4.1. Installation of pipelines must be performed by specialized installation organizations, while the installation technology should ensure high operational reliability of pipelines.
4.2. Details ,.Elements of pipelines (compensators, mud, insulated pipes, as well as pipelines and other products) must be manufactured centrally (in factory conditions, shops, workshops) in accordance with standards, specifications and project documentation.
4.3. In the laying of pipelines in the trench, the channel or overhead structures should be made according to the technology provided for by the project production project and excluding the occurrence of residual deformations in pipelines, a violation of the integrity of anti-corrosion coating and thermal insulation by applying the corresponding mounting devices, the correct placement of simultaneously working lifting machines and mechanisms.
The construction of mounting fixtures to the pipes should ensure the preservation of the coating and insulation of pipelines.
4.4. Pipeline laying within a panel support must be performed using the pipes of maximum supplied length. In this case, the ovar transverse seams of pipelines must, as a rule, are arranged symmetrically relative to the panel support.
4.5. The laying of pipes with a diameter of more than 100 mm with a longitudinal or spiral seam should be made with offset of these seams at least 100 mm. When laying pipes with a diameter of less than 100 mm, the seamless displacement should be at least three times the thickness of the pipe wall.
Longitudinal seams must be within the upper half of the circumference of the stacked pipes.
Cool and stamped pipeline taps are allowed to weld without a straight area.
Warding nozzles and taps into welds and bent items are not allowed.
4.6. When installing pipelines, movable supports and suspension should be shifted relative to the design position by the distance specified in the working drawings, to the side, the reverse movement of the pipeline in working condition.
In the absence of data in working drawings, movable supports and suspensions of horizontal pipelines should be displaced taking into account the correction to the outdoor air temperature during installation for the following values:
sliding supports and fastening elements of the suspension to the pipe - half the thermal elongation of the pipeline in the fastening site;
rollers of roller supports - on a quarter of thermal elongation.
4.7. Spring pendants When installing pipelines, it is necessary to delay in accordance with the working drawings.
During the performance of hydraulic tests of steam pipelines with a diameter of 400 mm and more, an unloading device should be installed in spring suspensions.
4.8. Pipe fittings should be mounted in a closed state. Flange and welded reinforcement compounds must be made without tension pipelines.
The deviation from the perpendicularity of the plane of the flange flange, welded to the pipe, relative to the axis of the pipe should not exceed 1% of the outer diameter of the flange, but be no more than 2 mm on the top of the flange.
4.9. Bellows (wavy) and gland compensators should be mounted assembled.
When underground heat network laying, the installation of compensators in the design position is allowed only after performing preliminary tests of pipelines for strength and tightness, backfill of the pipeless gasket pipelines, channels, cameras and panel supports.
4.10. Axial bellows and gland compensators should be installed on pipelines without a fracture of the axes of compensators and axes of pipelines.
Allowable deviations from the project position of the connecting pipes of compensators when they are installed and welding must be no more specified in technical conditions for the manufacture and supply of compensators.
4.11. When installing the bellows compensators, their twisting relative to the longitudinal axis and the sagging under the action of their own weight and weight of the adjoining pipelines are not allowed. The sling of compensators should be performed only by pipes.
4.12. The installation length of bellows and gland compensators should be accepted on working drawings, taking into account the correction on the outdoor air temperature during installation.
Stretching compensators to the mounting length should be made using fixtures provided for by the design of compensators, or tensioning mounting devices.
4.13. Stretching of the P-shaped compensator, followed after the installation of the pipeline, control the quality of welded joints (except for closure joints used for tension) and fixing the structures of fixed supports.
Stretching the compensator should be made by the amount specified in the working drawings, taking into account the correction to the outdoor temperature when welding the closure joints.
A stretching of the compensator must be performed simultaneously on both sides at the junctions located at a distance of at least 20 and no more than 40 diameters of the pipeline from the axis of the compensator symmetry, using the coupling devices, if other requirements are not substantiated by the project.
On the pipeline section between the joints used for the compensator stretching, should not be preliminary displacement of supports and suspension compared to the project (work project).
4.14. Immediately before assembling and welding pipes, it is necessary to make a visual inspection of each site on the absence of foreign objects and garbage in the pipeline.
4.15. The deviation of the liner of pipelines from the project is allowed by the value of ± 0.0005. In this case, the actual bias should be at least minimally permissible on SNIP II-G. 10-73 * (II-36-73 *).
Movable pipelines should be faced with the supporting surfaces of the designs without gap and skew.
4.16. By doing mounting work subject to acceptance with the preparation of acts of examination in the form shown in SNiP 3.01.01-85, the following types of hidden work: preparation of the surface of pipes and welded joints for anti-corrosion coating; Performing anticorrosive coating of pipes and welded joints.
The exercise of compensators should be drawn up in the form given in the required application 1.
4.17. The protection of thermal networks from electrochemical corrosion should be performed in accordance with the instructions for the protection of thermal networks from electrochemical corrosion approved by the USSR Ministry of Energy and the RSFSR Minzhilcomhoz and agreed with the USSR State Building.
Before installing compensators in the design position it is necessary to produce their conclusion by external inspection. As a rule, all compensators before the final connection to the pipeline must be pre-stretched or compressed by the value specified in the project, and are mounted on the pumping pipelines together with the spacer (or compressive) to the device, which is removed only after the final consolidation of the pipelines on fixed supports. The pre-stretching value of the compensator is indicated in the drawings.
Stretching is used for hot pipeline lines, and compression - for cold. The operation of stretching or compression is called cold natgom of the palporvode and is produced in order to reduce the voltage in the metal with thermal lengthening of the pipeline.
For stretching of compensators, regardless of the method of its execution, the act in which the construction lengths of compensators are indicated before and after stretching.
P-shaped incomes are usually installed in a horizontal position and only as an exception to verique or obliquely. When installing such compensators by windwise or obliquely at the bottom points from both sides of the compensators, it is necessary to place drainage fittings for the condensate removal, and at the top - air vent.
To provide normal work The P-shaped compensator is installed at least three moving supports (Fig. 5). Two supports are located on direct portions of the pipeline connected to the compensator (with the edge of the support should defend from the weld of at least 500mm), the third support is put under the back of the compensator, usually on a special column.
For pre-stretching of the P-shaped compensator, a screw fixture is used, consisting of two clamps, between which the screw and a strut with a tension nut is installed.
Before stretching, the length of the compensator is measured in a free state, and then the nuts turn it into the necessary value. The spacer device is installed parallel to the reference of the compensator. The junction that will stretch the compensator, indicate in the project. If there is no instructions, it is impossible to use a joint to avoid skewing for stretching. Directly adjacent to the compensator. For this purpose, you need to leave a gap in a nearby junction.
When lifting compensators should be captured in three points and in no case for the spacer device. Only after the tape of joints and the rigging, the compensator is disconnected from cargo-lifting tools. It is also necessary to check the reliability of the installation of the spacer device.
P-shaped compensators are installed in the design position using one or two cranes.
With the group arrangement of P-shaped compensators of parallel pipelines (one inside the other) and in some other cases, the preliminary stretch of compensators is replaced with the tension of the pipeline in the cold state. In this case, when installing compensators, the pipeline is collected in the usual way, but in one of the joints (welded or flanged), leave a gap equal to a given value of the compensator stretching.
Before stretching, you should make sure that all welded joints on this section of the pipeline are welded, fixed supports are finally fixed.
When installing compensators, without conclude, for the convenience of mounting the pipeline into the joint, scheduled for stretching, insert the nozzle length equal to the magnitude of the sentence, and grab the electric welding to both the edges of the pipeline. Sometimes ring rollers are filmed at the ends of the jackets and set the time clamps from the corners (Fig. 6). Through the holes in them, the elongated tie studs are passed and, tightening nuts, clamp the temporary plugging ring installed between the butt ends. After welding the joint, the clamps are removed.
The flange junction, left for stretching, in the same time (without constant pads) is tightened with elongated studs, installing them through one and leaving the holes for constant bolts. The diameter and number of studs for tensioning pipelines in the cold state is indicated in the project.
After installing the compensators in the design position, welding all joints (except one) and fixing the pipeline on all stationary supports on both sides of the compensator, the temporary laying ring is removed and the welding wrap is tightened by tightening nuts on extended studs. With a flange connection, a gasket provided for the project is installed before the final tightening. After tightening the flange compound with constant bolts, the elongated studs are removed, and constant bolts or studs are installed on their place.
When installing lenzov compensators, it is necessary to ensure that drainage joints (if available) are in the lower position, and the compensator guide boiler was welded in the direction of the product movement.
