Gas Pipeline Construction Organization Project

General part

1.1  Initial materials for the development of the construction organization project

- Route plan;

- Longitudinal profiles.

1.2  Basic standards and guidelines used to develop the construction organization project

SNiP 12012004 "Construction Organization."

SNiP 1.04.0385 * "Standards for the duration of construction and backlog in the construction of enterprises, buildings and structures."

Manual for determining the duration of construction of enterprises, buildings and structures (to SNiP 1.04.0385 * part I; II).

SNiP 12032001 "Occupational Safety in Construction," Part 1.

SNiP 12042002 "Occupational safety in construction," part 2.

SNiP 5.02.0286 "Construction Tool Demand Standards."

SNiP 3.01.0487 Acceptance for Operation of Completed Construction Facilities. Basic provisions. "

SNiP 3.02.0187 "Earthworks, Foundations and Foundations"

SNiP 3.01.0384 "Geodetic works in construction."

PPB0103 Fire Safety Regulations in the Russian Federation. (GPS EMERCOM OF THE RUSSIAN FEDERATION);

SNiP III4280 * "Main pipelines."

SP 1033496 "Preparation of construction strip." RAO GAZPROM.

SP 1093497 "Construction of crossings under roads and railways." RAO GAZPROM.

SP 421012003 "General provision for the design and construction of gas distribution systems made of metal and polyethylene pipes." CJSC "POLYMERGAZ."

VSN 00488 "Construction of main pipelines. Technology and organization. " Minneftegazstroy.

SN 45273 "Land Drainage Standards for Main Pipelines."

Manual to SNiP 3.05.0288 "Manual on Technology and Organization of Pipeline Construction of Gas Supply Systems in Rural Areas of Non-Black Earth Regions of Russia."

1.3  Construction Organization Solutions

year-round construction and installation works by contracting method;

Specialized organizations are engaged to perform special installation works according to contracts;

integrated mechanization of construction and installation works with the use of mechanisms in 2 shifts and with the use of means of small mechanization, ensuring the performance of works in the optimal time;

supply of construction parts, semi-finished products and carpentry products to the object under construction are provided from the Customer's enterprises and warehouses with centralized delivery of vehicles in 2 shifts;

provision of electric power and compressed air construction from mobile mobile sources. Water for household needs - imported.

Characteristics of construction conditions, structural solutions

2.1  Short description of the site

The construction strip of the gas pipeline for gas supply "Center for the sale and maintenance of cars LLC" Km/h "is located in the area of ​ ​ the village of Near Prudishchi, Leninsky district, Moscow region.

2.2  Engineering and geologic conditions

Toposurge in M 1:500 was carried out by Neftegazproektstroy LLC in September 2008. Geotechnical surveys were carried out by LLC GEOLAND in 2008 .

According to engineering and geological conditions, the surveyed area belongs to the I (simple) category of complexity.

Up to a depth of 4.0m, the track is composed of cover loams of semi-solid, refractory and soft-plastic consistency, covered with soil-vegetal and bulk soils from the surface.

Groundwater up to a depth of 3.0m is not met, but it should be borne in mind that during periods of heavy precipitation and intense snowmelt, a temporary groundwater horizon of the "headwaters" type may appear in the thickness of macroporous cover loams.

Soils do not have subsidence and swelling properties. In the depth range of 0.5m1.2m, soils have medium and high corrosion aggressiveness to steel.

The normative depth of seasonal freezing of loam is 1.40m. By the degree of frost hazard, loam semi-hardened-tugoplastic (IEG1), which occur in the layer of seasonal freezing, belong to medium-permafrost.

  Design Solutions

The designed gas pipeline is laid underground from steel and polyethylene pipes at a depth of 1.01.5m from the ground surface to the top of the pipe.

The gas pipeline high (R ≤ 1.2 MPas) pressure is mounted from steel electrowelded pipes in accordance with GOST 1070491/B10 of GOST 1070580.

Medium pressure gas pipeline is installed from PE 80 "GAZ" PE pipes SDR17.6 GOST R 5083895 and PE 80 "GAZ" SDR11 GOST R 5083895 (basement entry), connecting parts are finished products certified in Russia.

It is allowed to replace pipes in accordance with the recommendations of SNiP 42012002 and SP 421022003; SP 421032003.

Small sections of the medium pressure gas pipeline are designed from steel electric welded pipes according to GOST 1070491/B-10 GOST 1070580.

For steel inserts with a length of not more than 10 m on the linear part of polyethylene gas pipelines and sections of connection of polyethylene gas pipelines with steel entrances to the building (directly in front of the building and in the presence of electrically insulating inserts at the entrances) it is allowed not to provide EHZ .

Backfilling of the trench in this case along the whole length and depth shall be sandy (refer to PB 1252903 item 2.3.4.). To protect the underground steel gas pipeline, insulation of the "very reinforced" type is provided according to GOST 9.6022005.

Above-ground gas pipelines shall be painted with two layers of paint, lacquer or enamel intended for external works at the design ambient temperature in the construction area. External gas pipelines laid along the facade of the building can be painted with the color of the building enclosing structures (see PB 1252903 item 2.3.9).

