SNiP 3.05.03-85 - Thermal networks
BUILDING STANDARDS AND RULES
THERMAL NETWORKS
SNiP 3.05.03-85
USSR STATE COMMITTEE FOR CONSTRUCTION
Moscow 1996
DEVELOPED by the Orgenergostroy Ministry of Energy of the USSR( L. Ya. Mukomel -Candidate of Technical Sciences SS Yakobson).
was introduced by the Ministry of Energy of the USSR.
PREPARED TO APPROVAL by the Glavtechnormation of the USSR State Construction Committee( NA Shishov ).
With the introduction of SNiP 3.05.03-85 "Thermal networks", SNiP III-30-74 "Water supply, sewerage and heat supply. External networks and facilities ".
Coordinated with Gosgortechnadzor of the USSR on April 15, 1985
When using the normative document, it is necessary to take into account the approved changes to the construction norms and rules and state standards published in the magazine "Bulletin of construction equipment", "Compendium of changes to construction norms and rules" of the USSR Gosstroy and informationthe index "State Standards of the USSR" of the State Standard.
| State Committee of the USSR for construction | Construction regulations | SNiP 3.05.03-85 |
| Thermal networks | Instead of SNiP III-30-74 |
These rules apply to the construction of new, expansion and reconstructionoperating thermal networks transporting hot water with a temperature t ≤ 200 ° C and a pressure Py ≤ 2.5 MPa( 25 kgf / cm2) and a vapor temperature of t440 ° C and a pressure P6 of 6.4 MPa( 64 kgf / cm2) fromsource of heat energy to heat consumers( buildings, structures).
1. GENERAL PROVISIONS
1.1. In the construction of new, expansion and reconstruction of existing heating networks, in addition to the requirements of working drawings, production plans( PPR) and these rules, the requirements of SNiP 3.01.01-85, SNIP 3.01.03-84, SNIP III-4-80 andstandards.
1.2. The work on the manufacture and installation of pipelines subject to the requirements of the Rules for the Arrangement and Safe Operation of Steam and Hot Water Pipelines of the USSR Gosgortechnadzor( hereinafter - the Rules of the Gosgortechnadzor of the USSR) must be carried out in accordance with the specified Rules and the requirements of these rules and regulations.
1.3. Terminated heat networks should be commissioned in accordance with the requirements of SNiP III-3-81.
2. LAND WORKS
2.1. Earthwork and foundation works must be carried out in accordance with the requirements of SNiP III-8-76, SNIP 3.02.01-83, SN 536-81 and this section.
2.2. The minimum width of the bottom of the trench for non-channel pipe laying shall be equal to the distance between the outer lateral faces of the insulation of the outermost pipelines of the heating networks( associated drainage) with addition to each side for pipelines of nominal diameter Dy up to 250 mm - 0.30 m, over 250 to 500 mm- 0.40 m, more than 500 to 1000 mm - 0.50 m;the width of the trenches in the trench for welding and insulation of pipe joints for non-channel pipelines should be taken equal to the distance between the outer side edges of the insulation of the outermost pipelines with the addition of 0.6 m to each side, the pit length 1.0 m and the depth from the lower edge of the pipeline insulation -0,7 m, if other requirements are not substantiated by working drawings.
| | dated October 31, 1985 | was approved was issued on July 1, 1986. |
2.3. The minimum width of the bottom of the trench for channel laying of heat networks should be equal to the width of the channel, taking into account the formwork( on monolithic sections), waterproofing, associated drainage and drainage devices, a trench fixing structure with 0.2 m addition. At the same time, the trench width must be at least1,0 m.
If it is necessary for people to work between the outer edges of the canal structure and the walls or slopes of the trench, the width between the outer edges of the canal structure and the walls or slopes of the trench in the light must be not less than: 0.70 m - forI trenches with vertical walls and 0.30 m - for trenches with slopes.
2.4. Reverse backfilling of trenches for non-channel and channel pipelines laying should be carried out after preliminary testing of pipelines for strength and tightness, full implementation of insulation and construction and installation works.
The backfilling needs to be done in the specified process sequence:
the sinus filling between the ducts of the non-channel gasket and the base;
simultaneous uniform filling of the sinuses between the walls of trenches and pipelines in the case of channelless laying, as well as between the walls of the trench and the canal, the chamber with a channel laying to a height of at least 0.20 m above the pipelines, channels, chambers;
backfilling of the trench to project marks.
Backfilling of trenches( excavations) for which additional external loads( other than own weight of the ground) are not transferred, as well as trenches( excavations) at the intersections with existing underground utilities, streets, roads, driveways, squares and other facilities of settlements and industrialsites should be carried out in accordance with the requirements of SNIPIII-8-76.
2.5. After disconnection of temporary depreciation devices, channels and chambers should be visually inspected for the absence of groundwater in them.
2. LAND WORKS
2.1. Earthwork and foundation works must be carried out in accordance with the requirements of SNiP III-8-76, SNIP 3.02.01-83, SN 536-81 and this section.
2.2. The minimum width of the bottom of the trench for non-channel pipe laying shall be equal to the distance between the outer lateral faces of the insulation of the outermost pipelines of the heating networks( associated drainage) with addition to each side for pipelines of nominal diameter Dy up to 250 mm - 0.30 m, over 250 to 500 mm- 0.40 m, more than 500 to 1000 mm - 0.50 m;the width of the trenches in the trench for welding and insulation of pipe joints for non-channel pipelines should be taken equal to the distance between the outer side edges of the insulation of the outermost pipelines with the addition of 0.6 m to each side, the pit length 1.0 m and the depth from the lower edge of the pipeline insulation -0,7 m, if other requirements are not substantiated by working drawings.
| | dated October 31, 1985 | was approved was issued on July 1, 1986. |
2.3. The minimum width of the bottom of the trench for channel laying of heat networks should be equal to the width of the channel, taking into account the formwork( on monolithic sections), waterproofing, associated drainage and drainage devices, a trench fixing structure with 0.2 m addition. At the same time, the trench width must be at least1,0 m.