Lens compensators are recommended to be installed on pipes, nodes or blocks to a rise in the project position. The assembled node or block with lens compensators is necessary at the time of transportation, lifting and planting to protect against deformations and damage. For this, additional stiffness on compensators are used. After installing the nodes to support and securing, temporary hardness is removed.
When installing vertical sections of pipelines, it is necessary to take action, excluding the possibility of compression and defomation of compensators under the action of gravity of pipelines. It was done in parallel to compensators on the pipelines welded three staples that are cut at the end of the pipeline mounting.
Lens compensators stretch on half of their compensating ability.
The lens compensator is stretched when mounting after its welding or final connection on the flanges with a pipeline, as well as after the installation of all supports and suspensions of pipelines and fixing pipelines in fixed supports.
In this case, the compensator stretching is made due to tightening the compensator of the mounting joint, which specifically leave the appropriate additional clearance.
The compression of the compensator is carried out after the final connection with the pipeline, but before consolidation on fixed supports. To compress or stretching the lens compensator, a device consisting of two coupling clamps, fixed on the piperide on both sides of the compensator, and extended tie spills with nuts.
When installing several lens compensators on the line of the pipeline in the project, fixed supports must be provided for each compensator to eliminate the possibility of the deflection of the pipeline in compressed state, and ensure a more uniform deformation of all compensators installed on the pipeline, as the actual rigidity of all compensators can be unequal.
In wavy compensators before installing check building length; With the help of spacers and studs, the gap corresponds to the pre-stretching.
Axial compensators are mounted in such a sequence. First, they are welded with one end to the pipeline. Between the second end and the weldable tube check the gap equal to the pre-stretch magnitude, produce a stretching of the compensator using existing nuts on it with pins, weld the second end of the compensator to the pipeline, and then remove studs and nuts.
When installing hinged or universal compensators, they are welded to the pipeline with both ends in accordance with the montade scheme, without removing the bolts that fasten the cheeks of the joints and protected compensator from bending.
Silence compensators When installing, it is necessary to install strictly soono with a pipeline, without distinguishing to avoid hot portions and damage the compensator. The guide devices of pipelines in connecting places to the gland compensators should tightly crimp the pipes fit into them with rollers and centen the pipe in horizontal and vertical surfaces, without creating large longitudinal friction efforts.
Slip compensators are not stretching after installation, since when welding a compensator to the pipeline, it is moved to the value specified in the project and determined by distance between the risks applied on its body and glass. At the same time, there should be a gap in the case of lowering the temperature compared to the air temperature at the time of installation of the thrust rings on the nozzle and in the compensator housing. The minimum value of the gap with the length of the pipeline 100mm should be at an outdoor temperature at the time of the mounting below -5 o C - 30mm, from -5 ° C to +20 ° C - 50mm, over +20 o C - 60mm. When installing, it is necessary to envisage so that in the event of a breakdown of fixed supports, the moving part of the pipe did not break out of the compensator housing. In most cases, it is welded to a sliding portion of the pipe so that it does not interfere with the work of the compensator.
Compensation devices In thermal networks serve to eliminate (or significant reduction) efforts arising from thermal lengthening pipes. As a result, the voltages in the walls of pipes and force acting on the equipment and supporting structures are reduced.
Pipe lengthening as a result of thermal expansion of metal is determined by the formula
where and - Linear expansion coefficient, 1 / ° C; l.- Pipe length, m; T. - working temperature walls, 0 C; t. M - Mounting Temperature, 0 C.
Special devices are used to compensate for pipe lengthening - compensators, and also use pipe flexibility on the turns of the thermal networks (natural compensation).
On the principle of operation, compensators are divided into axial and radial. Axial compensators are installed on rectilinear areas Heat resistant, as they are intended to compensate for efforts arising only as a result of axial elongation. Radial compensators are installed on the heating network of any configuration, as they compensate for both axis and radial efforts. Natural compensation does not require the installation of special devices, so it must be used primarily.
In thermal networks, the axial compensators of the two types are used: the glands and lenzovy. In the gland compensators (Fig. 29.3), the temperature deformations of the pipes lead to the movement of the glass 1 inside the housing 5, between which the sealing package is placed 3. The packing between the stubborn ring 4 and the industry 2 is clamping with bolts 6.
Figure 19.3 Slip compensators
a - one-sided; B - Bilateral: 1 - Glass, 2 - Grundbuks, 3 - Ladder,
4 - Stubborn Ring, 5 - Case, 6 - Depending Bolts
Asbestos, directed cord or heat-resistant rubber apply as a seelnite packing. In the process of work, the packing is wears and loses its elasticity, so it is required periodic suspension (clamp) and replacement. For the possibility of carrying out these repairs, the gland compensators are placed in the chambers.
The connection of compensators with pipelines is carried out welding. When installing, it is necessary to leave the gap between the glass of the glass and the stubborn ring of the housing, which eliminates the possibility of stretching efforts in pipelines in the event of a decrease in temperature below the installation temperature, as well as to carefully unscrew the axial line to avoid breakdown and hot glass in the housing.
Slip compensators are manufactured by one-sided and two-sided (see Fig. 19.3, a and b). Bilateral applied usually to reduce the number of cameras, since in the middle of them a fixed support is installed, separating pipes of pipes whose elongation is compensated for by each of the sides of the compensator.
The main advantages of the gland compensators are small dimensions (compactness) and low hydraulic resistance, as a result of which they found wide use in thermal networks, especially with underground gasket. In this case, they are installed at d y \u003d 100 mm and more, with an overnight gasket - with D y \u003d 300 mm and more.
In lens compensators (Fig. 19.4), with temperature lengthening of pipes, there is a compression of special elastic lenses (waves). It provides complete tightness in the system and no compensator service is required.
Made lenses from sheet steel or stamped semi-linsel with a thick wall of 2.5 to 4 mm gas welding. To reduce hydraulic resistances inside the compensator along the waves inserted smooth trumpet (shirt).
Lens compensators have a relatively small compensating ability and a large axial response. In this regard, to compensate for temperature deformations of pipelines of thermal networks, a large number of waves are set or produced pre-stretching. They usually apply to about 0.5 MPa to pressures, since at high pressures, there may be swelling of the waves, and increasing the rigidity of the waves by increasing the thickness of the walls leads to a decrease in their compensating ability and an increase in the axial reaction.
Ryas. 19.4. Lenzaya threewall compensator
Natural compensation Temperature deformations occurs as a result of the bending of pipelines. Bottles (turns) increase the flexibility of the pipeline and increase its compensating ability.
With natural compensation on the rotations of the track, temperature deformations of pipelines lead to transverse displacements of the plots (Fig. 19.5). The displacement value depends on the location of the stationary supports: the larger the length of the site, the greater its extension. This requires an increase in the width of the channels and makes it difficult to work with mobile supports, and also does not make it possible to apply a modern chapeless gasket on the rotations of the track. Maximum bending voltages arise from a fixed support of a short plot, as it shifts to a large amount.
Fig. 19.5 Scheme of operation of the G-shaped heat pipeline
and - with the same shoulder lengths; b. - at different lengths of the shoulder
TO radial compensatorsapplicable in thermal networks flexible and wavy Hinged type. In flexible compensators, the temperature deformations of pipelines are eliminated using bends and twists of specially bent or cooked areas of pipes of various configurations: P-and S-shaped, line-shaped, omeh-shaped, etc. The most dissemination in practice due to ease of manufacture ,and). Their compensating ability is determined by the sum of deformations along the axis of each of the pipelines of the Δ l.= ∆l./2+∆l./ 2. At the same time, the maximum bending stresses occur in the segment - the back of the compensator, most distant from the axis of the pipeline. The latter, bending, shifts the value of y, to which it is necessary to increase and the dimensions of the compensatory niche.
Fig. 19.6 WORK SCHEME OF THE PHACTED COMMATOR
and - without prior stretching; b. - with a preliminary stretching
To increase the compensation ability of the compensator or reduce the amount of displacement, it is set with a preliminary (assembly) stretching (Fig. 19.6, b.). At the same time, the backrest of the compensator is in a non-working condition bent into and experiencing bending stresses. When lengthening the pipes, the compensator comes first in an unbalanced state, and then the back is bent outward and bending the reverse sign voltages arise. If in extreme positions, i.e., at a pretrant and in working condition, maximum allowable voltages are achieved, the compensatory ability of the compensator increases twice as compared to the compensator without prior stretching. In the case of compensation of the same temperature deformation in a pre-stretch compensator, the backrest will not be displaced and, therefore, the dimensions of the compensatory niche will decrease. The work of flexible compensators of other configurations occurs in about the same way.
Suspension
Pipeline suspension (Figure 19.7) are performed using 3, connected directly with pipes 4 (Fig. 19.7, and) or with traverse 7 to which on the clamps 6 suspended pipe (Fig. 19.7, b.), as well as through spring blocks 8 (Fig. 19.7, in). Hinged compounds 2 ensure the movement of pipelines. The guide staps of 9 spring blocks welded to the support plates 10 allow you to exclude the transverse deflection of the springs. The suspension tension is provided by nuts.
