SY 0401 Std for Constr. & Acceptance of Oil & Nat. Gas PL Prjct. (ENG)

7/29/2019 SY 0401 Std for Constr. & Acceptance of Oil & Nat. Gas PL Prjct. (ENG).

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Standard for Construction and Acceptance

of Oil and Natural Gas Pipeline Project

SY 0401 - 98

Compiler: Chine Oil/Gas Pipeline Bureau Project Construction Corporation

Approving authority: National Petroleum and Chemistry Industrial Bureau

Petroleum Industry Publishing Firm

1999 Bei Jing



China Petroleum Standardization Committee (CPSC)

Catalogue

1. General Principles

2. Pile handover, Pile move, construction site cleaning,

measure and line layout and construction pavement building

2.1 General regulations

2.2 Pile handover, Pile move

2.3 Construction site cleaning

2.4 Measure and line layout

2.5 Construction pavement building

3．Pipeline Ditch

3.1 Size of Pipeline Ditch3.2 Ditch digging

3.3 Pipeline ditch acceptance

4. Main construction materials, pipeline accessories,

equipment and inspection


4.2 Material and equipment inspection and repair

5. Material storage and steel pipe loading,

unloading, transportation, and pipe laying

5.1 Material storage

5.2 Steel pipe loading and unloading

5.3 Vehicle transportation for the Steel pipe

5.4 Pipe laying

6. Pipeline anticorrosion and insulation project

7. Pipeline welding and acceptance


7.2 Pipe paring and welding

7.3 Welding seam inspection and acceptance

8. Pipeline laying and backfill

8.1 Pipeline laying8.2 Pipeline ditch backfill

9. Oil/gas pipeline pigging， pressure test, and gas pipeline drying


9.2 Pigging

9.3 Hydraulic pressure test

9.4 Air pressure test

9.5 Inter-station pressure test

9.6 Inter-station pigging

9.7 Pipeline drying

10 Pipeline crossing/spanning over projects



and underground pipeline/cables

10.1 Pipeline crossing/spanning over projects

10.2 Crossing over other pipeline and cables

11. Pipeline’s accessorial projects

11.1 Installation of block valve chambers and valves11.2 Cathodic protection project

11.3 Mileage Pile, turning point Pile, mark Pile and anchor Pile

11.4 Pipeline protection structures

12. Project completion and acceptance

Standard wording description

Attachment

“Standard for Construction and Acceptance of Oil and

Natural Gas Pipeline Project” Clause explanation




1.0.1 This standard is stipulated for the purpose to improve the construction standard of oil/gas

transmission pipeline projects, ensure the quality of pipeline construction, and lower the construction

cost.

1.0.2 This standard is applicable for the construction and acceptance of land oil/natural gas transmission

pipeline projects including new, rebuilding and expanding projects. This standard is not applicable for the

technical pipeline inside the oil/gas stations, oil/gas filed gathering transmission pipeline, city gas

transmission/distribution pipeline, the oil/gas pipeline inside industrial enterprises, rebuild and major

repair for the oil/gas pipeline which has been put into application.

1.0.3 Pipeline project construction can mainly divided into: measure and line layout, construction site

cleaning and construction pavement building, pipeline ditch digging, material and equipment inspection,

material storage and steel pipe transportation, pipeline anti-corruption and insulation, assembly and

welding, pipeline laying and backfill, pressure test, pipeline cleaning and drying, block valve installation,

pipeline crossing/spanning over project, and subordinate projects.

1.0.4 Before construction, it is necessary to carry out construction drawing joint checkup, design

explanation, and on site Pile handover, and keep good recording. Compile construction organization

design, properly arrange the construction according to the status of workload, project period, nature

conditions along the pipeline, etc.

1.0.5 Construction units shall erect quality assurance system, compile workable quality plan and

examination schedule, ensure project’s quality.

1.0.6 Enterprise undertaking the construction of oil/gas pipe line project must obtain the credential for oil

project construction enterprises issued by state or industrial authority, the contracted projects must within

the stipulated scope of the credential.

1.0.7 H.S.E., culture relic protection and other relevant requirements for the oil/gas pipeline project shall

be in accord with relevant state and local regulations.

1.0.8 Besides this standard, the construction and acceptance for oil/gas pipeline project shall be in accord

with state’s relevant compulsory standards (specifications).




2.1.1 After design unit and construction unit has finished control (turning point) Pile handover on site, the

construction unit shall carry out measuring and line layout, move the Piles to the edge of construction site,



then clean the construction site and build the construction pavement.

2.1.2 After ditch backfill, move the control (turning point) Piles to their original places.


2.2.1 When the design representative is handing over the control (turning point) Piles to the construction

unit, both sides shall check the Pile number, mileage, elevation and turning angle. After handover, the

construction unit shall take necessary measure to protect the control (turning point) Piles, any lost Piles

shall be re-measured and made up.

2.2.2 In plain area, Pile move shall use parallel moving method (see Fig. 2.2.2), move to the side for

assembly and welding, about 1 m inside the construction site boundary line. The turning point Piles shall

be moved to the direction of the angular bisector. The Piles after parallel moving are called auxiliary Piles.

In mountainous area, if Pile move is difficult, the guidance method can be used, i.e. set 4 guidance Piles

around the control (turning point) Pile, the cross point of their two diagonals is the position of the control

(turning point) Pile.

Fig. 2.2.2 Plain area Pile move method

Note: α is the equidistance for parallel moving


2.3.1 If without relevant prescription, the width of construction site generally shall be 20 m. At the section

crossing or spanning over the river, trench, road, railway, rich groundwater area, the area the pipeline ditch

is deeper than 5 m, or pipe car turning place, the width of construction site can be greater according to

actual necessity. In mountainous area for non-mechanical construction and in manual rock drilling area,

the width of construction site can be less.

2.3.2 In the construction site, clean the rocks, grass, or wood, level up the gutters or ridges, which might

affect the construction or machine passing, and drain the water accumulative area; be careful to protect the

soil layer, minimize or prevent water and soil loss.

2.3.3 When clean and level up the construction site, be careful to protect the construction mark Piles, if

there is any loss, recover it promptly.


2.4.1 Carry out the work of measure and line layout according to designed control (turning point) Piles or

their auxiliary Piles, must not willfully change the lines or positions. If it needs to alter the lines or

positions, it must be approved by design representative in written.

2.4.2 Pipeline measure and line layout shall lay out the pipeline’s axis line (or ditch digging side line) and

construction site boundary line. Set 100m-Piles on the pipeline’s axis line (or ditch digging side line) and

construction site boundary line, then tie the rope or spill the white lime between the Piles. The transect

layout for general section construction site is as Table 2.4.2.



2.4.3 If pipeline’s horizontal turning angle is big, it is necessary to add some Piles. For flexible laying

section or cold bend pipeline section, its horizontal turning angle shall be decided by relevant parameters

then lay the curve line on the ground. For the pipeline section using prefabricated elbow or bend, lay the

curve line according to curvature radius and angle.

Fig. 2.4.2 Construction site transect layout

2.4.4 For the pipeline at mountainous section or undulated landform section, its vertical angle grade

change point shall be laid the line according to grade change point position, angle, curvature radius and

other parameters marked on construction map or pipeline construction measure result sheet.

2.4.5 Mark Piles shall be set on the two sides of river, trench, road, railway, underground pipeline, cables,

optical fibers where the pipeline is crossing or spanning over, and the two sides of pipeline valve chamber,

the changing boundary of pipeline diameter, pipeline wall thickness, material, and anticorrosive layer; the

position of mark setting shall be on the side of pipeline assembly and welding, within 1 m of construction

site boundary line.


2.5.1 Construction pavement shall be flat, have enough carrying capacity, can ensure the safe running of

construction vehicles and equipment. The width of the pavement shall be greater than 4 m, and smoothly

connect to highway, at each 2 km shall set a car meeting place, the width at curve section and car meeting

section shall be greater than 10 m, the turning radius at curve section shall be greater than 18 m.

2.5.2 When the pavement is passing through riverlet or trench, make decision to see whether it is needed to

build a temporary culvert or to reinforce the original culvert according to actual situation, the carrying

capacity of the culvert shall be above 10 t.

2.5.3 When the pavement is built in the areas of marsh, paddy field, or desert, etc., take necessary

measures to reinforce the roadbed.

2.5.4 When the pavement is passing through underground pipeline, cables, trench or other underground

facilities, it is necessary to take proper protective measures.

3．Pipeline Ditch

3.1 Size of Pipeline Ditch

3.1.1 The depth of pipeline ditch shall be in accordance with design, the ditch depth at stone-work section

shall be 0.2m deeper than at earth-work section; the ditch depth at slope section shall be measured on

lower side of the cross-section of the ditch.

3.1.2 The gradient of ditch side slope shall be decided by earth type, mechanical property and the depth of

ditch. Within 5m of ditch depth (without support), the biggest ditch gradient can be decided from table



3.1.2.

Biggest side slope gradient

Earth type

Without top weight With top weight With moving top weight

Sand soil with intermediate density 1：1.00 1：1.25 1：1.50

Gravel soil with intermediate density

(filling material is sand soil)

1：0.75 1：1.00 1：1.25

Plastic light loam 1：0.67 1：0.75 1：1.00

Gravel soil with intermediate density

(filling material is clay soil)

1：0.50 1：0.67 1：0.75

Plastic clayey soil, clay soil 1：0.33 1：0.50 1：0.67

Old loess 1：0.10 1：0.25 1：0.33

Soft soil (through well point water) 1：1.00 - -

Hard rock 1：0 1：0 1：0

3.1.3 For the ditch deeper than 5m, its side slope may be gentler, supported or with steps.

3.1.4 Width of ditch bottom shall be decided by pipeline’s outer diameter, digging method, pipeline

assembling/welding technique and engineering geology elements, etc. for the ditch less than 5m deep, its

bottom width shall be decided by following formula (3.1.4):

B = Dm + K …………….. (3.1.4)

Of which:

B –— ditch bottom width (m), see Table 3.1.4;

Dm –— Steel pipeline’s total outer diameter (including anticorrosive layer and insulation layer) (m);

K –— overmeasure for ditch bottom (m); take the value from Table 3.1.4



Outside ditch welding Inside ditch manual arc

welding

Soil ditch Soil ditch

Conditions

With

water

Without

water

Rock

Blasting

ditch

Elbow,

cold bend

pipeline

ditch

With

water

Without

water

Rock

Blasting

ditch

Inside

ditch

Semi-auto

welding

ditch

Inside ditch

elbow, bend

and joint

welding ditch

Ditch depth

within 3m

0.7… 0.5 0.9 1.5 1.0 0.8 0.9 1.6 2.0K value

Ditch depth

in 3-5m

0.9 0.7 1.1 1.5 1.2 1.0 1.1 1.6 2.0

Note:

1. When use a machine to dig the ditch, if the calculated ditch bottom width is smaller than the scoop,

the actual ditch bottom width shall be the same as the scoop.

