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AT; 15.05.2019 1
CONTENTS 1. FIELD OF APPLICATION p. 2
2. PRODUCTION RANGE p. 2
3. RAW MATERIAL p. 3
4. GENERAL FEATURES OF VALROM PRODUCTS p. 5
5. WALL THICKNESS CALCULATION p. 6
6. NORMS p. 8
7. QUALITY CONTROL p. 8
8. COMPLIANCE MARK - QUALITY SYSTEM p. 8
9. NON-TOXICITY p. 8
10. RESISTANCE AGAINST CHEMICAL PRODUCTS p. 8
11. FIRE BEHAVIOR p. 16
12. RADIATIONS BEHAVIOR p. 16
13. STATIC ELECTRICITY p. 16
14. ENVIRONMENT INTERACTION p. 17
15. RECOVERY AND REUSE OF POLYETHYLENE USED BY VALROM p. 17
16. TRANSPORT AND STORAGE p. 17
17. LAYOUT p. 17
18. JOINING SYSTEMS p. 18
19. JOINTS AND SPECIAL PARTS p. 24
20. ANCHORING SPECIAL PARTS p. 25
21. WATER HAMMER p. 25
22. RESISTANCE AGAINST CRACK PROPAGATION p. 26
23. PIPELINES IN SEISMIC AREAS p. 26
24. RESISTANCE TO ABRASION p. 27
25. BURIED PIPELINES SUBJECTED TO LOADS p. 27
26. CALCULUS OF CRUSHING p. 28
27. THERMAL EXPANSION p. 32
28. SUSPENDED PIPELINES p. 34
29. SEWAGE PIPELINES UNDER PRESSURE p. 38
30. PIPE BENDING p. 38
31. PIPE TOWING p. 39
32. TRACTION TESTS p. 40
33. REHABILITATION OF PIPES BY LINING p. 41
34. UNDERWATER PIPES p. 41
FLOATING VERIFICATION p. 40
ANCHORING VERIFICATION p. 40
35. PRESSURE TESTING p. 42
36. MALFUNCTIONS AND REPAIRS p. 44
37. MECHANICAL PROCESSING OF HDPE p. 44
38. PAINTING p. 45
39. FUSION p. 45
40. HEAD LOSS FOR WATER p. 45
41. LAYING COSTS p. 54
AT; 15.05.2019 2
GENERAL TECHNICAL DATA
The information presented originate from various experiences and from literature-extracted data. Data are of a general nature. You are advised to contact our technical service in special circumstances, in order to obtain more detailed information.
Some formulas in this manual are empirical.
1. FIELD OF APPLICATION Pipelines manufactured by VALROM have a wide usage range, which is highlighted by the technical validity of same, the trust invested in same, easy mounting and maintenance. Hereafter a few usage fields of VALROM products shall be presented:
Drinkable water distribution networks;
Irrigation networks;
Mobile irrigation facilities;
Firefighting networks;
Food liquids transport lines;
Non-food liquids transport lines;
Gas distribution networks;
Urban sewage networks;
Water treatment facilities;
Drainage systems;
Drainage systems in special environments;
Civil discharge inside buildings;
Electronic cable protection systems;
Phone networks protection systems;
Special ventilation pipelines;
Abrasive liquid pipes. 2. PRODUCTION RANGE VALROM production is set by field-specific national and international norms and, given its diversity, provides users with a wide range of pipelines for meeting requirements raised in various fields of usage.