If it is necessary for people to work between the outer edges of the canal structure and the walls or slopes of the trench, the width between the outer edges of the canal structure and the walls or slopes of the trench in the light must be not less than: 0.70 m - forI trenches with vertical walls and 0.30 m - for trenches with slopes.
2.4. Reverse backfilling of trenches for non-channel and channel pipelines laying should be carried out after preliminary testing of pipelines for strength and tightness, full implementation of insulation and construction and installation works.
The backfilling needs to be done in the specified process sequence:
the sinus filling between the ducts of the non-channel gasket and the base;
simultaneous uniform filling of the sinuses between the walls of trenches and pipelines in the case of channelless laying, as well as between the walls of the trench and the canal, the chamber with a channel laying to a height of at least 0.20 m above the pipelines, channels, chambers;
backfilling of the trench to project marks.
Backfilling of trenches( excavations) for which additional external loads( other than own weight of the ground) are not transferred, as well as trenches( excavations) at the intersections with existing underground utilities, streets, roads, driveways, squares and other facilities of settlements and industrialsites should be carried out in accordance with the requirements of SNIPIII-8-76.
2.5. After disconnection of temporary depreciation devices, channels and chambers should be visually inspected for the absence of groundwater in them.
4. INSTALLATION OF
PIPELINE 4.1. Pipeline installation should be carried out by specialized installation organizations, and the installation technology should ensure high operational reliability of the pipelines.
4.2. Details, components of pipelines( compensators, mudguards, insulated pipes, as well as piping components and other products) must be manufactured centrally( in the factory, workshops, workshops) in accordance with standards, specifications and project documentation.
4.3. Laying of pipelines in a trench, canal or on above-ground structures should be carried out according to the technology provided by the design of works and excluding the occurrence of residual deformations in pipelines, violation of the integrity of the anticorrosive coating and thermal insulation by using appropriate mounting devices, the correct arrangement of simultaneously working hoisting machines and mechanisms.
The construction of fastening of mounting devices to pipes should ensure the safety of coating and insulation of pipelines.
4.4. Piping laying within the panel support must be carried out using pipes of maximum delivery length. In this case, the welded transverse seams of pipelines should, as a rule, be located symmetrically with respect to the shield support.
4.5. Stacking of pipes with a diameter of more than 100 mm with a longitudinal or spiral seam should be carried out with a displacement of these joints by at least 100 mm. When laying pipes with a diameter of less than 100 mm, the seams should shift at least three times the pipe wall thickness.
Longitudinal seams should be within the upper half of the circumference of the stacked pipes.
Steeply curved and stamped pipe bends can be welded together without a straight section.
Welding of branch pipes and bends in welded joints and bent elements is not allowed.
4.6. For the installation of pipelines, the mobile supports and suspensions shall be offset from the design position by the distance specified in the working drawings, in the direction opposite to the movement of the pipeline in working order.
In the absence of data in the working drawings, the movable supports and hangers of the horizontal pipelines must be offset with regard to the correction for the outside air temperature when mounted on the following values:
sliding supports and hanging fasteners to the pipe - half the thermal extension of the pipeline at the attachment point;
rollers roller bearings - a quarter of the thermal elongation.
4.7. Spring suspension for the installation of pipelines must be tightened in accordance with the working drawings.
During hydraulic testing of steam pipelines with a diameter of 400 mm or more, the unloading device should be installed in spring suspensions.
4.8. Pipe fittings should be installed in a closed condition. Flanged and welded joints of the reinforcement must be made without interference of the pipelines.
The deviation from the perpendicularity of the plane of the flange welded to the pipe with respect to the pipe axis should not exceed 1% of the outer diameter of the flange, but not more than 2 mm at the top of the flange.
4.9. Bellows( corrugated) and stuffing box expansion joints must be mounted assembled.
In the case of underground laying of heating networks, the installation of compensators in the design position is allowed only after the preliminary testing of the pipelines for strength and tightness, backfilling of pipelines for ducts, channels, chambers and panel supports.
4.10. Axial bellows and expansion joints should be installed on pipelines without fracturing the axes of expansion joints and pipeline axes.
The permissible deviations from the design position of the expansion joints of expansion joints during their installation and welding should be no more than specified in the technical conditions for the manufacture and supply of expansion joints.
4. 11. When installing bellows expansion joints, they are not allowed to twist relative to the longitudinal axis and sag under the weight and weight of the adjacent pipelines. Stretching compensators should be made only for the branches.
4.12. The mounting length of bellows and expansion joints must be accepted in accordance with the working drawings, taking into account the correction for the outside air temperature during installation.
Stretching the expansion joints to the installation length should be carried out using tools provided by the design of expansion joints, or tension mounting devices.
4.13. The stretching of the U-shaped compensator should be carried out after the installation of the pipeline, quality control of the welded joints( except for the closing joints used for tensioning) and fixing the structures of the fixed supports.
The expansion of the compensator must be carried out by the amount specified in the working drawings, taking into account the correction for the outside air temperature when welding the closing joints.
