of heating networks are filled with water at a temperature of no higher than 70 °C when heat consumption systems are turned off.
Pipelines should be filled with water at a pressure not exceeding the static pressure of the filled part of the heating network by more than 0.2 MPa.
To avoid water hammer and to better remove air from pipelines, the maximum hourly water flow rate G b when filling heating network pipelines with a nominal diameter D y should not exceed the values indicated below:
Filling of distribution networks should be done after filling the main pipelines with water, and branches to consumers - after filling the distribution networks.
6.2.22. During the start-up period, it is necessary to monitor the filling and heating of pipelines, the condition of shut-off valves, stuffing box expansion joints, and drainage devices.
The sequence and speed of starting operations are carried out in such a way as to exclude the possibility of significant thermal deformations of the pipelines.
The program for launching heating networks takes into account the features of launching a water heating network when negative temperatures ah of outside air (after a long emergency shutdown, major repairs or when starting up newly built networks).
Heating of network water when circulation is established should be done at a rate of no more than 30 °C per hour.
In the event of damage to the launch pipelines or associated equipment, measures are taken to eliminate this damage.
In the absence of coolant flow measuring devices, starting adjustment is made based on the temperature in the return pipelines (until the temperature from all consumers connected to the network is equalized).
6.2.23. Starting up steam networks consists of the following operations: warming up and purging steam lines;
filling and flushing condensate pipelines; connecting consumers.
6.2.24. Before heating begins, all valves on branches from the heated area are tightly closed. First, the main line is heated, and then its branches one by one. Small, lightly branched steam pipelines can be heated simultaneously throughout the entire network.
When hydraulic shocks occur, the steam supply is immediately reduced, and in the event of frequent and strong shocks, it is completely stopped until the condensate accumulated in it is completely removed from the heated section of the steam line.
The heating rate of the steam line is adjusted based on the appearance of light hydraulic shocks (clicks). When warming up, it is necessary to regulate its speed, while preventing the steam line from sliding off the movable supports.
6.2.25. During the current operation of heating networks, it is necessary to: maintain all equipment, building and other structures of heating networks in good condition, carrying out their timely inspection and repair;
monitor the operation of expansion joints, supports, fittings, drains, vents, instrumentation and other equipment elements, promptly eliminating identified defects and leaks;
identify and restore damaged thermal insulation and anti-corrosion coating;
remove water accumulating in channels and chambers and prevent groundwater and surface water from entering there;
disconnect idle sections of the network;
promptly remove air from heat pipelines through vents, prevent air from being sucked into heating networks, maintaining the constantly required excess pressure at all points of the network and heat consumption systems;
maintain cleanliness in the cells in the passage channels, do not allow unauthorized persons to stay in them;
take measures to prevent, localize and eliminate accidents and incidents in the operation of the heating network;
control corrosion.
6.2.26. To monitor the condition of heating network equipment and thermal insulation, and their operating modes, inspections of heating pipelines and heating points are carried out regularly according to schedule. The walk-through schedule provides for monitoring the condition of the equipment by both mechanics-inspectors and the foreman.
The frequency of inspections is set depending on the type of equipment and its condition, but at least once a week during the heating season and once a month during the non-heating period. Thermal chambers must be inspected at least once a month; chambers with drainage pumps - at least 2 times a week. Functionality check drainage pumps and automatic activation of them is required during each round.
The inspection results are recorded in the heating network defect log.
Defects that threaten an accident or incident are corrected immediately. Information about defects that do not pose a danger from the point of view of the reliability of operation of the heating network, but which cannot be eliminated without disconnecting the pipelines, is entered in the log of walk-through and inspection of heating networks, and in order to eliminate these defects during the next shutdown of pipelines or during repairs - in the log of current repairs . Control can be carried out by remote methods.
6.2.27. When inspecting the heating network and inspecting underground chambers, personnel are provided with a set of necessary tools, devices, lighting fixtures, and an explosion-proof gas analyzer.
6.2.28. To control hydraulic and temperature conditions heating networks and heat-consuming installations, it is necessary to check the pressure and temperature at network nodes using pressure gauges and thermometers during scheduled inspections.
6.2.29. When operating heating networks, coolant leakage should not exceed the norm, which is 0.25% of the average annual volume of water in the heating network and heat consumption systems connected to it per hour, regardless of their connection scheme, with the exception of hot water supply systems (hereinafter referred to as DHW) connected through water heater
When determining the rate of coolant leakage, the water consumption for filling heat pipelines and heat consumption systems during their planned repairs and connecting new sections of the network and consumers should not be taken into account.
6.2.30. To control the density of equipment of heat sources, heating networks and heat consumption systems, it is allowed in the prescribed manner to use coloring leakage indicators approved for use in heat supply systems.
6.2.31. At each heating network make-up node, the flow of make-up water corresponding to the standard leakage is determined, and instrumentation of the actual flow of make-up water is provided.
If a coolant leak exceeds the established standards, measures must be taken to detect the location of the leak and eliminate it.
6.2.32. In addition to tests for strength and density, organizations operating heating networks conduct tests for the maximum temperature of the coolant, to determine heat and hydraulic losses once every 5 years.
All tests of heating networks are carried out separately and in accordance with current guidelines.
6.2.33. For each section of the heating network that is newly put into operation (regardless of the parameters of the coolant and the diameter of the pipelines), a passport of the established form is drawn up (Appendix 5). The passport records the duration of operation of pipelines and heating network structures, records the results of all types of tests (except for annual tests for strength and tightness at the end of the heating season), and records information about repairs, reconstructions and technical examinations.
6.2.34. To monitor the condition of underground heating pipelines, thermal insulation and building structures, it is necessary to periodically carry out trenching on the heating network.