PE 100 PIPES SIZES - RATED PRESSURES – WEIGHTS
OD
SDR 27.6 PN=6 bar
SDR 26 PN=6 bar*
SDR 21 PN=8 bar
SDR 17 PN=10 bar
SDR 13,6 PN=12,5 bar
SDR 11 PN=16 bar
SDR9 PN=20bar
SDR 7,4 PN= 25 bar
inch
mm en mm
weight kg/m
en mm
weight kg/m
en mm
weight kg/m
en mm
inch mm en mm
weight kg/m
en mm
weight kg/m
en mm
weight kg/m
masa kg/m
1/2 20 - - - - - - 2,0 0,113 - - 2,0 0,113 2,3 0,128
3/4 25 - - - - - - 2,0 0,144 2,0 0,144 2,3 0,163 3,0 0,207 3,5 0,235
1 32 - - - - - - 2,0 0,188 2,4 0,222 3,0 0,272 3,6 0,320 4,4 0,380
1 1/4
40 - - - - “- - 2,4 0,282 3,0 0,347 3,7 0,420 4,5 0,499 5,5 0,593
1 1/2
50 2,0 0,300 2,0 0,300 2,4 0,357 3,0 0,441 3,7 0,535 4,6 0,652 5,6 0,777 6,9 0,929
2 63 2,3 0,436 2,5 0,473 3 0,562 3,8 0,703 4,7 0,856 5,8 1,036 7,1 1,239 8,6 1,461
2 1/2
75 2,8 0,632 2,9 0,653 3,6 0,803 4,5 0,991 5,6 1,214 6,8 1,448 8,4 1,747 10,3 2,081
3 90 3,3 0,894 3,5 0,946 4,3 1,151 5,4 1,427 6,7 1,743 8,2 2,094 10,1 2,520 12,3 2,984
4 110 4,0 1,324 4,2 1,388 5,3 1,733 6,6 2,131 8,1 2,577 10,0 3,122 12,3 3,752 15,1 4,474
125 4,6 1,729 4,8 1,801 6 2,229 7,4 2,717 9,2 3,326 11,4 4,043 14,0 4,851 17,1 5,760
140 5,1 2,148 5,4 2,269 6,7 2,788 8,3 3,413 10,3 4,171 12,7 5,047 15,7 6,092 19,2 7,240
6 160 5,8 2,792 6,2 2,977 7,7 3,661 9,5 4,463 11,8 5,459 14,6 6,627 17,9 7,940 21,9 9,441
180 6,6 3,573 6,9 3,729 8,7 4,602 10,7 5,655 13,3 6,921 16,4 8,376 20,1 10,033 24,6 11,933
AT; 15.05.2019 3
OD
SDR 27.6 PN=6 bar
SDR 26 PN=6 bar*
SDR 21 PN=8 bar
SDR 17 PN=10 bar
SDR 13,6 PN=12,5 bar
SDR 11 PN=16 bar
SDR9 PN=20bar
SDR 7,4 PN= 25 bar
inch
mm en mm
weight kg/m
en mm
weight kg/m
en mm
weight kg/m
en mm
inch mm en mm
weight kg/m
en mm
weight kg/m
en mm
weight kg/m
masa kg/m
8 200 7,3 4,392 7,7 4,623 9,6 5,706 11,9 6,988 14,7 8,503 18,2 10,329 22,4 12,419 27,4 14,763
225 8,2 5,550 8,6 5,810 10,8 7,222 13,4 8,851 16,6 10,799 20,5 13,087 25,2 15,717 30,8 18,671
250 9,1 6,843 9,6 7,204 11,9 8,845 14,8 10,866 18,4 13,303 22,7 16,107 27,9 19,343 34,2 23,038
10 280 10,2 8,591 10,7 8,995 13,4 11,152 16,6 13,649 20,6 16,681 25,4 20,187 31,3 24,299 38,3 28,897
315 11,4 10,804 12,1 11,441 15,0 14,047 18,7 17,296 23,2 21,132 28,6 25,569 35,2 30,744 43,1 36,581
355 12,9 13,776 13,6 14,494 16,9 17,836 21,1 21,992 26,1 26,796 32,2 32,446 39,7 39,074 48,5 46,402
16 400 14,5 17,449 15,3 18,373 19,1 22,710 23,7 27,839 29,4 34,011 36,3 41,211 44,7 49,576 54,7 58,959
450 16,3 22,067 17,2 23,237 21,5 28,758 26,7 35,280 33,1 43,075 40,9 52,230 50,3 62,758 61,5 74,582
500 18,1 27,227 19,1 28,672 23,9 35,519 29,7 43,601 36,8 53,209 45,4 64,425 55,8 77,371
560 20,3 34,199 21,4 35,979 26,7 44,448 33,2 54,595 41,2 66,721 50,8 80,745 62,5 97,059
630 22,8 43,215 24,1 45,581 30,0 56,187 37,4 69,183 46,3 84,360 57,2 102,274
* effective computed value = 6.4 bar
HDPE PIPES FOR GAS, SIZES - SERIES – WEIGHTS
OD SDR 11 S 5 Series SDR 17 S 8 Series
inch dext mm
en mm
masa kg/m
en mm
masa kg/m
3/4 25 3,0 0,207
1 32 3,0 0,272