The designation of the steel gas pipeline route is provided by installing identification marks (on the identification mark in accordance with the provisions of the SP 421012003 data on the diameter, pressure, depth of the gas pipeline, pipe material are applied; identification mark is installed on reinforced concrete column not less than 1.5 m high). The axis of the gas pipeline route in the building area is indicated by binding to buildings or other permanent landmarks at characteristic points (at the corners of the route, on branches, tees and plugs).

The axis of the gas pipeline route in the building area is indicated by binding to buildings or other permanent landmarks at characteristic points (at the corners of the route, on branches, tees and plugs).

Above the medium pressure polyethylene gas line, a yellow signal tape with a width of at least 0.2m is provided with the indelible inscription "Flammable - Gas" at a distance of 0.2m from the top of the gas line for warning during earthworks (see PB 1252903 item 3.1.12).

At the intersections with underground utilities, the signal tape shall be laid along the gas pipeline twice at a distance of not less than 0.2m between each other and 2m on both sides of the crossed structure (see PB 1252903, item 3.1.13).

Tavrovaya gas pipeline tie-in along UG 23.00.SB is provided (i.e. 5.90525.05); laying of gas pipeline in the case according to UG 16.00.SB (t.s. 5.90525.05); install identification columns as per NPP 1.00. SS (t.5.90525.05); laying of gas pipeline under cable along UG 20.00.SB (t.s. 5.90525.05).

To find the route of the polyethylene gas pipeline, it is provided to lay an insulated copper wire with a section of 4mm2 along the route and install control points (CP as per "Podolskmezhareigaz.") at the places where the copper wire is brought to the surface.

Connections of polyethylene gas pipelines with steel shall be provided as non-removable. Connection of polyethylene pipes is provided by welding using parts with embedded heaters or butt.

Connection of branches to polyethylene gas pipeline should be provided by means of connecting parts made of polyethylene (tees, saddle branches, saddles).

The polyethylene gas pipeline in the trench for compensation of temperature extensions must be laid with a snake in the horizontal plane, for this the trench width - not less than pipe DN + 300 mm and not less than 700 mm. There is a supply of pipes for snapping, for mechanical tests, emergency reserve used to eliminate damage to polyethylene pipes that can occur during operation, and other needs in the amount of ~ 2%.

The design provides an emergency reserve of steel pipes for mechanical tests and other needs in the amount of ~ 1%.

Perform operations on laying of polyethylene pipelines at temperature not lower than -150С and not higher than + 300С.

Non-standard turning angles on the gas pipeline route are used to break down and tie the route on the ground, only standard taps are taken into account in the specification, during the construction of the turn of the linear part of the gas pipeline, it is allowed to PK0 + 63,00PK2 + 22.00 to lay the high pressure gas pipeline through the Don highway using the existing gas pipeline from electric welded pipe Ø 820x9.0 laid in case DU 1000 (0m).

On the section of the medium-pressure gas pipeline laid along the facade of the building (the external walls of the Center are made of brick), the gas pipeline attachment should be used according to UKG 2.00. SS type. 5.90518.05 series with step not more than 5.0m.

Lightning protection of FRG is provided in accordance with RD 34.12.12290 with the device of rod lightning receptacle, support, current collector and earthing devices.

Plan a horizontal site under the FRG and fill it with crushed stone and sand with subsequent sealing, make a solid coating of the site and access to it from the nearest road. Power supply of FRG is designed from internal power supply networks of LLC "Km/h."

Basement gas entry into the Center building shall be made according to drawings of Gazstroy CJSC from polyethylene pipes with a permanent connection (I-shaped) - design solution 154.050GSN.TsVP.1,2.

Organizational and technological diagrams of construction

To ensure timely preparation and compliance with the technological sequence of construction, the project provides for two construction periods: preparatory and basic.

3.1 Preparatory period

3.1.1  Cleanup of territory

Removal from the territory of the construction strip of large technical and household garbage is carried out by bulldozer DZ42, in places where the use of equipment is not possible to clean manually. All collected garbage is removed from the territory by car dump trucks MAZ555102.

Clearance of the route for the construction period shall be carried out within the limits of the diversion lane and in other places established by the project.

In winter, clearance should be carried out in two stages: in the area of ​ ​ transport and construction machines - in advance of the start of the main work, and in the area of ​ ​ digging the trench - immediately before work, for the length that ensures work during the shift.

3.1.2  Cutting of vegetable layer

Ground cutting is performed by bulldozer DZ42 (depth of removal is determined as per GOST 17.5.3.0685). In the absence of shrub roots, one or two passes are conducted one trace at a depth of up to 15 cm; in the presence of shrub roots and trees - in two to three passes one trace at a total depth of up to 25 cm.

The cut vegetation layer suitable for subsequent use must be previously removed and stored in a specially designated place. The soil layer shall not be irrigated with oils and fuel during operation of internal combustion engines. Cutting of vegetable layer is carried out on the area of 24 meters (in each direction) from the axis of the route of the designed gas pipeline.