2. For inside ditch elbow, bend and joint welding, or semi-automatic welding, the overmeasure shall be

the scope 1m exceeding both sides of working point.

3.1.5 For the ditch deeper than 5m, its bottom width shall be decided by actual engineering geology

condition.

3.2 Ditch digging

3.2.1 Before digging the ditch, it is necessary to explain the distribution situation of underground facilities

to relevant construction workers. For the digging within 3m to underground facility shall be manual. For the facilities being dug out shall be properly protected. For important underground facilities, it must be

approved by relevant authority before start digging, or to dig under the authority’s supervision if necessary.

3.2.2 During digging, the excavated soil/stones shall be piled beside the ditch on the opposite side of

welding, 0.5m far from ditch side.

3.2.3 If digging in cropped area, the excavated surface layer soil and underlayer soil shall be separately

piled.

3.2.4 Blasting digging shall be finished before pipeline laying. Blasting operation shall be carried out by

qualified work team. Necessary safety protection measures and regulations shall be established including

safety distance without threatening the safety of nearby residents and passersby or damaging the

on-ground and underground facilities. For the important facilities that might be damaged by blasting, the

people in charge must inform relevant authority or person, only after taking necessary safety measures the

blasting can be started.

3.2.5 If there is any underground culture relic found during digging, the site must be properly protected

before reporting to relevant authority.




3.3.1 The tolerance for ditch central line, ditch bottom elevation, ditch bottom width, and grade change

point displacement shall be in accord with the specification of Table 3.3.1.

Table 3.3.1 Ditch Tolerance

Item Tolerance (mm)

Ditch central line displacement ＜100

Ditch bottom elevation + 50

-100

Ditch bottom width ±100

Grade change point displacement ＜100

3.3.2 Straight line pipeline section shall be straight; curve line pipeline section shall be smoothly bended,

and shall ensure the radius of designed curvature.

3.3.3 For stone section ditch, there must be no loose stones on ditch walls, and no stones under the ditch

bottom.

3.3.4 After finishing ditch digging, the acceptance procedure must be handled timely. If there is any

unqualified place, it must be fixed up straight away. Ditch inspection must be recorded properly. After

acceptance, the work handover procedure must be handled timely.

4. Main construction materials, pipeline

accessories, equipment and inspection


4.1.1 Construction materials, pipeline accessories, equipment materials, specification and types must

accord with design requirement, their quality must accord with relevant state or industrial standards.

Materials, accessories, and equipment shall have the certificate of conformity, certificate of quality

guarantee, material certificate and instruction, etc.

4.1.2 Pipeline accessories must not be made with cast iron, the elbows or bends are better to use seamless,

straight seam or double straight seam structure, not good to use spiral welding seam structure. The body of

elbows or bends shall not have T or O welding seam. The elbows or bends must be made and inspected in

accordance with relevant standards and design requirements.

4.1.3 Elbows, cold bends, flexible laying pipeline sections shall accord

with the prescription in Table 4.1.3.



Type Curvature radius R Appearance and mainsizes

Other regulations

Elbow ≥ 5 D No corrugation, crack,

repeat skin, mechanical

damage; when the ovality≤

2.0% and R = 5 D, the wall

thickness reducing rate

shall be ≤9.0%.

Can be cut into small angles,

but the length of short arc

shall be larger than 51 mm.

D≤323.9mm ≥30DCold bend

D≤323.9mm ≥40D

No corrugation, crack,


damage; the ovality≤ 2.0%

Keep the end with 2 m of

straight pipe, ovality≤ 1%

Flexible pipeline laying

section

≥1000D No corrugation, crack,


damage; the ovality≤ 2.0%

Design must accord

with requirment

Note: D is pipeline’s outer diameter.


4.2.1 The certificates of conformity, certificates of quality and certificates of material compositions for allmaterials, pipeline accessories and equipment used in the construction shall be inspected, if there is any

suspicion on their quality (or performance), it needs to double-check it, any unqualified ones must not be

used.

4.2.2 Check the deviations of steel pipe’s outer diameter, wall thickness, ovality according to the pipe

manufacturing standard. No cracks, scars, folds and other flaws whose deep has exceeded the lower limit

of deviation are allowed.

4.2.3 Fix up or eliminate any bending, concave, scar, flatting, and other harmful flaws on pipes before use

them:

1. Grind off any scars or interlayers on pipeline’s end, if not available, cut off this section of pipe, and

re-process a end bevel,

2. If the degree of pipe’s deformity or flatting has exceeded the relevant standard, this pipe must be

discarded.

3. Slight concave points not on focal point of stress with the depth not exceeding 2% of rating diameter,

length not exceeding 10 mm, might not be repaired, but they must not affect the joint welding. If there

are any concave points at welding place, this section of pipe shall be cut off.

4. Pipeline’s bending section must be cut off.

5. It is strictly prohibited to use laminating method for welding.



4.2.4 For any defects on welding seams, they shall be repaired according to the pipeline manufacturing

standard.

4.2.5 The material quality of elbows and bends shall be compatible with the physical, chemical and

welding characters of pipeline. The vertical welding seam on steel pipeline’s fire bending elbow or bend

shall be located on the 45 position of their inner arc. The deformity rate at any bending parts shall not

exceed 4.9% of pipeline’s rating diameter, and can meet the size for pig passing. The parameters of

pipeline’s bending angle, outer diameter, wall thickness, curvature radius, and material quality and type,

etc. shall be marked at each end of elbows and bends; other requirements shall accord with the Table 4.1.3

of this standard.

4.2.6 Carry out hydraulic pressure test before installing insulation joint and insulation flange, the test

pressure shall be 1.5 times of designed pressure, the pressure hold time shall be 5 min, no any leaking is

allowed. Clean away the remained water after test, and carry out insulation test. Use 500V ohmmeter to

measure the insulation test, its insulation impedance shall be greater than 2 MΩ.

4.2.7 Before installing pipeline block valve, carry out appearance inspection, valve’s opening and closing

inspection, and test the hydraulic pressure, whose requirements shall be in accord with Table 4.2.7.

Table 4.2.7 Block valve inspection and test stipulation

Item Content of inspection and test Standard

Sand hole No sand holeCase

Crack No crack Auxiliary equipment Complete

Appearance inspection

Anticorrosive layer for

underground valve

No leak point by electric spark

test

Opening and closing SmoothOpening and closing inspection

Opening/closing indicator Exact

Case strength test 1.5 times of maximum work

pressure, hold 5 min

No leakingHydraulic

pressure

Valve 1.1 times of maximum work

pressure, hold 2 min

No leaking

4.2.8 Various anticorrosive materials, including prime paint, base glue, and fix materials, shall go through

random covering or painting test before use according to relevant technical standard or design requirement;

if the test is unqualified, re-test the new samples with the doubled number of previous samples; if the test

still failed, this batch of products must not be put into application.






5.1.1 Storage for steel pipes, accessories, valves, painting materials, and other equipment and materials

shall accord with products’ instructions. During storage, it is necessary to inspect periodically to prevent

rusting, deforming, aging and performance reducing.

5.1.2 Glass cloth, plastic cloth, polythene, epoxy powder, coal tar enamel, inner (outer) swathing band,

welding material, heat shrink sleeve, etc., shall be stored in the storehouse, in which the epoxy powder and

welding material shall be stored at ventilative place, the relative humidity for long term welding rod

storage shall not exceed 60%.

Steel pipe, accessories, valve, pitch, coal tar enamel, etc., can be stored at open air place, the ground for

storing shall be flat without stones and water, with about 1%-2% gradient and drain. A pavement for car

and carne passing shall be built to the storage place, no power lines are hung above the ground. Storehouse

consisting of flammable or explosive products shall be equipped with fire fighting device according to

relevant regulation. .

5.1.3 Steel pipes or anticorrosive steel pipes shall be piled up by layers in same direction, the height of

piling shall not exceeding 3 m, with firm, without deformity or damaging anticorrosive layer. Steel pipes

or anticorrosive steel pipes of different specifications and quality shall be placed separately. Put some soft

mats between two layers, put two tiers of sleepers or sand bags under the bottom layer, the distance

between pipes and ground shall be bigger than 50 mm. For the purpose to ensure the stability of pile, use

some wedges to hold the pipes on the bottom layer firmly.

5.1.4 Store the valves with their original package, take necessary measure to keep off water.

5.1.5 Pitch is better to be stored on concrete ground, surrounded by fence; if the weather is hot, erect a sun

shed to keep off heat.


5.2.1 Use special sling to load or unload the pipes, the operation shall be gently to avoid knocking and

dropping. Be careful to protect the pipe ends and anticorrosive layer. If directly hook on the ends, must not

incur any break or scar on them.

5.2.2 Use pole-type sling for twin pipe lifting.

5.2.3 Pipe grabber can only allowed to grab the bare pipes shorter than 12 m, with gentle operation, must

not damage the pipe by forking or clamping, or hit or knock other objects.

5.2.4 When loading or unloading pipes at electrical controlled platform of railway station, the operation

shall be in accord with relevant railway industry regulations, and be approved by the administration

department of railway station.

5.2.5 During the course of vehicle running, lifting, loading and unloading, any part of any construction

equipment and tools shall keep a safety distance from overhead power lines, the safety distance is



stipulated as Table 5.2.5.

Table 5.2.5 The safety distance between construction equipment or tools and overhead power lines

Power line voltage

(KV)

＜1 1-35 60 110 220 330 n

Safety distance

(M)

＞1.5 ＞3 ＞5.1 ＞5.6 ＞6.7 ＞7.8 ＞0.01(n - 50)

+5


5.3.1 Steel pipe transportation shall accord with the relevant regulations of traffic department. When

transporting for the pipes in plain areas, the pile height shall not exceed 2.4 m; when transporting for the

pipes in mountainous areas, the pile height shall not exceed 2 m. The length for the pipes protruding out

the back of vehicle shall not exceed 4 m.

5.3.2 Before loading anticorrosive pipes, check the pipes’ anticorrosive degree and wall thickness, must

not mix the pipes of different anticorrosive degree and wall thickness together.