Scheduled excavations are carried out according to an annually drawn up plan, approved by the person responsible for the good condition and safe operation of thermal power plants and (or) heating networks (technical manager) of the organization.
The number of pittings carried out annually is established depending on the length of the network, methods of laying and thermal insulation structures, the number of previously identified corrosion damage to pipes, and the results of tests for the presence of stray current potential.
At least one pit is provided per 1 km of the route.
In new sections of the network, pitting begins from the third year of operation.
6.2.35. Testing is carried out first:
near places where recorded corrosion damage pipelines;
at intersections with drains, sewers, and water pipes;
in areas located near open drains (ditches), passing under lawns or near sidewalk stones;
in places with unfavorable hydrogeological conditions;
in areas with an expected unsatisfactory condition of thermal insulation structures (as evidenced, for example, by thawed spots along the heat pipeline route in winter);
in areas of channelless installation, as well as channel installation with thermal insulation without an air gap.
6.2.36. The dimensions of the hole are selected based on the convenience of inspecting the pipeline being opened from all sides. In channelless gaskets, the dimensions of the hole at the bottom are at least 1.5x1.5 m; in channel laying, the minimum dimensions ensure the removal of floor slabs to a length of at least 1.5 m.
6.2.37. During pit inspection, the insulation, the pipeline under the insulation and building structures are inspected. If there are noticeable traces of corrosion, it is necessary to clean the surface of the pipe and measure the thickness of the pipeline wall using an ultrasonic thickness gauge or flaw detector.
If the measurement results are questionable and if a wall thinning of 10% or more is detected, it is necessary to carry out control drilling and determine the actual wall thickness.
If local thinning of the wall is detected at 10% of the design (initial) value, these sections are subjected to re-inspection during the repair campaign of the next year.
Sections with a pipeline wall thinning by 20% or more must be replaced.
Based on the results of the inspection, a report is drawn up.
6.2.38. Work to protect heating networks from electrochemical corrosion is carried out by specialized organizations (divisions).
The operation of corrosion protection equipment and corrosion measurements are carried out in accordance with current regulatory and technical documents.
6.2.39. To determine the corrosive aggressiveness of soils and the dangerous effects of stray currents, systematic inspections of pipelines of underground heating networks and electrical measurements to the potential of stray currents.
6.2.40. Electrical measurements on the routes of newly constructed and reconstructed heating networks are carried out by organizations that developed the design of heating networks, or by specialized organizations that develop technical solutions for protecting heating networks from external corrosion.
Specific measurements electrical resistance soil tests are carried out as necessary to identify sections of the route of ductless heating networks in soils with high corrosive aggressiveness.
Corrosion measurements to determine the dangerous effect of stray currents on steel pipelines of underground heating networks should be carried out in zones influenced by stray currents once every 6 months, as well as after each significant change in the operating mode of power supply systems of electrified transport (changes in the operating schedule of electric transport, changes in the location of traction substations, suction points, etc.) and conditions associated with the development of a network of underground structures and sources of stray currents, the introduction of electrochemical protection equipment at adjacent structures.
In other cases, measurements are made once every 2 years.
6.2.41. Electrochemical protection installations are subject to periodic technical inspection, verification of their operating efficiency and scheduled preventive maintenance.
Electrical protection installations are always kept in a state of full functionality.
Preventive maintenance of electrochemical protection installations is carried out according to the schedule of technical inspections and scheduled preventive maintenance approved by the technical manager of the organization. The schedule provides a list of types and volumes of technical inspections and repair work, the timing of their implementation, instructions for organizing accounting and reporting on work performed.
6.2.42. Technical inspections and scheduled preventative repairs are carried out within the following periods:
technical inspection of cathode installations - 2 times a month, drainage installations - 4 times a month;
technical inspection with efficiency check – once every 6 months;
current repairs – once a year; major repairs – once every 5 years.
All malfunctions in the operation of the electrochemical protection installation are eliminated within 24 hours after their detection.
6.2.43. The effectiveness of drainage and cathode installations is checked 2 times a year, as well as with each change in the operating mode of electrochemical protection installations and with changes associated with the development of a network of underground structures and sources of stray currents.
6.2.44. The resistance to current spreading from the anode grounding conductor of the cathode station is measured in all cases when the operating mode of the cathode station changes sharply, but at least once a year.
6.2.45. The total duration of interruptions in the operation of electrochemical protection installations on heating networks cannot exceed 7 days during the year.
6.2.46. When operating electrically insulating flange connections, their technical inspections are carried out periodically, but at least once a year.
6.2.47. In water heating networks and condensate pipelines, systematic monitoring of internal corrosion of pipelines is carried out by analyzing network water and condensate, as well as using internal corrosion indicators installed at the most characteristic points of heating networks (at the outlets from the heat source, at the end sections, at several intermediate nodes ). Internal corrosion indicators are checked during the repair period.
6.2.48. Every year, before the start of the heating season, all pumping stations must be subjected to comprehensive testing to determine the quality of repairs, correct operation and interaction of all thermal-mechanical and electrical equipment, control equipment, automation, telemechanics, protection of heat supply system equipment and determine the degree of readiness of pumping stations for the heating season.
6.2.49. Routine inspection of the equipment of automated pumping stations should be carried out every shift, checking the load of electrical equipment, the temperature of the bearings, the presence of lubricant, the condition of the seals, the operation of the cooling system, and the presence of chart tapes in recording devices.
6.2.50. At non-automated pumping stations, equipment is serviced on a daily basis.
6.2.51. Before starting the pumps, and when they are running once per shift, it is necessary to check the condition of the pumping and associated equipment.
In drainage pumping stations, the effect of the level regulator on the automatic pump switching device should be monitored at least 2 times a week.
