The brochure is printed on
Product
Technical Manual
Pro
duct T
echn
ical Manual
WORLD'S LARGEST DUCTILE IRON PIPE MANUFACTUER
XINXINGPIPES XINXING
Contents
Chapter I, Ductile Iron Pipe Joint
and Anti-corrosion Solution
Chapter II Manufacturing Process
and Quality Control System
Chapter III. Requirements
for Storage and Transportation
of Ductile Iron Pipe
Chapter IV.Engineering
Design of Water Supply
& Drainage Pipeline
Chapter V Construction,
Installation and Acceptance of
Ductile Iron Pipe
Chapter VI Xinxing Ductile
Iron Fittings and Accesseries
Chapter VII Valves for
Water Supply and Drainage Pipeline
Company Profile
Company Profile
Xinxing Ductile Iron Pipes Co., Ltd., as a subsidiary of Xinxing Cathay International Group Co.,Ltd, adheres to the orientation of science and technology, environmental protection, quality and efficiency. At present, it has grown into a trans-regional and multi-industrial enterprise group integrating such wide industries as ductile iron pipe, steel and machinery, as well as various areas such as scientific research, production and trade. In 1997, Xinxing was listed on the Shenzhen Stock Exchange of China and has been selected as the Top 50 Most Promising Listed Companies for 8 consecutive years since then. Xinxing is primarily engaged in the centrifugal casting ductile iron pipes and fittings, steel smelting and rolling processing, special steel pipes, and foundry products, etc. At present, it has grown into an integrated processing enterprise with the annual output of more than 10 million tons of metal products, including eight major series, i.e. Xinxing ductile iron pipes, Xinxing steel, Xinxing special steel pipes, Xinxing gratings, Xinxing castings, Xinxing steel-plastic composite pipes, with the annual output of 8.0 million tons of steel, 1.8 million tons of ductile iron pipes, 40,000 tons of ductile iron fittings, 180,000 tons of special steel pipes, 3,000,000 m steel-plastic composite pipes and 80,000 tons of steel gratings. It has established production bases in Handan of Hebei, Wuhu of Anhui, Bazhou of Xinjiang, Huangshi of Hubei, Taojiang of Hunan, and Chongzhou of Sichuan, etc.
Xinxing Ductile Iron Pipes Co., Ltd. is the world’s largest supplier of ductile iron pipes and fittings. The domestic market share of its pipe products is about 45%, and the export ratio is about 30%. The products have been exported to more than 110 countries and regions around the world, including Middle East, America, Africa, Europe, Southeast Asia, etc.
Xinxing plastic-steel composite pressure pipe is the tubular product formed by extrusion molding with the intermediate layer made of welded steel pipe, the inner and outer layers made of polyethylene, the nominal diameter of DN20 ~ DN200, and the nominal pressure PN of 1.25 ~ 2.5MPa. The product can be widely used in building water supply, telecommunications, e l e c t r i c p o w e r, p e t r o l e u m , c h e m i c a l , pharmaceutical, food, mining, gas and other
fields.
Xinxing Ductile Iron Pipes Co., Ltd. has passed British Lloyd’s certification of ISO9001 quality management system, ISO14001 environmental management system, GB/T28001 occupational health and safety management system, and GB/ T19022 measurement management system. Ductile iron pipes and fittings have passed Italian BV and Chinese BV certification for standards such as BSEN545, BSEN598, ISO2531, KSD4311, ABNT NBR 7675, ISO7186, ISO8179-1, ISO8179-2, ISO4179, NF A 48-851, BSEN15189 and BSEN15655; flat steel and wire rods have passed CE certification by British Lloyd's Register Quality Assurance.
Chapter I ,
Ductile Iron
Pipe Joint and
Anti-corrosion
Solution
1.1 Ductile iron pipe wall thickness……… 1.2 T-type Joint ductile iron pipe……… 1.2.1 Joint description
1.2.2 Technical parameters
1.3 XT2-type joint ductile iron pipe……… 1.3.1 Joint description
1.3.2 Technical parameters
1.4 TF Self-anchored Joint ductile iron pipe……… 1.4.1 Joint description
1.4.2 Technical parameters
1.5 Xanchor self-anchored joint ductile iron pipe……… 1.5.1 Joint description
1.5.2 Technical parameters
1.6 Flange (welding) joint ductile iron pipe……… 1.6.1 Joint description
1.6.2 Technical parameters
1.7 XTJ Ductile Iron Jacking Pipe……… 1.7.1 Product description
1.7.2 Technical parameters
1.8 External anti-corrosion coating……… 1.8.1 Soil aggressivity
1.8.2 Selection of external coating
1.9 Internal lining……… 1.9.1 Evaluation on aggressivity of water for ductile iron pipes
1.9.2 Materials in contact with potable water 1.9.3 Lining Selection
1.9.4 Cement mortar lining
1.9.5 Cement mortar lining +epoxy seal coats 1.9.6 Polyurethane lining
1.9.7 Ceramic epoxy lining
1.10 Coating repairment……… 1.10.1 Repairment of zinc coating/Zn-Al rare earth alloy coating
1.10.2 Repairment of PU coating 1.10.3 Repairment of cement mortar lining
1.10.4 Repairment of cement lining with epoxy seal coats 1.10.5 Repairment of ceramic epoxy(PU)lining
7 9 11 13 15 17 18 21 32 47
Chapter I ,
Ductile Iron
Pipe Joint and
Anti-corrosion
Solution
Ductile iron material features similar mechanical properties with carbon steel, such as high mechanical strength and good ductility, and the same anti-corrosion performance as cast iron. Therefore, ductile iron pipe has gradually become one of the most secure and reliable pipes in the water supply and drainage area throughout the world.
Xinxing Ductile Iron Pipes Co., Ltd. provides ductile iron pipe products ranging from DN80 ~ DN2600 in accordance with ISO2531/7186 or EN545/598. Meanwhile, it can provide the most appropriate joints and internal and external anti-corrosion solutions according to the pipeline laying and using conditions. For details, see the table below:
Table 1 Xinxing Ductile Iron Pipes Joint and Anti-corrosion Solutions
Joint Type Specification Range
Anti-corrosion Coating Internal lining External Coating
Flexible joint T-type joint DN80~2000 Cement mortar lining
Cement mortar lining + epoxy seal coats Polyurethane lining Ceramic epoxy linning
Zinc + high chlorinated polyethylene finishing
layer Zinc+epoxy coating Polyurethane coating
XT2-type joint DN80~2600
Self-anchored joint TF joint DN80~1200
Xanchor joint DN1400~2000
Rigid Welded flange joint DN80~2000
XTJ jacking pipe DN250~2000
Type of casting e Limit Deviation
Pipes centrifugally cast 6 -1.3
＞ 6 -(1.3+0.001DN)
Pipes non-centrifugally cast and fittings 7 -2.3
＞ 7 -(2.3+0.001DN)
1.1 Ductile iron pipe wall thickness
Xinxing ductile iron pipes can be graded by the wall thickness class coefficient K or pressure class C. Executive standards are as following:
ISO 2531/ISO 7186 EN 545/EN 598
GB/T 13295, GB/T 26081 and other related standards for ductile iron pipes
Note: The wall thickness class coefficient K (or pressure class C) shall be specified in the agreement between the supplier and the purchaser.
——Graded by wall thickness class coefficient K
The nominal wall thickness of ductile iron pipe is calculated as per the function of nominal diameter DN, and the calculation formula is as following:
Where: enom —— Nominal wall thickness, mm DN—— nominal diameter, mm;
K——Wall thickness class coefficient, selected from a series of whole numbers ...9,10,11,12... The minimum nominal wall thickness of centrifugal casting ductile iron pipe is 6mm, and the minimum wall thickness of non-centrifugal casting ductile iron pipe and fittings is 7 mm; the tolerance on thickness for pipes and fittings is shown in the table below.