3.1.4  Arrangement of temporary roads

Plates of PDP-3.0h1.75 brand are applied to the device of temporary roads. Before laying the slabs, vertical layout is performed by bulldozer DZ42, according to design elevations with soil compaction. Under the slabs, a bottom layer of sand with a thickness of 10 cm is made. The stowage of the plates is carried out "from the wheels," by an automobile boom crane KS3577. Temporary road area 1100m2

At departures from the construction site, it is necessary to provide for the construction of vehicle wheel washing points, and in winter, a dirt cleaning point. In winter, at temperatures below - 5 ° C, washing stations are equipped with compressors for dry cleaning of wheels with compressed air.

Upon completion of operation, all temporary roads shall be dismantled.

3.1.3  Geodetic terrain breakdown

The Customer is obliged to create a geodetic breakdown basis for construction and transfer technical documentation to the general contractor before the start of construction. Geodetic layout, according to SNiP 3.01.0384 "Geodetic works in construction," shall be created on the construction site in the form of a network of points fixed with signs determining the position of structures under construction on the ground. For laying signs fixing the position of the designed gas pipeline, prepare free spaces, and for measuring segments, angles, lines clear strips with a width of at least 1 m.

3.2 Main period

Pipeline construction shall be carried out in-line, ensuring continuity of all works in strict process sequence.

Prior to the commencement of construction and installation works, it is necessary to obtain permission from the local administration.

All stages of the work should be carried out under the control of representatives of organizations entrusted with author's and technical supervision, as well as organizations operating related communications.

3.2.1  Earthworks

Excavation work is carried out by the excavator EO 2626 (replacement with a similar one in terms of characteristics is possible) with a dump of soil to the side or with loading into vehicles. The soil is moved by road to temporary storage places (to be determined in place) or to places of filling of the already laid gas pipeline. In places where the use of the excavator is impossible (intersection of communications, equipment tie-in, complex relief, constrained conditions), earthworks are carried out manually, soil dumping places are selected in place.

According to SNiP 3.02.0187 the width of the trench shall be Dn + 300 mm, but not less than 700 mm, except when the pipeline is laid by narrow trench method. During welding at the bottom of the pit, pits measuring 1.0x (D + 1.2) x0.7m for steel welded joints and 0.6x (D + 0.5) x0.2m for plastic joints are developed. The depth of the pits is indicated from the bottom of the trench. Extraction of not worked out soil (100mm) at the bottom of the trench is carried out manually.

In case of detection of any underground utilities or structures not specified in the design documentation, the work should be suspended. The project author and representatives of organizations operating related communications should be called to the place of work.

In order to prevent deformation of the profile of the dug trench, as well as the erosion of the soil dump, the replacement rates of insulation laying and earthworks should be the same.

The required gap between the earth-moving and insulation-laying columns shall be specified in the work execution design.

Work on backfilling the trench is carried out manually. When filling the pipeline with soil containing frozen clumps, crushed stone, gravel and other inclusions measuring more than 50 mm in the cross-section, the insulation coating should be protected from damage by spraying with soft soil for a thickness of 20 cm above the upper generatrix of the pipe or by the protective coating device provided for by the design. Upon completion of backfilling of the trench, soil is compacted with DC32 roller.

Measures to strengthen the slope of the trench

When carrying out earthworks in constrained conditions, as well as in the presence of groundwater, swimmers and other difficult hydrogeological conditions, when it is impossible to ensure the required laying of slopes, trenches must be fixed. The parameters of the fastening system are calculated in the work execution project.

The allowable depth of the excavation, at which the slope of the connected soil is kept in the vertical position without fixing the walls, is determined by the calculation .

Procedure for works at trench walls attachment:

- Along the border of the trench broken on the ground, hammer the posts with a pitch of 2 m below the bottom of the future trench by 11.2 m.;

- Simultaneously with soil development, take trench walls with a board width of 150mm and thickness of 20mm. Place the boards behind the posts. In sufficiently stable soils capable of at least a short time keeping a vertical slope, trenches are torn off by sections with a length of 34m. to the design depth, and the fence boards are installed by lowering from above - by building up. When installing trench attachments, it is necessary to extend the upper attachment boards above the eyebrows by at least 15 cm.;

- At a height of 500mm and 1000mm from the top of the trench, arrange a spacer made of wooden bar 100x100. Spacer is installed between two posts.

Disassembly of fasteners should be performed from below as soil backfills. The number of simultaneously removed boards by height in dense soils should not exceed three, and in bulk or unstable - one.

Earthworks in winter

Before starting earthworks in winter period perform preliminary loosening of soil by excavator (with replaceable working equipment - loosener) or bulldozer. In case of mechanical impact tillage, it is not allowed to find workers at a distance closer than 5 m from the tillage points.

When predicting ground freezing to a depth of more than 0.4m, it is advisable to protect the soil from freezing, in particular, by loosening by single or multipoint looseners.

In some places of a small area, it is possible to protect the soil from freezing by insulation with wood residues, sawdust, peat, applying a layer of foam styrene, as well as non-woven rolled synthetic materials.

To reduce the duration of thawing of frozen soil and in order to maximize the use of the fleet of earth-moving machines in warm time, it is recommended to remove snow from the strip of the future trench during the period of establishing positive temperatures.