6.2.52. When operating automatic regulators, periodic inspections of their condition are carried out, checking their operation, cleaning and lubricating moving parts, adjusting and tuning the regulators to maintain the specified parameters. Automation and technological protection devices for heating networks can be taken out of operation only by order of the technical manager of the organization, except in cases of disabling individual protections when starting up equipment, as provided for in local instructions.
6.2.53. The heating network is fed with softened, deaerated water, the quality of which meets the quality requirements for network and make-up water for hot water boilers, depending on the type of heat source and heat supply system.
6.2.54. Heat consumption systems connected according to an independent circuit are fed with water from the heating network.
6.2.55. Water pressure at any point in the supply line of water heating networks, heating points and in high points directly connected heat consumption systems when operating network pumps should be higher than the saturated vapor pressure of water when it maximum temperature no less than 0.5 kgf/cm2.
6.2.56. Excess water pressure in the return line of water heating networks during operation of network pumps must be at least 0.5 kgf/cm 2 . The water pressure in the return line should not be higher than permissible for heating networks, heating points and for directly connected heat consumption systems.
6.2.57. An idle heating network is filled only with deaerated water and must be under excess pressure of at least 0.5 kgf/cm 2 at the upper points of the pipelines.
6.2.58. For two-pipe water heating networks, the heat supply regime is based on a central quality control schedule.
If there is a hot water supply load, the minimum water temperature in the supply pipeline of the network is provided for closed heat supply systems at least 70 °C; for open heating systems of hot water supply – not lower than 60 °C.
6.2.59. The water temperature in the supply line of the water heating network, in accordance with the schedule approved for the heating supply system, is set according to the average outside air temperature over a period of time within 12–24 hours, determined by the heating network dispatcher depending on the length of the networks, climatic conditions and other factors.
Deviations from the specified mode at the heat source are provided for no more than:
according to the temperature of the water entering the heating network ±3%;
by pressure in the supply pipeline ±5%;
by pressure in the return pipeline ±0.2 kgf/cm 2.
The deviation of the actual average daily return water temperature from the heating network may exceed that specified by the schedule by no more than +5%. The decrease in the actual return water temperature compared to the schedule is not limited.
6.2.60. Hydraulic modes of water heating networks are developed annually for the heating and summer periods; for open heat supply systems during the heating period, modes are developed with maximum water withdrawal from the supply and return pipelines and in the absence of water withdrawal.
Measures to regulate water consumption among consumers are drawn up for each heating season.
The order of construction of new mains and pumping stations provided for by the heat supply scheme is determined taking into account the real growth of the connected heat load, for which purpose the organization operating the heating network is developing hydraulic modes of the heat supply system for the next 3–5 years.
6.2.61. For each control point of the heating network and at the make-up nodes, permissible values of flow rates and water pressures in the supply, return (and make-up) pipelines are established in the form of a regime map, corresponding to normal hydraulic conditions for the heating and summer periods.
6.2.62. In the event of an emergency interruption of power supply to network and transfer pumps, the organization operating the heating network ensures pressure in heating networks and heat consumption systems within acceptable levels. If this level can be exceeded, it is necessary to install special devices that protect the heat supply system from water hammer.
6.2.63. Repair of heating networks is carried out in accordance with the approved schedule (plan) based on the results of the analysis of identified defects, damage, periodic inspections, tests, diagnostics and annual tests for strength and density.
The schedule of repair work is drawn up based on the condition of simultaneous repair of pipelines of the heating network and heating points.
Before repairing heating networks, pipelines are freed from network water, and the channels must be drained. The temperature of water pumped from waste wells should not exceed 40 °C. Draining water from the heating network chamber to the surface of the earth is not allowed.
6.2.64. Each organization operating heating networks (in each operational area, section) draws up instructions, approved by the technical manager of the organization, with a clearly developed operational action plan in the event of an accident on any of the heating mains or pumping station in relation to local conditions and network communications.
The instructions must provide for the procedure for disconnecting highways, distribution networks and branches to consumers, the procedure for bypassing chambers and heating points, possible switches for supplying heat to consumers from other highways, and have diagrams of possible emergency switching between highways.
Plans for eliminating technological violations in heating networks of cities and large settlements are coordinated with local authorities.
6.2.65. According to the developed switching schemes, operational and operational-repair personnel of heating networks regularly conduct training according to the approved schedule (but at least once a quarter) to practice the clarity, consistency and speed of emergency operations with their reflection on the operational diagram.
6.2.66. To quickly carry out work to limit the spread of accidents in heating networks and eliminate damage, each operational area of the heating network provides the necessary supply of fittings and materials. The fittings installed on pipelines are of the same type in length and flanges.
The emergency supply of materials is stored in two places: the main part is stored in the pantry, and a certain amount of the emergency supply (consumables) is in a special cabinet at the disposal of the responsible person from the operational staff. Consumables used by operational personnel are replenished within 24 hours from the bulk of the stock.
The supply of fittings and materials for each operational area of the heating network is determined depending on the length of the pipelines and the number of installed fittings in accordance with emergency stock standards; a list of necessary fittings and materials is compiled, which is approved by the person responsible for the good condition and safe operation of the organization's heating networks.