1 1/4 40 3,7 0,420
1 1/2 50 4,6 0,652 3,0 0,441
2 63 5,8 1,036 3,8 0,703
2 1/2 75 6,8 1,448 4,5 0,991
3 90 8,2 2,094 5,4 1,427
4 110 10,0 3,122 6,6 2,131
125 11,4 4,043 7,4 2,717
140 12,7 5,047 8,3 3,413
6 160 14,6 6,627 9,5 4,463
180 16,4 8,376 10,7 5,655
8 200 18,2 10,329 11,9 6,988
225 20,5 13,087 13,4 8,851
250 22,7 16,107 14,8 10,866
10 280 25,4 20,187 16,6 13,649
315 28,6 25,569 18,7 17,296
355 32,3 32,446 21,1 21,992
16 400 36,4 41,314 23,7 27,839
450 40,9 52,230 26,7 35,280
500 45,5 64,552 29,7 43,601
560 50,9 80,888 33,2 54,595
630 57,3 102,435 37,4 69,183
AT; 15.05.2019 4
3. RAW MATERIAL Raw materials used by VALROM have been rigorously selected from Europe's best suppliers. These products resulted from polymerization of ethylene, are derived from long-term, detailed studies, effected within polymer products research labs in Europe. Results obtained so far confirm the validity of polymer usage in the field of pressurized pipelines. The polymer used for pipeline manufacturing has a molecular structure that guarantees conservation of mechanical features for at least 400,000 – 500,000 operating hours, at working pressure and fluid temperature of 20ºC. From a technical-economical viewpoint, the average facility lifetime was set to 50 years, as an increase of such period might lead to further network ageing, which immediately involves the replacement of same. Recent research shows that a 20 - 30 years working period is closer to reality, given the high variation rate of environment, defined as a whole of elements: urban, social, economic, etc. The method for checking pipe polymers validity mainly consists in sampling specimens from pipes manufactured within industrial facilities and submitting same to pressure tests. According to ISO procedures the wall stress
σ and test temperature T are being set, thus obtaining the duration of a assay series. The complete duration
results are given on the bilogarithmic graph (load σ, time t for various temperatures T); also, by means of ISO
elaboration, one obtains σ = f (time) graphs for different temperatures, known as “regression curves”.
Based on same material-specific curves, one could determine the product lifetime as a function of load σ.
One calculates wall thickness as a function of load σ, . Further, we present formulas for determining thickness (1) and specific load (2):
(1) sPN D
PN=
⋅
+2σ (2)
( )σ =
−PN D s
s2
One feature of these curves is a "peak" separating two phases of the viscous behavior which determines the type of breach. Above the "peak" there is a ductile behavior with large prior to break deformation; below the peak there is a microcrack, rather than a deformation. The current trend is to generate polymers with low incline regression curves in order to obtain better long-term performance. This evolution is visible in typical regression curves of a traditional and a high-performing polymer.