In order to avoid drifting of trenches with snow and erosion of soil dump during operation in winter, the pace of trenches development should correspond to the pace of insulation laying works .

Methods of trenches development in winter time are assigned depending on time of excavation works, soil characteristics and depth of its freezing. The choice of the process scheme of excavation work in winter should provide for the preservation of snow cover on the ground surface until the start of trench development.

3.2.2  Welding operations

Welding works are carried out using electric arc welding for sections of the gas pipeline from metal pipes and using a butt welding apparatus for polyethylene pipes RITMO VR 160 (replacement with similar devices is possible). Pipe joints are assembled on inventory beds using external or internal centralizers. The permissible displacement of the edges of welded pipes shall not exceed 0.15S + 0.5 mm, where S is the smallest of the wall thicknesses of welded pipes.

Before assembling and welding pipes it is necessary to:

- perform visual inspection of the pipe surface (at that the pipes must not have unacceptable defects regulated by the specification for pipe supply);

- clean the internal cavity of pipes from soil, dirt, snow that has fallen inside;

- straighten or trim deformed ends and pipe surface damage;

- clean the edges and adjacent internal and external surfaces of the pipes for a width of not less than 10 mm;

- (for steel pipes) check the geometric dimensions of the edges, straighten the smooth dents at the ends of the pipes up to 3.5% of the outer diameter of the pipe;

- (for steel pipes) clean the edges and adjacent inner and outer surfaces of the pipes to a width of not less than 10 mm.

When welding the pipeline to the thread, the welded joints shall be tied to the route stations and fixed in the as-built documentation.

If the operation is interrupted for more than 2 hours, the ends of the welded section of the pipeline should be closed with inventory plugs to prevent snow, dirt, etc. from entering the pipe.

Welding operations can be performed at air temperature up to minus 50 ° С. In case of wind exceeding 10 m/s, as well as in case of precipitation, it is forbidden to perform welding operations without inventory shelters.

Piping shall only be installed on inventory liners. Use of soil and snow prisms for pipeline installation is not allowed.

Welders who pass exams in accordance with the Rules for certification of welders of Gosgortekhnadzor with certificates are allowed to tack and weld main pipelines.

Ends of pipes of steel pipelines, having cracks, breaks, nicks, bevels with depth of more than 5 mm, are cut. If the air temperature is below minus 5 ° С, straightening the pipe ends without heating them is not recommended.

Welding of joints of steel different thickness pipes or pipes with connecting parts and fittings is allowed without special edge treatment at wall thickness less than 12.5 mm (if thickness difference does not exceed 2.0 mm).

Prior to welding operations of rotating and non-rotating joints of pipes, pipe ends and adjacent sections are dried or heated.

Drying of steel pipe ends by heating by 50 ° С is recommended:

- if there is moisture on the pipes regardless of ambient air temperature;

- at ambient temperature below plus 5 ° С.

Manual arc welding of non-rotating and rotary joints of pipes at wall thickness up to 6 mm shall be performed in at least two layers, at wall thickness more than 6 mm - in at least three layers. Each seam layer shall be thoroughly cleaned of slag and metal spatter before application.

3.2.3  Piping Laying

Process diagrams for the execution of laying (insulation laying) works are selected from among the standard ones or are developed at the stage of drawing up the work execution design (PDP).

By the time the pipeline is laid, the bottom of the trench must be aligned according to the design. Piping shall not be placed in a non-project trench.

Laying of pipeline from trench edge

For pipes supplied in the form of separate sections (612 meters), laying work is carried out by the method of sequential expansion, performing the installation of the thread directly in the design position.

Pipes are supplied to the trench using KS 3577 automobile crane (it is possible to replace it with a similar one in terms of characteristics). The crane operates:

- Parking number 1. Binding to the gas pipeline axis - 5350mm, to PK0 + 21.5 - 6600mm. Maximum reach of crane boom is 12 m. Limit of lifting height to elevation + 7.2m. Limits the rotation angle to 226 degrees.

- Parking number 2. Binding to gas pipeline axis - 5000mm, to PK0 + 62 - 10 800mm Maximum span of crane boom during installation - 12m, during unloading - 7m. Limit of lifting height to elevation + 7.2m. Limit the angle of rotation when mounting 112 degrees, when unloading 72 degrees.

- Parking lot No. 3 No. 5. The parking lot No. 3 is attached to the gas pipeline axis - 6500mm, to PK2 + 26.5 - 15 200mm. Subsequent parking is arranged along the gas pipeline route with a pitch of 30 m. Maximum reach of crane boom is 12 m. Limit of lifting height to elevation + 7.2m. Constrains the rotation angle to 200 degrees.

- Parking lots number 6. Binding to the gas pipeline axis - 6700mm, to PK2 + 26.5 - 105 200mm. Maximum reach of crane boom is 12 m. Limit of lifting height to elevation + 7.2m. Constrains the rotation angle to 200 degrees.

Use soft installation towels, special elastic slings and special crossarms for pipes as load-gripping devices in mechanized operation with single pipes (sections). The use of open steel ropes, mounting "knocks" and other devices that do not have soft contact surfaces is prohibited. When selecting load-gripping equipment (in particular, trolley suspensions), it is necessary to comply with the requirement for specific loads on the gas pipeline, which should not exceed the permissible values ​ ​ for this type of insulation coating.