Fig. 19.7 Pendants:
and - traction; b. - clad; in - spring; 1 - reference beam; 2, 5 - hinge; 3 - traction;
4 - pipe; 6 - clamp; 7 - Traverse; 8 - spring suspension; 9 - glasses; 10 - Plates
3.4 Methods for insulation of thermal networks.
Mastic isolation
Mastic insulation applies only during the repair of thermal networks, laid or indoors, or in the passing channels.
The insulation of mastic is superimposed by layers of 10-15 mm on a hot pipeline as the preceding layers dry out. Mastic insulation cannot be performed by industrial methods. Therefore, the specified insulating structure for new pipelines is not applicable.
For mastic insulation, it is applied to a sign, asbatereled and volcanic. The thickness of the thermal insulation layer is determined on the basis of technical calculations or for applicable standards.
The temperature on the surface of the insulating structure of pipelines in the passage channels and cameras should not be above 60 ° C.
The durability of the heat insulating structure depends on the mode of operation of heat lines.
Block insulation
Collected-block insulation of preformed products (bricks, blocks, peat slabs, etc.) are arranged hot and cold surfaces. Products with hanging seams in the rows are laid on a tagged bench of asbosurite, the coefficient of thermal conductivity of which is close to the coefficient of insulation itself; The submarine has a minimal shrinkage and good mechanical strength. Products from peat (peatoplittes) and plugs are placed on a bitumen or Idritol glue.
Flat and curvilinear surfaces, heat-insulating products are fixed with steel studs, in advance in a checkerboard with an interval of 250 mm. If the installation of the studs is not possible, the products are fixed as a mastic insulation. On vertical surfaces with a height of more than 4 m, the discharge belt belt from strip steel is installed.
In the process of installing the product, it is customized to each other, lapse and drill holes for studs. Mounted elements are fixed with studs or wire cleans.
With multi-layer insulation, each subsequent layer is laid after alignment and fixing the previous one with the overlapping of longitudinal and transverse seams. The last layer fixed with a frame or metal mesh is equalized with mastic under the rail and then apply a stucco with a thickness of 10 mm. Casting and painting are performed after complete drying of plaster.
The advantages of prefabricated insulation are industriality, standard and collection, high mechanical strength, the possibility of facing hot and cold surfaces. Disadvantages - Metorticness and complexity of installation.
Beep insulation
Horizontal and vertical surfaces building structures Apply falling insulation.
In the device of thermal insulation along horizontal surfaces (underacted roofs, overlap over the basement), the insulating material serves predominantly clay or perlite.
On vertical surfaces make bent insulation from glass or mineral wool, diatomic crumb, pelite sand, etc. To do this, in parallel, the insulated surface is protected by bricks, blocks or grids and in the resulting space is falling asleep (or stuffed) insulating material. With the mesh fencing, the mesh is fixed to a stiletto stiletto set in advance in checkered manifests. They stretch the metal woven mesh with a cell 15x15 mm. In the resulting space layerly at the bottom up with light ram, bulk material falls asleep.
After the end of the backfill, the entire surface of the mesh is covered with a protective layer of plaster.
Filing thermal insulation is quite effective and simple in the device. However, it is not resistant against vibration and is characterized by small mechanical strength.
Cast isolation
As insulating material used mainly foam concrete, which is prepared by mixing cement mortar With Penoza in a special stirrer. Heat insulating layer Located by two methods: conventional methods of concreting space between the formwork and insulated surface or torture.
At the first method A formwork is set to the vertical insulated surface in parallel. In the resulting space, the heat-insulating composition is placed by rows, moving with a wooden ironing. The laid layer is moisturized and covered with mats or agencies to ensure normal foam concrete conditions.
Togotrovita method Lithuania isolation is applied by mesh reinforcement from 3-5 mm wire with cells of 100-100 mm. The applied talker layer is tightly adjacent to the insulated surface, it does not have cracks, shells and other defects. Togotractions are produced at a temperature not lower than 10 ° C.
Cast thermal insulation is characterized by the simplicity of the device, monolithium, high mechanical strength. The disadvantages of cast heat insulation are a large duration of the device and the impossibility of producing work at low temperatures.
Installation of thermal networks, which should be carried out by a flow method, includes Earth, assembly and welding, stone, concrete, reinforced concrete, insulating, crimping, carpentry and other works.
With a properly organized streaming method, the construction of work is performed in a specific technological sequence. The flow is organized with such a calculation to manage the most economically to dispose of the forces and means, perform a large amount of work in a short time, with low costs and with high quality Construction.
Thermal networks in cities and other settlements are paved in specially designated for construction engineering facilities Stripes parallel to the red lines of streets, roads and travel outside the roadway and stripes of green plantings. When justifying, laying networks under the roadway and sidewalks.
For thermal networks, underground gasket is mainly provided, less often - overhead (in the territories of enterprises, outside the city, at a high level groundwater, in the districts of permafrost and other cases when an underground gasket is impossible or inexpedient).
With underground laying, pipelines of thermal networks (heat pipelines) are laid in channels - special building structures that enclosing pipelines, or beless. Channels can be passing and disadvantaged. Depending on the underground gasket, the heat networks are allowed to lay thermal networks together with others. engineering networks (plumbing, communication cables, power cables, pressure sewage).
With an overhead (open) laying, heat pipes are paved on brackets along the walls of buildings, on concrete, reinforced concrete and metal supports. When moving heat lines through railways And water barriers use bridge designs. Heat pipelines deployed under the river or channel channel, on the slopes and the bottom of the ravine, bended in accordance with the terrain. Such structures are called Dukeers. When laying under the line of the river, the heat pipes enter into steel pipes (case). Against the tubes are held by cargo. Thus, other types of underground networks are also built (water supply, gas pipeline and sewage) when crossing rivers, ravines and other similar obstacles.
Assembly steel pipes Large diameters in links with a pipe-layer crane. Prior to the start of the work of the pipe assembly in the links, pipes will be captured and lay them on a predetermined axis; Clean the ends of the pipes from dirt and straighten the deformed edges.
Steel pipes are collected in the links in such a sequence: they are placed and calm down, laid with a pipe layer pipe on a liter; Clean and prepare the edges of pipes to welding; Center the joints with a centralist, maintaining pipes with a pipe-waste crane during an electric welding junction; weld the joints of the pipes with turning the links; Remove the ice and install the assembled link on the inventory lining.
Laying and littering. Triplayers, stretching, roulette along the axis of the layout of the links, placed on it places of laying of a layer. Then they bring the ice and lay them on marking, while the middle of the lay should coincide with the layout axis. At the ends of the extreme liter, four metal pins are clogged and stretched between the extreme litters of the twine at the level of the top of the layer. Focusing on this level, set intermediate liters, cutting or hacking up the soil under them.
Laying pipes on the ice. Having placed the middle of the pipe using a roulette, the crane-pipe layer is installed so that its arrow is above the center of gravity of the pipe. The pipe is raining, and the crane driver lifts it by 20-30 cm. After making sure the reliability and correctness of the trim, the crane driver lifts the pipe to the height of 1 m and on the pipelayer laying the pipe on the ice. Triplayers, standing at both ends of the pipe, hold it from the turn.
Cleaning and preparation of pipe edges to welding. When loading, transporting or unloading at the ends of pipes, ellipsence can be formed, dents, etc., if necessary, the ends of the pipes should be strained. The curvature of the ends are straightened using screw jacks or manually blowing sledgehamming with pre-heating of the pipe at the point of editing.
In the event that the deformed ends can not be fixed, they are cut into a gas cutting with subsequent stripping edges.
Using chisels and hammers, pipe layers clean the edges of the pipes from dirt and sleep. Electroshlyphic machines, files, reversible angular pneumatic brushes, cleaned the edges to a metal gloss for a length of at least 10 mm outside l from the inside.
Centering the joint and maintenance of pipes when the junction sticks. The machinist sets the crane-pipe-layer opposite the middle of the pipe and lowers the sling towel. The pipelayer rows the pipe and gives the command to lift it on 0.5 m and move to the place of docking. After moving the pipe, the workers put it on the ice, visually centered the joint, rhythte and fix the pipe on the liter with wooden stoles. Then the centramore is installed at the joint and the knob is fixed by the junction.
The electric welder, checking the universal pattern the magnitude of the gap between the ends of the jackets of the pipes throughout the circumference and make sure that the size of the clearance corresponds to the norm, grabs the welding of the joint.