The expansion joint must be stretched simultaneously from both sides at joints located at a distance of at least 20 and not more than 40 pipeline diameters from the compensator axis of symmetry, using coupling devices, unless other requirements are justified by the design.
On the pipeline section between the joints used to stretch the compensator, do not pre-shift the supports and suspensions in comparison with the project( working project).
4.14. Immediately before assembly and welding of pipes it is necessary to make a visual inspection of each section for the absence of foreign objects and debris in the pipeline.
4.15. Deviation of the slope of pipelines from the design is allowed by ± 0.0005.In this case, the actual slope should be no less than the minimum allowed in SNiP II-G.10-73 *( II-36-73 *).
The movable pipe supports shall be adjacent to the supporting surfaces of the structures without clearance and misalignment.
4.16. When performing the installation work, the following types of concealed work are to be accepted with the preparation of certification reports according to the form given in SNiP 3.01.01-85: surface preparation of pipes and welded joints under anticorrosion coating;Execution of anticorrosion coating of pipes and welded joints.
To carry out the extension of the compensators, an act should be drawn up in the form given in the mandatory appendix 1.
4.17. The protection of heat networks against electrochemical corrosion must be carried out in accordance with the Instruction for the Protection of Heat Networks against Electrochemical Corrosion, approved by the Ministry of Energy of the USSR and the Ministry of Housing and Communal Services of the RSFSR and coordinated with the USSR State Construction Committee.
5. ASSEMBLY, WELDING AND QUALITY CONTROL
OF
WELDING CONNECTIONS GENERAL PROVISIONS
5.1. Welders are allowed to weld and weld pipelines in the presence of documents for the right to produce welding operations in accordance with the Welding Certification Rules approved by the Gosgortechnadzor of the USSR.
5.2. Before the work permit for welding of pipe joints, the welder should weld the access joint in production conditions in the following cases:
for a break in operation for more than 6 months;
when welding pipelines with a change in the group of steel, welding materials, technology or welding equipment.
On pipes with a diameter of 529 mm or more, it is allowed to weld half the perimeter of the inlet joint;In this case, if the sealing joint is a vertical non-rotary joint, the ceiling and vertical weld portions must be welded.
The tolerance joint should be of the same type as the production joint( the definition of the same joint is given in the Welding Rules of the Gosgortechnadzor of the USSR).
The tolerance joint is subjected to the types of control to which the production welded joints are subjected in accordance with the requirements of this section.
PRODUCTION OF WORKS
5.3. The welder is obliged to knock out or stamp the seal at a distance of 30-50 mm from the joint from the side accessible for inspection.
5.4. Before assembling and welding, it is necessary to remove the end caps, to clean up to the pure metal of the edge and the adjacent inner and outer surfaces of the pipes to a width of at least 10 mm.
5.5. Welding methods, as well as types, structural elements and dimensions of welded joints of steel pipelines shall comply with GOST 16037-80.
5.6. Pipe joints with a diameter of 920 mm or more, welded without the remaining backing ring, must be made with root root welding inside the pipe. When performing welding within the pipeline, the responsible executor must be issued a work permit for the production of work of increased danger. The procedure for issuing and the form of the permit must be in accordance with the requirements of SNiP III-4-80.
5.7. When assembling and welding joints of pipes without an underlay ring, the edging of the edges inside the pipe should not exceed:
for pipelines subject to the requirements of the Gosgortechnadzor Regulations of the USSR, in accordance with these requirements;
for other pipelines - 20% of the pipe wall thickness, but not more than 3 mm.
In pipe joints that are assembled and welded on the remaining backing ring, the clearance between the ring and the inner surface of the pipe must not exceed 1 mm.
5.8. The assembly of joints of pipes for welding should be done using mounting centering devices.
The correction of smooth dents at pipe ends for pipelines that are not subject to the requirements of the Gosgortechnadzor Rules of the USSR is allowed if their depth does not exceed 3.5% of the pipe diameter. Sections of pipes with dents of greater depth or having tears should be cut out. The ends of pipes with nicks or scuffs of chamfers with a depth of 5 to 10 mm should be cut off or corrected by surfacing.
5.9. When assembling the joint with hooks, the number of them should be for pipes with a diameter of up to 100 mm - 1-2, diameter from 100 to 426 mm - 3-4.For pipes with a diameter of more than 426 mm, the tack must be placed every 300-400 mm along the circumference.
Stitches should be located evenly around the perimeter of the joint. The length of one tack for pipes up to 100 mm in diameter is 10-20 mm, diameter from 100 to 426 mm is 20-40, diameter is more than 426 mm - 30-40 mm. The height of the tack must be at the wall thickness S up to 10 mm -( 0,6-0,7) S , but not less than 3 mm, with a larger wall thickness - 5-8 mm.
The electrodes or welding wire used for tackers should be of the same grades as for welding the main seam.
5.10. Welding of pipelines that are not subject to the requirements of the USSR Gosgortechnadzor Rules can be made without heating the welded joints:
at an ambient temperature of minus 20 ° C - when using carbon steel pipes with a carbon content of not more than 0.24%( irrespective of the pipe wall thickness), as well as pipes made of low-alloy steel with a wall thickness of not more than 10 mm;
at an ambient temperature of minus 10 ° C - when using carbon steel pipes with a carbon content of more than 0.24%, as well as pipes made of low-alloy steel with a wall thickness exceeding 10 mm.
When boglev low temperature outdoor air welding should be done in special cabs, in which the air temperature in the welded joints should be maintained at least the specified.