DURATION [h] 50 years
DURATION [h]
E F O R T
T A N G E N T I A L
[MPa]
Regression curves for PE 80 MRS 8.0 σσσσ63 (average density)
E F O R T
T A N G E N T I A L
[MPa]
PN = pipe rated pressure [MPa] D = outer pipe diameter [mm] s = pipe thickness [mm]
σ = wall tangential stress [MPa]
Regression curves for PE 80 MRS 8.0 σσσσ63 (traditional high density)
DURATION [h] 50 years
AT; 15.05.2019 5
Characteristics for the PE100 material *)
Physical characteristics Method Measure unit Value Density (volumic mass). at 23ºC ISO 1183 Kg/m3 958÷960
Melting Flow Rate MFR (5kg/190grd) ISO 1133 g/10 min 0.2÷0.4
Mechanical characteristics Method Measure unit Value Stress. at 23ºC and 50 mm/min
ISO 527 MPa 23÷25
at 100 mm/min ISO 527 MPa 24÷26 Stress at break. at 23ºC and 100 mm/min
ISO 527 MPa 30÷36
Strain at break. at 23ºC and 50 mm/min
ISO 527 % >350%
at 100 mm/min ISO 527 % >600% Modulus at 23ºC ISO 527 MPa 900÷1100
Thermic characteristics Method Measure unit Value Average termic linear expansion coefficient
ASTM D696 K-1 2.0 x 10-4
*) indicative average values 4. GENERAL CHARACTERISTICS OF VALROM PIPELINES Usage of high-quality raw materials, along with high-productivity extrusion lines (modern and material-specific) allow constant manufacturing pipelines with special technological features, with following results:
♦ optimum stress-cracking resistance with large time reliability of pressurized pipelines;
♦ excellent chemical resistance;
♦ high UV rays protection, guaranteed by using raw materials with an initial addition of soot;
♦ total, wide range safety of national and international non-toxicity norms;
♦ insensitivity to electro-chemical corrosion phenomena;
♦ high resistance to temperatures lower than -40ºC;
♦ high flexibility;
♦ optimum hydraulic characteristics consistent in time;
♦ very low roughness, which includes those powders in the category of smooth pipes;
♦ outstanding abrasion resistance makes them the ideal choice for transporting silt and abrasive liquids;
♦ low mass;
E F O R T
T A N G E N T I A L
[MPa]
Regression curves
PE 100 MRS 10 σσσσ80 (high density for high
performance)
DURATION [h] 50 years
AT; 15.05.2019 6
♦ safety and simplicity of connection systems;
♦ high mounting productivity.
5. WALL THICKNESS CALCULATION Based on premises laid out in section 3 (Raw material), one calculates the pipe thickness based on the following formula:
PN2
D*PN=s
+σ
The value assumed by σ is material-specific, as being extracted from the regression curve chart at 20ºC, extrapolated for a 50 years period. The value is correct for a safety coefficient of 1.25. According to the classification in EN12201:1, one identifies the following PE classes, designated as follows:
DEFINITION OF MATERIAL AND DESIGN STRESS
Designation Minimum required strength (MRS) MPa
Design stress σ(σ(σ(σ(HDS) MPa
PE 100 10.0 8.0 PE 80 8.0 6.3
where: MRS = Minimum Required Strength = minimum required strength (MPa) extracted according to EN12201:1 from regression curves at 20ºC
σ = Hydrostatic Design Stress (HDS) (MPa) These items allow the calculation of pipe thicknesses used in various PN to be performed.
Temperature (T - ºC) variation of the traction elastic modulus (E - MPa).
[MPa]
Temperature (T - ºC) variation of impact resistance (KJ / m2).
[KJ/m2]
ºC ºC
[MPa]
Temperature (T - ºC) variation of the traction stress (MPa).
Temperature (T - ºC) variation of elongation (MPa).
%
ºC
ºC
s = pipe thickness [mm] PN = nominal pressure [MPa] D = outer pipe diameter [mm]
σ = tangential calculus stress at 20ºC [MPa]
AT; 15.05.2019 7
Should pipes be continuously used in temperatures higher than the standard 20ºC a pressure lowering coefficient needs to be applied: For PE80 and PE100 pipes, acc. to EN12201-1:2011:
TºC Pressure lowering coefficient
20 1.00
30 0.87
40 0.74 DEFINITION OF TERMS USED PN = maximum internal allowed pressure (bar) for continuous operation at 20ºC S = series according to ISO E4065
SDR = Standard Dimension Ratio - ratio of rated nominal diameter (ΦE) and rated thickness (s) 6. NORMS Pipelines produced by VALROM complies with norms EN 12201, ISO 4427, EN 1555, ISO 4437 as well as major European national norms. Further, the ISO norms are designated:
ISO 161 - Thermoplastics pipes for the conveyance of fluids - Nominal outside diameters and nominal pressures
ISO 1167 - Thermoplastics pipes for the conveyance of fluids. Determination of the resistance to internal pressure
ISO/TR 7472; ISO/TR 10358 - High density polyethylene (HDPE) pipes and fittings: chemical resistance with respect to fluids conveyed.