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STATE COMMITTEE OF THE RUSSIAN FEDERATION
ON CONSTRUCTION AND HOUSING AND COMMUNAL COMPLEX
(GOSSTROY RUSSIA)
System of regulatory documents in construction
BUILDING STANDARDS AND RULES OF THE RUSSIAN FEDERATION
HEATING NETWORK
THERMAL NETWORKS
SNiP 41-02-2003
UDC 69+697.34 (083.74)
Date of introduction 2003-09-01
PREFACE
1 DEVELOPED by JSC Association VNIPIenergoprom, Perm State Technical University, JSC Teploproekt with the participation of the Association of developers and manufacturers of anti-corrosion protection products for the fuel and energy complex, the Association of manufacturers and consumers of pipelines with industrial polymer insulation, JSC Firm ORGRES, JSC All-Russian Thermal Engineering Institute", "SevZapVNIPIenergoprom", JSC "TVEL Corporation", Mosgorekspertizy, JSC "Mosproekt", State Unitary Enterprise "Mosinzhproekt", JSC NTP "Truboprovod", JSC "Roskommunenergo", JSC "Lengazteplostroy", Irkutsk State technical university, JSC "Insulation Plant", Tyumen Academy of Construction and Architecture
INTRODUCED by the Department of Technical Standardization, Standardization and Certification in Construction and Housing and Communal Services of the Gosstroy of Russia
2 ADOPTED AND ENTERED INTO EFFECT from September 1, 2003 by Resolution of the State Construction Committee of Russia dated June 24, 2003 No. 110 (did not pass state registration - Letter of the Ministry of Justice of the Russian Federation dated March 18, 2004 No. 07/2933-UD)
3 INSTEAD SNiP 2.04.07-86*
INTRODUCTION
These building codes and regulations establish a set of mandatory regulatory requirements for the design of heating networks, structures on heating networks in conjunction with all elements of centralized heat supply systems in terms of their interaction in a single technological process of production, distribution, transportation and consumption of thermal energy, rational use fuel and energy resources.
Requirements for safety, reliability, and survivability of heat supply systems have been established.
When developing SNiP, regulatory materials from leading Russian and foreign companies were used, and 17 years of experience in applying current standards by design and operating organizations in Russia were taken into account.
IN building codes and rules for the first time:
standards for environmental and operational safety, readiness (quality) of heat supply have been introduced; the application of the probability of failure-free operation criterion has been expanded;
the principles and requirements for ensuring survivability in off-design (extreme) conditions were formulated, the characteristics of centralized heat supply systems were clarified;
standards have been introduced for the application of reliability criteria when designing heating networks;
criteria for choosing thermal insulation structures taking into account fire safety are given.
The following people took part in the development of SNiP: Ph.D. tech. Sciences Ya.A. Kovylyansky, A.I. Korotkov, Ph.D. tech. Sciences G.Kh. Umerkin, A.A. Sheremetova, L.I. Zhukovskaya, L.V. Makarova, V.I. Zhurina, Ph.D. tech. Sciences B.M. Krasovsky, Ph.D. tech. Sciences A.V. Grishkova, Ph.D. tech. Sciences T.N. Romanova, Ph.D. tech. Sciences B.M. Shoikhet, L.V. Stavritskaya, Doctor of Engineering. Sciences A.L. Akolzin, Ph.D. tech. Sciences I.L. Maisel, E.M. Shmyrev, L.P. Kanina, L.D. Satanov, P.M. Sokolov, Doctor of Engineering. Sciences Yu.V. Balaban-Irmenin, A.I. Kravtsov, Sh.N. Abaiburov, V.N. Simonov, Ph.D. tech. Sciences V.I. Livchak, A.V. Fisher, Yu.U. Yunusov, N.G. Shevchenko, Ph.D. tech. Sciences V.Ya. Magalif, A.A. Khandrikov, L.E. Lyubetsky, Ph.D. tech. Sciences R.L. Ermakov, B.S. Votintsev, T.F. Mironova, Doctor of Engineering. Sciences A.F. Shapoval, V.A. Glukharev, V.P. Bovbel, L.S. Vasilyeva.
1 AREA OF USE
These rules and regulations apply to heating networks (with all associated structures) from the output shut-off valves (excluding them) of heat source collectors or from the external walls of the heat source to the output shut-off valves (including them) of heating points (input nodes) of buildings and structures transporting hot water with temperatures up to 200 °C and pressure up to 2.5 MPa inclusive, water steam with temperatures up to 440 °C and pressure up to 6.3 MPa inclusive, water vapor condensate.
Heat networks include buildings and structures of heat networks: pumping stations, heating points, pavilions, chambers, drainage devices and so on.
These standards consider centralized heat supply systems (hereinafter referred to as DHS) in terms of their interaction in a single technological process of production, distribution, transportation and consumption of heat.
These rules and regulations must be observed when designing new and reconstructing, modernizing and technically re-equipping existing heating networks (including structures on heating networks).
3 TERMS AND DEFINITIONS
The following terms and definitions are used in these standards.
A centralized heat supply system is a system consisting of one or more heat sources, heat networks (regardless of the diameter, number and length of external heat pipelines) and heat consumers.
The probability of failure-free operation of the system [P] is the ability of the system to prevent failures leading to a temperature drop in heated rooms of residential and public buildings below +12 °C, in industrial buildings below +8 °C, more than the number of times established by the standards.
The system availability (quality) coefficient is the probability of the system’s operational state at any time to maintain the calculated internal temperature in heated rooms, except for periods of temperature decrease allowed by regulations.
System survivability [Zh] - the ability of the system to maintain its functionality in emergency (extreme) conditions, as well as after long-term (more than 54 hours) shutdowns.
Service life of heating networks - a period of time in calendar years from the date of commissioning, after which an expert examination should be carried out technical condition pipeline in order to determine the admissibility, parameters and conditions of further operation of the pipeline or the need for its dismantling.
4 CLASSIFICATION
4.1 Heating networks are divided into main, distribution, quarterly and branches from main and distribution heating networks to individual buildings and structures. The separation of heating networks is established by the project or operating organization.
4.2 Heat consumers are divided into three categories according to the reliability of heat supply:
The first category is consumers who do not allow interruptions in the supply of the calculated amount of heat and a decrease in the air temperature in the premises below those provided for by GOST 30494.