If, when checking the template, the size of the gap between the ends of the pipes does not meet the regulatory requirements, the pipelayers weaken the central, the driver of the boom by movement of the boom changes the size of the gap, while the pipe-layers help him with lows. After receiving the required amount of the gap, the position of the pipe is finally fixed with wooden wedges, the central arm is tightened to the failure and then the junction sticks with welding. After tuning the joint, the pipelayers remove the centralist.
Turning the link when welding pipes. After applying a seam on a quarter of the circle of the pipe on each side of the pipe layers turn the link, fastening it with wooden wedges on the lept away at the junction.
Installation and welding of mobile supports. The movable supports perceive the load on the weight of the heat resistant, in addition, ensure the movement of the pipeline in the axial direction occurring due to the change in its length when the temperature changes. Movable factory manufacturers are sliding, stool, roller, suspended. From the listed designs of mobile supports most widely used sliding supports.
Sliding supports can be low and high, normal length and shortened. The type of support is chosen depending on the thickness of the heat insulation and the distance between the supports. Low (lining) and high supports protect pipes from abrasion when displacements of thermal conductors. In addition, high supports protect thermal insulation from contact with the base of the channel.
Sliding supports are installed on supporting stones with some displacement towards fixed support. At launch hot water The pipeline is heated and somewhat extends; The sliding support is welded to the pipeline, will shift towards the compensator and will take the working position on the support stone. If you set the sliding support on the supporting stone without a mounting displacement, then it can get away from the supporting stone during the operation of the heat pipe. The sliding support moves along a metal lining concreted into the supporting stone and protruding over its upper plane.
The distance between the sliding supports depends on the distance between the supporting stones, which in turn is taken depending on the conditional passage of the pipes.
In places of welded joints, welded sliding supports are not allowed. The support must be welded without lateral displacements in relation to the vertical axis of the pipeline.
Having placed the installation site of the supports on the pipes, they are customized at the place, stick and weld. Sliding supports are welded before pressing the pipeline, since on the pipeline, the hydraulic or pneumatic test of pa density and strength is not allowed to produce welding.
Installation of salon compensators. Slip compensators perceive the axial temperature deformations of the pipelines of thermal networks and thereby protect the pipeline and reinforcement from the destructive stresses.
Slip compensators produce one-sided and bilateral. The compensating ability of the bilateral compensator is twice as a maxilated compensating ability.
The compensator connects to the main pipeline on welding.
The compensator is installed in the extended position on the full length, which depends on the compensating ability, with the gap between the stubborn ring of the housing and the safety ring on the glass. The gap compensates for the change in the length of the pipeline when the temperature of the pipes decreases after installing the compensator (due to the decrease in the outdoor air temperature).
When installing the compensator, it is necessary to thoroughly fill the gland seals (gland), since the replacement of packages during operation leads to a stop of the operation of thermal networks. The junction of the oscillation rings must be shifted one relative to the other, the seams of gland compensators must be smooth, and the crater is welded.
Installing flanges. Pipe fittings and linear equipment are connected to the pipeline on the welding or on the flanges, tightened by bolts, studs and nuts. With conditional internal pressure in the pipeline up to 40 kgf / cm2 (4 MPa), bolts are used, at 40 kgf / cm2 and more studs. The density of the flutter compound depends on the accuracy of the surface treatment of the flanges, the quality of the bolts and the uniformity of their tightening. Flanges must be parallel to one another.
Flanges are welded perpendicular to axes of nozzles. The blocking should not exceed 1 mm per 100 mM of the outer diameter of the flange (but not more than 3 mm). After a fit of the flanges, two or three bolts are installed on the site, then the remaining bolts are mounted, screw the nuts and the flange connection is delayed. So that there is no skew, the nuts are tightened gradually in a crucible order.
The diameter of the bolts must correspond to the diameter of the holes of the connected flanges. The heads of the bolts are located on one side of the connection. The flange compound bolts can perform above the nut less than three threads of the thread and no more than half the diameter of the bolt. It is necessary that the internal laying diameter corresponds to internal diameter Pipes with a tolerance of 3 mm, and its outer diameter should be at least a diameter of the connecting protrusion and no more diameter of the circle tangent to bolts.
For a more dense fixing of the gasket, sometimes on one of the connected flanges make the protrusion, on the other - the depression. The protrusion is included in the depression, and thus the gasket is securely attached between the flanges. For the same purpose, concentrically arranged deepening - risks are applied to the flanges mirror.
When installing pipe fittings, for example, valves cannot be allowed to excessive flanges bolts, as the density and strength of the flange compound decreases.
Stretching P-shaped compensators. To increase the compensation ability, P-shaped compensators stretch. The magnitude of the stretch, indicated in the project, should be equal to half the elongation of the compensated area. The compensator is stretched only after fixed supports will be installed from the two sides; Thus, when stretching the compensator, the pipeline remains fixed in places of its welding to supports. Only one junction remains intact - in the place of the compensator stretching.
The compensator stretches with the help of corner screeds, jacks, tale, etc.. At an equal distance in the circumference of the pipe of the P-shaped compensator, four plates are welded, as well as four plates - to a previously laid tube. The distance between the plates should not exceed the length of the tie bolts. Coupling bolts are inserted into the hole of the plates and, screws the nuts, stretch the compensator, bringing the edge of the pipes to the clearance required for welding. The joints stick to the electric welding, the plates are cut by a gas cutter and the joint is welded.
Installation of nodes of thermal networks. Pipe layer with steel brush or file cleans the ends of the nozzles and pipes from rust and dirt. Then, using a lifting crane, the node is supplied to the heat chamber, where it is installed in the design position. After that, it is customized and cut the edges and center the joints with an external central. The joints are welded, the centralist is transferred to the following works.
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SNiP 3.05.03-85
________________
Registered by Rosstandard as SP 74.13330.2011. -
Note database manufacturer.
BUILDING REGULATIONS
HEATING NETWORK
Date of introduction 1986-07-01
Developed by the Institute of Organizhergostroy Midnergo of the USSR (L. Ya. Mukomel - Head of the topic; Cand. Tech. Sciences S. S. Jacobson).
Made by the USSR Ministry of Energy.
Prepared for the approval of the head of the USSR (N. A. Shishov).
Approved by the Decree State Committee USSR on the construction of October 31, 1985 N 178.
With the introduction of SNIP on 3.05.03-85 "Heat Networks" loses force SNIP III-30-74 "Water supply, sewage and heat supply. External networks and structures".
Coordinated with Gosgorthnadzor of the USSR on April 15, 1985
These rules apply to the construction of new, expansion and reconstruction of existing thermal networks,
transporting hot water temperature T | 200 hail and pressure | 2.5 MPa (25 kgf / sq. CM) |
from the source of thermal energy to heat consumers (buildings, structures).
1. GENERAL PROVISIONS
1. GENERAL PROVISIONS
1.1. During the construction of new, expanding and reconstruction of existing thermal networks, in addition to the requirements of work drawings, work projects (PPR) and these rules, the requirements should also be observed. Snip 3.01.01-85, SNiP 3.01.03-84, SNIP III-4-80 and standards .
1.2. Work on the manufacture and installation of pipelines, which apply to the requirements of the rules of the device and the safe operation of the pair and hot water pipelines of the USSR State Migorekhnadzor (in the future, the USSR State University Rules) must be carried out in accordance with the specified rules and requirements of these standards and rules.
1.3. Finished construction heating network It should be commissioned in accordance with the requirements of SNiP III-3-81.
2. Earthwork
2.1. Earthworks and work on the base device must be carried out in accordance with the requirements of SNIP III-8-76, SNIP 3.02.01-83, CH 536-81 and this section.
2.2. The smallest width of the trench bottom with a volatile tubing of pipes should be equal to the distance between the outer lateral edges of the insulation of the extreme pipelines of thermal networks (associated drainage) with the addition to each side for pipelines with a conditional diameter
the width of the pit in the trench for welding and insulation of the joints of pipes with a volatile laying of pipelines should be taken equal to the distance between the outer lateral glands of insulation of extreme pipelines with the addition of 0.6 m per side, the length of the pitfall is 1.0 m and the depth of the lower edge of the pipeline insulation - 0.7 m, if other requirements are not substantiated by work drawings.
2.3. The smallest width of the trench bottom with a channel laying of thermal networks should be equal to the channel width, taking into account the formwork (on monolithic sites), waterproofing, associated drainage and waterproof devices, trench mounting designs with adding 0.2 m. In this case, the width of the trench must be at least 1.0 m.
If you need to work between the outer edges of the channel design and walls or slopes of the trench, the width between the outer edges of the channel design and walls or slopes of the trench in the light should be at least: 0.70 m - for trenches with vertical walls and 0.30 m - for trenches With slopes.