SDR
S PE 80 PN (bar)
PE 100 PN (bar)
41 20 3.2 4 33 16 4 5
27.6 13.3 - 6 26 12.5 5 6 (6.4) 21 10 6 8
17.6 8.3 6 17 8 8 10
13.6 6.3 10 12.5
11 5 12.5 16 9 4 16 20
7.4 3.2 20 25 6 2.5 25 -
Note: 1.25 is the safety coefficient set by referring to the pressure of a water column at 20ºC for a 50 years duration.
PE high-density pipelines are defined according to following parameters:
♦ PN = rated pressure [bar]
♦ S = series
♦ SDR = standard dimensions ratio
SDR =ΦE
s, σ =
MRS
1,25, S =
SDR -1
2 PN=
⋅10 σ, PN =
10
S SDR -1
⋅=
⋅σ σ20
Relationships between:
σσσσ, S, SDR, PN.
AT; 15.05.2019 8
7. QUALITY CONTROL The assay and testing lab ensures the verification of the manufacturing process and guarantees the pipeline quality. VALROM has elaborated its own quality control program in order to guarantee - in a high-quality manner - the finite product compliance to internal and international standards. Controls are effected during each and every pipe manufacturing stage, from raw material to production parameters, from product dimensional control to determination of product characteristics. These stages, complete with careful control and lab testing, result in a manufacturing system with a well-defined quality control. By consistently pursuing the production process from the polymer to the finite product, the technical quality control is a fundamental component of VALROM philosophy. The final product quality is the result of knowledge and mastering of production techniques and problems. 8. THE QUALITY SYSTEM Manufacturing is performed on full automatic extrusion facilities, while control is performed on a daily basis in VALROM labs.
9. NON-TOXICITY One of the underlying features of VALROM pipes is full compliance with national and international sanitary norms on conveyance of drinking water and food liquids. This compliance is obtained by using both non-toxic polymers as well as an efficient storage and conveyance technology. 10. RESISTANCE AGAINST CHEMICAL PRODUCTS VALROM pipelines demonstrate excellent resistance to chemical agents as a whole, both organic and inorganic. HDPE could be easily attacked solely by aliphatic and aromatic hydrocarbons as well as their halogenated derivatives, at temperatures higher than 90ºC. High-concentration oxidizers attack HDPE in a more or less obvious manner - this is the reason why using HDPE pipes is not recommended in certain situations. In order to allow for a correct usage of HDPE in conveying industrial liquids, the norm ISO TR 7474 has been elaborated; this norm indicates the behavior of high-density PE pipelines in the presence of specific gas and liquid chemical products. It is therefore possible to check the compatibility of VALROM pipes for conveying chemical products; prior to conveying special liquids, we recommend that usage correctness be also checked with our technical office. Key: R = resistant
RL = limited resistance N = unsatisfactory Sat. sol. = saturated solution at 20ºC Sol. = aqueous solution with a contraction lower than 10%, yet unsaturated Dil. sol. = diluted aqueous solution with concentration 10% Aq. sol. dil. = aqueous solution, normally concentrated
AT; 15.05.2019 9
Reagent or product Concentration Temperature
20ºC 60ºC Acetate (see acetate norm) Acetic, glacial acid Acetic acid Acetic aldehyde Acetic anhydride Acetic acid Acetone Acid (see name of acid) Water Chlorine water Oxygenated water Oxygenated water Aqua regia Adipic acid Alcohol Sulphate Aluminum chloride Aluminum fluoride Aluminum sulphate Ammonia (gas) Ammonia (liquefied) Ammonia water Ammonium chloride Ammonium fluoride Ammonium nitrate Ammonium sulphate Ammonium sulphide Aniline Antimony chloride Silver acetate Silver cyanide Silver nitrate Arsenic Anhydride (see anhydride norm) Barium carbonate Barium chloride Barium hydroxide Barium sulphate Benzaldehyde Benzene Petrol (aliphatic hydrocarbons) Benzoic acid Beer Boric salt Boric acid Bromine (liquid) Bromine (dry vapors) Hydrobromic acid Hydrobromic acid Buthane (gas) Butyl alcohols Butyric acid Lime carbonate Calcium chlorate
> 96% 10%
100% 100%
100%
Sat. sol. 30% 90%
HCL/HNO3 = 3/1 Sat. sol.
96% Sol.
Sat. sol. Sat. sol. Sat. sol. 100% 100% 100% 100%
Dil. sol. Sat. sol.