For example, hospitals, maternity hospitals, children's preschool institutions with 24-hour stay for children, art galleries, chemical and special industries, mines, etc.
The second category is consumers who allow a decrease in temperature in heated rooms for the period of liquidation of the accident, but not more than 54 hours:
residential and public buildings up to 12 °C;
industrial buildings up to 8 °C.
The third category is the remaining consumers.
5 GENERAL PROVISIONS
5.1 Solutions for the long-term development of heat supply systems for settlements, industrial hubs, groups of industrial enterprises, districts and other administrative-territorial entities, as well as individual central heating systems should be developed in heat supply schemes. When developing heat supply schemes, the calculated heat loads are determined:
a) for the existing development of settlements and existing industrial enterprises - according to projects with clarification on actual heat loads;
b) for industrial enterprises planned for construction - according to the enlarged standards for the development of the main (core) production or projects of similar production;
c) for residential areas planned for development - according to aggregated indicators of the density of thermal loads or according to the specific thermal characteristics of buildings and structures in accordance with the master plans for the development of areas of the settlement.
5.2 Design heat loads when designing heating networks are determined based on data from specific new construction projects, and existing ones - based on actual heat loads. In the absence of data, it is permissible to follow the instructions of 5.1. Average loads on hot water supply of individual buildings can be determined according to SNiP 2.04.01.
5.3 Estimated heat losses in heating networks should be determined as the sum of heat losses through the insulated surfaces of pipelines and the average annual coolant losses.
5.4 In case of accidents (failures) at the heat source, its output collectors must be provided with the following during the entire repair and restoration period:
supply of 100% of the required heat to consumers of the first category (unless other modes are provided for by the contract);
supply of heat for heating and ventilation to housing, communal and industrial consumers of the second and third categories in the amounts indicated in Table 1;
Table 1
Indicator name Estimated outside air temperature for heating design to, °C
Allowable reduction in heat supply, %, up to 78 84 87 89 91
Note - The table corresponds to the outside air temperature of the coldest five-day period with a probability of 0.92.
emergency mode of steam and process hot water consumption specified by the consumer;
emergency thermal operating mode of non-switchable ventilation systems specified by the consumer;
average daily heat consumption during the heating period for hot water supply (if it is impossible to turn it off).
5.5 When several heat sources work together on a single heating network of a district (city), mutual redundancy of heat sources must be provided, ensuring emergency operation in accordance with 5.4.
6 HEAT SUPPLY AND HEAT NETWORK DIAGRAMS
6.1 The choice of an option for a heat supply scheme for an object: centralized heat supply systems from boiler houses, large and small thermal and nuclear power plants (CHP, TPP, NPP) or from decentralized heat supply sources (DHS) - autonomous, rooftop boiler houses, from apartment heat generators is made through technical and economic comparison options.
The heat supply scheme adopted for development in the project must ensure:
standard level of heat and energy saving;
standard level of reliability, determined by three criteria: probability of failure-free operation, availability (quality) of heat supply and survivability;
environmental requirements;
safety of operation.
6.2 The operation of heating networks and central heating systems in general should not lead to:
a) to an unacceptable concentration during operation of substances that are toxic and harmful to the population, maintenance personnel and the environment in tunnels, channels, chambers, rooms and other structures, in the atmosphere, taking into account the ability of the atmosphere to self-purify in a specific residential area, microdistrict, locality etc.;
b) to a persistent violation of the natural (natural) thermal regime vegetation cover (grass, shrubs, trees) under which heat pipelines are laid.
6.3 Heat networks, regardless of the installation method and heat supply system, should not pass through the territory of cemeteries, landfills, cattle burial grounds, radioactive waste burial sites, irrigation fields, filtration fields and other areas that pose a risk of chemical, biological and radioactive contamination of the coolant.
Technological devices of industrial enterprises, from which they can be supplied to heating networks harmful substances, must be connected to heating networks through a water heater with an additional intermediate circulation circuit between such a device and the water heater while ensuring pressure in the intermediate circuit is less than in the heating network. In this case, provision should be made for the installation of sampling points to monitor harmful impurities.
Hot water supply systems for consumers must be connected to steam networks through steam-water heaters.
6.4 Safe Operation heating networks should be ensured by developing measures in projects that exclude:
contact people directly with hot water or with hot surfaces of pipelines (and equipment) at coolant temperatures above 75 °C;
the flow of coolant into heat supply systems at temperatures above those determined by safety standards;
reduction in air temperature in residential and production premises consumers of the second and third categories are below permissible values (4.2);
draining network water in places not provided for by the design.
6.5 The temperature on the surface of the heat-insulating structure of heat pipes, fittings and equipment should not exceed:
when laying heat pipes in the basements of buildings, technical undergrounds, tunnels and passage channels 45 ° C;
for overhead installation, in chambers and other places accessible for maintenance, 60 °C.
6.6 The heat supply system (open, closed, including with separate hot water supply networks, mixed) is selected on the basis of a technical and economic comparison of various systems presented by the design organization, taking into account local environmental, economic conditions and the consequences of making a particular decision.
6.7 Direct tapping of network water from consumers in closed heat supply systems is not permitted.
6.8 In open heat supply systems, the connection of some hot water supply consumers through water-to-water heat exchangers at heat points of subscribers (via a closed system) is allowed as a temporary connection, provided that the quality of network water is ensured (maintained) in accordance with the requirements of current regulatory documents.
6.9 With nuclear heat sources, as a rule, open heat supply systems should be designed, eliminating the possibility of unacceptable concentrations of radionuclides in network water, pipelines, central heating equipment and heat receivers of consumers.