2.4. The backflow of trenches with a non-channel and channel laying of pipelines should be performed after conducting preliminary tests of pipelines for strength and tightness, full of insulating and construction and installation work.
Reverse backfill must be produced in the specified technological sequence:
skipping sinuses between the pipelines of the infantal gasket and the base;
simultaneous uniform folding of the sinuses between the walls of the trenches and pipelines in the volatile gasket, as well as between the walls of the trench and the channel, the chambers with a channel gasket at a height of at least 0.20 m above the pipelines, channels, cameras;
flipping trenches to design marks.
Reverse filling of trenches (butt), which are not transmitted to additional external loads (except for their own weight of the soil), as well as tranches (pita) in areas of intersection with existing underground communications, streets, roads, roads, squares and other structures settlements and industrial sites should be performed in accordance with the requirements of SNiP III-8-76.
2.5. After turning off the temporary water supply devices, the channels and cameras should be visually examined on the absence of groundwater in them.
3. Construction structures and installation of building structures
3.1. Manufacture of construction and installation of construction structures should be performed in accordance with the requirements of this section and requirements:
SNIP III-15-76 - when constructing monolithic concrete and reinforced concrete structures foundations, supports for pipelines, cameras and other structures, as well as when the joints are deployed;
SNIP III-16-80 - when installing concrete and reinforced concrete structures;
SNIP III-18-75 - when installing metal structures supports, spans under pipelines and other structures;
SNIP III-20-74 - when waterproofing channels (cameras) and other building structures (structures);
Snip III-23-76 - when protecting building structures from corrosion.
3.2. The outer surfaces of the channels and cameras supplied on the track should be coated with a coating or inlet waterproofing in accordance with working drawings.
The installation of channel elements (cameras) to the design position should be performed in the technological sequence, linked to the project work on the installation and preliminary testing of pipelines for strength and tightness.
Supporting pillows for sliding supports of pipelines must be installed at distances stipulated in SNiP II-g. 10-73 * (II-36-73 *).
3.3. Monolithic fixed panel supports must be performed after installing pipelines on the panel of the panel support.
3.4. In places input pipelines of the infantal gasket in the canals, cameras and buildings (facilities) cases of passing salons, it is necessary to wear on the pipes during their installation.
In the inputs of the underground gasket pipelines, the buildings must be performed (in accordance with working drawings) of the device, preventing the penetration of gas into the building.
3.5. Before installing the upper trays (plates), the channels must be cleaned of soil, garbage and snow.
3.6. The deviation of the bottom of the bottom of the heat network channel and the drainage pipelines from the project is allowed by +/- 0.0005, while the actual bias should be at least minimally permissible on SNIP II-G. 10-73 * (II-36-73 *).
The deviation of the installation parameters of other building structures from the project should comply with the requirements of SNiP III-15-76, SNIP III-16-80 and SNiP III-18-75.
3.7. The project for organizing construction and project production project should be provided for the advanced construction of drainage pumping and water production devices in accordance with working drawings.
3.8. Before laying in a trench, drainage pipes should be examined and cleaned of soil and garbage.
3.9. The layer-by-layer filtering spray of drainage pipelines (except for pipe filters) gravel and sand must be performed using inventory dividing forms.
3.10. The straightness of the drainage pipelines between adjacent wells should be checked by the "on the light" inspection using the mirror before and after the trench frowning. Reflected in the mirror Circle of the pipe must be of the right form. The permissible value of the deviation from the horizontal circle should be no more than 0.25 diameter of the pipe, but not more than 50 mm in each direction.
Deviation OT proper form Vertical circles are not allowed.
4. Installation of pipelines
4.1. Installation of pipelines must be performed by specialized installation organizations, while the installation technology should ensure high operational reliability of pipelines.
4.2. Details, pipeline elements (compensators, mud, insulated pipes, as well as pipelines and other products) must be manufactured centrally (in factory conditions, shops, workshops) in accordance with standards, specifications and project documentation.
4.3. Stacking pipelines in a trench, a channel or overhead designs should be made according to the technology provided for in the project manufacturing project and excluding the occurrence of residual deformations in pipelines, a violation of the integrity of anti-corrosion coating and thermal insulation by applying the appropriate mounting devices, the correct placement of the simultaneously working lifting machines and mechanisms.
The construction of mounting fixtures to the pipes should ensure the preservation of the coating and insulation of pipelines.
4.4. Pipeline laying within a panel support must be performed using the pipes of maximum supplied length. At the same time, welded transverse seams of pipelines should, as a rule, are arranged symmetrically relative to the panel support.
4.5. The laying of pipes with a diameter of more than 100 mm with a longitudinal or spiral seam should be made with offset of these seams at least 100 mm. When laying pipes with a diameter of less than 100 mm, the seamless displacement should be at least three times the thickness of the pipe wall.
Longitudinal seams must be within the upper half of the circumference of the stacked pipes.
Cool and stamped pipeline taps are allowed to weld without a straight area.
Warding nozzles and taps into welds and bent items are not allowed.
4.6. When installing pipelines, movable supports and suspension should be shifted relative to the design position by the distance specified in the working drawings, to the side, the reverse movement of the pipeline in working condition.
In the absence of data in working drawings, movable supports and suspensions of horizontal pipelines should be displaced taking into account the correction to the outdoor air temperature during installation for the following values:
sliding supports and fastening elements of the suspension to the pipe - half the thermal elongation of the pipeline in the fastening site;
rollers of roller supports - on a quarter of thermal elongation.
4.7. Spring pendants When installing pipelines, it is necessary to delay in accordance with the working drawings.
During the performance of hydraulic tests of steam pipelines with a diameter of 400 mm and more, an unloading device should be installed in spring suspensions.
4.8. Pipe fittings should be mounted in a closed state. Flange and welded reinforcement compounds must be made without tension pipelines.
The deviation from the perpendicularity of the plane of the flange flange, welded to the pipe, relative to the axis of the pipe should not exceed 1% of the outer diameter of the flange, but be no more than 2 mm on the top of the flange.
4.9. Bellows (wavy) and gland compensators should be mounted assembled.
When underground heat network laying, the installation of compensators in the design position is allowed only after performing preliminary tests of pipelines for strength and tightness, backfill of the pipeless gasket pipelines, channels, cameras and panel supports.
4.10. Axial bellows and gland compensators should be installed on pipelines without a fracture of the axes of compensators and axes of pipelines.
The allowable deviations from the design position of the connecting pipes of compensators during their installation and welding should be no more specified in the technical specifications for the manufacture and supply of compensators.
4.11. When installing the bellows compensators, their twisting relative to the longitudinal axis and the sagging under the action of their own weight and weight of the adjoining pipelines are not allowed. The sling of compensators should be performed only by pipes.
4.12. The installation length of bellows and gland compensators should be accepted on working drawings, taking into account the correction on the outdoor air temperature during installation.
Stretching compensators to the mounting length should be made using fixtures provided for by the design of compensators, or tensioning mounting devices.
4.13. The stretching of the P-shaped compensator should be performed after the installation of the pipeline, control the quality of welded joints (except for closing joints used for tension) and fixing the structures of fixed supports.
Stretching the compensator should be made by the amount specified in the working drawings, taking into account the correction to the outdoor temperature when welding the closure joints.
A stretching of the compensator must be performed simultaneously on both sides at the junctions located at a distance of at least 20 and no more than 40 diameters of the pipeline from the axis of the compensator symmetry, using the coupling devices, if other requirements are not substantiated by the project.
On the pipeline section between the joints used for the compensator stretching, should not be preliminary displacement of supports and suspension compared to the project (work project).
4.14. Immediately before assembling and welding pipes, it is necessary to make a visual inspection of each site on the absence of foreign objects and garbage in the pipeline.
4.15. The deviation of the liner of pipelines from the project is allowed by +/- 0.0005. In this case, the actual bias should be at least minimally permissible on SNIP II-G. 10-73 * (II-36-73 *).
Movable pipelines should be faced with the supporting surfaces of the designs without gap and skew.
4.16. When performing installation works are subject to acceptance with the compilation of certification acts in the form shown in SNiP 3.01.01-85, the following types of hidden work: Preparation of the surface of pipes and welded joints for anti-corrosion coating; Performing anticorrosive coating of pipes and welded joints.
The exercise of compensators should be drawn up in the form given in the required application 1.
4.17. The protection of thermal networks from electrochemical corrosion should be performed in accordance with the instructions for the protection of thermal networks from electrochemical corrosion approved by the USSR Ministry of Energy and the RSFSR Minzhilcomhoz and agreed with the USSR State Building.
5. Assembly, welding and quality control of welded connections
5.1. Welders are allowed to tack and welding pipelines in the presence of documents for the right to produce welding work in accordance with the rules of welders approved by the USSR State University.