The PWP shall develop measures for safe method of works and reduction of hazardous area size from crane operation (limitation of lifting height at unloading site; freight tracking by means of braces).

To improve the safety of the crane, it is recommended to use a computer system for limiting the work area.

Lifting of elements must be smooth without jerks and tremors. During lifting, swinging of elements is not allowed, it is forbidden to transfer structures with a crane above the work center of the installers and above the adjacent grip.

To assemble single pipes in a ply at the bottom of the trench, only standardized centralizers should be used to ensure reliable and geometrically correct fixation of pipes on both straight and curved sections of the route.

It is recommended to perform works on laying of gas pipelines at ambient air temperature not lower than 15 ° С and not higher than plus 30 ° С.

When laying gas pipelines at a lower ambient temperature, it is necessary to organize their heating to the required temperature. This condition can be fulfilled by passing heated air through a gas pipeline prepared for laying. At that heated air temperature must not be more than plus 60 ° С.

3.2.4  Laying of gas pipeline using existing steel gas pipeline

The gas pipeline on the site from the PK0+63.0 - To lay the PK2+22.0 with use of the existing gas pipeline from el. welded pipe Ø820x9.0 of Ø1000 laid in a case.

Prior to the commencement of construction and installation works, it is necessary to obtain permission from the local administration, to carry out measures to prepare the construction work in an amount that ensures the implementation of all works as soon as possible, including general organizational and technical training, preparation of the gas pipeline for reconstruction and equipment for installation work.

Open sections of the steel gas pipeline must be completely cleared of the ground. The distance in the light between the bottom generatrix of the pipe and the bottom of the pit shall be sufficient for cutting, installation of plugs and purging of the existing gas pipeline. Excavation of the lower layers of soil and cleaning of the opened gas pipeline shall be carried out by manual tools. The irregularities of the bottom of the pits should not exceed 20-30 mm.

Cut off the reconstructed section from the main network after the gas supply is cut off by cutting out the coils.

Blow the area to be reconstructed with inert gas or air. Cutting of coils is performed by operating organization on gas pipeline disconnected and released from gas with subsequent welding of plugs from the side of operating sections of gas pipeline. Clean the ends of the cut steel section to eliminate sharp edges.

Prior to drawing of the designed gas pipeline, the reconstructed section should be previously cleaned by pulling of metal gage or by other method.

If, during cleaning or inspection drawing, an additional pit is broken off or a length of pipe is stuck at the location of an obstacle fixed by the length of the rope inside the steel gas pipeline, a section of the gas pipeline is cut out and the cause preventing the passage of the pit or inspection sample of pipe is eliminated. If it is impossible to install an additional pit, a television inspection and removal of the obstacle using a repair robot are carried out.

The pipeline is laid in a protective casing by pulling several parts of the pipeline in series with the help of a tractor in the following technological order:

- at the bottom of the trench set up a platform with roller supports for pipes;

- supply the pipe on the installation towels to the trench door with a car crane. (for crane operation to be developed in PPM);

- a rope is connected to the pipe, which is attached to the tractor-tractor through the protective casing with the other end;

- the head of the pipe is inserted into the protective casing, and the whole pipe is brought to the coaxial position with the protective casing;

- by longitudinal movement of tractor-tractor the pipe is pulled into protective casing;

The complete length of the reconstructed part of the pipeline is gained by increasing the raft and then pushing it into the protective casing.

When pulling the working raft into the protective casing, the outer surface of the pipe (insulation coating) should be protected from damage by fixing on it support-centering devices made of polymer (dielectric) materials.

3.2.5  Reclamation of fertile layer

It is recommended to perform work on removal and restoration of the layer within the construction strip in accordance with a special land reclamation project. The land reclamation project should be developed by the project organizations taking into account the specifics of specific sections of the route and be agreed with the land users of these sections.

The fertile soil layer shall be removed and moved to the storage dump on one or both sides of the gas pipeline axis by a distance ensuring separate placement of the mineral soil dump, preventing its mixing with the fertile soil layer. On recultivated lands filling of gas pipeline is performed with layer-by-layer compaction of soil and without arrangement of roller above gas pipeline. Work on the removal of a fertile soil layer can be carried out at any time of the year, and work on its return - only in the warm season.

When performing reclamation on irrigation lands, irrigation furrows, ditches, etc. should be restored.

3.2.6  Insulation works

Insulation of joints of steel gas pipeline shall be performed with heat-shrinking tape according to GOST-R 51164-98, GOST 9.6022005.