K(0.5+ 0.001DN) enom=
Table 2 Limit Deviation on Nominal Wall Thickness for Pipes and Fittings (Unit: mm)
——Graded by pressure class C
When the ductile iron pipes are classified by pressure class C, its allowable operating pressure is expressed by Arabic numerals prefixed by the letter C, and its unit is bar. Minimum wall thickness of the pipe is calculated by the allowable operating pressure.The formula is as following:
——Sealing principle
Structure of T-type joint is shown in Figure 1. During joint installation, the external spigot is extruded on the rubber ring inside the socket.The compression deformation can generate a certain degree of contact pressure. And it is the so-called sealing action of the rubber ring that keeps the joint tight. The self-sealing effect means, when the rubber ring is under the fluid pressure, the actual contact pressure on the rubber ring is the sum of the contact pressure of the pre-compressed rubber ring and the new contact pressure on the rubber ring brought by the fluid pressure. Since the contact pressure is higher than the fluid pressure, so that the joint is well tightened.
——Joint features
The joint features simple structure, easy installation and sound sealing performance. The positioning of sealing ring and deflection of joint are taken into consideration during socket structure design. By controlling the insertion depth of the spigot, the joint can have certain axial flexibility. Therefore this type of joint is able to adapt to certain foundation settlement, while long-distance deflection of pipeline can be achieved through its deflection angle θ. Joint deflection installation is shown in Figure 2.
The rubber ring consists of two parts, i.e. the hard rubber and soft rubber. The hard rubber can support and align the pipe joints, and greater thrust is needed during installation.
T-type Joint is unable to prevent pipe slippage, therefore the concrete blocks to resist the axial forces should be set at the bend of pipeline, or certain length of self-anchored joint ductile iron pipe should be laid.
——Application Field
Pressure/non-pressure water supply (potable water, sewage, etc.) pipeline;
Underground/overground laying, and the pipe laying slope does not exceed 20% (overground laying) or 25% (under ground laying).
—— Installation method
Please refer to “5.2.2 T-type joint ductile iron pipe installation”
1.2 T-type joint ductile iron pipe
1.2.1 Joint description
Type of casting Tolerance
Pipes Centrifugally Cast +1.3+0.001DN Pipes Non-centrifugally
Cast and fittings +2.3+0.001DN
Specification Range Preferred Pressure Class
DN80~DN300 C40 DN350~DN600 C30 DN700~DN2000 C25
Spigot Socket Rubber Gasket
Figure 2 Joint Deflection PFA × SF× DE
20Rm+ PFA×SF emin=
Where emin —— Minimum wall thickness of pipe, mm; PFA——Allowable operating pressure, bar SF——Safety factor of PFA (SF = 3); DE——External diameter of pipe, mm
Rm——Minimum tensile strength of ductile iron pipe, in MPa(Rm=420 MPa);
For pipes centrifugally cast, the minimum wall thickness shall not be less than 3mm; for pipes non-centrifugally cast, the minimum wall thickness shall not be less than 4.7 mm; the tolerance on thickness for pipes is shown in table 3. Specification range for preferred pressure class of C-class pipes are shown in Table 4.
Table 3 Tolerance on Wall Thickness For C-Class Pipes and Fittings (Unit: mm)
Table 4 Specification Range for Preferred Pressure Class of C-class Pipes
Figure 3 T-type joint ductile iron pipe
Table 5 Technical Parameters of T-type Joint Ductile Iron Pipe
DN DE (mm) D (mm) P (mm) θ (°) Lu (mm) K9 C-Class1 enom(mm) PFA (bar) enom(mm) PFA (bar) 80 98 140 85 4 6000 6 64 4.4 40 100 118 163 88 6 4.4 125 144 190 91 6 4.5 150 170 217 94 6 4.5 200 222 278 100 6.3 62 4.7 250 274 336 105 6.8 54 5.5 300 326 393 110 7.2 49 6.2 350 378 448 3 7.7 45 6.3 30 400 429 500 8.1 42 6.5 450 480 540 120 8.6 40 6.9 500 532 604 9 38 7.5 600 635 713 9.9 36 8.7 700 738 824 150 10.8 34 8.8 25 800 842 943 160 2 11.7 32 9.6 900 945 1052 175 12.6 31 10.6 1000 1048 1158 185 13.5 30 11.6 1100 1152 1267 200 6000/8150 14.4 29 12.6 1200 1255 1377 215 15.3 28 13.6 1400 1462 1610 239 17.1 15.7 1500 1565 1710 250 18 27 16.7 1600 1668 1820 262 18.9 17.7 1800 1875 2050 300 20.7 26 19.7 2000 2082 2266 319 22.5 21.8
1 C-Class pipe of preferred pressure class complying with ISO2531-2009
D
DE
enom
P Lu
1.3 XT2-type joint ductile iron
pipe
1.3.1 Joint description
Figure 4 XT2-type joint
——Sealing principle
Structure of XT2-type Joint is shown in Figure 4. Its sealing principle is similar with that of T-joint (see 1.2.1 Joint description - Sealing principle);
——Joint features
Similar with T joint. As the sealing ring of XT2-type joint adopts the lip-shaped structure, the pipe is subject to less rubber seal resistance during installation;
——Application Field
The same with T-type joint (see 1.2.1 Joint description - Application Field).
——Installation method
The same with the T-type joint, please refer to “5.2.2 T-type joint ductile iron pipe installation”.
Spigot Socket Rubber Gasket
1.2.2 Technical parameters
1.3.2 Technical parameters:
The main technical parameters of XT2-type joint ductile iron pipe are shown in Figure 5 and Table 6.
Figure 5 XT2-type Joint Ductile Iron Pipe
Table 6 Technical Parameters of XT2-type Joint Ductile Iron Pipe
D DE P Lu enom DN (mm)DE (mm)D (mm)P (°)θ Lu (mm) K9 C-Class1 enom(mm) PFA (bar) enom(mm) PFA (bar) 80 98 140 92.5 5 6000 6 64 4.4 40 100 118 163 94.5 6 4.4 150 170 217 100.5 6 4.5 200 222 278 105.5 4 6.3 62 4.7 250 274 336 6.8 54 5.5 300 326 393 107.5 7.2 49 6.2 350 378 448 110.5 3.5 7.7 45 6.3 30 400 429 500 112.5 8.1 42 6.5 450 480 540 115 8.6 40 6.9 500 532 604 117.5 9 38 7.5 600 635 713 122.5 9.9 36 8.7 700 738 824 147.5 3 10.8 34 8.8 25 800 842 943 11.7 32 9.6 900 945 1052 1.8 12.6 31 10.6 1000 1048 1158 157.5 13.5 30 11.6 1200 1255 1377 167.5 6000/8150 15.3 28 13.6 1400 1462 1610 245 17.1 15.7 1600 1668 1820 275 18.9 27 17.7 1800 1875 2050 285 20.7 19.7 2000 2082 2266 290 22.5 26 21.8 2200 2288 2482 317 24.3 25 23.8 2400 2495 2702 336.5 26.1 25.8 2600 2702 2921 353 27.9 27.9
1 C-Class pipe of preferred pressure class complying with ISO2531-2009
1.4 TF Self-anchored joint ductile iron pipe
1.4.1 Joint description
Figure 6 TF self-anchored joint structure
Welded Bead Locking Ring
Gland Bolts and Nuts
Rubber Gasket
——Joint structure
As shown in Figure 6, TF self-anchored joint adopts the T-joint sealing structure. Compared with T-joint, it adds a welded bead on spigot, an open-end locking ring, a special gland and connecting bolts to provide the joint with good anti-slippage performance. The locking ring and the gland can slide between each other, so that the joint has certain axial stretching and deflection capability.
——Working principle
The axial thrust forces generated at the bending places and tees of the pressure pipeline will cause the socket and spigot components to have relative displacement. Axial stress generated at spigot is passed on to the socket through welded bead, locking ring, gland and connecting bolts, enabling the transmission of axial stress to equip the joint with good anti-slippage performance. When the friction between the restrained pipeline and its surrounding soil is greater than the axial stress generated inside the pipe, safe operation of the pipeline can be guaranteed, thus avoiding the set-up of concrete block.