It is allowed to perform welding work in the open air when heating welded pipe ends at a length of at least 200 mm from the joint to a temperature of at least 200 ° C.After the end of welding, a gradual reduction in the temperature of the joint and the adjacent pipe zone should be ensured by covering them with an asbestos cloth or by using a different method.
Welding( at a negative temperature) of pipelines subject to the requirements of the Gosgortechnadzor Regulations of the USSR must be carried out in compliance with the requirements of the said Rules.
In the event of rain, wind and snow, welding work can only be carried out if the welder and the welding location are protected.
5.11. Welding of galvanized pipes should be carried out in accordance with SNiP 3.05.01-85.
5.12. Before the welding of pipelines, each batch of welding consumables( electrodes, welding wires, fluxes, shielding gases) and pipes must be subjected to the incoming inspection:
for the presence of a certificate, verifying the completeness of the data given therein and their compliance with state standards or technical specifications;
for the presence on each box or other packaging of the appropriate label or tag with verification of the data presented on it;
for the absence of damage( spoilage) of the package or the materials themselves. If damage is detected, the issue of the possibility of using these welding materials must be resolved by the welding organization;
on the technological properties of electrodes in accordance with GOST 9466-75 or departmental regulatory documents approved in accordance with SNiP 1.01.02-83.
5.13. When applying the main seam, it is necessary to completely cover and digest the stitches.
QUALITY CONTROL
5.14. Quality control of welding operations and welded joints of pipelines should be performed by:
checking the serviceability of welding equipment and measuring instruments, the quality of the materials used;
operational control during the assembly and welding of pipelines;
external inspection of welded joints and measurements of joint dimensions;
tests of continuity of joints by non-destructive methods of control - radiographic( X-ray or gamma-ray) or ultrasonic flaw detection in accordance with the requirements of the USSR Gosgortechnadzor Rules, GOST 7512-82, GOST 14782-76 and other standards approved in accordance with the established procedure. For pipelines that are not covered by the USSR Gosgortechnadzor Rules, it is permissible to use magnetographic inspection instead of radiographic or ultrasonic testing;
of mechanical tests and metallographic investigations of welded welded joints of pipelines subject to the requirements of the Gosgortechnadzor Rules of the USSR, in accordance with these Rules;
tests for strength and tightness.
5.15. When checking the quality of welded joints of steel pipes, it is necessary to check the compliance with the standards of structural elements and dimensions of welded joints( blunting and edge trimming, the size of the gaps between the edges, width and reinforcement of the welded seam), as well as welding technology and regime, the quality of welding materials, tack welds andwelded seam.
5.16. All welded joints are subject to external inspection and measurement.
Pipe joints welded without a backing ring with root root welding are subjected to external inspection and measurement of joint dimensions outside and inside the pipe, otherwise only on the outside. Before inspection, the welded seam and adjacent pipe surfaces must be cleaned of slag, spray of molten metal, scales and other contaminants for a width of at least 20 mm( on both sides of the seam).
The results of external inspection and measurement of the dimensions of welded joints are considered satisfactory if:
there are no cracks of any sizes and directions in the seam and adjacent area, as well as undercuts, sags, burns, unplated craters and fistulas;
the dimensions and the number of volume inclusions and sagging between the rollers do not exceed the values given in Table.1;
the dimensions of the defect, concavity and excess of the melting at the root of the seam of the butt joints made without the remaining cover ring( if the joint can be inspected from inside the pipe) do not exceed the values given in Table.2.
Joints not satisfying the above requirements are subject to correction or deletion.
Table 1
| Defect | Maximum permissible defect linear size, mm | Maximum allowable number of defects for any 100 mm seam length |
| Volumetric inclusion of round or elongated shape at nominal wall thickness of welded pipes in butt joints or smaller joint seam in angular joints, mm: | ||
| up to 5.0 | 0.8 | 2 |
| st.5.0 to 7.5 | 0.8 | 3 |
| »7.5» 10.0 | 1.0 | 4 |
| st.10.0 | 1,2 | 4 |
| The groove between the rollers and the scaly surface of the joint surface with the nominal wall thickness of the welded pipes in the butt joints or with the smaller joint in the joints, mm: | ||
| up to 15.0 | 1,5 | Notlimited to |
| st.15,0 | 2,0 | Same |
Table 2
| Pipelines to which the Rules of Gosgortechnadzor USSR | Defect | Maximum permissible height( depth),% of the nominal wall thickness | Maximum permissible total length along the joint perimeter |
| Distributed by | Concavity and non-penetration inroot | 10, but not more than 2 mm | 20% of the perimeter |
| Excess of the floating | 20, but not more than 2 mm | Same | |
| Do not extend | Concavity, excess penetration and penetration in the root of the joint | 10 | 1/3 permeter |
5.17. Weld connections:
of pipelines subject to the requirements of the USSR Gosgortechnadzor Regulations, with an external diameter of up to 465 mm - in the volume stipulated by these Rules, with diameters in excess of 465 to 900 mm - in the volume not less than 10%( not less thanfour joints) with a diameter of more than 900 mm - in the volume of at least 15%( but not less than four joints) of the total number of the same joints made by each welder;
pipelines, which are not subject to the requirements of the Gosgortechnadzor regulations of the USSR, with an external diameter of up to 465 mm - in the volume of at least 3%( but not less than two joints), with a diameter of more than 465 mm - in a volume of 6%( not less than three joints)joints performed by each welder;in the case of testing the continuity of welded joints by magnetographic inspection, 10% of the total number of joints subjected to inspection should be checked, moreover, by radiographic methods.