5.3.3 Take necessary measure to protect the pipes’ anticorrosive layer when transporting for the

anticorrosive pipes. Put rubber boards or other soft mats on the contact points between pipes and between

pipes and other objects. Cover the tying ropes with sleeves or other soft sleeves.

5.3.4 When anticorrosive pipes have arrived at construction site, the construction unit shall inspect the pipes one by one, and transact the handover procedure.

5.4 Pipe laying

5.4.1 Pipes shall be laid in accordance to the position, pipe type and anticorrosive layer stipulated on the

blueprint. Before laying, measure the perimeter and diameter of the pipe ends to ensure matching with

each other.

5.4.2 Place for piling the pipes shall be flat without stones and water and other hard roots or stems to

damage the anticorrosive layer. If necessary, put two tiers of earth, sand bags or straw bags under the

pipes.

5.4.3 The position of pipe piling shall keep far away from overhead power lines, and put as near as

possible to the pipeline. Distance between piles shall not be farther than 500 m.

5.4.4 Lay (build) pipe supports before laying pipes into ditch, each pipe shall have a pipe support

underneath. The height of pipe support at plain area shall be 0.4-0.5 m, for mountainous area, the height

may be various according to the landform. The pipe support may be built by earth, and tamp it. If it is not

handy to take earth, it can be replaced by sacks filled with soft material.

5.4.5 When laying the pipes, the degree of closing between pipes shall be proper, one end to another shall



be staggered about 1 diameter far, so as easy to clean the inner wall and end bevel of pipe and easy for

lifting. Pipelayer shall lift the pipes one by one when start to lay the pipes, if it needs to lift the pipes two

by two or more, necessary protective measures shall be taken to prevent damaging the anticorrosion layer.

5.4.6 If laying and assembling the pipes outside the ditch, the pipe edge shall have a safety distance to

ditch edge, this value is stipulated in Table 5.4.6.

Table 5.4.6 The safety distance A between pipe edge and ditch edge

Soil type Dry hard soil Wet soft soil

A (m) ≥1.0 ≥1.5

The distance from pipe support center (assembly pipe center) to ditch center (pipeline center) is calculated

by following formula (5.4.6):

K S≥Dm +—— + α + A （5.4.6）

2

hα = ——

i

In which: S ——distance from pipe support center (assembly pipe center) to ditch center (pipeline center)

Dm—— steel pipe structural outer diameter (m)

K —— ditch bottom overmeasure (m) (take the value from Table 3.1.4)

α —— horizontal projection distance of ditch side slope (m)

h —— ditch depth (m)

i —— side slope gradient (take value from Table 3.1.2)

A —— safety distance (m) (take value from Table 5.4.6)

5.4.7 When laying the pipes inside the ditch, 2 neighbouring pipes shall have about 100mm of distance,

with two ends staggered.


6.0.1 Anticorrosion and insulation for steel pipes, elbows and cold bends as well as on site repairs shall be

operated by the prescriptions of design and relevant standards.

6.0.2 Surface of anticorrosive layer shall be smooth, flat, no paint missing, folding, dripping, bubbles and

needle holes, or other flaws; the coating of anticorrosive layer shall be firm on the pipe; anticorrosive

repairs shall use the matchable materials to anticorrosive layer; the repair materials including polythene

heat shrink sleeve (tape), polythene cold adhesive tape, bicomponent epoxy powder repair liquid, and hot

melting repair stick, shall be used by the instructions of their manufacturers.

6.0.3 The anticorrosive status on pipeline anchor supports, crossing pipeline sections and cathodic

protection test line welding points shall be inspected by the QC personnel before going to next process.



The anticorrosive material used on cathodic protection test line welding point shall be matchable to

anticorrosive layer, and connect well with test line surface.

6.0.4 Anticorrosive layer at the sections in where the pipeline is going in/out the ground shall be 100 mm

higher than ground, protected by covering heat shrink sleeve or other protective measures. Covering of

heat shrink sleeve shall be smooth and no breaks and leaks.



7.1.1 Pipeline welding methods include manual welding, semi-automatic welding, automatic welding, or

combination of any above methods.

7.1.2 Welding equipment shall have the performance required by the welding design, with good working

status and safety feature, applicable for field working condition.

7.1.3 Before starting welding, constitute detailed welding process instruction according to the design

requirement, with which review the welding technique. Then base on the qualified welding technique,

constitute welding regulation. The evaluation for welding technique shall accord with the relevant

stipulation in “Steel Pipe Welding and Acceptance” SY/T 4103.

7.1.4 Welders shall have relevant certificates for welding. Welders’ qualification test shall meet the

relevant regulation in SY/T4103.

7.1.5 Under any of following environmental conditions, it is not allowed to start welding if no necessary

protective measure is taken:

1. raining or snowing;

2. relative humidity is exceeding 90%;

3. when in covered welding rod manual welding, the wind speed exceeding 8 m/s; when in gas

shielded welding, the wind speed exceeding 2.2 m/s; when in cored welding rod self protecting

welding, the wind speed exceeding 11 m/s.

4. environment temperature lower than that stipulated in relevant welding regulation.


7.2.1 Butt welding end bevel design shall accord with Fig. 7.2.1.

7.2.2 Equal wall thickness butt welding joint design shall accord with Fig. 7.2.2.

7.2.3 Unequal wall thickness butt welding joint design shall accord with Fig. 7.2.3 -1 ~ Fig. 7.2.3 – 3.

7.2.4 Pipe pairing shall accord with Table 7.2.4.

Fig. 7.2.1 End bevel design

Fig. 7.2.2 Equal wall thickness butt welding joint design

Fig. 7.2.3 – 1 Equal outer diameter, unequal wall thickness butt welding joint design

Fig. 7.2.3 – 2 Equal inner diameter, unequal wall thickness butt welding joint design

Fig. 7.2.3 – 3 Unequal inner/outer diameter, unequal wall thickness butt welding joint design



Table 7.2.4 Pipe paring regulation

Serial

No.

Inspection item Requirement

1 Inner-pipe cleaning No any wastes

2 Pipe mouth cleaning (within 10 mm) and

mouth trimming

No damage, rust, oil and or paint on pipe

mouth

3 Spiral welding seam or straight welding

seam level drop grinding

Grinding within 10 mm on the end to eliminate

the level drop, and make the surface smooth

4 Space length of spiral welding seam or

straight seam on two mouths.

Staggered distance bigger or equal to 100 mm

5 Staggered mouths and correction

requirement

Staggered mouths less or equal to 1.6 mm, evenly

located around the perimeter, some can use hammering

6 Short piece length of steel pipe Greater than pipe diameter, and not less than

0.5 m

7 Length of straight pipe between two neighbou-

ring flexible pipes of opposite directions

Greater or equal to 0.5

8 Length of straight pipe between two

neighbouring bends of opposite directions

Not less than pipe’s outer diameter, and not

less than 0.5 mm

9 Short arc length of mall angle elbow after

cutting

Greater than 51 mm

10 Pipe butting deviation Less or equal to 3”, no slanting cut is allowed

(bending jointing is prohibited)11 Twin pipe rotation welding platform Twin pipe is aligned, no jumping when turning

12 Manual welding work space Greater than 0.4 m (to pipe wall)

13 Semi-automatic welding work space Greater than 0.5 m (to pipe wall), two sides

greater than 0.8 m when welding in the ditch

7.2.5 Welding material shall meet the following requirements:

1. Welding rod shall not have break, mildew, grease, or rust; welding weld shall not have rust and

bending; welding flux shall not be degenerative; the purity and dryness of protective gas shall meet

the welding technical regulation.

2. Drying the welding rods of low hydrogen type before welding，the drying temperature shall be 350 ~

400 , constant temperature period is 1 ~ 2 h, then stored in 100 ~ 150 temperature after drying.

Only take the rods when using, and put them into the welding rod heat preservation tube, but the

reserve time shall not exceed 4 h. The spare rods of that day shall be reclaimed, and use them before

others after re-drying them. No more than 2 times for re-drying.

3. Drying temperature for cellulose welding rod shall be 80 ~ 100 , the drying time be 0.5 ~ 1 h. If

the packaging is good, and not moistened, the cellulose welding rod may not have to be dried.

4. During the course of welding, if it occurs that the welding rod cover has become red, is burning or is

seriously arc bias，this rod must been changed immediately.

7.2.6 During welding, following regulation shall be followed to protect the pipe and anticorrosive layer:



1. When start welding, don’t arc strike on the pipe wall other than on end bevel;

2. Connect the earthing line of welding machine to the pipe firmly, to prevent that the earthing line may

product electric arc with the pipe wall causing the burning on pipe;

3. For epoxy power anticorrosive pipe, before welding, wrap a round of protective band with 0.8 m

width over the pipe on two sides of welding seam, to prevent the pipe from being burned by flying

sparks.

7.2.7 Using of line-up clamp shall meet the following requirements:

1．When using internal line-up clamp, detach and move the line-up clamp after finishing root welding。

Keep the pipe stable when moving the line-up clamp.

2. When using external line-up clamp，only detach it after the root welding is 50% finished, the finished

root welding shall be divided into several evenly distributed sections.

7.2.8 Preweld warm-up shall meet the following requirements:

1. Carry out preweld warm-up with the temperature stipulated by welding technical regulation;

2. The interlayer temperature during welding shall not be lower than its warm-up temperature;

3. If welding two kinds of materials with different warm-up temperature requirement, take the material

requiring higher warm-up temperature as the standard;

4. Width of warm-up is during 50 mm of both sides of welding seam, use infrared thermoscope or other

gauge to measure the temperature. The temperature when finishing warm-up shall be higher than

stipulated temperature, but shall not be above 50 higher than it.

7.2.9 Pipe welding shall meet following requirements:

1. Downward welding shall accord with the stipulation of “Pipeline downward welding technical

regulation” SY/T 4071.

2. root welding shall melt thoroughly, with good back form. After finishing root welding, the welder

shall carefully check whether there is any crack; if there is, remove if before welding again.

3. Sand the welding point slightly; the welding points on neighbouring two layers shall not overlap each

other, shall be staggered above 20 mm;

4. During welding, be careful to control the interlayer temperature, reheat it if the interlayer temperature

is lower than prescribed.

5. When finishing each cover of welding, check the dregs carefully, remove the air holes and dregs etc.

on the surface, and clean the powder from grinding wheel also.

6. The diameter of welding rods used, welding polarity, current, voltage, welding speed, and rod sending

method, etc, shall meet the stipulation of welding technical regulation.