6.10 The SCT must include:
emergency services (ABC), the number of personnel and technical equipment of which must ensure full recovery heat supply in case of failures in heating networks within the time limits specified in Table 2;
own repair and maintenance bases (REB) - for districts of heating networks with an operating volume of 1000 conventional units or more. The number of personnel and the technical equipment of the electronic warfare are determined taking into account the composition of the equipment, the applied designs of heat pipelines, thermal insulation, etc.;
mechanical workshops - for sections (shops) of heating networks with an operating volume of less than 1000 conventional units;
unified repair and maintenance bases - for heating networks that are part of divisions of thermal power plants, district boiler houses or industrial enterprises.
Heat network diagrams
6.11 Water heating networks should be designed, as a rule, as two-pipe systems, simultaneously supplying heat for heating, ventilation, hot water supply and technological needs.
Multi-pipe and single-pipe heating networks may be used during a feasibility study.
Heat networks transporting network water in open heat supply systems in one direction, when laid above ground, can be designed in a single-pipe design with a transit length of up to 5 km. If the length is greater and there is no backup supply of the central heating system from other heat sources, the heating networks must be constructed in two (or more) parallel heat pipelines.
Independent heating networks for connecting process heat consumers should be provided if the quality and parameters of the coolant differ from those accepted in heating networks.
6.12 The layout and configuration of heating networks must ensure heat supply at the level of specified reliability indicators by:
application of the most advanced designs and technical solutions;
collaboration heat sources;
laying backup heat pipelines;
installation of jumpers between heating networks of adjacent thermal areas.
6.13 Heat networks can be ring and dead-end, redundant and non-redundant.
The number and location of backup pipeline connections between adjacent heat pipelines should be determined according to the criterion of the probability of failure-free operation.
6.14 Heating and ventilation systems for consumers must be connected to two-pipe water heating networks directly using a dependent connection scheme.
According to an independent scheme, which provides for the installation of water heaters in heating points, it is allowed to connect other consumers when justifying the heating and ventilation system of buildings of 12 floors and above, if the independent connection is due to the hydraulic operating mode of the system.
6.15 The quality of source water for open and closed heat supply systems must meet the requirements of SanPiN 2.1.4.1074 and the rules for the technical operation of power plants and networks of the Ministry of Energy of Russia.
For closed heat supply systems in the presence of thermal deaeration, it is allowed to use process water.
6.16 The estimated hourly water consumption to determine the productivity of water treatment and the corresponding equipment for replenishing the heating supply system should be taken:
in closed heat supply systems - 0.75% of the actual volume of water in the pipelines of heating networks and the heating and ventilation systems of buildings connected to them. At the same time, for sections of heating networks longer than 5 km from heat sources without heat distribution, the calculated water flow should be taken equal to 0.5% of the volume of water in these pipelines;
in open heat supply systems - equal to the calculated average water consumption for hot water supply with a coefficient of 1.2 plus 0.75% of the actual volume of water in the pipelines of heating networks and the heating, ventilation and hot water supply systems of buildings connected to them. At the same time, for sections of heating networks longer than 5 km from heat sources without heat distribution, the calculated water flow should be taken equal to 0.5% of the volume of water in these pipelines;
for individual heating networks of hot water supply in the presence of storage tanks - equal to the calculated average water consumption for hot water supply with a coefficient of 1.2; in the absence of tanks - according to the maximum water consumption for hot water supply plus (in both cases) 0.75% of the actual volume of water in the network pipelines and the hot water supply systems of buildings connected to them.
6.17 For open and closed heat supply systems, additional emergency make-up with chemically untreated and non-deaerated water must be provided, the flow rate of which is assumed to be 2% of the volume of water in the pipelines of heating networks and the heating, ventilation systems connected to them and in hot water supply systems for open heat supply systems. If there are several separate heating networks extending from the heat source manifold, emergency make-up can be determined only for one heating network with the largest volume. For open heat supply systems, emergency make-up should be provided only from domestic drinking water supply systems.
6.18 The volume of water in heat supply systems, in the absence of data on actual volumes of water, can be taken equal to 65 m3 per 1 MW of calculated heat load with a closed heat supply system, 70 m3 per 1 MW with an open system and 30 m3 per 1 MW of average load with separate networks hot water supply.
6.19 Placement of hot water storage tanks is possible both at the heat source and in heat consumption areas. In this case, storage tanks with a capacity of at least 25% of the total design capacity of the tanks must be provided at the heat source. The inner surface of the tanks must be protected from corrosion, and the water in them from aeration, while continuous renewal of the water in the tanks must be provided.
6.20 For open heat supply systems, as well as for separate heating networks for hot water supply, storage tanks of chemically treated and deaerated make-up water with a design capacity equal to ten times the average hourly water consumption for hot water supply must be provided.
6.21 In closed heat supply systems at heat sources with a capacity of 100 MW or more, provision should be made for the installation of storage tanks for chemically treated and deaerated make-up water with a capacity of 3% of the volume of water in the heat supply system, and the renewal of water in the tanks must be ensured.
The number of tanks, regardless of the heat supply system, is accepted to be at least two, each 50% of the working volume.
6.22 In central heating systems with heat pipelines of any length from the heat source to heat consumption areas, the use of heat pipelines as storage tanks is allowed.
6.23 If a group of storage tanks is located outside the territory of heat sources, it must be fenced with a common shaft of at least 0.5 m in height. The embanked area must accommodate the volume of water in the largest tank and have water drainage to the sewer.
6.24 It is not allowed to install hot water storage tanks in residential areas. The distance from hot water storage tanks to the border of residential areas must be at least 30 m. Moreover, on soils of the 1st type of subsidence, the distance must, in addition, be at least 1.5 times the thickness of the subsidence soil layer.
When placing storage tanks outside the territory of heat sources, they should be fenced with a height of at least 2.5 m to prevent unauthorized persons from accessing the tanks.