——Application Field
In the following conditions, certain length of pipeline with TF-joints could be applied in order to prevent pipeline slippage:
1. Places such as bends, tees, reducers and plugs, etc;
2. When the pipeline laying slope exceeds 20% (laying overground) or 25% (laying underground);
3. When it is uneconomical (such as large-diameter high-pressure pipelines, etc.) or unable to set concrete buttress, for example:
A. The construction site is too narrow; there is no space to set up specified concrete block; B. Construction schedule is tight;
—— Installation method
1.4.2 Technical parameters
Figure 7 TF Self-anchored Joint Ductile Iron Pipe
D
DE
P Lu
The technical parameters of TF self-anchored joint ductile iron pipe are shown Figure 7 and Table 7.
enom
Table 7 Technical Parameters of TF Self-anchored Joint Ductile Iron Pipe
DN DE
(mm)
DGland
(mm) P(mm) θ(°) Lu(mm)
K9
enom(mm) PFA1(bar)
80 98 243 85 2 6000 6 30 100 118 264 88 6 150 170 321 94 6 200 222 375 100 6.3 250 274 433 105 6.8 300 326 509 110 7.2 350 378 567 1.5 7.7 25 400 429 591.6 8.1 450 480 675 120 8.6 500 532 700 9 600 635 811 9.9 700 738 935 150 1 10.8 800 842 1048 160 11.7 900 945 1158 175 12.6 23 1000 1048 1308 185 13.5 22 1100 1152 1420 200 6000/8150 14.4 21 1200 1255 1539 215 15.3 20
1 By adjusting the wall thickness class of the pipe and material of connecting bolts, etc., TF joint's PFA can reach 25bar. Please consult us for detailed technical parameters.
1.5 Xanchor self-anchored joint ductile iron pipe
1.5.1 Joint description
——Joint structure
Xanchor self-anchored joint, as shown in Figure8, adopts the sealing structure of XT2 joint. Its socket is designed to have two annular chambers, i.e. sealed chamber and anchoring chanber. The sealed chamber is where the sealing ring is set, and the stopper chamber is used to house the self-anchored components which are comprised of the front blocks, the rear blocks, the supporting ring and welded bead.
——Working principle
Working principle of Xanchor joint is quite different from that of the traditional self-anchored joint. The essential mechnism is to effectively prevent slippage through the two rows of rigid blocks . Meanwhile, the circular sliding of the front and rear rows of blocks along the stopper chamber provides the joint with greater flexibility. Compared with other self-anchored joint, Xanchor joint features simpler structure, easier installation, better anti-axial-splippage performance and flexibility.
——Application Field
The same with TF joint, please refer to "1.4.1 Joint description – Application Field ";
——Installation method
Please refer to "5.2.6 Xanchor self-anchored joint installation
Front Stopper Rear Stopper Rubber Supporter Rubber Gasket
The technical parameters of Xanchor self-anchored joint ductile iron pipe are shown in Figure 9 and Table 8:
Figure 9 Xanchor self-anchored joint ductile iron pipe
Table 8 Technical Parameters of Xanchor Self-anchored Joint Ductile iron pipe
DN DE(mm) D(mm) P(mm) θ(°) Lu(mm)
K9
enom(mm) PFA1(bar)
1400 1462 1610 330 1.2 8000 17.1 19 1500 1565 1710 341 1.1 18 18 1600 1668 1820 363 1.1 18.9 17 1800 1875 2050 410 1.0 20.7 16 2000 2082 2266 430 0.8 22.5 15
1 By adjusting the wall thickness class, Xanchor joint’s allowable operating pressure can reach PN25.
1.5.2 Technical parameters:
D DE P Lu enom1.6.2 Technical parameters
Xinxing can provide flange (welded) components ranging from DN80 ~ DN2000. Length of flanged pipe and the number and position of puddle flange would be customized according to customer requirements. For detailed product information, please refer to Table 9.
Executive Standards for Flange: ISO 7005-2 or EN 1092-2, for detailed dimensions please refer to:
——For centrifugally cast pipes with welded flanges please refer to “6.2 Technical Parameters for Fittings and Accessories (42)”;
——For welded puddle flange please refer to “6.2 Technical Parameters for Fittings and Accessories (43)”
1.6 Flange (welding) joint ductile iron pipe
1.6.1 Joint description
Sealing Gasket Bolts & Nuts
Figure 10 Flange (welding) joint structure
——Sealing principle
Structure of Flange-joint is shown in Figure 10. Its sealing is realized through the flange’s compressing the sealing ring, which is achieved by fastening the bolts.
——Joint features and application field
Flange joint is rigid joint with sound sealing performance. It is usually used in the following places, such as the connection with pumps, valves, fire hydrant as well as crossing foundation, walls and so on.
Table 9 Flange (Welded) Pipe Catalogue
Name Symbol Name Symbol
Double Flanged Pipe Double-Spigot Pipe with
Puddle Flange Double Flanged Pipe with
puddle flange
Socket-Spigot Pipe with Puddle Flange
Flanged Spigot Pipe Socket Flange Pipe
Flange Spigot Pipe with Puddle Flange
Socket Flange Pipe with Puddle Flange
Allowable Operating Pressure for Welded Flanged Pipes of K9: DN80~DN1200 PN10/PN16/PN25
DN1400~DN1600 PN10/PN16 DN1800~DN2000 PN10
1.7 XTJ Ductile Iron Jacking Pipe
Flange Spigot
Rubber Gasket Concrete Cement
Stiffened Plate Socket
Figure 11 XTJ Ductile Iron Jacking Pipe structure
1.7.1 Product description
——Pipe structure
XTJ jacking pipe, as shown in Figure 11, is to make a tubular reinforced concrete protective jacket on the external wall of T-type joint pipe. There’s a jacking flange welded on the spigot of the pipe. During the pipe jacking, the pushing force is evenly passed from the flange with ribbed plate welded at the spigot to the socket, thus ensuring the pushing operation will not cause deformation of the spigot and will not damage the outer protective sleeve;
——Application Field
XTJ jacking pipes are applied when the pipeline need to cross obstructions such as roads, railways, rivers and buildings, while trench excavation is not allowed or difficult to prepare on the construction site.
XTJ jacking pipe adopts T-type flexible joint. It features sound sealing performance, faster installation, more reliable internal and external anti-corrosion coating, and is adaptive to various soil environments and different transmitted media.
Table 10 Technical Parameters of XTJ Ductile Iron Jacking Pipes Size DN Dimensions Total weight (kg)
Allowable jacking force Wall
thickness
class DE(mm) D(mm) A(mm) Lu(mm) KN Tonf
250 K9 274 342 95 4000 518 920 94 6000 773 300 326 397 100 4000 639 1240 127 6000 953 350 378 448 100 4000 766 1270 129 6000 1145 400 429 502 100 4000 907 1350 138 6000 1353 450 480 551 110 4000 1045 1560 159 6000 1554 500 532 616 110 4000 1268 1910 195 6000 1890 600 635 725 110 4000 1626 2720 278 6000 2423 700 738 850 150 4000 2281 2720 277 6000 3385 800 842 956 150 4000 2661 3300 337 6000 3992 900 945 1064 165 4000 3171 4140 422 6000 4706 1000 1048 1170 175 4000 3684 5080 518 6000 5376 1200 1255 1396 205 4000 5027 7240 739 6000 7436 1400 1462 1630 229 4000 6841 9020 920 6000 10151 1600 1668 1840 252 4000 8310 12360 1261 6000 12380 1800 1875 2060 290 4000 10110 12360 1261 6000 14895 2000 2082 2280 330 4000 12046 16970 1731 6000 17740
Note: 1. The jacking pipe with grouting hole can be provided according to customer requirements;
2. We could also supply jacking pipe with other wall thickness class. Please contact us for detailed technical parameters.
1.7.2 Technical parameters
A
Lu
D
DE
Technical parameters of XTJ jacking pipes are shown in Figure 12 and Table 10;
Figure 12 XTJ Ductile Iron Jacking Pipe
1.8 External anti-corrosion coating
1.8.1 Soil aggressivity
1.8.1.1 Soil aggressivity evaluation
Pipelines buried underground will be exposed to various corrosive elements, including the aggressive soil and backfilled soil, and soil polarity caused by local topographical and backfilling. Therefore, technicians should familiarize themselves with the topographical and geography of the targeted area through topographical map, based on which initial analysis shall be formed on the corrosivity of the soil. Then, through on-site examination, further analysis shall be made. Finally, through lab-test of the sample soil, precise judgement will be made.