5.18. Non-destructive testing methods should be subjected to 100% welded joints of pipelines of heating networks laid in non-passages under the roadway, in casings, tunnels or technical corridors in conjunction with other engineering utilities, as well as at intersections:
of railways and tramways -not less than 4 m, electrified railways - not less than 11 m from the axis of the last track;
of the railways of the common network - at a distance of at least 3 m from the nearest construction of the roadbed;
of motorways - at a distance of at least 2 m from the edge of the roadway, a reinforced curb strip or the bottom of the embankment;
subway - at a distance of not less than 8 m from the facilities;
cables power, 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 rejected if non-destructive inspection methods check for cracks, unreleased craters, burns, fistulas, and also non-welds in the root of the joint made on the backing ring.
5.20. When checking radiographically the welded joints of pipelines subject to the requirements of the USSR Gosgortechnadzor Rules, pores and inclusions are considered as acceptable defects, the dimensions of which do not exceed the values indicated in Table.3.
Table 3
| Nominal pipe wall thickness, mm | Maximum permissible pore size and inclusions, mm | Total length of pores and inclusions for any 100 mm weld, mm | |||||
| of individual | clusters | chains | |||||
| width( diameter) | length | width( diameter) | length | width( diameter) | length | ||
| up to 2,0 | 0,5 | 2,0 | 0,8 | 2,0 | 0,5 | 3,0 | 4,0 |
| St 2,0up to 3.0 | 0.6 | 2.5 | 1.0 | 2.5 | 0.6 | 4.0 | 6.0 |
| "3.0" 5.0 | 0.8 | 3.5 | 1,2 | 3.5 | 0.8 | 5.0 | 10.0 |
| "5.0" 8.0 | 1.2 | 4,0 | 2,0 | 4,0 | 1,2 | 6.0 | 15.0 |
| "8.0" 11.0 | 1.5 | 5.0 | 2.5 | 5.0 | 1.5 | 8.0 | 20.0 |
| "11.0" 14.0 | 2.0 | 5.0 | 3.0 | 5.0 | 2.0 | 8.0 | 20.0 |
| "14.0" 20.0 | 2.5 | 6.0 | 4,0 | 6,0 | 2,5 | 9,0 | 25,0 |
Height( depth) of non-fusion, concavity and excess of the deposit in the root of the welded joint, made with one-sided welding without an underlay ring, not up tozhny exceed the values specified in Table.2.
Admissible defects of welded joints based on the results of ultrasonic testing are defects, measured characteristics, the number of which does not exceed those specified in Table.4.
Table 4
| Nominal pipe wall thickness, mm | Size of artificial corner reflector, mm 'mm | Allowable conditional length of single defect, mm | Number of defects for any 100 mm weld | |
| large and chalky) in total | of large | |||
| 4.0 to 8.0 | 2.0X1.0 | 10.0 | 7 | 2 |
| Sv. 8.0 "14.5 | 2.5X2.0 | 20.0 | 8 | 3 |
| " 14.5 "20.0 | 3, 5X2.0 | 20,0 | 8 | 3 |
| Notes: 1. A defect whose conditional length exceeds 5.0 mm with a wall thickness of up to 5.5 mm and 10 mm at a thickness ofIf the nominal length of the defect does not exceed the specified values, it is considered to be shallow 2. When electric arc welding without an underlay ring with unilateral access to the joint, the total conventional length of defects located in the root of the weld is allowed up to 1/3 of the perimeter of the pipe3. The amplitude level of the echo signal from the measured defect must not exceed the level of the echo signal amplitude from the corresponding artificial corner reflector( "notch") or an equivalent segment reflector. |
5.21. For pores that are not subject to the requirements of the USSR Gosgortechnadzor Rules, pores and inclusions are considered as acceptable defects in the radiographic method of control, the dimensions of which do not exceed the maximum permissible according to GOST 23055-78 for welded joints of the 7th class, as well as non-welded,melting in the root of the seam made by one-sided electric arc welding without an underlay ring, the height( depth) of which should not exceed the values indicated in Table.2.
5.22. If non-destructive methods detect unacceptable defects in welded joints of pipelines subject to the requirements of the Gosgortechnadzor Regulations of the USSR, repeated quality control of the seams established by these Rules should be carried out, and in welded joints of pipelines that are not subject to the requirements of the Rules - in the double number of jointsin comparison with that specified in clause 5.17.
In case of detection of impermissible defects during repeated control, all joints made by the given welder should be checked.
5.23. Correction by local sampling and subsequent welding( without re-welding of the entire joint) are subject to welded joints with impermissible imperfections if the sample size after removing the defective area does not exceed the values indicated in Table.5.
Welded seams, in the seams of which, in order to correct a defective area, it is required to sample the size of the boluses allowed in Table.5, should be completely removed.
Table 5
| Sampling depth,% of the nominal wall thickness of the welded pipes( design joint height) | Length,% of the nominal outer perimeter of the pipe |
| Up to 25 | Any |
| Constant 25 to 50 | No more than 50 |
| St 60 | "" 25 |
| Note. When fixing several sections in one connection, their total length may exceed the one indicated in Table.5 is not sore than 1.5 times at the same depth standards. |
5.24. The cuts should be corrected by surfacing the yarn rollers with a width of no more than 2.0 - 3.0 mm. Cracks must be drilled at the ends, cut down, carefully cleaned and brewed in several layers.
5.25. All patched areas of welded joints should be inspected by external inspection, radiographic or ultrasonic flaw detection.
5.26. In the execution drawing of the pipeline, compiled in accordance with SNiP 3.01.03-84, the distances between the welded joints, as well as from the wells, chambers and subscriber inputs to the nearest welded joints, should be indicated.