Surface Preparation:

- preliminary machining of the steel surface of the pipe. Using a grinding machine, filler or sandpaper, remove burrs, sharp grat edges from the steel surface of the pipe;

- drying of insulated surface. Using a gas burner, it is necessary to heat the insulated surface to a temperature of 40 ° C. The surface temperature is checked by a contact thermometer or pyrometer. The heated surface shall be free of soot, which is achieved by adjusting the burner flame;

- final machining and cleaning of the steel surface of the pipe. Using sandpaper, it is necessary to treat the steel surface of the pipe to the degree of cleaning 2 as per GOST 9.40280. Once finished, the pipe shall be light grey, with no traces of rust and scale. The surface of the pipe must not be greasy (if there are oil stains on the pipe, they must be removed with rags wetted in whitewash or other solvent) and dusty (dust must be removed with dry clean rags);

- processing of factory coating. To ensure high-quality shrinkage of the polymer coating, it is necessary to smooth the sharp edges of the factory insulation. It is recommended to mow the edges with a grinding machine or a filler at an angle of at least 30 ° to the pipe axis. Factory insulation shall be treated with sandpaper at a distance of 100mm from the edge on both sides of the weld. It is necessary to wipe the entire treated area of the pipe with clean, dry rags.

Installation of heat shrinkable tape:

- heating. Heat the steel surface and the factory insulation coating at a distance of 75100mm from the joint to a temperature of 110 ± 5 ° С (local surface overheating up to 120 ° С is allowed). The surface must be soot-free, as achieved by adjusting the burners;

- tape preparation. Cut the required tape size;

- tape installation. It is necessary to wrap the tape around the pipe with polyethylene coating up with a small slack from below. The tape overlap shall be at least 100mm and be located on the side of the pipe, the width of the tape shall cover the factory coating on both sides of the weld by at least 75mm. Heat the inner layer of the tape at the overlap with the flame of the burner (prevent shrinkage of polyethylene) and press the tape using a roller or heat-resistant gloves.

- installation of lock plate. Lock plate is installed on overlapping of heat-shrinking tape with polyethylene layer at the top. The middle of the overlap must pass in the middle of the lock plate. Before installation, the adhesive layer of the plate is heated until the adhesive is visually melted. Then lock plate is located on overlapping and it is heated by yellow flame of burner until overlapping circuits protrude and glue of heat-shrinking tape flows out. Further, it is necessary to roll the lock plate with a roller or a heat-resistant glove, if necessary, remove air bubbles from under it.

- heat shrinkage of the obtained cuff. Heat shrinkage of the resulting cuff must be started immediately after installation of the lock belt. Heat shrinkage is performed by gas burner. The flame of the burner shall be yellow and directed opposite to the wind direction. Shrink the tape from the weld to one side, then from the weld to the other side. At the same time, the tape sag is shrunk and the tape tightly covers the pipe along the entire surface. Tape shrinkage is performed by movement of burners along pipe diameter without lock tape heating. The bubbles and corrugations of the shrinkable tape must be smoothed with a roller or heat-resistant gloves.

Requirements for joint insulation:

- heat shrinkable tape shall tightly cover insulated surface of metal and factory pipe coating and have surface without bubbles, corrugations, folds, as well as without traces of polyethylene burning;

- the profile of the welded joint of the pipe, overlapping of the tape must pass through the insulation;

- on both sides of the joint, an adhesive of several millimeters shall protrude on the factory coating along the entire diameter of the pipe;

- the tape must cover the factory coating by at least 50 mm on both sides of the joint.

Instructions on how to exercise instrumental control over the production and quality of work

4.1  Quality control of earthworks

Operational quality control of earthworks performed by single-bucket excavators is carried out during construction and must meet the requirements of SNiP 3.02.0187 "earthworks, foundations and foundations."

Control over the performance of work and inspection of the quality of work is carried out daily by the work manufacturer (foreman) and the foreman of the excavation team.

Acceptance of completed excavation works on a certain site, object or structure is carried out by the master or manufacturer of works with the execution of an act containing instructions on the number and quality of works performed.

Upon acceptance of completed facilities or structures, the following shall be checked:

- conformity of geometrical dimensions of the structure to design dimensions, both in plan and in sections;

- compliance with design of trench base elevations;

The deviation of the dimensions of the earth structure from the design ones shall not exceed the tolerances specified in SNiP 3.02.0187 "earth structures, bases and foundations."

4.2  Welding Quality Control

During the construction of gas pipelines to ensure the required level of quality, the following are carried out:

- qualification check of welders;

- incoming quality control of used pipes, connectors and synthetic materials;

- technical inspection of welding devices as well as other process equipment;

- systematic operational quality control of assembly for welding and welding modes;

- visual inspection (external inspection) of welded joints and instrumental inspection of their geometric parameters;

- mechanical tests of welded joints;

- inspection of welded butt joints by physical methods (if necessary) in accordance with the requirements of SNiP 4201;

- quality control of performed works using a video camera;

- pneumatic tests of the installed gas pipeline at its commissioning in accordance with the requirements of SNiP 4201.

Check shall be performed according to the requirements and scope stipulated by SP 421032003, SNiP 4201, SP 42101, with equipment operation manual for compliance with passport data.

Inspection of welding equipment and process equipment in service is carried out in accordance with the recommendations of the service center. Date of technical inspection and its results shall be reflected in the work log.

Technical requirements

to quality control of welded joints

Acceptance and control joints made by welder in accordance with SNiP 4201 standards and SP 421032003 provisions shall be checked.

Welded joints rejected during external inspection and measurements shall not be corrected and shall be removed from the gas pipeline.