7.2.10 After finishing seam welding, clean the dregs and droppings on the surface.

7.2.11 Welding seams that need after-heat or heat treatment shall be handled according to the prescription

of welding technical regulation.

7.2.12 Every day before finishing work, cover the pipe mouth tightly to prevent the entering of exterior

things, be careful to prevent water entering for the pipes in ditch.



7.2.13 Welding point mark is composed by welder code or flow work welding group code and their

finished welding point quantity, it can be written on the surface of anticorrosive layer 1 m to the welding

point on downstream side (the direction of oil/gas flowing), and make welding record as well.


7.3.1 Inspect the appearance of welding seam firstly, if no problem, followed by flaw detection. The

appearance inspection shall meet the prescription of SY/T 4103 – 1995, Clause 6.4. The cover size of

welding seam shall meet following specifications:

1. Width: the width of end bevel’s upper mouth + (2 – 4) mm;

2.. Level drop：0 – 1.6 mm. Not exceeding 3 mm at local part, and the length not bigger than 50

mm.

7.3.2 For radial and sonar ultrasonic flaw detection, the welding seam acceptance standard shall adopt

“Oil/Natural Gas Steel Pipeline Butt Welding Seam Radial Photography and Quality Classification” SY

4056 standard and “Oil/Natural Gas Steel Pipeline Butt Welding Seam Ultrasonic Flaw Detection and

Quality Classification” SY 4065 standard. The qualified classes shall meet the following regulations:

1. If oil pipeline design pressure is less than or equal to 6.4 MPa, the qualified class is Class Ⅲ; if the

design pressure is greater than 6.4 MPa, the qualified class is Class Ⅱ.

2. If oil pipeline design pressure is less than or equal to 4 MPa, the qualified class for Class 1 and Class

2 areas is Class Ⅲ, and for Class 3 and Class 4 areas is ClassⅡ; if the design pressure is greater than

4 MPa, the qualified class is Class Ⅱ.

7.3.3 As necessity, the welding seam flaw detection acceptance standard can also select the prescription in

SY/T 4103 – 1995, Chapter 9.

7.3.4 Any one of following proportions can be selected for oil pipeline flaw detection:

1. After 100% ultrasonic flaw detection, take 5% of all finished welding points carried out by each

welder or each flow work welding group in one day to carry through radial flaw detection rechecking;

2. Without carry through ultrasonic flaw detection, only carry through radial flaw detection random

inspection. The proportion is 15% of all finished welding points carried out by each welder or each

flow work welding group in one day

7.3.5 Any one of following proportions can be selected for gas pipeline flaw detection:

1. After 100% ultrasonic flaw detection, carry through radial flaw detection rechecking for all finished

welding points carried out by each welder or each flow work welding group in one day, the

proportion of rechecking shall meet the following prescription:

Class 1 area 5%

Class 2 area 10%

Class 3 area 15%

Class 4 area 20%

2. Without carry through ultrasonic flaw detection, only carry through radial flaw detection random

inspection. The proportion of random inspection for all finished welding points carried out by each

welder or each flow work welding group in one day shall meet following prescription:

Class 1 area 10%



Class 2 area 15%

Class 3 area 40%

Class 4 area 75%

7.3.6 For radial flaw detection rechecking and random inspection, if the welding point number per day can

not achieve the prescribed proportion, it can be alternative to set each kilometer to be a test section, and to

test straight away after finishing welding by the prescribed proportion, evenly carry through rechecking

and random inspection.

7.3.7 During radial flaw detection rechecking and random inspection, if there is one welding point that is

not qualified, it is necessary to check with doubled number the other finished welding points carried out by

this welder or this welding group in this day or on this test section; if there is still more unqualified one,

then carry through radial flaw detection one by one for the rest of these welding points.

7.3.8 For the welding points on the pipeline that crossing/spanning over river, reservoir, highway, railway,

and crossing underground pipeline, cables or optical fibers, the welding points on the connection of steep

pipe and elbow, and for the end connection points after pressure test, shall carry through 100% radial flaw

test.

7.3.9 Eliminating and re-welding of defective welding points shall meet the prescription of SY/T 4103 –

1995, Chapter 10. For the pipes of Class X60 or above, after re-welding, they shall carry through

penetration test according to “Normal Pressure Steel Welded Tank and Pipeline Penetration Test Technical

Standard”, SY/T 0443.

7.3.10 The flaw detection personnel shall acquire the qualification certificate according to the regulation of

relevant authority, their inspection work shall be limited within the stipulated scope of their relevant grade.


8.1 Pipeline laying

8.1.1 After finishing welding, flaw detection and fix-up, the pipeline shall be laid into ditch and filled back

as soon as possible. For a work (machine unit) section, the continuous pipeline length laid outside the ditch

shall not exceed 8 km.

8.1.2 Before laying the pipeline into ditch, it is necessary to double-check the ditch depth, clean out all

fallen down soil, stones, water or ice/snow. For the ditch at stone section or desert section, the ditch

bottom shall be filled with 200mm thick fine soil firstly, the maximum granule diameter shall not exceed

10mm.

8.1.3 To lay the pipeline into ditch, it is better to use pipelayer, it is strictly prohibited to use bulldozer or

crow bar or other non-lifting tools. To use nylon lifting rope or rubber roller basket for lifting is preferable,

it is strictly prohibited to use steel rope directly for lifting. The height of lifting rope shall be around 1.5m.

The number of pipelayers is better for 3 sets, if the diameter of the pipeline is smaller than 500mm, 2 sets



is better. The distance of 2 hanging points shall be in accord with the specification in Table 8.1.3.

Table 8.1.3 Pipe laying hanging point distance

Steel pipe

Rating Dia-

meter (m)

100 150 200 250 300 350 400 450 500 600 650 700 800 900 1000

Maximum

Distance

(m)

6 9 12 13 15 16 17 18 19 21 2 23 24 25 26

8.1.4 Before laying the pipeline, electric spark leak detector shall be used to detect the pipeline’

anticorrosive layer, if there are any breaks or needle points, they must be fixed up immediately. The

voltage for detection shall be in accord with design or relevant standards.

8.1.5 Before laying the pipeline, be careful not to touch the ditch walls, if necessary, put some wooden

boards or straw bags on the walls where are protruding to avoid damaging pipeline’s anticorrosive layer.

The pipeline shall be properly laid on the central line position, the deviation to the central line shall be less

than 250mm. The maximum hanging height from ditch bottom to the pipeline shall be less than 250mm,

and the maximum hanging length shall be less than 15m.

8.1.6 Before laying the pipeline, the operation shall be directed by an appointed person. No one is allowed

to stay in the ditch section under pipe laying operation, proper protective methods shall be applied to avoid

pipe roll into ditch.

8.2 Pipeline ditch backfill

8.2.1 After pipeline has been laid into the ditch, backfill work must be carried out within 10 days. Before

backfill, if there is water in the ditch, the water shall be cleaned out then backfill the soil immediately. If

the water level in the ditch is high, and can not be drained completely, use some sand bags to press down

the pipeline to the bottom, then backfill the soil.

8.2.2 For the ditch at cropped area, the backfill shall be carried out layer by layer; the soil for surface

cultivation shall be laid on the top.

8.2.3 Before backfill, the test lead wire for cathodic protection shall be welded properly and led out to the

ground, or preserve the place without backfill it.

8.2.4 For the ditch at stone or desert section, firstly put the fine soil around the pipeline, the maximum

granule diameter of the fine soil shall not exceed 10mm. Backfill the fine soil to the height 300mm above

the pipeline, then backfill the original soil/stones, but stones’ maximum diameter shall not exceed 250mm.

8.2.5 On the pipeline end that for next time construction, leave over 30mm without backfill.

8.2.6 Backfill soil shall be 0.3-0.5m higher than ground surface, whose width shall be the same as the top



width of ditch, and shall have a regular form.

8.2.7 Damaged flood wall, field ridge, gutter, pavement, and other ground facilities, caused by

construction, shall be recovered to their original state.

8.2.8 For recovering of the land feature which has special requirement, shall recover it by required design.

8.2.9 For earth dike pipe laying, shall carry out the construction in accordance with the design. If there is

not a special design, dike’s top width shall be 1-2 m, side slope gradient shall be: clay 1: (1-1.5), sand soil

1: (1.5-2).

8.2.10 After backfill, for the ditch that might later on suffer from flooding or water soaking, necessary

measures shall be taken to prevent soil washing and pipeline floating, such as to tamp the soil, drain the

water or put sand bags on ditch top, etc.

9. Oil/gas pipeline pigging，pressure test, and gas pipeline drying


9.1.1 Oil/gas pipeline shall carry out sectional pigging and pressure test after backfill. If it is specially

required by the design, pipeline will also carry through inter-station pressure test and inter-station pigging

as well as gas pipeline drying before put into production.

9.1.2 Pipeline sections that are crossing (spanning) over the large or middle sized river, railway, grade 2

highway or above, or expressway, shall carry through separated pigging and pressure test.

9.1.3 After sectional pressure test is passed, the end connection welding seams only need 100% radial flaw

detection, without needing pressure test again. The pipeline block valves or other equipment which have

been pressure tested may not carry through pressure test with pipeline again.

9.1.4 If there is any leaking during pressure test, discharge the pressure before fix up the leaking, followed

by pressure test again.

9.1.5 Before pipeline pigging, pressure test and drying, compile a construction scenario, set up necessary

safety protection measure, and take full consideration of the safety of construction workers, nearby

residents and facilities, etc.

9.1.6 Selection of medium for the pressure test shall meet following prescription:

1. If condition allows, use clean water to be the medium for pressure test firstly;

2. For the pipeline on class 1 or class 2 area, air can be used as the medium for pressure test;

3. For the pipeline on class 3 or class 4 area, clean water shall be used as the medium for pressure

test.

9.2 Pigging



9.2.1 Use spherical pig to clean the pipeline before sectional pressure test for at least two times.

9.2.2 Set up temporary pig receiving and sending device for sectional pigging, the pig receiving device

shall set at higher elevation position, no residents and buildings within 50 m scope.

9.2.3 After water filling, the overmeasure of pig shall be 5% - 8% of pipeline’s inner diameter.

9.2.4 Before pigging, make sure that the block valve within the pigging section shall be in full open status.

9.2.5 The maximum pressure for pigging shall not exceed the pipeline’s design pressure.

9.2.6 Spherical pig shall be suitable for the curvature radius of pipeline’s bends.


9.3.1 Hydraulic pressure test shall be in accordance with the stipulation of “Liquid Petroleum Pipeline

Pressure Test” GB/T 16805.