5.2. Before adequate to work on welding joints of pipelines, the welder must weld the tolerance in production conditions in the following cases:
when breaking in work more than 6 months;
when welding pipelines with a change of steel group, welding materials, technology or welding equipment.
On pipes with a diameter of 529 mm and is more allowed to weld half the perimeter of the tolerance; At the same time, if the tolerance is vertical non-reflective, welding must be subjected to ceiling and vertical seam sections.
The tolerance should be the same type with production (the definition of the same type of joint is given in the rules of certification of welders of the USSR Gosgortkhnadzor).
The tolerable bog is subject to the types of control that production welded connections are subjected to in accordance with the requirements of this section.
Manufacturing jobs
5.3. The welder is obliged to knock out or removing the stamp at a distance of 30-50 mm from the joint from the side available for inspection.
5.4. Before assembling and welding, it is necessary to remove the end plugs, clean the edge metal and adjacent to them the inner and outer surface surface to the width of at least 10 mm.
5.5. Welding methods, as well as types, structural elements and the size of welded joints of steel pipelines must correspond to GOST 16037-80.
5.6. The joints of the pipelines with a diameter of 920 mm and more, welded without the remaining lining ring, must be made with the welder of the seam root inside the pipe. When performing welding inside the pipeline, the responsible performer must be issued an outfit for the production of work of increased danger. The procedure for issuing and the form of outfit must comply with the requirements of SNiP III-4-80.
5.7. When assembling and welding the joints of the pipes without a lining ring, the displacement of the edges inside the pipe should not exceed:
for pipelines, which the requirements of the USSR Gosgortkhnodzor rules are subject to, - in accordance with these requirements;
for other pipelines - 20% of the thickness of the pipe wall, but not more than 3 mm.
In the joints of pipes collected and welded on the remaining lining ring, the clearance between the ring and the inner surface of the pipe should not exceed 1 mm.
5.8. Assembling joints of pipes for welding should be made using mounting centering devices.
Edit smooth dents at the ends of pipes for pipelines, which do not apply to the requirements of the USSR State University Rules, is allowed if their depth does not exceed 3.5% of the pipe diameter. Plots of pipes with dents of greater depth or having holes should be cut. The ends of the pipes with fears or scams of the champers depth from 5 to 10 mm should be cut or fix the surfacing.
5.9. When assembling a joint using taps, their number should be for pipes with a diameter of up to 100 mm - 1 - 2, with a diameter of over 100 to 426 mm - 3 - 4. For pipes with a diameter of over 426 mm, the tapes should be placed every 300-400 mm around the circle.
Tapes must be located evenly around the perimeter of the junction. The length of one tack for pipes with a diameter of up to 100 mm - 10 - 20 mm, a diameter of more than 100 to 426 mm - 20 - 40, with a diameter of over 426 mm - 30 - 40 mm. The height of the tape should be with the wall thickness of s to 10 mm - (0.6 - 0.7) s, but not less than 3 mm, with a greater thickness of the wall - 5 - 8 mm.
The electrodes or welding wire used for tapes should be the same grades as for the welding of the main seam.
5.10. Welding pipelines that do not apply to the requirements of the USSR Gosgorthenzor Rules are allowed to produce without heating the joints of the joints:
at an outdoor temperature to minus 20 degrees - when using carbon steel pipes with a carbon content of not more than 0.24% (regardless of the thickness of the pipe wall), as well as pipes from low-alloyed steel with a wall thickness of no more than 10 mm;
at the outdoor temperature to minus 10 degrees - when using pipes from carbon steel with a carbon content of more than 0.24%, as well as pipes from low-alloyed steel with a wall thickness of over 10 mm.
At a lower outer air temperature, welding should be made in special cabins, in which the air temperature in the area of \u200b\u200bthe junctions must be maintained at no lower than the specified one.
It is allowed to produce welding work in the open air when heating the welded ends of pipes at a length of at least 200 mm from the joint to a temperature not lower than 200 hails. After the end of the welding, a gradual decrease in the joint temperature should be provided and the pipe zone adjacent to it by covering them asbestos or the use of another method.
Welding (at a negative temperature) of pipelines to which the requirements of the USSR Gosgortkhnodzor Rules are subject to the requirements of the specified rules.
When rain, wind and snowfall, welding works can be performed only subject to the protection of the welder and welding location.
5.11. Welding galvanized pipes should be performed in accordance with SNiP 3.05.01-85.
5.12. Before welding pipelines, each batch of welding materials (electrodes, welding wires, fluxes, protective gases) and pipes must be subjected to input control:
for a certificate with verification of the full data given in it and their compliance with the requirements of state standards or technical conditions;
for the presence on each box or other packaging the corresponding label or tag with the verification of the data given on it;
in the absence of damage (damage) of packaging or materials themselves. If damage is detected, the question of the possibility of using these welding materials should be resolved by a welding organization;
on the technological properties of electrodes in accordance with GOST 9466-75 or departmental regulatory documentsapproved in accordance with SNiP 1.01.02-83.
5.13. When applying the main seam, it is necessary to completely overlap and digest the tape.
Quality control
5.14. Quality control of welding and welded pipelines should be carried out by:
checks for the health of welding equipment and measuring instruments, the quality of the materials used;
operational control in the process of assembling and welding pipelines;
external inspection of welded joints and measuring sizes of seams;
explosions of the intestinal joints non-destructive methods Control - radiographic (x-ray or gamma-rays) or ultrasonic flaw detection in accordance with the requirements of the GOSGORTECHANDZOR GOST 7512-82, GOST 14782-76 and other standards approved in the prescribed manner. For pipelines that are not subject to the USSR State University Rules, allowed instead of radiographic or ultrasound control to apply magnetographic control;
mechanical testing and metallographic studies of control welded joints of pipelines, which are subject to the requirements of the USSR State University Rules, in accordance with these rules;
tests for strength and tightness.
5.15. With operational control of the quality of welded joints of steel pipelines, it is necessary to check the compliance with the standards of structural elements and the size of welded connections (dull and stripping edges, the size of the gaps between the edges, width and enhancement of the weld), as well as the technology and welding mode, the quality of welding materials, tapes and welds seam.
5.16. All welded joints are subject to external inspection and measurement.
The joints of the pipelines, welded without a lining ring with a seam root core, are subjected to an external inspection and measurement of seam sizes outside and inside the pipe, in other cases - only outside. Before inspecting the weld and the surfaces adjacent to it should be cleaned of slag, splashes of molten metal, scale and other contaminants per width of at least 20 mm (on both sides of the seam).
The results of the external inspection and measurement of the sizes of welded connections are considered satisfactory if:
there are no cracks of any sizes and directions in the seam and adjacent area, as well as cutting, influx, burn, unwitting crater and fistula;
the dimensions and number of volume inclusions and wests between the rollers do not exceed the values \u200b\u200bgiven in Table. one;
the dimensions of the income, concurrant and excess of the propellant in the root of the seam joints, made without the remaining lining ring (with the inspection of the joint from the inside of the pipe) do not exceed the values \u200b\u200bshown in Table. 2.
Shakes that do not satisfy the listed requirements are subject to correction or removal.
Table 1
Maximum allowable | Maximum |
|
The volumetric inclusion of a rounded or extended form at the nominal thickness of the wall of the welded pipes in the butt connections or a smaller knife of the seam in the angular connections, mm: | ||
sv. 5.0 to 7.5 | ||
Slore (deepening) between rollers and the scaly structure of the seam surface at the nominal thickness of the wall of the welded pipes in the butt connections or with a smaller knife of the seam in the angular connections, mm: | ||
Not limited |
||
table 2
Pipelines | Maximum allowable height (depth),% of the nominal wall thickness | Maximum allowable total length of the junction perimeter |
|
Distribute | Bending and impairment in the root of the seam | 10, but not more than 2 mm 20, but not more than 2 mm | 20% perimeter |
Do not apply | Bending, excess of the propagation and impairment in the root of the seam | 1/3 |
5.17. Welded connections are exposed to non-destructive testing methods:
pipelines covered by the requirements of the USSR State University Rules, an outer diameter of up to 465 mm - in the amount provided for by these rules, a diameter of over 465 to 900 mm in a volume of at least 10% (but at least four joints), with a diameter of over 900 mm in volume at least 15% (but at least four joints) of the total number of the same type of joints, made by each welder;
pipelines that do not apply to the requirements of the USSR State Minor Support Rules, an outer diameter of up to 465 mm in a volume of at least 3% (but at least two joints), with a diameter of more than 465 mm - in the amount of 6% (but at least three joints) of the total number of the same type of joints performed by each welder; In the case of checking the continuity of welded compounds with the help of magnetographic control of 10% of the total number of joints subjected to control, must be checked, in addition, the radiographic method.