The list of test methods required during quality control of welded joints and the criteria for assessing the appearance of joints made with a heated tool is given in the corresponding sections of SP 421032003.

4.3  Gas Pipeline Testing and Acceptance

Acceptance of gas pipelines is carried out in accordance with the requirements of SNiP 4201 and the provisions of SP 42101, as well as with the following measures:

- Axial tension tests. When testing for axial tension, the elongation at break is determined (according to GOST 11262, with the exception of item 1.5 and item 4.2, the last paragraph). Based on the test results, a report is drawn up in accordance with Appendix C of SP 42101.

- Ultrasonic inspection. The number of welded joints subject to ultrasonic inspection should be determined according to SNiP 4201 standards depending on the gas pipeline laying conditions and the degree of automation of welding equipment.

- Pneumatic tests of welded joints. Pneumatic tests of the joints shall be carried out simultaneously with the tests of the entire gas pipeline constructed in accordance with the requirements of SNiP 4201 and the provisions of the section "Tests and acceptance of gas pipelines" SP 42103 and SP 42101.

- Flattening test. Tests are carried out on samples-segments by compression of pipes at the joint end to the value equal to double wall thickness.

- Tear-off test. Welded joints of pipes and saddle taps with embedded heaters are subjected to tear tests.

- Static bending test. Tests are carried out on strip samples with a weldment located in the center.

- Constant internal pressure test. Tests are carried out in accordance with the requirements of GOST R 50838 and GOST 24157.

- Long-term stretching test. Tests are carried out before cracks appear in at least 50% of tested samples. Test results are compared by mean time to crack occurrence.

- Impact resistance test. Joints made with crane saddle taps are subjected to impact resistance tests. Tests are carried out on samples in the form of branch pipes with saddle branch located in the middle.

- Leak tests. Site boundaries and test scheme are determined by working documentation. Leak tests of polyethylene gas pipelines are performed after full (up to design elevations) backfilling of the trench or after pulling of the polyethylene mould in accordance with the requirements of SNiP 4201 to this category of the gas pipeline and the provisions of SP 42101.

Justification for the need for temporary buildings and structures

7.1  Domestic premises

Considering that it is not possible to locate a temporary residential camp in close proximity to the construction site - it is not possible to provide for the placement of workers in the dormitories of the contractor and organize their delivery by road to the site of work.

7.2  Arrangement of storage sites

Pipes are stored according to GOST 15150. The height of the stack of pipes in sections during storage above 2 months shall not exceed 2 m. With shorter storage periods, the height of the stack should be no more than 3 m. Place temporary storage of pipes in place.

Basic Safety Guidelines and Fire Safety Measures

During construction and installation works it is necessary to follow the requirements of SNiP 12032001 and SNiP 12042002 "Safety of labor in construction."

At the construction site, areas dangerous to traffic should be marked with warning signs.

Work in the area of underground communications is allowed only with the written permission of the organization responsible for the operation of these facilities. Signs indicating location of underground utilities shall be installed prior to commencement of works.

In the places of detection of underground utilities not specified in the working drawings, earthworks must be stopped until the nature of communications is clarified and permission for the work is obtained.

Pits and trenches in places where the movement of people and transport passes must be fenced. Signal lighting must be set on the fences in the dark, pedestrian bridges with a width of 0.8m with railings of 1m are installed at the crossings through the trenches.

If it is impossible to remove the voltage from the overhead power transmission line, construction machines in the security zone of the power transmission line may be operated provided that the following requirements are met:

- the distance from the lifting or retractable part of the construction machine in any position to the energized overhead power transmission line shall be not less than 2.0m;

- machine bodies, with the exception of tracked vehicles, when they are installed directly on the ground, shall be grounded by means of inventory portable grounding.

All works shall be carried out under the supervision of the person responsible for safe performance of works. Workers of all specialties should be provided with protective helmets and workwear.

Workers must have certificates for the right to perform a specific type of work, and must also undergo safety training in accordance with the requirements of GOST 12.0.00.479, "SSBT. Organization of occupational safety training for workers. " Temporary domestic premises shall be equipped with automatic fire alarm with the output to the security station with round-the-clock duty.

Storage of lubricants and gas cylinders at the construction site is not provided. Deliver as required according to process requirements.

Electrical safety at the construction site and work sites shall be ensured in accordance with GOST 12.1.03081 *.

Timely training, study and verification of the knowledge of workers and technical personnel in the field of safety shall be carried out.

New construction workers can be admitted to work after receiving an introductory safety training and instruction directly at the workplace. In addition, within a period of not more than 3 months from the date of employment, they must be trained in safe working methods under the approved programme. Safety training shall be provided when transferring to a new job, as well as when working conditions change. Workers are allowed to work in particularly hazardous and harmful industries (installation of structures at height, refractory, acid-resistant and insulating works, processes using radioactive substances, etc.) only after appropriate training and passing the exam.

It is necessary to ensure high quality of materials, products, structures, construction machines and mechanisms, effective sound or light alarm. Construction equipment and devices used, as well as installation equipment, must meet all safety requirements and be certified by the relevant control bodies.

Lighting of non-working places during non-working hours, with the exception of duty lighting, must be turned off and wiring must be de-energized.