6.25 Hot water storage tanks for consumers should be provided in the hot water supply systems of industrial enterprises to align the shifting schedule of water consumption by facilities that have concentrated short-term water consumption for hot water supply.
For industrial facilities with a ratio of the average heat load for hot water supply to the maximum heat load for heating less than 0.2, storage tanks are not installed.
6.26 To reduce losses of network water and, accordingly, heat during planned or forced emptying of heat pipes, it is allowed to install special storage tanks in heating networks, the capacity of which is determined by the volume of heat pipes between two sectional valves.
Reliability
6.27 The ability of designed and existing heat sources, heating networks and central heating systems in general to provide, within a given time, the required modes, parameters and quality of heat supply (heating, ventilation, hot water supply, as well as the technological needs of enterprises for steam and hot water) should be determined by three indicators (criteria): probability of failure-free operation [P], availability factor [Kg], survivability [W].
Calculation of system indicators taking into account reliability must be carried out for each consumer.
6.28 Minimum acceptable indicators of the probability of failure-free operation should be taken for:
heat source Rit = 0.97;
heating networks Rts = 0.9;
heat consumer Rpt = 0.99;
MCT as a whole Рст = 0.9 0.97 0.99 = 0.86.
The customer has the right to set higher indicators in the design specifications.
6.29 To ensure the reliability of heating networks, the following should be determined:
maximum permissible length of non-redundant sections of heat pipelines (dead-end, radial, transit) to each consumer or heating point;
locations of backup pipeline connections between radial heat pipelines;
sufficiency of diameters selected when designing new or reconstructed existing heat pipelines to ensure backup heat supply to consumers in case of failures;
the need to replace the structures of heating networks and heat pipelines in specific areas with more reliable ones, as well as the feasibility of switching to above-ground or tunnel installation;
the order of repairs and replacements of heating pipelines that have partially or completely lost their service life;
the need to carry out work on additional insulation of buildings.
6.30 The readiness of the system for proper operation should be determined by the number of hours of waiting for readiness: heat source, heating networks, heat consumers, as well as the number of hours of non-design outdoor air temperatures in a given area.
6.31 The minimum acceptable indicator of readiness of the central heating system for proper operation Kg is accepted as 0.97.
6.32 To calculate the readiness indicator, the following should be determined (taken into account):
readiness of the central heating system for the heating season;
sufficiency of the installed thermal power of the heat source to ensure proper functioning of the central heating system during unusual cold snaps;
the ability of heating networks to ensure proper functioning of the central heating system during unusual cold snaps;
organizational and technical measures necessary to ensure proper functioning of the central heating system at the level of specified readiness;
maximum permissible number of standby hours for a heat source;
outside air temperature at which the set internal air temperature is ensured.
Reservation
6.33 The following backup methods should be provided:
application of rational thermal schemes at heat sources that ensure a given level of readiness of power equipment;
installation of the necessary backup equipment at the heat source;
organizing the joint work of several heat sources into a single heat transportation system;
reservation of heating networks in adjacent areas;
arrangement of backup pumping and pipeline connections;
installation of storage tanks.
When laying heating networks underground in non-passing channels and channelless installation, the amount of heat supply (%) to ensure the internal air temperature in heated rooms is not lower than 12 ° C during the repair and restoration period after a failure should be taken according to Table 2.
table 2
Diameter of heating network pipes, mm Heat supply restoration time, h Estimated outside air temperature for heating design tо, °C
Minus 10 minus 20 minus 30 minus 40 minus 50
Allowable reduction in heat supply, %, up to
300 15 32 50 60 59 64
400 18 41 56 65 63 68
500 22 49 63 70 69 73
600 26 52 68 75 73 77
700 29 59 70 76 75 78
800-1000 40 66 75 80 79 82
1200-1400 Up to 54 71 79 83 82 85
6.34 Sections of overhead laying up to 5 km in length may not be reserved, except for pipelines with a diameter of more than 1200 mm in areas with design air temperatures for heating design below minus 40 °C.
Reservation of heat supply through heating networks laid in tunnels and passage channels may not be provided.
6.35 For consumers of the first category, the installation of local backup heat sources (stationary or mobile) should be provided. It is allowed to provide for redundancy, ensuring in case of failures 100% heat supply from other heating networks.
6.36 To reserve heat supply for industrial enterprises, it is allowed to provide local heat sources.
Vitality
6.37 The minimum heat supply through heat pipes located in unheated rooms and outside, in hallways, staircases, attics, etc., must be sufficient to maintain the water temperature during the entire repair and restoration period after a failure at least 3 °C.
6.38 Projects must develop measures to ensure the survivability of elements of heat supply systems located in areas of possible exposure to negative temperatures, including:
organization of local circulation of network water in heating networks before and after the central heating substation;
drainage of network water from heat use systems at consumers, distribution heat networks, transit and main heat pipelines;
warming up and filling heating networks and heat utilization systems of consumers during and after completion of repair and restoration work;
checking the strength of heating network elements to ensure that the safety margin of equipment and compensating devices is sufficient;
ensuring the necessary load on ductless heating pipelines in case of possible flooding;
temporary use, if possible, of mobile heat sources.
Condensate collection and return
6.39 Systems for collecting and returning condensate to the heat source should be closed, and the excess pressure in the condensate collection tanks should be at least 0.005 MPa.
Open condensate collection and return systems may be provided when the amount of condensate returned is less than 10 t/h and the distance to the heat source is up to 0.5 km.
6.40 Condensate return from steam traps via a common network may be used if the difference in steam pressure in front of the steam traps is no more than 0.3 MPa.
When returning condensate by pumps, the number of pumps supplying condensate to the general network is not limited.