9.3.2 The length for sectional hydraulic pressure test shall not exceed 35 km, the elevation difference shall

not exceed 30 m; if the elevation difference has exceeded 30 m, it shall be necessary to work out the

hydrostatic pressure at low point by this section’s vertical section chart, and work out the hoop stress at the

low point, the value of this hoop stress shall not be greater than 0.9 time of the pipeline’s lowest yield

strength。 The pressure value measured at the highest point shall be served as the standard, the pressure

value measured at the lowest point is the sum of test pressure and hydrostatic pressure.

9.3.3 When filling the pipeline with water, use batching sphere to prevent the air deposit in the pipeline.

The batching sphere can be taken out after pressure test. Do best to avoid opening the vent at the top part

of the pipeline.

9.3.4 The values of hydraulic test pressure, pressure hold time and allowable pressure drop when the

oil/gas pipeline is carrying out sectional pressure test shall accords with Table 9.3.4.

Table 9.3.4 The values for hydraulic test pressure, pressure hold time and allowable pressure drop

Classification Strength test Tightness test

Pressure value (MPa) 1.25 times of design pressure 1.1 times of design pressureOil pipeline

Hold time (h) 4 4

Pressure value (MPa) 1.1 times of design pressure Design pressureClass 1 area

gas pipeline Hold time (h) 4 24






gas pipeline Hold time (h) 4 24Allowable pressure drop (MPa) 1% test pressure value, and 1% test pressure value, and



not more than 0.2 not more than 0.1

9.3.5 Before adopting hydraulic pressure test for the overhead gas pipeline, it is important to work out the

strength of pipeline and its supporting structure, and reinforce it if necessary, to prevent pipeline and itssupporting structure from deforming.

9.3.6 Pressure test shall be carried out in the temperature above 5, otherwise it is necessary to take

freeze protection method.

9.3.7 Clean out the water deposited in the pipeline after pressure test is passed.


9.4.1 Sectional pipeline for air pressure test shall not be longer than 18 km.

9.4.2 Pressure gauge for pressure test shall be inspected and calibrated, and in the period of validity; its

precision shall not be less than 1.5 degree, measure scope is 1.5-2 times of maximum tested pressure, the

dial’s diameter not less than 150 mm, minimum scale can display 0.05 MPa. There are at least two pieces

of pressure gauges for pressure test, installed at the two ends of the tested pipeline respectively. The

measure of pressure hold time is started when the pressures at two ends are in balance. Set 1 thermometer

at each end of the tested pipeline and avoid exposing to direct sunshine, its minimum scale shall be equal

to or less than 1.

9.4.3 Valves and pipeline, and other devices can only be used after passing the press test. On-site hole

opening and welding shall meet the stipulations of relevant pressure vessel manufacture and installation

standards.

9.4.4 Pressure rising speed shall be steady and smooth without too fast, not exceeding 1 MPa/h. Stop the

rising respectively when the pressure is arriving at 0.3 and 0.6 time of test pressure values, and hold for 30

minutes, meanwhile inspect whether there is any abnormal instance, then continue to rise the pressure if

everything is normal.

9.4.5 When the inspectors are in leak checking, make sure that the pipeline’s hoop stress is not exceeding

20% of the rating minimum yield stress; during the period that the pipeline’s hoop stress is starting to rise

from 50% of the rating minimum yield stress to the highest test pressure, then drop to design pressure, not

other personnel are allowed to stay in the test area except the test inspectors, and the inspectors shall keep

above 6 m away from the pipeline. The test area is the scope within 50 m of distance to the test equipment

and tested pipeline.

9.4.6 Sequence for air pressure test is to pass the strength test firstly, followed by tightness test. The

pressure value and hold time for sectional air pressure test of oil/gas pipeline shall meet the prescription of

Table 9.4.6:

Table 9.4.6 Pressure value and hold time for air pressure test



Classification Strength test Tightness test

Pressure value (MPa) 1.25 times of design pressure 1.1 times of design pressureOil pipeline

Hold time (h) 4 4

Pressure value (MPa) 1.1 times of design pressure Design pressureClass 1 areagas pipeline Hold time (h) 4 24



9.4.7 Strength test is considered qualified if there is not any rupture or leaking on the pipeline; Tightness

test is considered qualified if the pressure drop is not greater than 1% of test pressure.


9.5.1 Before starting inter-station pressure test, make sure that the works for pipeline, block valves,

crossing/spanning pipeline section and pipe end connections have all been finished; the pipelines passing

in/out the stations, pig receiving/sending device and temporary drainages have all been installed.

9.5.2 Inter-station pressure test for oil pipeline is better to use water as the test medium; for gas pipeline, it

is better to use gas as the test medium.

9.5.3 Inter-station test pressure value is the design pressure value, the hold time is 4 h. Air pressure test is

considered qualified if there is not any rupture or leaking on the pipeline; hydraulic pressure test is

considered qualified if the pressure drop is not greater than 1% of test pressure and is less than 0.1 MPa.

9.5.4 Pressure rising speed shall be steady and slow. Stop the rising respectively when the pressure is

arriving at 0.3 and 0.6 time of test pressure values to inspect whether there is any abnormal instance, then

continue to rise the pressure if everything is normal. The important locations for inspection are pig

receiving and sending device, pigging bends, pigging T junctions, insulation joints (flanges), crossing

(spanning) pipeline sections, block valves, instrument connections, and end connection welding seams, etc.

The petrol inspectors shall keep communications with headquarters.

9.5.5 Before starting inter-station test, it is important to isolate away the other pipelines that are irrelative

to the tested pipeline, and take proper measure to prevent pressure misleading.


9.6.1 Inter-station pigging shall use station pig receiving and sending device, and use the pig that specified

by the design. The pig shall be usable for pigging T junctions and pigging bends.

9.6.2 Isolate away the other pipelines that are irrelative to the tested pipeline to prevent the entering of

wastes. The block valves in the pipeline shall keep in full open status.

9.6.3 Inter-station pigging is better to use compressed air, the air inlet is better to be positioned at the vent

pipe of pig sending barrel or at other proper places.



9.6.4 Dirt that having been cleaned out shall be put one row for one station, not allowed to pollute the

environment or be pushed to next station.

9.6.5 Inter-station pigging shall use the pig equipped with tracker, and have someone to follow the pig

moving during pigging; the pig follower shall keep communications with the headquarters.

9.7 Pipeline drying

9.7.1 Pipeline shall be dried before putting into production.

9.7.2 Before drying, use the pig to clean the water deposited in the pipeline for several times, clean again

after injecting the hygroscopic agent, then use dry air to blow away the volatile of hygroscopic agent until

the air’s dew point in the pipeline is 5 lower than the lowest environmental temperature under

transmission condition.

9.7.3 Measure the air dew point in the pipeline at pig receiving end, if it meets the prescription of Clause

9.7.2, test again after 2 hours; if the result of second test is still qualified, close the pipeline of this section.

9.7.4 Keep proper management of hygroscopic agent during the course of transportation, storage and

application, and take necessary safety measure to prevent fire and personnel poisoning. The waste liquid of

hygroscopic agent shall be disposed according to the relevant environmental protection regulation, must

not be freely drained to pollute the environment.




10.1.1 Construction and acceptance for pipeline crossing/spanning over projects shall respectively accord

with “Construction and Acceptance Specifications for Oil/gas Pipeline Crossing Over Project” SY/T4079

and “Construction and Acceptance Specifications for Oil/gas Pipeline Spanning over Project” SY 4047.

10.1.2 For the pipeline using case pipes for crossing, before the transmission pipeline being put into the

case pipe, the sacrificial anode strap shall be welded according to the design. After welding, test whether

the pipeline’s electric potential has met the requirement of protection potential. The pipeline’s insulation

support shall be installed firmly, the position of insulating mat shall be correct. The insulation support

must not connect with sacrificial anode strap.

10.1.3 Before the transmission pipeline has been put into the case pipe, it is necessary to carry out hidden

construction inspection, the dirt inside the case pipe shall be cleaned out. After leak detection for

anticorrosive layer has been finished and all are up to the requirement, the transmission pipe can be put

into the case pipe, then use 500V ohmmeter to test the insulation impedance between transmission pipeline

and case pipe, the impedance shall be larger than 2M Ώ. After all tests are qualified, seal two ends of the



case pipe according to relevant design requirement.


10.2.1 Under general situation, the pipeline shall cross other underground pipeline or cables from

underneath. The crossing work shall be carried out by construction design, and by the regulations of the

authority for these pipeline and cables, give them proper protection without damaging these facilities.

10.2.2 When oil/gas pipeline is crossing over other underground pipeline, their vertical clear distance shall

not less than 0.3 m; when crossing over underground communication cables or power cables, their vertical

clear distance shall not less than 0.5 m. On the cross point, the pipeline on its two sides within 10 m shall

be well anticorrosive and insulated.

10.2.3 If for the condition’s sake, when the pipeline is crossing over other pipeline, if their vertical

distance is less than 0.3 m, a solid insulating spacer must be used within these two pipelines, but in any

circumstance, their clear distance must not less than 50mm.


11.1 Installation of block valve chambers and valves

11.1.1 Civil construction for block valve chamber shall accord with the relevant stipulations of state’s

building project construction and acceptance specification.

11.1.2 Constitute a lifting installation scenario before block valve installation, properly arrange the cross

work of valve chamber civil construction and valve installation.

11.3 Valves shall be installed and inspected by the instruction of manual or manufacturer.

11.1.4 The underground pipeline and valve in the valve chamber shall carry through electric spark leak test

before backfill, to make sure that the anticorrosive layer and insulative layer is up to the standard.

11.1.5 The gaps left by the pipeline passing through the walls or foundation of the valve chamber shall be

stopped up tightly according to the design requirement.

11.1.6 The space around the underground pipeline and valve shall be backfilled with fine soil and tamped.

11.1.7 After finishing construction, recover the landform and clean the construction site properly, and

handle vertical arrangement according to the design requirement.

11.2 Cathodic protection project

11.2.1 Construction and acceptance for pipeline’s cathodic protection project shall accord with the

prescription of “Standard for Construction and Acceptance of Long Distance Transmission Pipeline

Cathodic Protection Project”



11.2.2 Test piles can only be installed after inspection; the port of test pile shall open/close very flexible

with good tightness; the line connection is correct, bolts’ specification meets the design requirement, and

the label plate is firm.

11.2.3 The connecting line between test line and pipeline shall use braze welding or heat melting welding,

the welding points shall be strong without false joint. Laying of test line shall leave certain excess, and

keep it protective when backfilling.