5.18. Non-destructive testing methods should be subject to 100% of welded joints of thermal networks, laid in non-passing channels under the passage of roads, in cases, tunnels or technical corridors together with others engineering communicationsas well as when intersections:
railways and tram tracks - at a distance of at least 4 m, electrified railways - at least 11 m from the axis of the extreme way;
railways of the general network - at a distance of at least 3 m from the nearest construction of the earth canvas;
road - at a distance of at least 2 m from the edge of the carriageway, the fortified strip of the curb or soles of the mound;
metro - at a distance of at least 8 m from structures;
power cables, control and communication - at a distance of at least 2 m;
gas pipelines - at a distance of at least 4 m;
main gas pipelines and oil pipelines - at a distance of at least 9 m;
buildings and structures - at a distance of at least 5 m from the walls and foundations.
5.19. Welded seams should be made if, when checking non-destructive testing methods, cracks, unwitting craters, burns, fistulas, as well as non-verbal seam made on the lining ring are detected.
5.20. When checking the radiographic method of welded seams of pipelines to which the requirements of the USSR Gosgortkhnodzor rules are applied, pores and inclusions are considered permissible defects, the dimensions of which do not exceed the values \u200b\u200bspecified in Table. 3.
Table 3.
Nominal | Extremely permissible dimensions pores and inclusions, mm | Total pore length and |
|||||
individual | clusters | inclusions |
|||||
width (diameter) | width (diameter) | width (diameter) | on any 100 mm seam, mm |
||||
St. 2.0 to 3.0 | |||||||
The height (depth) of the undevelopment, concavity and excess of the propellant in the root of the joint of the compound made by one-sided welding without a lining ring should not exceed the values \u200b\u200bindicated in Table. 2.
The permissible defects of welded joints according to the results of ultrasound control are defects, measured characteristics, the number of which does not exceed those specified in Table. four.
Table 4.
Nominal wall thickness | Size artificial | Permissible conditional | The number of defects on any 100 mm seam |
|
pipes, mm. | angular reflector ("Cubs"), | length of a separate defect, mm | large and small total | large |
From 4.0 to 8.0 | ||||
St. 8.0 "14.5 | ||||
Notes: 1. The defect is considered to be large, the conditional length of which exceeds 5.0 mm with a wall thickness of up to 5.5 mm and 10 mm with a wall thickness above 5.5 mm. If the conditional length of the defect does not exceed the specified values, it is considered small. |
||||
5.21. For pipelines that do not apply to the requirements of the USSR State Unit, permissible defects with a radiographic control method, pores and inclusions are considered, the dimensions of which do not exceed the maximum permissible according to GOST 2,055-78 for welded compounds of the 7th grade, as well as income, concave and excess of the propellant At the root of the seam made of unilateral electric arc welding without a lining ring, the height (depth) of which should not exceed the values \u200b\u200bindicated in Table. 2.
5.22. When identifying non-destructive methods of control of unacceptable defects in welded seams Pipelines covered by the requirements of the USSR State University Rules, it is necessary to re-control the quality of the seams established by these rules, and in the welds of pipelines, which the requirements of the rules are not subject to, in the double count of the joints compared to those specified in clause 5.17.
In the case of unacceptable defects, all the joints performed by this welder should be monitored during re-control.
5.23. Correction by local sampling and subsequent fittings (without re-welding of the entire compound) are subject to sections of a weld with unacceptable defects, if the sample dimensions after removing the defective section do not exceed the values \u200b\u200bindicated in Table. five.
Welded joints, in seams of which to correct the defective area, it is necessary to sample the dimensions of more allowable. 5, must be completely removed.
Table 5.
Sampling depth | Length, |
St. 25 to 50 | No more than 50. |
Note. When corrected in one connection of several sections, their total length may exceed the specified in Table. 5 no more than 1.5 times with the same standards in depth. |
|
5.24. Subsums should be corrected by the surfacing of the width of no more than 2.0 - 3.0 mm wide. Cracks must be sewed at the ends, cut down, thoroughly clean and brew into several layers.
5.25. All corrected areas of welded joints must be tested by external inspection, radiographic or ultrasonic flaw detection.
5.26. At the executive drawing of the pipeline, compiled in accordance with SNiP 3.01.03-84, the distances should be specified between welded joints, as well as from wells, cameras and subscriber inputs to the nearest welded joints.
6. Thermal insulation of pipelines
6.1. Installation of thermal insulation structures and protective coatings must be made in accordance with the requirements of SNiP III-20-74 and this section.
6.2. Welded and flange compounds should not be isolated on a width of 150 mm on both sides of the connections before performing testing of pipelines for strength and tightness.
6.3. The possibility of production insulation work On pipelines to be registered in accordance with the rules of the USSR Gosgortkhnadzor, prior to the fulfillment of durability and tightness tests, it is necessary to agree with the local government of the Gosgortkhnadzor of the USSR.
6.4. When performing filler and flowing isolation with a non-locking laying of pipelines in the project's work project, it is necessary to provide temporary devices that prevent the ingregation of the pipeline, as well as entering the solar insulation.
7. Transitions of thermal networks through passages and roads
7.1. Production of works with underground (above-ground) intersection by heat networks of railway and tram tracks, roads, urban passages should be carried out in accordance with the requirements of these Rules, as well as SNiP III-8-76.
7.2. When punctured, melting, horizontal drilling or other methods of trenchless laying of cases, the assembly and tack of links (pipes) of the case must be performed using a centrator. The ends of the welded links (pipes) must be perpendicular to their axes. Fractures of the axes of links (pipes) of cases are not allowed.
7.3. Reinforced torcret-concrete anti-corrosion coating of cases in their trenchless laying should be made in accordance with the requirements of SNiP III-15-76.
7.4. Pipelines within the case should be performed from the pipes of the maximum supply length.
7.5. The deviation of the axis of the transition cases from the project position for samotane condensate pipelines should not exceed:
vertically - 0.6% of the length of the case under the condition of ensuring the design slope of condensate pipelines;
horizontally - 1% of the case of the case.
Deviation of the axis of transition cases from the project position for the remaining pipelines should not exceed 1% of the case of the case.
8. Testing and flushing (purge) pipelines
8.1. After completion of construction and installation work, pipelines must be subjected to final (acceptable) tests for strength and tightness. In addition, condensate pipelines and pipelines of water heat networks must be washed, steam pipelines - produced by steam, and pipelines of water heat networks with an open heat supply system and hot water supply network - washed and disinfected.
Pipelines laid in case of infantless and non-passing channels are also subject to preliminary tests for strength and tightness in the production and installation process.
8.2. Preliminary testing of pipelines should be made to the installation of gland (bellows) compensators, partitioning valves, closing channels and backfill of the pipeless gasket pipelines and channels.
Preliminary tests of pipelines for strength and tightness should be carried out, as a rule, hydraulically.
Under the negative temperatures of the outer air and the impossibility of heating water, as well as in the absence of water, it is allowed in accordance with the project manufacturing the performance of preliminary tests by a pneumatic method.
It is not allowed to perform pneumatic tests of overhead pipelines, as well as pipelines deployed in one channel (section) or in one trench with existing engineering communications.
8.3. Pipelines of water thermal networks should be tested by a pressure of 1.25 workers, but not less than 1.6 MPa (16 kgf / sq. Cm), steam pipelines, condensate pipelines and a hot water supply network - a pressure of 1.25 workers, if other requirements are not justified by the project (work project).
8.4. Before performing testing and tightness tests:
to control the quality of welded joints of pipelines and the correction of detected defects in accordance with the requirements of section. five;
turn off the plugs test pipelines from acting and from the first locking reinforcement installed in the building (construction);
install the plugs at the ends of the test pipelines and instead of salon (bellows) compensators that partitioning valves under preliminary tests;
provide throughout the test pipelines access to their external inspection and inspection of welded seams at the time of testing;
open fully fittings and bypass lines.
Using shut-off valves to disable the test pipelines is not allowed.
Simultaneous preliminary tests of several pipelines for strength and tightness are allowed to be carried out in cases substantiated project manufacturing project.
8.5. Pressure measurements When performing testing of pipelines for strength and tightness should be made according to the two (one-control) system at the prescribed manner (one - control) spring pressure gauges not less than 1.5 with a diameter of a housing of at least 160 mm and a scale with rated pressure 4/3 Measured.
8.6. Tests of pipelines for strength and tightness (density), their purge, flushing, disinfection must be made according to technological schemes (agreed with operational organizations), regulating technology and equipment for the safety of work (including the borders of the security zones).
8.7. On the results of testing pipelines for strength and tightness, as well as their flushing (purge), these are acts of forms given in mandatory applications 2 and 3.