Data collection
—— Collect the topographical information for the area of pipeline burrial, such as the distribution and altitudes of level ground, hills, swamp lands, paddy fields, rivers and beaches, soil types of various regions, transitional areas of two different soils and the terrains with great changes. For example, in the dry area in high altitude, the soil tends to be less aggressive; while in damp areas in low altitude such as ponds, lakes, marshes and peat beds, the soil tends to be more aggressive due to rich humic acid and anaerobes. In the river mouths, lowland, marshes, saline and alkaline lands and other regions along the sea, the aggressivity of soil is probably high.
—— Collect potential corrosive elements for the embedded ductile iron pipes along the pipeline, including corrosive sewage discharged from livestock farms, wineries, paper mills and other factories, or from local residence.
—— Collect potential disturbing power sources near the pipelines that probably corrode ductile iron pipes, such as power plants, substations, HV transmission lines, and other forms of DC and AC interfering power sources.
——Gather local meteorological data, including maximum and minimum temperature, average temperature per year, soil temperature at the burial depth of ductile iron pipes, soil freezing depth, underground water level, rainfall volume and sunlight intensity, etc.
—— A report shall be issued with information mentioned above for the reference of designers. Site surveys
—— The selection of site surveys shall be based on following principles: a. At least 2 test points shall be chosen for every soil type;
b. For the same type of soil, one test point shall be chosen every 400~500m;
c. Test points shall be typical for the topographical features of the area along the pipeline;
Corrosion level Pipelines generality (most of the soil belongs to this level) Zinc+HCPE finishing layer
corrosive Zn-Al rare earth alloy + blue epoxy coating
Zinc+HCPE finishing layer+PE sleeve
highly corrosive special coating (PU coating)
—— Identify soil texture, color and appearance
—— Investigate the status of underground water and backfill soil
—— Soil resistivity test: soil resistivity, as an important index of evaluating soil aggressivity, is a comprehensive factor of soil water content and salt content, and reflects soil conductivity. In general, the smaller the soil resistivity is, the stronger the soil aggressivity is. AC quadrupole test method is adopted on the site.
—— ORP test (Eh7): oxidation reduction potential is an index that can reflect comprehensively oxidation reduction degree, which has a lot to do with the activity of bacteria in the soil. To certain extent, the lower Eh7 is, the greater corrosive action of sulphate reducing bacteria on metals is. Therefore, oxidation reduction potential can become an index of soil microbiological corrosion under the condition of strong reducibility.
Laboratory analysis
Laboratory analysis is supplementary to the analysis mentioned above. Chemical analysis conducted in the laboratory mainly includes the following items:
PH value, total soluble salt, moisture content, soil bulk density, air content, Cl-, SO42-, S2-, microorganisms,
etc.
1.8.2 Selection of external coating
Zinc coating is the basic external coating solution provided by Xinxing. It features satisfactory anti-corrosion performance in most of the soil environments. However, in strong corrosive soil where zinc coating would not be enough, PE sleeve will be used as additional anti-corrosive coating; or special coatings and other strong anti-corrosion methods shall be taken to protect the pipelines. Xinxing can help customers design cost-effective external anti-corrosion solutions for pipelines that can fulfill requirements of the soil environment. Table 11 is a proposed anti-corrosion coating solution based on different corrosion levels of the soil.
Table 11 External Coating Solution for Soils at Different Corrosion Levels
—— Anti-corrosion mechanism
Active anti-corrosion : Sacrifice zinc anode to protect ductile iron cathode.
Stable protective layer: Zinc will corrode gradually to generate insoluble zinc salt in the process of contacting with environmental soil, which will tightly adhere to the pipe walls so as to form a layer of continuous, tight and insoluble protective film that is impermeable.
The porous finishing layer sprayed on zinc coating also plays an important role. It is good for cathodic protection and self-healing, and also for converted products of zinc to generate stable and tight insoluble protective film.
1.8.2.1 Zinc+HCPE finishing layer
—— Product description
Zinc coating used as external protection has proved to be one of the most effective anti-corrosion solutions throughout the world. It can prolong the service life of pipelines. Standard anti-corrosion coating provided by Xinxing is metallic zinc coating applied by electric arc (C-Class pipe 200g/m2, K-Class pipe 130g/m2). A
HCPE finishing layer of at least 70um thickness will be sprayed outside the zinc coating. Structure of such coating solution is shown in Figure 13. The finishing layer is in porous structure, as shown in Figure 14.
Pore-sealer zinc ductile iron pipe wall
Figure 14 Porous Structure of the coating solution of Zinc+HCPE finishing layer Figure 13 Zinc+HCPE finishing layer
cast iron pipe metallic zinc finishing layer
epoxy coating Zn-Al rare earth alloy Cement mortar lining cast iron pipe
Figure 16 Zn-Al rare earth alloy + blue epoxy coating
In short, zinc coating plays an important role of anti-corrosion: on one hand, it will generate tight insoluble protective film which will adhere to pipe walls, thereby reducing electrochemical corrosion to great extent; on the other hand, the anti-corrosion performance of zinc coating and finishing layer also is reflected on their mutual action. There is excellent adhesiveness between zinc and cast iron & zinc and finishing layer, forming a complete protective screen between pipe and the external environment, and preventing anti-corrosion failure.
—— Application field
This kind of coating is applicable to most of the soil environments with slight aggressivity.
—— Executive standards:
ISO 2531, ISO 8179, GB /T 13295, GB/T 17456, BS EN 545
1.8.2.2 Zn-Al rare earth alloy + blue epoxy coating
—— Product description
Zn-Al rare earth alloy (i.e. add trace amount of rare earth element in 85Zn15Al) is sprayed on the surface of ductile iron pipes by electric arc with the coating mass of 400g/m2; epoxy coating (at least 100μm in
thickness) is sprayed on the alloy coating so as to form active anti-corrosion coating. Coating structure is shown in Figure 16.
——Anti-corrosion mechanism
Active anti-corrosion: Just like pure zinc, Zn-Al rare earth alloy is also a kind of active anti-corrosion coating.
Stable protective layer: Being similar with zinc coating, a layer of continuous, impermeable and insoluble protective film that is hardly penetrated forms on ductile iron pipe walls. Aluminum in the alloy features inactivation, and it can reduce the consumption rate of zinc even in the soil with high corrosivity; the addition of a small amount of rare earth element (Re) can purify the coating structure to reduce active points of the surface during the coating corrosion; it can also refine the crystal grains and reduce porosity of the coating so as to compact the coating structures, thereby reducing the corrosion passages, as shown in Figure 17. Self-healing of damaged zinc coating: Some pipes may be locally damaged probably during
transportation or installation. Zinc will transform into zinc ion rapidly under the action of primary cells. Zinc ion can migrate through pores of finishing layer and cover the damaged portions, generating stable and insoluble protective layer, as shown in Figure 15.
metallic zinc coating Pores of finishing layer
Damage cast iron
Zn++ ions
zinc corrosion products
current
Zn-Al rare earth alloy
blue epoxy ductile iron pipe wall
Zn-Al rare earth alloy coating features self-healing effect just like coating zinc.
——Advantages of Zn-Al rare earth alloy coating
Due to the addition of rare earth, Zn-Al rare earth alloy coating features the following advantages compared with Zn-Al alloy coating:
Reinforcement effect
With strong chemical activity, rare earth element can react with many elements in Zn-Al alloy to generate intermetallic compounds with strong hardness. Distributed in crystal boundary in a mesh pattern, these compounds can hinder creep slip, thereby improving the hardness and wear-resistant property of alloy coating to prolong the service life significantly.
Refining effect
During solidification of the coating, rare-earth element can reduce the surface tension of plating solution to increase the crystal core so as to refine the crystalline grains. Such fine eutectic structures can prevent the extension of cracks, even the structures and eliminate bare spots on the surface of coating. This is the important mechanism of rare earth to improve the plasticity and flexibility of the coating, and it is also a special feature of the rare-earth alloy coating.