3. CONSTRUCTION AND INSTALLATION OF
BUILDING STRUCTURES 3.1. Construction and erection of structures should be carried out in accordance with the requirements of this section and the requirements:
SNiP III-15-76 - for the construction of monolithic concrete and reinforced concrete structures of foundations, supports for pipelines, chambers and other structures, as well as for embeddingjoints;
SNiP III-16-80 - when assembling prefabricated concrete and reinforced concrete structures;
SNiP III-18-75 - for the installation of metal structures of supports, span structures for pipelines and other structures;
SNiP III-20-74 - for waterproofing channels( chambers) and other building structures( structures);
SNiP III-23-76 - when protecting building structures from corrosion.
3.2. The external surfaces of the elements of the channels and chambers supplied to the track must be covered with a coating or a waterproofing in accordance with the working drawings.
Installation of the elements of the channels( chambers) in the design position should be carried out in a technological sequence, linked to the design of the installation and preliminary testing of pipelines for strength and tightness.
Support cushions for sliding supports of pipelines should be installed at distances provided for in SNiP II-G.10-73 *( II-36-73 *).
3.3. Monolithic fixed panel supports must be carried out after installation of pipelines in the area of the panel support.
3.4. In the places where the pipes for ductless laying are inserted into channels, chambers and buildings( structures), the enclosure of the gland should be worn on the pipes during their installation.
Devices that prevent the penetration of gas into buildings must be made( in accordance with working drawings) at the inlets of the underground laying pipelines.
3.5. Before installing the upper trays( slabs) the channels must be cleaned of soil, debris and snow.
3.6. Deviation of the slopes of the bottom of the channel of the heating network and drainage pipelines from the design one is allowed by the value of ± 0.0005, while the actual slope must be at least the minimum allowed in SNiP II-G.10-73 *( II-36-73 *).
Deviation of the installation parameters of other building structures from the design must comply with the requirements of SNiP III-15-76.SNiP III-16-80 and SNIP III-18-75.
3.7. The project of the organization of construction and the project for the production of works should provide for the advance construction of drainage pumping stations and devices for the production of water in accordance with the working drawings.
3.8. Before laying in a trench, drainage pipes should be inspected and cleaned of soil and debris.
3.9. The layer-by-layer filtering of drainage pipelines( excluding pipe filters) with gravel and sand must be performed using inventory separation forms.
3.10. The straightness of the sections of drainage pipelines between adjacent wells should be checked by inspection "on light" with a mirror before and after the trench is filled. The circle of the pipe reflected in the mirror must have the correct shape. The permissible deviation from the circle in the horizontal direction should not be more than 0.25 of the pipe diameter, but not more than 50 mm in each direction.
A vertical deviation from the correct shape of the circle is not allowed.
8. TEST AND WASHING
( PURGE) OF
PIPELINES GENERAL
8.1. After completion of construction and installation work, the pipelines must be subjected to final( acceptance) tests for strength and tightness. In addition, the condensate lines and pipelines of the water heating networks must be washed, the steam pipelines must be blown with steam, and the pipelines of the water heating networks with the open heat supply system and the hot water supply network - washed and disinfected.
Pipelines, laid out without channel and in non-flow channels, are also subject to preliminary tests for strength and tightness in the process of construction and installation works.
8.2. Preliminary testing of pipelines should be carried out before the installation of gland( bellows) expansion joints, sectioning valves, closing of channels and backfilling of pipelines of the channelless laying and channels.
Preliminary tests of pipelines for strength and tightness should be carried out, as a rule, in a hydraulic way.
In case of negative ambient temperatures and the impossibility of heating water, and also in the absence of water, preliminary testing by pneumatic means is allowed in accordance with the design of the work.
It is not allowed to perform pneumatic tests of aboveground pipelines, as well as pipelines laid in one channel( section) or in one trench with operating engineering communications.
8.3. Pipelines of water heating systems should be tested at a pressure equal to 1.25 working, but not less than 1.6 MPa( 16 kgf / cm2), steam pipelines, condensate lines and hot water networks - pressure equal to 1.25 working, if other requirements are not justifiedproject( working project).
8.4. Before carrying out the strength and tightness tests it is necessary:
to check the quality of welded joints of pipelines and to correct the detected defects in accordance with the requirements of section.5;
shut off the tested pipelines from the existing and from the first stop valves installed in the building( s);
install plugs at the ends of the tested pipelines and instead of gland( bellows) expansion joints, sectioning valves during preliminary testing;
provide access throughout the tested pipelines for their external inspection and inspection of welded joints at the time of testing;
open completely the valve and bypass lines.
The use of shut-off valves to disconnect the tested pipelines is not permitted.
Simultaneous preliminary tests of several pipelines for strength and tightness are allowed in cases justified by the design of the work.
8.5. Pressure measurements during pipeline testing for strength and tightness should be carried out in accordance with the established in the established order two( one - control) spring manometers of class not less than 1.5 with a body diameter of at least 160 mm and a scale with a nominal pressure of 4/3 of the measured.
8.6. Tests of pipelines for strength and tightness( density), their purging, washing, disinfection should be carried out according to the technological schemes( agreed with operating organizations), regulating the technology and safety engineering of work( including the boundaries of security zones).
8.7. The results of testing the pipelines for strength and tightness, as well as their washing( blowing), should be compiled according to the forms given in the mandatory annexes 2 and 3.