Hydraulic tests
8.8. Pipeline testing should be performed in compliance with the following basic requirements:
test pressure must be provided at the top point (mark) of pipelines;
the water temperature during testing should be no less than 5 degrees;
with a negative temperature of the outer air, the pipeline must be filled with water with a temperature not higher than 70 degrees and to ensure the possibility of filling and emptying it for 1 hour;
with gradual filling with water from pipelines, air must be completely removed;
the test pressure must be sustained for 10 minutes and then reduced to the worker;
at operating pressure, the pipeline is inspected along its entire length.
8.9. The results of hydraulic tests for strength and tightness of the pipeline are considered satisfactory if there was no pressure drop during their conduct, there were no signs of breaking, leaks or fogging in welds, as well as leaks mainly metal, flange connections, reinforcement, compensators and other pipeline elements , There are no signs of shift or deformation of pipelines and fixed supports.
Pneumatic tests
8.10. Performing pneumatic tests should be made for steel pipelines with a working pressure not higher than 1.6 MPa (16 kgf / sq. Cm) and temperatures up to 250 degrees, mounted from pipes and parts tested for strength and tightness (density) manufacturers In accordance with GOST 3845-75 (while the factory test pressure for pipes, reinforcements, equipment and other products and parts of the pipeline should be 20% higher than the test pressure adopted for the mounted pipeline).
Installation of cast-iron fittings (except for the valves from the ductile cast iron) for the time of testing is not allowed.
8.11. Filling the pipeline with air and pressure lift should be performed smoothly at a speed of no more than 0.3 MPa (3 kgf / sq. Cm) in 1 h. Visual inspection of the track [input to a security (dangerous) zone, but without descent to trench] is allowed at a magnitude Pressure equal to 0.3 test, but not more than 0.3 MPa (3 kgf / sq. cm).
For the period of inspection of the route, the pressure lift must be discontinued.
When the values \u200b\u200bof the test pressure is reached, the pipeline must be designed to align the air temperature along the pipeline length. After alignment of the air temperature, the test pressure is maintained for 30 minutes and then smoothly decreases to 0.3 MPa (3 kgf / sq. Cm), but not higher than the size of the working pressure of the coolant; At the same time, a pressure inspection of pipelines with a mark of defective places is made.
The leakage points are determined by the sound of a seerful air, according to bubbles when coating welded joints and other places with soap emulsion and the use of other methods.
Defects are eliminated only by reducing excess pressure to zero and disconnect the compressor.
8.12. The results of preliminary pneumatic tests are considered satisfactory if there was no pressure drop in the pressure gauge during their conduct, defects were detected in welds, flange connections, pipes, equipment and other elements and pipeline products, there are no signs of shift or strain pipeline and stationary supports.
8.13. Water network pipelines in closed systems Heat supply and condensate pipelines should, as a rule, are subjected to hydropneumatic flushing.
A hydraulic washing is allowed to re-use flushing water by passing it through time mud, installed in the course of water movement at the ends of the feed and return pipelines.
Flushing, as a rule, should be made technical water. It is allowed to flushing with drinking water with a justification in the project's work project.
8.14. Pipelines of water networks of open heat supply systems and hot water networks need to be washed with a hydropneumatic method of drinking quality water to completely lightening the washing water. At the end of the flushing, pipelines must be disinfected by filling them with water with an active chlorine in a dose of 75-100 mg / l at a contact time of at least 6 hours. Pipelines with a diameter of up to 200 mm and a length of up to 1 km are resolved, by agreement with local bodies Sanitary and epidemiological service, chlorinations do not expose and restrict ourselves to washing with water corresponding to the requirements of GOST 2874-82.
After washing, the results of laboratory analysis of samples of wash water must comply with the requirements of GOST 2874-82. The results of washing (disinfection) by the sanitary and epidemiological service are concluded.
8.15. Pressure in the pipeline during washing should be no higher than the worker. Air pressure during hydropneumatic flushing should not exceed operating pressure coolant and be no higher than 0.6 MPa (6 kgf / sq. cm).
Water velocities for hydraulic flushing should be not lower than the calculated coolant velocity indicated in the working drawings, and with hydropneumatic - exceed the calculated at least 0.5 m / s.
8.16. Steam pipelines must be produced by steam with a discharge into the atmosphere through specially installed purge nozzles with shut-off reinforcement. To warm the steering pipes, all launcher drains should be opened before purging. The heating rate should ensure the absence of hydraulic shocks in the pipeline.
The velocity of the steam when the purge of each site should be at least working velocities at the calculated coolant parameters.
9. Environmental Protection
9.1. In the construction of new, expanding and reconstruction of existing thermal networks measures for the protection ambient It should be taken in accordance with the requirements of SNiP 3.01.01-85 and this section.
9.2. Not permitted without coordination with the relevant service: to produce earthworks at a distance less than 2 m to the trunks of trees and less than 1 m to the shrub; Moving cargo at a distance less than 0.5 m to crowns or tree trunks; Storage of pipes and other materials at a distance less than 2 m to the trunks of trees without a device around them temporary enclosing (protective) structures.
9.3. Washing pipelines by hydraulically should be performed with reuse of water. Emptying pipelines after washing and disinfection should be in place indicated in the project manufacturing project and coordinated with the relevant services.
9.4. Territory construction site After the end of construction and installation work should be cleaned of garbage.
Appendix 1. Act of the extension of compensators
ATTACHMENT 1
Mandatory
g .________________________ "_____" _________________ 19 _____ g.
Commission composed:
(surname, name, patronymic, position)
_____________________________________________________________,
1. A stretching of the compensators listed in the table was presented to the examination and acceptance, on the site from the camera (picket, mines) No. _______ to the camera (picket, mines) No. _______.
Compensator number | Drawing number | Type of compensation | Stretching magnitude, mm | Temperature |
|
according to the drawings | design | actual | air, hail |
||
2. Works are performed by design and estimate documentation ____________
_______________________________________________________________
Commission decision
Work performed in accordance with design and estimate documentation, state standards, construction standards and rules and meet the requirements of their acceptance.
(signature)
(signature)
Appendix 2. Act of testing pipelines for strength and tightness
Appendix 2.
Mandatory
g ._____________________ "_____" ____________ 19 ____ g.
Commission composed:
representative of the construction and assembly organization _________________
_____________________________________________________________,
(surname, name, patronymic, position)
representative of the technical supervision of the customer _____________________
_____________________________________________________________,
(surname, name, patronymic, position)
representative of the Operational Organization ______________________
_____________________________________________________________
(surname, name, patronymic, position)
made an inspection of work performed ___________________________
_____________________________________________________________,
(Name of a construction and installation organization)
and amounted to this act of the following:
1. To examination and acceptance is presented ________________
_____________________________________________________________
(hydraulic or pneumatic)
pipelines, tested for strength and tightness and listed in the table, on the site from the camera (picket, mines) No. ________ to the camera (picket, mines) No. _________ RUIDS ___________
Length __________ m.
(pipeline name)
Pipeline | Test pressure | Duration, Min. | Outer inspection at pressure, MPa (kgf / sq. CM) |
2. Works are performed by design and estimate documentation __________________
_____________________________________________________________________
(Name of the project organization, drawings numbers and date of their compilation)
Commission decision
Representative of the construction and assembly organization ________________
(signature)
Representative of the technical supervision of the customer _____________________
(signature)
(signature)
Appendix 3. Act of the washing (purge) of pipelines
Appendix 3.
Mandatory
g ._______________________________________ "_____" _______________ 19 _____ g.
Commission composed:
representative of the construction and assembly organization ________________
_____________________________________________________________,
(surname, name, patronymic, position)
representative of the technical supervision of the customer _____________________
_____________________________________________________________,
(surname, name, patronymic, position)
representative of the Operational Organization _____________________
_____________________________________________________________
(surname, name, patronymic, position)
made an inspection of work performed ____________________________
_____________________________________________________________,
(Name of a construction and installation organization)
and amounted to this act of the following:
1. Flushing (purge) of pipelines on the plot from the camera (picket, mines) No. __________ to the camera (picket, mines) No. ______ tracks ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________
_____________________________________________________________________________________
(pipeline name)
length ___________ m.
Flushing (purge) produced ________________________________
_____________________________________________________________.
(Name of the environment, pressure, consumption)
2. Works are performed by design and estimate documentation _________________
____________________________________________________________________
_____________________________________________________________________.
(Name of the project organization, drawings numbers and date of their compilation)
Commission decision
Works are performed in accordance with design and estimate documentation, standards, construction standards and regulations and meet the requirements of their acceptance.
Representative of the construction and assembly organization ________________
(signature)
Representative of the technical supervision of the customer _____________________
(signature)
Representative of the operational organization _____________________
(signature)
The text of the document is drilled by:
official edition
M.: CITP Gosstroy USSR, 1986