Anti-corrosion performance
Re element can refine microstructure of the coating and reduce its porosity. Meanwhile, it can strengthen Zn-Al alloy coating. Therefore, addition of a small amount of Re element can further improve the anti-corrosion performance of Zn-Al alloy coating.
—— Application fields
Zn-Al rare earth alloy coating is an enhanced anti-corrosion solution. It is applicable to the soil with strong aggressivity (i.e. soil with low resistivity, soil influenced by underground water or mixed soil), where PE sleeve is not needed, except the following situations:
Acid peat soil;
Soil containing garbage, oxide skin and slag, or soil polluted by waste water and industrial effluent; Soil below the sea level and with resistivity less than 500Ω•cm.
When applied to the soil types listed above, including the one with stray current, other type of external coatings (such as PU coating) will be recommended.
—— Executive standards:
ISO 2531, GB /T 13295 and BS EN 545
1.8.2.3 Polyurethane coating
—— Product description:
PU coating of ductile iron pipe and fitting is formed by the PU material sprayed and cured on the surface of pipe/fitting that is bi-component, solvent-free and 100% solid. This kind of coating has excellent anti-corrosion performance, high impact resistance and wearing resistance, which is applicable to the soil with very strong aggressivity and all other types of the soil.
Coating structure is shown in Figure 18
epoxy coating PU coating ductile iron pipe wall
Figure 18 External PU Coating
Location Adopted material Average thickness μm Minimum thickness μm
pipe body PU coating 900 700
socket and spigot epoxy coating 250 200
Table 12 Thickness of External PU Coating
Requirements for material
PU coating: complying with EN 15189.
Epoxy coating: complying with EN 14901 and certified by WRAS for BS 6920 Specification range
Xinxing can provide products ranging from DN80 ~ DN2200.
No. Tested items Requirement
1
Water resistance Less than 15% weight increase after immersion in 50℃ deionzed water Less than 2% weight loss after drying
Chemical resistance Less than 10% weight increase after immersion in 10% H2SO4 for 100 days The weight change ≤4% after drying.
2 Impact strength 8 J/ mm of PU on the pipe body coated with polyurethane,the PU coating
shall be free from damage.
3 Indentation hardness Under 10Mpa pressure, the depth of indentation < 10 %
4 Elongation at break ≥2.5%
5 Specific coating resistance ≥ 108Ωm2
6 The ratio (resistance after 100 days)/
(resistance after 70 days) ≥ 0.8
7 Non-porosity When tested with 4.2kV voltage,the PU coating shall be free from porosity.
8 Hardness Shore D > 70
9 Adhesion Adhesion≥11 MPa under 23℃
Table 13 Properties of External PU Coating
—— advantages of PU coating
With strong mechanical strength, rock impact resistance and soil stress resistance, it can hardly be damaged during handling and installation.
Due to good water resistance and zero anti-permeability coefficient, the coating won’t suffer from shellfish erosion when applied in the marine environment for a long time.
Due to its good performance in chemical resistance and electric corrosion resistance, ductile iron pipes with PU coating can be applied to complicated soil environment, with prolonged life span.
——Application fields
Pipes and fittings with PU coating can be applied to the soil environment with very strong aggressivity and all other types of soil listed below:
Humid regions such as harbor and marshes; Hydrous area that is salty and alkaline etc.
——Executive standards:
ISO 2531, GB /T 13295, GB/T 24596, BS EN545 and BS EN15189
—— Properties of PU coating are shown in Table 13
Additional protection
For the soil with very strong aggressivity, proper additional protection shall be made for the joints during installation of pipelines, e.g. application of external heating shrink sleeve.
Tested items Test results Test standard
thickness/μm ≥200 ISO 8180
material density/kg/m3 910~935 ISO 1183-1
impact resistance/g ≥900 ISO 7765-1 Method A
tensile strength/MPa ≥20 ISO 527-3 Type 2
elongation/% ≥500 ISO 527-3 Type 2
propagation and tear resistance/N ≥20 ISO 6383-2
1.8.2.4 Polyethylene sleeve
——Product description:
PE sleeve is the Polyethylene or a mixture of polyethylene and/or ethylene and olefin copolymers sleeve (film) with thickness of 0.2mm that is wrapped on external walls of the pipe on the construction site. It can prevent direct contact between cast iron pipes and the soil. Meanwhile, it also prevents underground moisture from corroding the pipelines. It is used to supplement the basic pipe coating (metalic Znic + HCPE finishing layer) in certain case of highly corrosive soils or in the presence of stray current.
Requirements for material
The properties of polyethylene sleeve listed in table 14:
Specification range
This kind of anti-corrosion coating is applicable to ductile iron pipes of all sizes.
——Anti-corrosion mechanism
The anti-corrosion mechanisms for PE sleeve (film) wrapped outside zinc coating are as following:
First of all, PE sleeve can separate the pipelines from corrosive soil and inhibit the generation of electrochemical cell. At the same time, it can also isolate stray current.
The PE sleeve is a kind of anti-corrosion method whose performance is achieved through the changing of corrosive environment: it can change the corrosive environment from non-homogeneous soil with strong aggressivity into one that is homogeneous with weak aggressivity.
—— Application fields
It is suggested to adopt this kind of protective layer for corrosive soil, for example: Soil with low resistivity (with indicator of high aggressivity);
Regions with stray current;
Regions with high chlorine or sulphur content or active bacteria indicated by the analysis.
—— Executive standards:
ISO 2531, ISO 8180 and GB /T 13295
1.9 Internal lining
The internal lining of ductile iron pipes must be equipped with excellent hydraulic and anti-corrosion performance. Factors such as corrosivity, flow speed and environment temperature of the conveyed fluid have to be taken into consideration while choosing the pipe lining. Surface smoothness is also one of the features that to be taken into consideration.
Adopted for the delivery of potable water, the anti-corrosion lining of ductile iron pipes should be nontoxic. This is the most basic requirement for the choice of lining.
While adopted for sewerage delivery, the anti-corrosion performance that features microorganism resistance and liquid erosion resistance becomes very important for the lining. And it is those linings with high abrasion resistance and strong acid resistance (especially sulfuric acid resistance) that can provide long-term, reliable protection for the pipes.
1.9.1 Evaluation on aggressivity of water for ductile iron pipes
Corrosivity of water
Water can be divided into corrosive water (propersity to attack exposed metal) and aggressive water (propersity to attack cement mortar lining).
—— Corrosive water
Corrosive water refers to water that corrodes the metal of pipe without lining. Oxygen contained in most of the water can react chemically with iron, which causes its oxidization, generating nodules and tuberculation on internal pipe wall. It will reduce the pipe cross section and significantly cause water head loss increasing over time. This phenomenon often happens in the old pipe without cement mortar lining.
—— Aggressive water
Aggressive water is the water that corrodes calcareous materials (such as cement). Based on chemical analysis, three results will be caused by the changes in mineral content, PH value and temperature of the water:
Under the given temperature, the water with carbon balance will neither cause attack nor calcium-carbon deposition.
Scale deposition water tends to generate calcium salt deposition (e.g. calcium carbonate) on the internal surface of pipe.
Aggressive water can attack the cement mortar containing calcium (e.g. lime, calcium carbonate, or aluminum silicate, etc.)
According to the relevant international standards, potable water can be neither corrosive nor aggressive.
Material Application Area
Cement mortar lining linings of ductile iron pipe and fitting
Solvent-free PU special linings for ductile iron pipe and fitting
Water borne epoxy coating seal coats
Epoxy coating Socket and spigot of pipes with special coating
Rubber gasket Sealing rings for joints of pipes and fittings
Lining material
Standard lining Portland cement mortar lining
Enhanced lining
High-alumina cement mortar lining Sulphur resistant cement mortar lining
Cement mortar lining + seal coats
Special lining PU, ceramic epoxy lining
1.9.2 Materials in contact with potable water
The materials in contact with potable water shall not influence water quality.
All above materials adopted by Xinxing for ductile iron pipes have passed the WRC-NSF test of BS6920 of the U.K. and WRAS certification, which proves that such materials can be used for the delivery of portable water.
Lining materials for ductile iron pipes provided by Xinxing are listed in Table 15.