HYDRAULIC TESTS 8.8. Pipeline tests should be performed in accordance with the following basic requirements:
the test pressure must be ensured at the top point( mark) of the pipelines;
the water temperature during testing should not be lower than 5 ° C;
at a negative outdoor temperature the pipeline must be filled with water at a temperature of no higher than 70 ° C and allow filling and emptying it within 1 hour;
with the gradual filling of water from the pipelines should be completely removed air;
Thetest pressure shall be conditioned for 10 minutes and then reduced to a working pressure;
at working pressure, the pipeline must be inspected along its entire length.
8.9. The results of hydraulic tests for the strength and tightness of the pipeline are considered satisfactory if there was no pressure drop during the process, no signs of rupture, leakage or fogging in the welds, and leaks in the base metal, flange connections, fittings, expansion joints and other elementspipelines, there are no signs of shear or deformation of pipelines and fixed supports.
PNEUMATIC TESTS
8.10. Pneumatic tests shall be carried out for steel pipelines with operating pressures not exceeding 1.6 MPa( 16 kgf / cm2) and temperatures up to 250 ° C, assembled from pipes and components tested for strength and tightness( density) by the manufacturer in accordance withwith GOST 3845-75( in this case the factory test pressure for pipes, fittings, equipment and other items and piping parts should be 20% higher than the test pressure accepted for the installed pipeline).
Installation of cast iron fittings( except for malleable cast iron valves) is not allowed for the duration of the test.
8.11. Filling the pipeline with air and lifting the pressure should be carried out smoothly at a speed of not more than 0.3 MPa( 3 kgf / cm2) per hour. Visual inspection of the route( entrance to the guard [dangerous) zone, but without descending into the trench] is allowed at the pressure value, equal to 0.3 test, but not more than 0.3 MPa( 3 kgf / cm2).
For the inspection period of the route, the pressure rise must be stopped.
When the test pressure is reached, the pipeline must be designed to equalize the air temperature along the length of the pipeline. After equalizing the air temperature, the test pressure is maintained for 30 minutes and then smoothly reduced to 0.3 MPa( 3 kgf / cm2), but not higher than the operating pressure of the coolant;at this pressure inspection of pipelines with a mark of defective places is made.
The leakage points are determined by the sound of percolating air, by bubbles when coating welded joints and other places with a soapy emulsion and using other methods.
Defects are eliminated only when the excess pressure drops to zero and the compressor is turned off.
8.12. The results of preliminary pneumatic tests are considered satisfactory if, during the tests, there was no pressure drop across the manometer, no defects in welds, flange connections, pipes, equipment and other pipeline components and items, no signs of shear or deformation of the pipeline and fixed supports.
8.13. Water pipelines in closed heat supply systems and condensate lines should normally be subjected to hydropneumatic flushing.
Hydraulic rinsing with repeated use of rinsing water is allowed by passing it through temporary muds installed along the water flow at the ends of the supply and return pipelines.
Washing, as a rule, should be carried out by technical water. It is allowed to flush with household and drinking water with justification in the project of production.
8.14. Pipelines of water networks of open heat supply systems and hot water networks must be rinsed hydropneumatically with drinking water until the clarification of the washing water is complete. After the rinsing, the pipelines must be disinfected by filling them with water with an active chlorine content in a dose of 75-100 mg / l with a contact time of at least 6 hours. Pipelines up to 200 mm in diameter and up to 1 km in length are allowed, in consultation with local sanitary-epidemiological service, do not subject chlorination and limit it to washing with water that meets the requirements of GOST 2874-82.
After washing, the results of the laboratory analysis of the samples of washing water must comply with the requirements of GOST 2874-82.A conclusion is drawn up about the results of washing( disinfection) by the sanitary and epidemiological service.
8.15. The pressure in the pipeline during flushing must be no higher than the operating pressure. Air pressure during hydropneumatic flushing should not exceed the working pressure of the coolant and not be higher than 0.6 MPa( 6 kgf / cm2).
Water flow rates during hydraulic flushing should not be lower than the design speeds of the coolant specified in the working drawings, and for hydropneumatic - exceed the calculated speeds by at least 0.5 m / s.
8.16. Steam lines must be purged with steam and vented to the atmosphere through specially installed purging connections with stop valves. To warm up the steam pipe before blowing, all starting drains must be opened. The heating rate should ensure that there are no hydraulic shocks in the pipeline.
The steam speeds for blowing each section must be no less than the operating speeds with the design parameters of the heat carrier.
9. ENVIRONMENTAL PROTECTION
9.1. In the construction of new, expansion and reconstruction of existing thermal networks, environmental protection measures should be taken in accordance with the requirements of SNiP 3.01.01-85 and this section.
9.2. Not allowed without agreement with the relevant service: excavate at a distance of less than 2 m from the tree trunks and less than 1 m before the bush;moving cargo at a distance of less than 0.5 m to crowns or tree trunks;storage of pipes and other materials at a distance of less than 2 m to tree trunks without the device around them temporary protective( protective) structures.
9.3. Hydraulic piping should be rinsed with repeated use of water. Emptying of pipelines after flushing and disinfection should be carried out at the sites indicated in the project of production and agreed with the relevant services.
9.4. The area of the construction site after the completion of construction and installation works must be cleared of debris.
APPENDIX 1
Mandatory
ACT
ACCOUNT FOR EXPANSION OF COMPENSATORS
| d. _________________ | "_____" _______________ 19_____ | ||||||||||||||||||
Commission consisting of: representative of construction and installation company ______________________ ____________________________________________________________________( name, patronymic, post) of the customer's technical supervision representative___________________________ _____________________________________________________________( surname, name, patronymic, position) carried out an inspection of the works carried out __________________________________ ____________________________________________________________________( namesconstruction organization) and was present act as follows: 1. By inspection and acceptance charged compensators stretching listed in the table in the area from the chamber( picket shaft) to number ______ chamber( picket shaft) № ______.