Parallel operation of pumps and condensate drains that discharge condensate from steam consumers to a common condensate network is not permitted.
6.41 Pressure condensate pipelines should be calculated based on the maximum hourly flow of condensate, based on the operating conditions of pipelines with a full cross-section in all modes of condensate return and protecting them from emptying during interruptions in the supply of condensate. The pressure in the condensate pipeline network must be assumed to be excessive in all modes.
Condensate pipelines from condensate traps to condensate collection tanks should be designed taking into account the formation of a steam-water mixture.
6.42 Specific pressure loss due to friction in condensate pipelines after pumps should be taken no more than 100 Pa/m with equivalent roughness inner surface condensate pipelines 0.001 m.
6.43 The capacity of condensate collection tanks installed in heating networks at consumer heating points must be at least 10-minute maximum condensate flow. The number of tanks for year-round operation should be at least two, with a capacity of 50% each. For seasonal operation and less than 3 months a year, as well as with a maximum condensate flow rate of up to 5 t/h, it is permissible to install one tank.
When monitoring the quality of condensate, the number of tanks should, as a rule, be at least three, with a capacity of each that provides time for analyzing the condensate according to all the necessary indicators, but not less than a 30-minute maximum flow of condensate.
6.44 The flow rate (performance) of pumps for pumping condensate should be determined by the maximum hourly flow rate of condensate.
The pump head should be determined by the amount of pressure loss in the condensate line, taking into account the height of the rise of condensate from the pump station to the collection tank and the amount of excess pressure in the collection tanks.
The pressure of pumps supplying condensate to the general network must be determined taking into account the conditions of their parallel operation in all modes of condensate return.
The number of pumps in each pumping station should be at least two, one of which is a reserve one.
6.45 Permanent and emergency discharges of condensate into rainwater or domestic sewage systems are allowed after it has been cooled to a temperature of 40 °C. When discharged into an industrial sewage system with constant wastewater, condensate may not be cooled.
6.46 Condensate returned from consumers to the heat source must meet the requirements of the rules for the technical operation of power plants and networks of the Ministry of Energy of Russia.
The temperature of the returned condensate for open and closed systems is not standardized.
6.47 Condensate collection and return systems should provide for the use of its heat for the enterprise’s own needs.
7 COOLANTS AND THEIR PARAMETERS
7.1 In centralized heat supply systems for heating, ventilation and hot water supply of residential, public and industrial buildings, as a rule, water should be used as a coolant.
The possibility of using water as a coolant for technological processes should also be checked.
The use of steam as a single coolant for enterprises for technological processes, heating, ventilation and hot water supply is allowed during a feasibility study.
7.2 The maximum design temperature of network water at the outlet of the heat source, in heating networks and heat receivers is established on the basis of technical and economic calculations.
If there is a hot water supply load in closed heat supply systems, the minimum temperature of the network water at the outlet of the heat source and in the heating networks must ensure the possibility of heating the water supplied to the hot water supply to a standardized level.
7.3 The temperature of network water returned to thermal power plants with combined heat and electricity generation is determined by technical and economic calculations. The temperature of network water returned to boiler rooms is not regulated.
7.4 When calculating graphs of network water temperatures in district heating systems, beginning and end heating season at the average daily outside air temperature the following are accepted:
8 °C in areas with a design outside air temperature for heating design up to minus 30 °C and an average design temperature internal air heated buildings 18 °C;
10 °C in areas with a design outside air temperature for heating design below minus 30 °C and an average design temperature of internal air in heated buildings of 20 °C.
The average design temperature of the internal air of heated industrial buildings is 16 °C.
7.5 If the heat receivers in the heating and ventilation systems do not have automatic individual devices for regulating the temperature inside the premises, the following should be used in heating networks to regulate the temperature of the coolant:
central quality for the heating load, for the combined load of heating, ventilation and hot water supply - by changing the coolant temperature at the heat source depending on the outside air temperature;
central qualitative and quantitative for the combined load of heating, ventilation and hot water supply - by regulating both the temperature and the flow of network water at the heat source.
Central qualitative and quantitative regulation at the heat source can be supplemented by group quantitative regulation at heating points, mainly during the transition period of the heating season, starting from the break point of the temperature curve, taking into account heating connection schemes, ventilation units and hot water supply, pressure fluctuations in the heating system, the presence and location of storage tanks, the heat storage capacity of buildings and structures.
7.6 With central qualitative and quantitative regulation of heat supply for heating water in hot water supply systems to consumers, the water temperature in the supply pipeline must be:
for closed heat supply systems - at least 70 °C;
for open heat supply systems - at least 60 °C.
With central qualitative and quantitative regulation for the combined load of heating, ventilation and hot water supply, the break point of the water temperature graph in the supply and return pipelines should be taken at the outside air temperature corresponding to the break point of the control graph for the heating load.
7.7 In heat supply systems, if the heat consumer in the heating and ventilation systems has individual devices for regulating the air temperature indoors by the amount of network water flowing through the receivers, central qualitative and quantitative regulation should be used, supplemented by group quantitative regulation at heating points in order to reduce fluctuations in hydraulic and thermal regimes in specific quarterly (microdistrict) systems within the limits ensuring the quality and stability of heat supply.
7.8 For separate water heating networks from one heat source to enterprises and residential areas, it is allowed to provide different schedules of coolant temperatures.
7.9 In public and industrial buildings for which it is possible to reduce the air temperature at night and during non-working hours, regulation of the temperature or coolant flow in heating points should be provided.
7.10 In residential and public buildings in the absence of heating devices thermostatic valves should be provided automatic regulation By temperature chart to maintain the building's average indoor air temperature.
7.11 It is not allowed to use temperature control schedules for heat supply for heating networks.