1.9.3 Lining Selection
As per the corrosivity of delivered water, anti-corrosion linings of the ductile iron pipes and fittings provided by Xinxing can be divided into three categories:
—— Standard lining: Applicable for most raw water and portable water;
—— Reinforced anti-corrosion lining: Applicable for water which can attack ordinary cement (soft water, slightly acidic water or highly abrosive water);
—— Special lining: Applicable for very special cases or corrosive water (e.g. industrial discharged water) Xinxing will recommend proper internal linings based on water composition analysis. Table 16 summarizes the types of anti-corrosion linings of Xinxing.
Table 15 Lining Materials
Table 16 Types of Lining
Usually, various types of water are available to be supplied. Sometimes, it is water with low mineral content (e.g. soft water), which may attack the materials just like corrosive or aggressive water.
Xinxing can provide ductile iron pipes with various internal linings, which are applicable for the conduction of various types of water; based on the features of delivered water, proper lining materials (such as cement mortar lining, cement mortar lining with epoxy seal coats, PU lining, or ceramic epoxy lining) shall be chosen through calculation and analysis.
1.9.4 Cement mortar lining
—— Product description
Cement mortar lining of ductile iron pipes is applied through centrifugal application method:
When pipes are rotating on the lining machine, certain amount of cement mortar is poured into the pipes. Through high-speed revolution with acceleration about 30G under the centrifugal force, such cement mortar will fully cling to the internal surface of pipe, forming a dense and smooth lining with uniform thickness, which can provide good mechanical properties after curing for certain amount of time. Thickness of cement mortar lining shall comply with specifications in Table 17.
—— Requirements for materials
Different types of cement can be chosen for the cement mortar lining of ductile iron pipe on the basis of delivered water, such as ordinary cement (silicate, Portland), sulphur resistant cement (including slag cement), and high-alumina cement.
—— Anti-corrosion mechanism
As an active anti-corrosion coating, cement mortar lining possesses long-term anti-corrosion effect. The anti-corrosion mechanism is that cement mortar lining can release alkaline substance upon its contact with water. Such substance will gather on internal surface of ductile iron pipe, resulting in its passivation, so as to provide electrochemical protection for base material, as shown in Figure 19. Therefore, this kind of lining mainly relies upon its alkaline environment to passivate internal wall of ductile iron pipe, so as to achieve corrosion resistance.
—— Features of cement mortar lining
Self-healing
With the proceeding hydration reaction of cement, the cement mortar lining will shrink gradually. Therefore, it is inevitable to form radial displacement and small cracks. This is a unique feature of cement mortar, which is allowable by the standard. Thus, no unfavorable influence on the mechanical stability of the lining will be brought by such cracks and radial displacement, as well as other cracks caused during manufacturing or transportation.
When the pipe with cement mortar lining contact water, these cracks and radial displacement will be closed and healed along with expansion of the linings and continuous hydration of cement; therefore, the anti-corrosion effect won’t be influenced.
Good mechanical property
—— Expansion coefficient
The linear thermal expansion coefficient of cement mortar lining is 12 x 10-6/ ℃ , which is almost equal to
that of ductile iron (11 x 10-6/℃ ). Therefore, it can reduce the risk of crack generation due to difference of
thermal expansion coefficients.
—— Good adherence and anti-vacuum performance —— Good resistance to longitudinal bending and to ovality —— Good resistance to vibration and impact
—— With excellent abrasion resistance, cement mortar lining can be used to convey raw water with highly abrasive particles
Excellent hydraulic performance
Xinxing adopts centrifugal processing technology for its production of ductile iron pipes with cement mortar linings, which contributes to the lining’s smoothness. According to the test of Testing Center of China Institute of Water Resources and Hydropower Research, the equivalent roughness K of such lining is 0.030mm. Taking into consideration of the roughness caused by fittings, valves and other devices, as well as the tolerance, it is suggested that the value of K selected as 0.10mm for the design purpose.
—— Application fields
Table 19 shows the substances that can be conveyed by various cement mortar linings.
Ductile iron pipe with common silicate cement mortar lining is applicable for water-supply project;
Ductile iron pipe with sulphur resistant cement mortar lining is applicable for water supply project and water transmission project with water quality listed in Table 19;
Ductile iron pipes with high-alumina cement mortar lining are applicable for the conduction of sewages and industrial wastewater containing certain chemical substances. Nitrile butadiene rubber (NBR) gasket will be used as accessories for sewage pipelines.
Table 17 Thickness of Cement Mortar Lining
NominalDN Nominal thickness (mm)Lining thicknessMinimum thickness at one point(mm)
80—300 3 2 350—600 5 3 700—1200 6 3.5 1400—2000 9 6 2200—2600 12 7 -2 -1.4 -0.6 -0.20 0.6 1.0 1.8 0 1 3 5 7 9 11 13 15 PH b a d c Fe+3 Fe HFeO 2 Fe++ Fe2O3 Fe3O 4 FeO4 potentia l V(S .H. E) (immunity) (corrosion) (passivation)
Figure 19 Potential-pH diagram of Fe/H2O system (Peurbax diagram)
Water properties Silicate cement mortar lining Sulphur resistant cement mortar lining High-alumina cement mortar lining PH Value ≥6 ≥5.5 ≥4 Corrosive CO2 (mg/l) ≤7 ≤15 unlimited SO42-(mg/l) ≤400 ≤3000 unlimited Mg2+(mg/l) ≤100 ≤500 unlimited NH4+(mg/l) ≤30 ≤30 unlimited
Table 18 Conveyable Substances of Different Cement Mortar Linings
—— Executive standards:
ISO 2531, ISO 7186, ISO4179, GB /T 13295, GB /T 26081, GB /T 17457, BS EN 545 and BS EN598
1.9.5 Cement mortar lining +epoxy seal coats
1.9.5.1 Product description
As shown in Figure 20, cement mortar lining with epoxy seal coats is formed by the curing of water borned epoxy spayed on the surface of cement mortar lining. Generally, the thickness of epoxy seal coats around 70um except for special requirements. With excellent anti-corrosion performance, this kind of lining can ensure the delivered water against pollution.
finish coating ductile iron pipe wall zinc cement mortar lining epoxy seal coats
Figure 20 Cement mortar lining +epoxy seal coats
Stop or slow down releasing alkaline substances from the cement mortar
Ca(OH)2 Ca(OH)2 Ca(OH)2 Ca(OH)2 Ca(OH)2
epoxy seal coats cement lining
Ductile iron pipe wall
2 1 3 4 a 7 5 6 8 14 13 12 11 10 9
Requirements for material
Material of seal coats: pass WRC—NSF sanitary test of BS6920 and WRAS certification. Specification range
Xinxing can provide DN80~DN2200 full range of products Certification
In compliance with requirements of ISO16132:2004, it can prevent PH value from increasing in the initial period of water introduction and prolong service life of the lining, thus guarantee water quality. We have obtained BV certification on this standard.
1.9.5.2 Anti-corrosion mechanism
Anti-corrosion mechanism for cement mortar lining with epoxy seal coats
Structure of cement mortar lining with epoxy seal coats is shown in Figure 23. Ductile iron pipes with cement mortar lining plus epoxy seal coats combine active anti-corrosion with passive anti-corrosion. On one hand, epoxy seal coats provides a physical barrier for internal wall of ductile iron pipe, which can reduce water contacting with or isolate water from the internal wall of ductile iron pipe, namely passive corrosion resistance;on the other hand, this kind of lining can also slow down or stop releasing alkaline substances from the cement mortar into water, so it can ensure alkaline substances’s enrich on internal wall of ductile iron pipe, and thereby provide chemical protection by means of passivation, namely active corrosion resistance. In this way, long-term corrosion resistance can be provided for this lining.
Figure 21 Structure of cement mortar lining with epoxy seal coats
Figure 22 Sealing Performance Test
1.9.5.3 Product features
Excellent corrosion resistance
With combined performance of active and passive anti-corrosion, in case epoxy seal coats is damaged or some voids exist in the seal coats, cement mortar lining can provide active anti-corrosion protection, thus enabling the coating solution with long-term corrosion resistance performance.