11.2.4 Test the natural potential before the cathodic protection being put into operation; after operation,

test the protection potential and protection current. The test record shall be complete. Inform the design

personnel quickly if the natural potential is abnormal.


11.3.1 Inspect the Mileage Pile, turning point Pile, mark Pile before acceptance, their surface shall be

smooth without breaking sides or corners, the allowable size difference is ±10mm, the strength of

concrete shall accord with design. Painting shall be smooth and even, use print form characters. The

positions and depth of burying shall accord with design.

11.3.2 The size, specification and material of the anchor Pile prefabricated parts shall accord with design

requirement. Be careful not to damage the pipeline’s base material. After welding, grind off the edges and

burrs, clean out the dregs and rust on the surface, the rust cleaning degree shall be up to Grade St3

stipulated in “Rust Grade and Rust Cleaning Grade for Steel Products Before Paint Coating” GB/T 8923.

The concrete can only be poured after the anchor Pile and the pipeline anticorrosive layer within 2 m area

having passed electric spark leak test. The concrete shall be properly maintained.

11.3.3 Setting up, mark content and mark format of mileage Pile, turning point Pile and mark Pile shall

accord with the stipulation of “Trunk Pipeline Mark Setting Technical Regulation” SY/T 6064.


11.4.1 Pipeline protection structures for bank protection revetment, pipe culvert, fortress or ridge, water

flooded road, water (soil) retention wall, and sand fixation, etc., shall accord with design requirement and

state’s relevant project construction specification.

11.4.2 Pipeline protection structures shall be built immediately after the pipeline has been laid into ditch,

and finished before the coming of rain (flood) season. Firstly start to build at the place where may affect

the safety of construction.


12.0.1 When the project is finished, the proprietor (supervision) unit shall organize the design and

construction units together to inspect the pipeline construction project before acceptance according to this

standard and design data.

12.0.2 During inspection and acceptance, use ground leak detector to test the pipeline’s anticorrosive layer



at random, the length of random inspection shall be 20% total pipeline length. The acceptable standard is

that there are not more than 5 leaking points within continuous 10 km pipeline length.

12.0.3 During inspection and acceptance, use depthometer to test the pipeline’s depth at random, the

number of random inspection is not less than 1 point for each kilometer. For the unacceptable points that

have been found out, detect out the scope of insufficient pipeline depth detailedly, and take necessary

measure for recovery.

12.0.4 During acceptance, the construction unit shall provide following completion map and key technical

data:

1. Pipeline laying completion map, separate crossing (spanning) project completion map;

2. Design modification and material replacement documents;

3. Construction contact paper;

4. Factory’s certificates of quality and certificates of conformity for the materials, pipes and equipment

provided, and equipment (blueprint) instructions;

5. After-heat and heat treatment report;

6. Pipeline welding record;

7. Anticorrosive and insulation project inspection report;

8. Flaw detection report;

9. Pipeline hidden project report;

10. Pipeline pressure test report;

11. Pipeline pigging report;

12. Gas pipeline drying report;

13. Cathodic protection device acceptance report;

14. Crossing (spanning) over river, railway and highway project acceptance report;

15. Valve pressure test report;

16. “3 Piles” burying statistic table;

17. Pipeline protection structures completion report;

18. Ground leak detection for underground pipeline anticorrosive layer report;

19. Pipeline depth detection report;

20. Project quality evaluation report.



Standard wording description

For the purpose to give different treatment for different instance when carrying out this Standard,

following wordings in this Standard shall have different degrees of strictness:

1. The word to express very strict, no other selections but to do so:

Positive word is “must”, negative word is “must not”;

2. The word to express strict, have to do so under normal situations:

Positive word is “shall” or “can”, negative word is “shall not” or “can not”;

3. The word to express a slight degree of optional, to do like this first of all if condition allows:

Positive word is “should” or “could”, negative word is “should not” or “could not”;

To express alternative or can do so under certain condition, the word is “may” or “might”.



Attachment

Standard for Construction and Acceptance

of Oil and Natural Gas Pipeline Project

Clause explanation

Revision explanation

In recent years, oil/gas pipeline construction has made great development, new technology and new

measures have been widely used in practice, the requirement on design is also higher than before. So the

previous “Standard for Construction and Acceptance of Long Distance Transmission Pipeline Project” SYJ

4001 – 90 is not more suitable for current situation, revision of this Standard has become necessary and

important.

This revision has absorbed the experience accumulated in recent years of pipeline construction, widely

asked for the advices of the construction personnel from all areas, and also consulted and quoted many

standards and specifications from at home and abroad, make effort to joint track with international

advanced construction stands and specifications, scientifically control the whole course of construction, so

as to ensure the projects’ quality and safety, and consider to lower the projects’ cost, evaluate the reasons

and operability of the Standard. Main content of modification is as below:

1. Name change. “Standard for Construction and Acceptance of Long Distance Transmission Pipeline

Project” is replaced by “Standard for Construction and Acceptance of Oil/Gas Pipeline Project”, the word

“long distance” is replaced by “oil/gas ”, it specifies the medium of transmission and represents the

industry’s feature.

2. The are many general characters among oil pipeline and gas pipeline, so they are compiled in one

standard. For their different requirements on construction, such as flaw detection, pipeline pressure test,

gas pipeline drying, etc., they are described separately.

We apologize for any errors or insufficient places in this revision. If you have found any problems in this

standard, please inform us (post code: 065000; address: No.46 Jin Guang Dao Rd., Lang Fang, He Bei

Province), we will review your opinions for the reference of next revision.

China Oil/Gas Pipeline Bureau

Project Construction Corporation

Jan. 1998



China Petroleum Standardization Committee (CPSC)

Catalogue









3．Pipeline Ditch


3.2 Ditch digging


4. Main construction materials, pipeline accessories,

equipment and inspection








5.4 Pipe laying







8.1 Pipeline laying


9. Oil/gas pipeline pigging， pressure test, and gas pipeline drying


9.2 Pigging





9.7 Pipeline drying
















1.0.1 This clause is to describe the purpose of constituting this standard. In recent years, pipeline project

has joined the tracks to international conventions in this field step by step, so to establish this standard is

to solve the problem of to joint track to international standards.

1.0.2 This clause is to describe the application scope of this standard. Oil/gas pipeline project denotes

petroleum/natural gas transmission trunk line and branch line projects. Because there are many general

characters among petroleum and natural gas transmission pipelines on their construction and acceptance,

so they are compiled in one standard. The transmission pipelines for hydrocarbon (gas, liquid), anhydrous

ammonia, alcohols, liquids, high-pressure water transmission steel pipeline for oil/gas fields, etc, their

construction requirements have not much difference from oil/gas transmission pipeline, if not other special

standards for them, they can refer to this standard. But this standard is not applicable for the technical

pipeline inside the oil/gas stations, oil/gas filed gathering transmission pipeline, city gas

transmission/distribution pipeline, the oil/gas pipeline inside industrial enterprises, rebuild and major

repair for the oil/gas pipeline which has been put into application, because they are much difference with

oil/gas pipeline, so they are not included in this standard.

1.0.3 It describes the main content of pipeline project. In which for pipeline anti-corruption and insulation,

assembly and welding, pressure test, pipeline crossing/spanning over project, they have separate

construction and acceptance standards. So except this standard, many specifications will refer to their

corresponding standards.

1.04 This clause is to specify the technical and managerial requirements. Before construction, compile the

construction design according to the project’s content, and set up detailed regulations under this standard

to direct the work. The design documents are the base of construction, so it’s necessary to acquire the

design’s detailed content and learn the design’s requirements by joint checkup, to ensure the best

construction work.

1.05 Basic requirements for quality assurance. It requires the construction units to erect quality assurance

system. The quality plan is the document that to make special quality measures and activity sequence for a

specified construction project.

1.06 By state’s construction regulations, the construction units shall have their relevant qualification and

technical degree as well as their work scope. They must not contract the projects that have exceeded their

technical degree and limited work scope.

1.0.7 H.S.E., culture relic protection and other relevant requirements shall accord with relevant state or

local rules and regulations.






2.1.1 Pipeline layout shall be surveyed by the design unit, and pipeline control Piles must be laid; design

unit and construction unit have to hand over the work on site. The works of Pile handover, Pile move,

construction site cleaning, measure and line layout and construction pavement building shall be finished

according to the prescribed work sequence.

2.1.2 Control Piles are the results of survey and design, they are the benchmark of other Piles. It is

necessary that after ditch backfill, move the control Piles to their original places.


2.2.1 By checking of the Pile number, mileage, elevation and turning angle, and making up of lost Piles, to

avoid the possible miPiles.

2.2.2 Because the design control Piles are within the ditch excavation scope, so they need to be moved in

parallel before construction, or to find out the original Piles by guiding. The auxiliary Piles may not be set

on the side piling the soil, because the piled soil may bury the auxiliary Piles, that will be difficult for later

work.


2.3.1 The width of construction site is stipulated by actual situation. Mechanical flow process will need

wider construction site, but the diameter of pipeline will have not much requirement on the site’s width, so

it is stipulated that the width of construction site is 20 m, but it can be increased for special land sections.

In mountainous area for non-mechanical construction, the width of construction site might not be limited.

2.3.2 Cleaning of construction site will provide favorable condition for the work of measuring, line laying

and machine/tool entering.


2.4.1 If the design is not reasonable, the line must not be willfully changed except after the approval of

design unit.

2.4.2 For the purpose to strictly control the pipeline’s axis line (or digging line) and boundary, set

100m-Piles then tie the rope or spill the white lime between the Piles.

2.4.3 - 2.4.4 Turning point and grade change point are the key control positions in pipeline construction, so

it needs to increase the Piles and lay the lines according to their parameters, so as to precisely control the

pipeline’s position.

2.4.5 To add mark Piles is for the convenience to find the positions of some special points and for

comparing inspection.


2.5.1 For economical and practical purpose, construction pavement does not consider the foundation and

drainage requirements, only consider the vehicle passing under favorable weather, and ensure that the pipe



layer can have 20 km/h speed on this pavement.

2.5.2 By pipe layer, it is defined that the carrying capacity of the culvert is 10 t.

2.5.3 Pavement shall be built in the area of marsh according to the condition of roadbed.

2.5.4 Many underground facilities and structures have not the design to allow the passing of heavy

construction machines and vehicles, so it is necessary to take proper protective measures when the pipeline

construction machines and vehicles are passing through these pavements.