Systematic and rigorous monitoring of safety compliance is required.

Daily control. It is carried out by the foreman, foreman and public inspector for labor protection. At the beginning of the shift, the safety of construction and installation work and compliance with sanitary and hygienic services of workers are checked. Special attention is paid to the organization of work with increased danger. If a deviation from the accepted norms is found, the master is obliged to take urgent measures.

Weekly monitoring. It is carried out by the head of the site and the chairman of the commission on labor protection, mechanics and electrician. Checked by:

the state of safety and industrial sanitation;

operation of the first stage;

execution of the work execution project;

serviceability and safety of used machines, mechanisms, power plants and vehicles;

timely issuance of workwear and protective devices;

fulfillment of labor protection obligations, proposals and comments recorded in the inspection log at the first stage. All detected violations and deviations are recorded in the log.

Monthly control. It is carried out by the chief engineer, chief mechanic, chief power engineer and safety engineer. Checked by:

implementation of planned measures, decrees and orders to ensure safe working conditions and living conditions;

correct registration and reporting of accidents;

observance of the established deadlines and organization of tests of individual protective equipment, devices and other devices subject to periodic tests; operations of the first and second stages.

The results of the inspection are discussed at the meeting. The adopted decisions are drawn up in the form of an order.

Fire safety at the construction site and work sites shall be ensured in accordance with the requirements of the "Fire Safety Rules in the Russian Federation" PPB 0103 approved by the Ministry of Emergencies of the Russian Federation and the "Fire Safety Rules for Welding and Other Fire Work at Facilities."

At the construction site, it is necessary to ensure the correct storage of materials and products in order to prevent the ignition of flammable and combustible materials, to enclose welding sites, to remove construction debris in a timely manner, to allow smoking only in strictly designated places, to keep all fire extinguishing equipment (water supply lines with hydrants, fire extinguishers, alarm devices, fire equipment) in constant readiness.

Storage of oil paints, resins, oils and lubricants together with other combustible materials is not allowed.

Store gas cylinders under a canopy that protects against direct sunlight. Storage in one room of bottles with oxygen and combustible gases is not allowed.

Bonfires in the construction area are prohibited. All work related to the use of an open flame can be carried out with the permission of the person responsible for fire safety. During these works, fire safety measures shall be taken: cleaning of combustible materials, setting of fire stations, provision of fire extinguishing equipment, etc.

Environment and construction waste management conditions

When organizing construction production, it is necessary to carry out measures and work on environmental protection.

When performing vertical planning work, vegetation soil suitable for further use shall be cut, stored in specially designated places. When operating internal combustion engines, the soil layer cannot be irrigated with oils and fuel.

Waste and construction debris should be removed in a timely manner for further disposal. Burial of defective products and construction is prohibited. Incineration of combustible waste and construction debris at the construction site is prohibited. It is prohibited to reduce wood and shrub vegetation not provided for in the design documentation. Contaminated water must be trapped to prevent contamination of surface and above ground waters. All industrial and domestic effluents shall be cleaned.

It is not allowed to discharge water from the construction site directly to the slopes without adequate protection against erosion.

When preparing the facility for delivery, it is necessary to carry out a full range of work on vertical planning, landscaping and restoration of off-site sections of roads used during construction.

During works, it is forbidden to pass machines and mechanisms closer to 1 m from the crown of trees that do not fall into the clearing strip. If this requirement cannot be met, a special protective coating shall be laid within the specified area.

In order to protect the root system of trees, surface filling devices are necessary. Coarse sand, gravelly or crushed stone soils without harmful impurities are suitable for backfilling. It is not allowed to lay non-draining soils or layers of non-draining materials of any thickness within the root system. Removal of soil above the roots is not allowed.

Sections of branches are made in case of necessity near the trunk. The surfaces of the cut of branches, as well as roots, must be treated with special compositions against infection. In order to preserve trees in the area of ​ ​ work, it is not allowed: to hammer nails, pins, etc. into the trunks of trees to attach signs, fences, wires, etc.; tie wire to trunks or branches for various purposes; bury or clog pillars, necks, piles in the area of ​ ​ active tree development; fold materials, structures, put construction cars and trucks under the crown of the tree. In the area with a radius of 10 m from the barrel it is not allowed: to drain fuel and lubricants; install working machines; store on the ground chemically active substances (salts, fertilizers, toxic chemicals). Tree trunks shall be lined with lumber to a height of 2 m.

Places of incineration and burial (burial) of felling residues when clearing the route from the forest, if the residues cannot be used, shall be determined at the place taking into account fire and environmental safety with full responsibility of the contractor (exclusion of fire spread, formation of promontory, subsidence of soil in the places of burial, etc.).

Environmental protection requirements must also be observed in GOST 17.1.3.1386 "Nature Protection. Hydrosphere. General requirements for the protection of surface waters of pollution, "GOST 17.4.3.0285" Nature protection. Soil. Requirements for protection of fertile soil layer during earthworks, "GOST 17.5.3.0483" Nature Protection. Lands. General requirements for land reclamation, "GOST 17.2.2.0597" Nature protection. Atmosphere.

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