With excellent alkali resistance, it can withstand the alkaline environment of cement mortar linings in long run; with excellent acid resistance, it can withstand the erosion of delivered water (e.g. weak acidic water).
Inhibit precipitation of alkaline substances
After 3-month’s closed cyclic test conducted under conditions of 6 bar pressure and 2m/s flow velocity, the PH of the test water is far less than 9.5 as required by ISO 16132 (Figure 24 below shows testing procedure and testing apparatus ).
The result of short-term sealing performance test is around 8.2, which is far less than the requirement of PH≤9.5 specified by ISO 16132.
Safe and environmental friendly
The epoxy seal coats doesn’t contain any organic solvent, thus won’t pollute the environment or cause harm to constructors;
The seal coats is non-toxic after curing, neither polluting water nor producing substances harmful to people’s health.
It has passed British WRAS sanitary property test of BS6920
The water-bored epoxy coating is compatible with drinking water and has passed WRC-NSF Sanitary test of BS 6920 and WRAS certification.
DN
Pipe body (contacting with water)Socket and spigot Socket and spigot without contacting with
water Average thickness µm Minimum thickness µm Average thickness µm Minimum thickness µm 80~200 1300 800 300µm 250µm Minimum thickness µm ＞ 200 1500 150um DN
Pipe body (contacting with water)Socket and spigot
Socket and spigot without contacting with
water Average thickness µm Minimum thickness µm Average thickness µm Minimum thickness µm Minimum thickness µm 80~200 ≥1300 ≥800 300µm 250µm 150um 250~700 ≥1500 ≥800 700~1000 ≥1800 ≥1000 ＞ 1000 ≥2000 ≥1000 PU lining metallic zinc cast iron pipe Epoxy coating
Friction reducing affect
Cement mortar lining with epoxy seal coats is smoother than cement mortar lining, which can reduce the friction resistance. Xinxing has entrusted an authorized testing organization to test roughness coefficient of ductile iron pipes with cement mortar lining epoxy seal coats, and the result shows that its roughness coefficient of K is 0.020mm, which is lower than K of cement mortar lining (K=0.03mm).
1.9.5.4 Application fields
It is applicable for branch pipelines with small diameter,for example, the small- diameter pipeline network in small towns where the water tends to stay in the pipelines for longer time ;
It is in compliance with green, low-carbon and environment-friendly development direction of ductile iron pipe industry.
It can be upgraded product to replace the traditional ductile iron pipe with cement mortar lining.
1.9.5.5 Executive standards
Applicable standards for ductile iron pipes and fittings: ISO 2531, GB/T 13295 and BS EN 545 Applicable standard for seal coats of ductile iron pipe with cement lining: ISO16132
1.9.6 Polyurethane lining
1.9.6.1 Product description
PU lining of ductile iron pipe and fitting is formed by the PU material sprayed and cured on the surface of pipe/fitting bodies that is bi-component, solvent-free system. This kind of lining has excellent anti-corrosion performance and wearing resistance, as well as high impact resistance specific to various transmission mediums (such as portable water, wastewater, softened water, municipal sewage, and industrial wastewater), which is applicable to all water supply projects and municipal sewage drainage projects from soft water to hard water.
Figure 23 Ductile Iron Pipe with PU Lining
Lining thickness
The thickness of PU lining varies with water quality and pipe diameter. The thickness of the linings are shown in Table 19 and Table 20:
Table 19 Lining Thickness of Pipes and Fittings Applied to Portable Water Delivery as Required in ISO2531
Table 20 Lining Thickness of Pipes and Fittings Applied to Sewage Water Delivery as Required in ISO7186 Lining structure
—— Stability of PU lining
PU lining of ductile iron pipe produced by Xinxing can provide excellent chemical stability and ageing resistance: the increased weight of coating won’t exceed 4% after its immersion in 50℃ distilled water for 180 days; the adhesion of PU lining is greater than 8Mpa after it is exposed outdoor for 6 months.
—— Good flexibility
PU lining also has good flexibility, which can withstand the impact and deformation from transportation, installation or overload with deformation (ovalisation) in compliance with requirement of ISO2531
—— With smooth surface, it features small friction and excellent hydraulic performance. Xinxing has entrusted authorized testing organization to test roughness coefficient of K of ductile iron pipes with PU linings, and the test result is 0.010mm. Considering roughness arising from fittings, valves and other devices, as well as tolerance, it is suggested that K value shall be 0.050mm for the design purpose.
1.9.6.3 Properties of PU lining
PU lining produced by Xinxing complys with requirements of GB/T 24596 and BS EN 15655, as shown in Table 21.
No. Tested items Technical requirements
1
water resistance
Less than 15% weight increase after immersion in 50℃ deionized water for 100 days.
Less than 2% weight loss after drying Chemical resistance
Less than 10% weight increase after immersion in 50℃ 10% sulfuric acid for 100 days.
The weight change≤4% after drying
2 Indirect impact strength Impacted with energy E with the minimum value of 50J/mm, the PU lining shall be free from damage. 3 Ovality resistance DN Ovality of pipe 100~250 2% ~ 4% 300~600 3% ~6% 700~2000 4%~ 8%
The coating shall be free from damage.
4 Elongation at break ≥2.5%
5 Resistance of coating in
0.1M NaCl solution ≥ 108Ωm2
6 ratio of 100d resistance/70d
resistance ≥ 0.8
7 Resistance to light ageing Adhesion≥8 MPa after the lining is exposed outdoor for 6 months.
8 Non-porosity
When average thickness of the lining≤1500µm, No breakdown with Holiday detector at 3.0kv;
When average thickness of the lining > 1500µm, No breakdown with Holiday detector at 4.0kv.
9 Hardness Shore D > 70
10 Adhesion At 20℃ , adhesion ≥11 MPa
11 Abrasion resistance The wearing depth of the lining ≤0.2mm after 100000 movements (50000 cycles)
Requirements for material
PU coating: complying with EN 15655, passing WRC—NSF test of BS6920 and obtaining WRAS Certification.
Epoxy coating: complying with EN 14901, passing WRC-NSF test of BS6920 and obtaining WRAS Certificate.
Specification range
Xinxing can provide DN100~DN2200 full range of products Certification
PU linings of ductile iron pipes produced by Xinxing comply with requirements of GB/T 24596 and BS EN 15655 and have passed BV certification.
1.9.6.2 Product features
—— As a passive anti-corrosion coating, the effectiveness of PU lining depends on its sustainability, adhesion and stability over time.
—— Continuity and sealing performances of PU linings: Holiday test must be conducted for each ductile iron pipe with PU lining produced by Xinxing under the testing voltage of 6kV, which is higher than 4kV as specified in BS EN 15655, so as to guarantee the sustainability of PU linings.
—— PU lining can provide excellent adhesion, where Xinxing requires that it shall be no less than 11Mpa under 23℃ ;
Transmitted mediums PH of transmitted mediums
Portable water 1~13
Sewage water 1~13
Industrial water ＜13
Pipe body (ceramic epoxy) Area contacting with waterSocket and spigot (epoxy coating)Area without contacting
with water
Minimum thickness µm Minimum thickness µm Minimum thickness µm
1000 250 µm 150um
1.9.6.4 Application fields
Ductile iron pipes with PU linings can be used to deliver water as follows:
—— all types of portable water, sewage water with PH 1~13 and industrial water shown in Table 22:
—— Soft water or pure water, such as water desalted from seawater.
—— Maximum temperature of the substances transmitted by such lining is 45℃ .
1.9.6.5 Executive standards
Applicable standards for ductile iron pipe and fitting: ISO 2531, ISO 7186, GB /T 13295, GB /T 26081, BS EN 545 and BS EN598
Applicable standards for PU lining of ductile iron pipe: GB/T 24596 and BS EN 15655
Lining thickness
In order to ensure overall corrosion resistance of the pipe lining, the thickness of ceramic epoxy lining and coating of socket and spigot shall comply with requirements in the table 23:
Routine test
—— Adhesion test: Ceramic epoxy lining possesses excellent adhesion. Xinxing’s requirement on adhesion for such lining≥10Mpa under 23℃
—— Thickness test: Thickness test shall be conducted for each product.