3．Pipeline Ditch


3.1.1 Ditch depth at slope section shall be measured on lower side of the ditch, such can ensure the

covering depth of ditch; at stone-work section, the ditch depth shall be 0.2m deeper than at earth-work

section, this depth is for fine soil backfill on the bottom.

3.1.2 It stipulates the gradient of ditch side slope. In actual situation, there may be many vehicles passing

through, such as bulldozer, excavator, pipelayer, tractor, and pipe car, etc., so the side slope gradient shall

be decided by traveling load consideration. This data is in accord with “Oil Transmission Pipeline

Engineering Design Specification” GB 50263-94.

3.1.4 Ditch bottom width has been modified a little. At elbow or bend section, K = 1.5, because pipeline

will expand with hot and contract with cold, the position of elbow or bend may have some degree of

changing, only by increase the K value, can the affection be eliminated. When carry out welding in the

ditch, K = 1.6 by semi-automatic welding regulations; at flaw section, K = 2.0, because it must be

necessary to carry out radial flaw detection in ditch.

3.2 Ditch digging

3.2.1 Any underground facilities shall be properly protected. When use machine for excavation, it is very

easy to damage the underground facilities, such as cable and optical fiber, that may cause serious accident.

So it is stipulated that within 3m to the facility, the excavation shall be carried out manually.

3.2.2 For to preserve ground for construction, the excavated soil shall be piled on one side of the ditch.

3.2.3 For to protect surface layer of cropped soil.

3.2.4 To stipulate necessary blasting safety regulations.

3.2.5 According to culture relic protection regulation, the construction organization has the responsibility

to protect the underground culture relic from damage.



3.3 Ditch acceptance

3.3.1 This clause has consulted the relevant specifications on oil/gas filed gathering transmission line, the

pipeline ditch tolerance values have been stipulated.

3.3.4 Reinforce the handover work for ditch inspection, the purpose is to ensure the digging quality, to

avoid the problems which might occur during pipe laying.

4. Main construction materials, pipeline

accessories, equipment and inspection


4.1.1 Construction materials, pipeline accessories, equipment materials, specification and types must

accord with design requirement, their quality must accord with relevant state or industrial standards.

Materials, accessories, and equipment shall have the certificate of conformity, certificate of quality

guarantee, material certificate and instruction, etc. The relevant standards are as below:

1. Steel pipe standards:

GB/T 9711.1 Oil/Natural Gas Industry Transmission Steel Pipe Delivery Technical Issues, Part 1:

Grade A steel pipes

GB/T 8163 Seamless Pipes for Liquid Transmission

API Spec 5L Pipeline Specification

2. Pipeline accessories standards:

GB/T 13401 Steel Plate Butt Welding Pipes

GB/T 13402 Large Diameter Carbon Steel Pipe Flanges

SY/T 0510 Steel Butt Welding Pipes

SY/T 0516 Insulation Flange Design Technical Regulation

SY/T 5257 Steel Bends

3. Pipeline block valve standards:

GB/T 12234 Common Valves Flange and Butt Welding Connection Steel Gate Valves

GB/T 12237 Common Valves Flange and Butt Welding Connection Steel Ball Valves

SY/T 4102 Inspection and Installation Specification for the Valves

4. Welding material standards:

GB/T 5117 Carbon Steel Welding Rods

GB/T 5118 Low Alloy Steel Welding Rods

GB/T 5293 Welding Flux for Carbon Steel Submerged Arc Welding

GB/T 8110 Carbon Steel, Low Alloy Steel Welding Wires for Gas Protection Electric Arc Welding

5. Anticorrosive steel material standards:

SY/T 0315 Steel Pipeline Epoxy Powder Sintered Fused Exterior Coating Technical Standard

SY/T 0379 Underground Steel Pipe Coal Tar Enamel Exterior Anticorrosive Layer Standard

SY/T 0407 Pre-painting Steel Surface Pre-treatment Specification



SY/T 0414 Steel Pipe Polythene Glue Tape Anticorrosive Technical Standard

SY/T 0415 Underground Steel Pipe Hard Polyurethane Foam Plastic Anticorrosive/Insulation Layer

Technical standard

SY/T 0420 Underground Steel Pipe Petroleum Pitch Anticorrosive Layer Technical Standard

SY/T 0447 Underground Steel Pipe Epoxy Coal Pitch Anticorrosive Layer Technical Standard

SY/T 4013 Underground Steel Pipe Polythene Anticorrosive Layer Technical Standard

4.1.2 Please refer to “Gas Transmission Pipeline Project Design Specification” GB 50251 – 1994

(5.3.1.4) and “Oil Transmission Pipeline Project Design Specification” GB 50253 – 1994 (5.4.5.5)

(5.4.5.6), this clause has regulated that the pipeline’s accessories will not use cast iron and spiral pipe as

the materials.

Pipeline accessories must not be made with cast iron, the elbows or bends are better to use seamless,

straight seam or double straight seam structure, not good to use spiral welding seam structure. The body

of elbows or bends shall not have T or O welding seam. The elbows or bends must be made and

inspected in accordance with relevant standards and design requirements.

4.1.3 This clause mainly uses following standards:

1. Elbows: GB 50251 – 1994, Clause 4.3.13.1, “Petroleum, Anhydrous Ammonia and Alcohol Liquid

Pipeline Transmission System” ASME B 31.4 and “Gas Transmission and Distribution Pipeline

System” ASME B 31.8.

2. Cold bends: GB 50253 – 1994, Clause 5.4.12

3. Flexible laying: GB 50253 – 1994, Clause 4.2.3.


4.2.1 Inspection for quality and technical data is for the purpose to control the quality of materials,

accessories and equipment; for those key materials, accessories and equipment whose quality

(performance) may have important affection to the whole project, they must be re-checked if there is any

suspicion on them.

4.2.2 Check the steel pipes’ deviations and appearance to ensure the steel pipes’ quality.

4.2.3 For the treatment of defective steel pipes, the regulation of ASME B31.8 has been adopted. The

serious defections will affect the welding, pigging, and pipeline’s safety, so they must be cut off.

4.2.5 Regulations for elbows and bends have referred “Steel Bends” SY/T 5257.

4.2.6 Insulation joint hydraulic pressure test is decided by valve pressure test, insulation inspection is

decided by “Petroleum Construction Project Quality Inspection Evaluation Standard – Long Distance

Pipeline Project” SY 4029 – 93, Table 10.3.1.

4.2.7 Pressure test accords with “Valve Test and Installation Specification” SY/T 4102 – 95, Clause 4.2.1.1

and Table 4.2.2 – 2, and Clause 4.3.1.4 and Table 4.3.3 – 1, to confirm the pressure and hold time, in

which the tightness pressure is 1.1 times of work pressure, which is decided by pipeline pressure test.



4.2.8 For various anticorrosive materials, if anyone is found unacceptable in covering or painting test, it is

necessary to analyse the cause of failure; if it is because some technical problem on anticorrosive

processing flow, adjust and improve the technique before starting test again; if it is because of the material

itself, replace the anticorrosive material.




5.1.2 All glass cloth, plastic cloth, polythene, epoxy powder, coal tar enamel, inner (outer) swathing band,

welding material, heat shrink sleeve, etc., shall be properly stored to keep away from rain, and it is

required to keep them in the storehouse, and be on guard of fire. Keep ventilative and dry for the

storehouse containing special materials.

5.1.4 Prevent earth, sand/stone and rain going into the valves, store them with their original packages.

5.1.5 Requirement for storage of pitch: set concrete ground and fence, if the weather is hot, erect a sun

shed to keep off heat, so as to avoid that the pitch may melt and mix up with dirt, and pollute the

environment.


5.2.2 Because the length of twin pipe is longer (16 – 24 m), so it needs to use pole-type sling for lifting.

5.2.4 Because above the electrical controlled railway there are power lines, which is different from general

railways, so for the safety sake, the operation of loading and unloading shall be in accord with relevant

railway industry regulations, and be approved by the administration department of railway station.

5.2.5 This clause accords with “Safety Engineer Manual” publised by Si Chuan People’s Publishing House,

1995.


5.3.1 This clause is the safety regulation for the steel pipe vehicles when passing through the bridges,

tunnels, mountainous areas and slopes, etc.

5.3.3 To take necessary measure to protect the pipes’ anticorrosive layer when transporting for the

anticorrosive pipes is very significant, because it can minimize the repair and improve the quality.

5.4 Pipe laying

5.4.4 The height of pipe support for the pipe laying outside the ditch will vary by the landforms. Sacks to

be served as pipe support have the advantages of stable, soft and durable, not easy to damage the

anticorrosive layer, and they are light and easy to move. 0.4 m of height is to ensure the necessity of

welding.



5.4.5 Pipe layer may not lift the pipe more than 1 piece at one time, because it may knock each other when

in lifting, and thus may damage their anticorrosive layer.

5.4.6 In original standard, the distance between pipe wall to ditch edge shall be larger than 0.5 m; in this

revision, this distance has been modified to 1.0 m (moist soft soil is 1.5 m). The original standard is too

small, which will not be easy for the works of welding, anticorrosion and flaw detection, and more

important it is for safety sack, because the pipe might be easy to roll into the ditch. Sometimes pipe

welding work is ahead of ditch digging work, the edges of the excavating machine may exceed the ditch

sides for about 0.8 m. The given formula is to confirm the position of pipe laying.

5.4.7 When laying the pipes inside the ditch, 2 neighbouring pipes shall have about 100mm of distance,

with two ends staggered, the purpose is to avoid pipe end knocking, and for easy to clean the inside and

the bevel of pipes, as well as to take off the hook.


6.0.3 The anticorrosive status on pipeline anchor supports, crossing pipeline sections and cathodic

protection test line welding points are weak links, which are the key quality control points, so only after

these places have been inspected and approved qualified, the next process can be started.

6.0.4 Anticorrosive layers at the sections in where the pipeline is going in/out the ground are easy to be

damaged, and usually they are applied by 2 types of different anticorrosive materials, so they shall be

treated properly, and it is necessary to add heat shrink sleeves on them.



7.1.1 – 7.1.5 Constituted according to SY/T 4103. For detailed regulation see SY/T 4103.

7.2 Pipeline pairing and welding

7.2.1 – 7.2.3 According to the regulation of GB 50251 – 1994, Attachment H

7.2.4 The base standards for Table 7.2.4

3 Level drop grinding on the spiral seam and straight seam of pipe’s end can make the welding seam

smooth that will eliminate the source of cracking.