2. The work was carried out according to the design estimates _______________ ___________________________________________________________________ ____________________________________________________________________ ( name of the project organization, numbersdrawings and the date of their drawing up) COMMISSION SOLUTIONThe work was carried out in accordance with the design estimates, the statestandards, building codes and rules and meet the requirements for their acceptance. Based on the above, consider the extension of the expansion joints listed in the certificate.
Representative of the Construction and Installation Organization _____________________ ( signature)
Technical Supervisor of the Customer ___________________________ ( Signature)
|
ANNEX 2
Mandatory
ACT
FOR THE TEST OF
PIPELINES ON STRENGTH AND SEALING
| ____________ | "_____" ___________ 19___ | |||
Commission consisting of: representative of the construction and installation company _______________________ _____________________________________________________________________( last name, first name, patronymic, position) of the customer's technical supervision representative ___________ ________ _______ __ _____________________________________________________________________( surname,name, patronymic, position) of the representative of the operating organization ____________________________ _____________________________________________________________________( surname, name, patronymic, position) carried out an inspection of the works carried out ___________________________________ _____________________________________________________________________( name of the construction and installation organization) and has drawn up this certificate as follows: 1. Pipelines tested for strength and tightness and listed in the table are shown for inspection and acceptance on the section from the chamber( picket, shaft) No. ________ to the camera( picket, mine) _______________ Route _____________________________________________ __________________________________ length __________ m.( Name of the pipeline)
2. Works performed in accordance with the design estimates _____________________________ ____________________________________________________________________ _____________________________________________________________________ ( name of the projectorganizations, drawing numbers and the date of their compilation) COMMISSION SOLUTION The works are executed in accordance with the design estimates, standards, building codes and regulations and fromechayut requirements of their acceptance. Based on the foregoing, consider the strength and leakproofness tests for the pipelines listed in the certificate. representative of the installation company _______________________ ( signature) technical supervision representative of the customer ___________ __________ _______ ( signature) representative of the operational organization ____________________________ ( signature) |
ANNEX 3
Required
ACT
ON THE WASHING( PURGE) PIPELINES
| . _____________________ | "_____" _______________ 19_____. |
| Commission consisting of: of the representative of the construction and assembly organization _______________________ ____________________________________________________________________ ( last name, first name, middle name, position) of the technical supervision representative of the customer ____________________________ ____________________________________________________________________ ( last name, first name, patronymic, position) of the representative of the operating organization ____________________________ _____________________________________________________________________( name,name, patronymic, position) performed an inspection of the works performed ___________________________________ _____________________________________________________________________( name of the construction and installation organization) and has drawn up this certificate as follows: 1. Pipeline flushing( purging) at the site from the chamber( picket, mine) No. __________ to the chamber( picket, mine) is submitted to the survey and acceptance. No_____ of the route _________________________________________ _____________________________________________________________________(name of the pipeline) with a length of ___________ m. Flushing( blowdown) was carried out _______________________________________ _____________________________________________________________________( medium name, pressure, flow) 2. Works performed on the projecto-budget documentation ____________________________________________________________________ _____________________________________________________________________( name of the project organization, drawing numbers and the date of their compilation) DECISION OF THECOMMISSION The works are executed in accordance with the design estimates, standards, building codes and rules and meet the requirements for their acceptance. On the basis of the foregoing, consider the flushing( purging) of the pipelines listed in the act performed. Representative of the construction and installation company _______________________( signature) Technical representative of the customer ____________________________( signature) Representative of the operating organization ____________________________( signature) |
6. THERMAL INSULATION OF
PIPELINE 6.1. Installation of thermal insulation structures and protective coatings must be carried out in accordance with the requirements of SNiP III-20-74 and this section.
6.2. Welded and flanged joints shall not be insulated for a width of 150 mm on both sides of the joints before the pipeline tests for strength and tightness.
6.3. The possibility of producing insulation works on pipelines subject to registration in accordance with the Rules of the Gosgortechnadzor of the USSR must be coordinated with the local Gosgortechnadzor of the USSR before carrying out tests for strength and tightness.
6.4. When performing filling and filling isolation for ductless laying of pipelines, the design of the work must be provided with temporary devices to prevent the pipeline from surfacing, as well as getting into the ground insulation.
7. TRANSITIONS OF THERMAL NETWORKS
THROUGH TRAVEL AND ROADS
7.1. Work on underground( overground) intersections by heating networks of railway and tram ways, roads, city driveways should be carried out in accordance with the requirements of these rules, as well as SNiP III-8-76.
7.2. When digging, punching, horizontal drilling or other ways of trenchless laying of cases, the assembly and clamping of the parts( pipes) of the case must be performed with the help of a centralizer. The ends of the welded links( pipes) must be perpendicular to their axes. Fractures of the axes of the links( pipes) of the cases are not allowed.
7.3. The reinforced shotcrete-concrete anticorrosion coating of cases with their trenchless laying should be made in accordance with the requirements of SNIP III-15-76.
7.4. Piping within the enclosure should be made of pipes of maximum delivery length.
7.5. The deviation of the axis of the transfer cases from the design position for gravity condensate lines should not exceed:
in vertical - 0,6% of the length of the case provided that the design slope of the condensate lines is provided;
horizontally - 1% of the length of the case.
The deviation of the axis of the transfer cases from the design position for the remaining pipelines should not exceed 1% of the length of the case.