—— Non-porosity: Each ductile iron pipe with ceramic epoxy lining shall be subject to holiday test under 3kv, so as to ensure the continuity of epoxy ceramic lining.
Requirements for material
Ceramic epoxy is bi-component and solvent-free paint with ceramic fillers added at least 20% in volume; such fillers consist of quartz powder and aluminum oxide powder with different size proportion so as to provide a hard and wearable ceramic lining.
Specification range
Xinxing can provide DN100~DN2200 full range of products
1.9.7.2 Product features
—— With excellent anti-corrosion performance and abrasion resistance, the coating is featured as compact and tough;
—— The coating surface is smooth as the mirror with small friction and excellent hydraulic performance. It is suggested to take K as 0.050mm for design purpose.
—— The coating is solvent-free, without volatile solvent released during usage, so it complies with safety and environmental protection requirements.
1.9.7.3 Properties of linings
Table 25 shows the properties of ductile iron pipe with ceramic epoxy lining produced by Xinxing:
1.9.7 Ceramic epoxy lining
1.9.7.1 Product description
The ceramic epoxy lining of ductile iron pipe and fitting is formed by the ceramic epoxy paint sprayed on the surface of pipe/fitting bodies that is bi-component, solvent-free system. The thickness of the lining≥1000um. Ceramic epoxy coating contains ceramic fillers at least 20% in volume, so this kind of the lining has excellent anti-corrosion performance and abrasion resistance performance, as well as good anti-corrosion and abrasion resistance performance to various transmission mediums (such as municipal sewage and industrial wastewater), which is applicable to municipal sewage discharge projects.
Lining structure
Table 22 Characteristics of Water Conveyed
Table 23 Thickness of Ceramic Epoxy Lining
ceramic epoxy lining metallic zinc cast iron pipe
Epoxy coating
Items Performance requirement Testing method abrasion depth after 100,000 movements
(or 50,000 cycles) ≤0.075mm ISO 7186
Impact resistance ≥5J no damage of the coating can be found during
the visual inspection ISO 6272-1
Water vapor permeability 30d 0.00 ASTM E96 method A
Salt spray resistance (scratch), 5% 30d
No blistering on the coating, no decrease for adhesion, and no spreading of corrosion at
scratches.
ISO 7253 ISO 4628
Chemical resistance
Distilled water (70℃ ) No changes of the coating for 4 weeks
ISO 4628 evaluation
25% NaOH(60℃ ) No changes of the coating for 4 weeks
20% H2SO4 No changes of the coating for 4 weeks
tap water (scratch)(50℃ ) no spreading of corrosion at scratches for 4 weeks
Adhesion ≥10Mpa ISO 4624
Coating thickness ≥1000um ISO 2808
Non-porosity 3KV NACE PR0188
Table 24 Properties Ceramic Epoxy Lining
1.9.7.4 Application fields
It is applicable to municipal sewage and industrial wastewater discharge projects containing higher amount of solid particles.
1.9.7.5 Executive standards
Applicable standards for ductile iron pipes and fittings: ISO 7186, GB/T 26081 and EN 598
•Equipment required brush paint brushes roller gas torch •Repairing paint: Zinc-rich primer:10kg •Procedure Brush to remove dirt
• The temperature of surface to be repaired shall be 5 ℃ above the dew point at least. In case that the surface is wet or the ambient temperature is very low, the surface can be heated by gas torch so as to keep it dry and at least 5℃ above the dew point.
• According to the requirements in Zinc-Rich Primer Product Specification provided by the supplier, the paint shall be mixed in proportion evenly and brushed on the surface to be repaired. The coating thickness shall reach at least 200g/m2 (When the coating is Zn-Al rare earth alloy, the thickness shall be
equivalent to the weight of Zn-Al rare earth alloy coat). The coating appearance shall be smooth without bubble, void or other defect.
1.10.1.1 Repairment of Zinc Coating/Zn-Al Rare Earth Alloy coating
1.10 Coating repairment
1.10.1 Repairment of Zinc coating + HCPE finishing layer/Zn-Al rare earth alloy + epoxy
coating
Repairment ofsuch coatings consists of two steps:
Step 1: Repairment zinc coating/Zn-Al rare earth alloy coating Step 2: Repair blue epoxy coating or HCPE finishing layer
•Equipment required
wire brush paint brushes spatula chisel
rotary wire brush gas torch
•Repairing materials
SPUA-R300 solvent-free PU paint
•Procedures
Remove the damaged coating and its surrounding coat with poor adherence by knife or other tools and remain the coat with sound adhesion and no defect. Clean the surface of ductile iron with a motor wire brush or other tool until its surface reaches St3. Brush away debris and dust to keep the repair-to-be surface clean.
• The temperature of surface to be repaired shall be 5℃ above the dew point at least. In case that the surface is wet or the ambient temperature is very low, the surface can be heated by gas torch so as to keep it dry and at least 5℃ above the dew point.
According to the requirements in Product Specification provided by the material supplier, the repairing material shall be mixed evenly in proportion and brushed on the surface to be repaired. The coating thickness shall be 700 um at least, and the coating appearance shall be smooth without bubble, void or other defect.
•Equipment required brush paint brushes roller gas torch •Repairing materials:
Blue epoxy paint - used to repair Zn-Al rare earth alloy + epoxy coating HCPE anticorrosion paint - used to repair zinc coating + HCPE finishing layer
•Procedures
Brush to remove dirt
• The temperature of surface to be repaired shall be 5 ℃ above the dew point at least. In case that the surface is wet or the ambient temperature is very low, the surface can be heated by gas torch so as to keep it dry and at least 5 ℃ above the dew point.
• According to the requirements in product specification provided by the paint supplier, the paint shall be mixed in proportion evenly, and brushed on the surface to be repaired. The thickness of black finishing layer is at least 70 um, and the thickness of blue epoxy coating is at least 100um. The coating appearance shall be smooth without bubble, void or other defect.
1.10.2 Repairment of PU coating
•Equipment required
brush paint brushes roller
•Repair materials:
WB-108 epoxy paint (gray)
Proportion
Weight ratio A:B = 5:1
• Stir component A before mixing. Weigh five portions of component A and one portion of component B prior to use as required. Place them into a container. Stir them at least 3 - 4 minutes with a blender or stirrer driven by low-speed electric drill, until they are mixed evenly.
• The ready mixture shall be used up under 25 ℃ within 2h. Otherwise, it shall be discarded.
•Procedure
Brush to remove dirt
• Brush the ready paint on the surface to be repaired with thickness of gray epoxy seal coats of 70 um. The coating appearance shall be smooth without bubble, void or other defect.
• The coating shall be naturally cured above 5 ℃ ; In case that temperature is too low, it is necessary to appropriately heat the coating for cure.
•Equipment required wire brush paint brushes Trowel spatula chiselhammer palette knife repair products •Procedures
Turn the area to be repaired to face upwards.
Remove the damaged area and surrounding hollow lining with a hammer or driver
The edges shall be vertical to the ductile iron pipe wall and ductile iron surface shall be exposed
Remove any loose debris with a wire brush
Clean the surface to be repaired thoroughly, including part of the rusted substrate.
Wet the area to be repaired
Wet cement mortar lining around the area to be repaired a few minutes before the repairing work
•Preparation of repairing material
Ratio of components
Firstly mix two kinds of powder materials, and then add certain amount of water, mixing to obtain the continuous slurry. If necessary, add small amount of water according to the viscosity.
Fill the defective parts with new mortar, smear the mortar on it to a uniform thickness with a trowel and make it dense. Operate evenly to obtain flat and smooth surface. If required, regularly water the trowel to facilitate troweling
The repaired part shall be fully cured and not exposed in sunshine. It shall be covered with plastic cloth to keep the humidity
Material Weight Ratio
Cement 100
Fine sand 200
Water 35~40
1.10.3 Repairment of cement mortar lining
1.10.4 Repairment of cement lining with epoxy seal coats
The repairing of this coating consists of two steps: Step 1: Repairing cement mortar lining (see 1.11.3) Step 2: Repairing epoxy seal coats
Repairment of epoxy seal coats
20kg 4kg
B A