4 In accordance with “Standard for Construction and Acceptance of Long Distance Transmission

Pipeline Project” SYJ 4001.

5 In accordance with “Pipeline Welding and Relevant Equipment” API Std 1104 (4.2) and ASME B

31.8.

6 Basically in accordance with SYJ 0401. The length of short piece is modified to be bigger than

pipeline diameter, it will not affect the quality, and is more suitable for large-diameter pipeline

construction in mountainous area.



7 In accordance with GB 50251 – 1994 (4.3.14.1) .

8 In accordance with GB 50251 – 1994 (4.3.14.1) .

9 In accordance with ASME B 31.8 (841.233) and B 31.4, the length of short arc is bigger or equal to

51 mm.

10 In accordance with ASME B 31.8 (841.232) (a), the butting deviation is less or equal to 3.

7.2.5- 7.2.12 Basically in accordance with SY/T 4071 and the relevant construction technical requirements

in recent years.

7.2.13 Because the strength of steel material is high, so it is not proper to be steel-printed, just replaced by

pen marking, and write it on anticorrosive layer. These marks can maintain for a certain period, and can be

found out without damaging the anticorrosive layer.


7.3.1 The appearance inspection for this clause is in accordance with SY/T 4103; the cover size of welding

seam is basing on SY/T 4103, and integrating the pipeline’s construction characters.

7.3.2 This clause has adopted the standards of SY 4056 and SY 4065, but these two standards have not the

welding seam classification regulation for the oil/gas pipeline, so it adopts the API Std 1104 and SY/T

4103 standards.

7.3.3 This clause is served as the standard to be selected.

7.3.4 Define the proportions of flaw detection according to GB 50253.

7.3.5 Define the proportions of flaw detection according to GB 50251. The method for gas pipeline area

class classification see GB 50251 – 1994, Clause 4.2.2, as following:

Within 200 m along the pipeline’s center line, casually divide it into several sections with length 2 km

for each, and each of them can contain maximum households; they will be divided into 4 classes

according to the household number in each section. In the populated rural area, each separated house or

building will be counted as a household.

1. Class 1 area: the sections with household number is 15 or less;

2. Class 2 area: the sections with household number is above 15 and under 100;

3. Class 3 area: the sections with household number is 100 or above, including city suburb area,

commercial area, industrial area, economic development area, and other densely populated areas

not yet up to the Class 4 standard;

4. Class 4 area: the sections contains the buildings of 4 or more storeys (not including basements),

where the residents are wide and dense, traffic is busy and underground facilities are many.

7.3.6 This clause is to ensure the quality of re-check and random inspection.

7.3.7 This clause is for the regulation of doubled-number inspection.

7.3.8 For to ensure the quality of important welding points, it is required to give 100% flaw detection for



them.

7.3.9 Re-welding of defective welding points. Adding the regulation that penetration test is necessary for

the re-welding of X60 or above steel material.


8.1 Pipeline laying

8.1.1 This clause is to protect the pipeline’s anticorrosive layer and avoid affecting the work and living

activities of nearby residents. The welded pipes outside the ditch shall be laid into the ditch as soon as

possible.

8.1.2 There is not much variance comparing with original standards. The requirement for fine soil is added.

By experience, the maximum granule diameter 10mm will basically have not affection on anticorrosive

layer.

8.1.5 The stipulated pipeline’s maximum hanging height and long is to prevent that after backfill, the

pipeline might suffer from high bending stress.

8.1.6 Measures for preventing pipe rolling include: put safety cross arms on the top of ditch, or use a

tractor to pull the pipes transversely.


This clause mainly gives stipulations on backfill, pipe floating preventing, backfill at stone section, land

feature recovering and earth dike constructing, etc.

9. Oil/gas pipeline pigging，pressure test, and gas pipeline drying


9.1.1 This clause regulates the sectional pigging and pressure test, and matches with the design

specification. Inter-station pressure test and inter-station pigging have not been included in the design

specification, they are carried out just by the project’s condition. But in recent years, for some pipeline

projects with higher quality requirement, they have special requirements on inter-station pressure test,

inter-station pigging and as gas pipeline drying.

9.1.2 Regulation of separated pigging and pressure test for pipeline sections that are crossing (spanning)

over other objects.

9.1.3 Regulation for the end connection welding seams, pipeline block valves and other equipment that

they don’t need repeated pressure test. Please refer to ASME B 31.8.

9.1.5 It gives the regulation for the safety of construction workers, nearby residents and facilities during



pipeline pigging and pressure testing. ASME B 31.8 is consulted.

9.1.6 In according with GB 50251 and GB 50253, it regulates the use of medium for pressure test.

9.2 Pigging

9.2.1- 9.2.6 These 6 regulations are made by reviewing the pigging experience, the purpose is to ensure the

quality of pigging. Select high place for pig receiving end is to avoid back filling of drainage.

9.3.2 Because the hydraulic pressure test has the regulation of “Liquid Petroleum Pipeline Pressure Test”

GB/T 16805, so this chapter has fewer regulations on operation and equipment. The length for sectional

hydraulic pressure test shall not exceed 35 km, which is 15 km longer than previous 20 km, this is because

the construction quality has been improved in recent years, the ratio of success in pressure test is higher, so

longer pressure test section not only can improve the work efficiency, but also can minimize the work of

pipe end connection and the wastage of water, and can improve the project’s economic benefit as well.

9.3.3 Air discharging by hole opening in the past is replaced by adding batching sphere at present, so it can

minimize the hole opening on pipeline.

9.3.4 The values of hydraulic test pressure and pressure hold time are all in accordance with GB 50251,

GB 50253. The allowable pressure drop is in accordance with previous standard. When the pipeline’s

height difference exceeds 30 m, work out the hoop stress at the lowest point, this regulation can ensure to

avoid overpressure.


9.4.1 It is recommended that the sectional pipeline for air pressure test is not more than 18 km, which is 3

km longer than gathering pipeline’s specification, it is because the gas pipeline can be classified by areas,

and the strength test pressure is lower comparing with previous specification, plus the ratio of success in

recent years is improved, so it can be 3 km longer than before, such can also reduce the pipeline’s end

connections.

9.4.2 – 9.4.4 The conventional regulations to ensure the precision and safety of pressure test.

9.4.6 The pressure value and hold time is in accordance with GB 50251, GB 50253.

9.4.7 The acceptance standard for the pressure test is completely consulting the specification of natural gas

gathering transmission pipeline. It is reasonable to consider that the strength pressure test is acceptable if

there is no rupture and leaking on the pipeline, because its pressure hold time is short, it is mainly for

checking the pipeline’s status. But the time for tightness test is longer, so it is mainly for checking the

pressure drop.


9.5.1 This clause is the regulation in accordance with GB 50253.

9.5.2 The mediums for the inter-station pressure test are recommended for oil and gas transmission



pipelines respectively. After sectional pressure test, gas pipeline will not be dangerous to use air for

pressure test, such can also reduce the work of pipeline cleaning and drying after water pressure test. By

considering it is practicable and can reduce the cost, so air is recommended to be the medium for gas

pipeline inter-station pressure test. For oil pipeline, use oil pump for water pressure test.

9.5.3 Inter-station pressure test is for the purpose to further inspect the tightness of whole pipeline, so the

test pressure is only the design pressure, and the hold time is 4 h only. Inter-station gas pressure test does

not need to test the pressure drop, only needs to keep watch and hold the pressure for only 4 h.

9.5.4 The regulation for the work content during the course of pressure test.

9.5.5 To prevent the other pipeline sections to be affected by pressure misleading.

9.6. Inter-station pigging

This chapter only gives general regulation. Because inter-station distance is long, so it needs to use the pig

equipped with a tracker.

9.7 Pipeline drying

9.7.1 The regulation in accordance with GB 50251.

9.7.2 – 9.7.3 The regulation to ensure the quality of drying. Use the pig to clean the water deposited in the

pipeline, use the hygroscopic agent to absorb the residual water, then use dry air to blow the pipeline.

9.7.4 It regulates the safety issues of using. The common hygroscopic agent is methanol, poisonous and

flammable, shall be properly stored.




10.1.1 SY/T4079 and SY 4047 has stipulated special requirements for pipeline crossing/spanning over

project, including pipeline pressurization requirement. When carry out this standard, those two

specifications must also be carried out.

10.1.2 In recent years, the design is more frequent that to install the sacrificial anode strap onto the

transmission pipeline in the case pipe, so relevant install and inspection requirements are added.

10.1.3 If the insulation between pipeline and case pipe is not good, it will make the sacrificial anode strap

invalid. This clause has consulted the technical requirements of insulation flange, the insulation impedance

is regulated on 2M Ώ.




10.2.1 – 10.2.3 This 3 clauses are newly added, the purpose is to better protect other underground pipelines

and communication/power cables, at the same time to protect the oil/gas pipelines also. Of which, the

distance specification is in accordance with ASME B31.8 and GB 50251.



11.1.1 After the valve chamber is built, the heavy and bulky valve might not be easy to be moved into the

chamber, the door has to be taken down then, so it needs to arrange the cross work properly.

11.1.4 The anticorrosive work for the underground pipeline and valve in the valve chamber is key point of

quality control, make careful inspection for it before backfill.

11.1.5 The gaps going through the walls shall be stopped up tightly to prevent in-running of exterior

ground water, or for multi-room valve chamber to prevent the cross-running of oil or gas when leaking

occurs.


11.2.3 For the purpose not to damage the pipeline’s material, so this clause regulates that the welding of

test wire shall use braze welding or heat melting welding.

11.2.4 Only after test one can know whether the cathodic protection is normal of not. Because of exterior

current disturbance, it needs the design personnel to solve the problem if the natural potential is abnormal.


This part is newly supplemented, it is the regulation for making of pipe Piles, pipe supports and the setting

of Piles.


Pipeline protection structures are very important for pipeline’s safety, so it needs to abide by the state’s

construction and acceptance standard for pipeline construction projects.


12.0.2 Upon the completion of pipeline laying, the completion inspection is mainly on ground checking;

the result of ground leaking detection for anticorrosive layer will conclude the final result of anticorrosive

project.

12.0.3 Pipeline’s laying depth is important to the pipeline’s safe operation, the result of depth inspection

will conclude the pipeline’s final laying result and safety degree.



12.0.4 It lists the main technical data that shall be provided for the project acceptance; for the technical

data that has not included the special requirement of design unit or proprietor, it needs to be supplemented

according to the requirement.

Documents

SY 0401 Std for Constr. & Acceptance of Oil & Nat. Gas PL Prjct. (ENG)