Sol. Sat. sol. Sat. sol.
Sol. 100% 90%
Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sat. sol. Sat. sol. Sat. sol. Sat. sol. 100% 100%
Sat. sol.
Sat. sol. Sat. sol. 100% 100% 50%
100% 100% 100% 100%
Sat. sol. Sat. sol.
R R R R R RL
R RL R R N R R R R R R R R R R R R R R R R R R R R R R
R R R R R RL R R R R R N N R R R R R R R
RL R
RL RL R
RL
R N R N N R R R R R R
RL RL R R R R R R R R
RL R R R R R
R R R R
RL RL RL R R R R N
NR R R R R
RL R R
AT; 15.05.2019 10
Reagent or product Concentration Temperature
20ºC 60ºC Calcium chloride Calcium hydroxide Calcium hypochlorite Calcium nitrate Calcium sulphate Calcium sulphide Carbonic anhydride Carbon oxide Carbon tetrachloride Carbon sulphide Hydrocyanic acid Cyclohexanol Cyclohexanone Citric acid Chlorhydrate Hydrocloric acid Hydrocloric acid Monochloroacetic acid Dry chlorine (gas) Chloroform Methylbenzoic acid Chromic acid Chromic acid Decaldronaphtalene Dextrin Dioxane Diothylphthalate Heptane Ethanol / ethanediol (see ethyl alcohol) Ethyl acetate Ethyl alcohol Ethyl ether Phenol Iron chloride (II) Iron sulphate (II) Iron chloride (III) Iron nitrate (III) Iron sulphate (III) Hydrofluoric acid Hydrofluoric acid Hydrofluoric acid Fluorine Fluorosilicic acid Formaldehyde Formic acid Formic acid Phosphorus trichloride Phosphoric acid Phosphoric acid Furfuryl alcohol Glucose Glycerin Ethylene glycol Glycolic acid Hydrogen Hydrogen peroxide (see oxygenated water)
Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol. Dil. sol. 100% 100% 100% 100% 10%
100% 100%
Sat. sol.
10% Conc. Sol.
100% 100%
Sat. sol. 20% 50%
100% Sol.
100% 100% 100%
100% 40%
100% Sol.
Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol.
4% 60%
100% 100% 40% 40% 50%
98% ÷ 100% 100% 50% 95%
100% Sat. sol. 100% 100% Sol.
100%
R R R R R RL R R RL RL R R R R
R R R RL N RL R R R R R R R
R R RL R R R R R R R R RL N R R R R R R R R R R R R R
R R R R R
RL R R N N R R
RL R
R R R N N -
RL RL RL R R
RL N
N RL RL R R R R R R R
RL N N R R R R
RL R
RL RL R R R R R
AT; 15.05.2019 11
Reagent or product Concentration Temperature
20ºC 60ºC
Hydrogen sulphide Hydroquinine Lactic acid Milk Beer yeast Magnesium carbonate Magnesium chloride Magnesium hydroxide Magnesium nitrate Maleic acid Molasses Mercury Mercury nitrate Mercury cyanide Mercury chloride Methanol (see ethyl alcohol)
Methyl chloride Methyl chloride Methyl alcohol Nickel chloride Nickel nitrate Nickel sulphate Nicotinic acid Nitric acid Nitric acid Nitric acid Nitric acid Oleic acid Oils and fats Mineral oils Oxalic acid Oxygen Ozone
Propionic acid Propionic acid Picric acid Lead acetate Pyridine Potassium bicarbonate Potassium bicromate Potassium bisulphate Potassium bromate Potassium bromate Potassium carbonate Potassium chlorate Potassium chloride Potassium chromate Potassium cyanide Potassium ferricyanide / Potassium ferrocyanide Potassium fluoride
Potassium phosphate Potassium hydroxide Potassium hydroxide Potassium hypochlorite Potassium nitrate Potassium perchlorate
100% Sat. sol. 100%
Sol.
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Aq. sol. dil. 100% Sol.
Sat. sol. Sat. sol.
100% 100% 100%
Sat. sol. Sat. sol. Sat. sol. Dil. sol.
25% 50% 75%
100% 100%
Sat. sol. 100%
50% 100%
Sat. sol. Sat. sol. 100%
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol.
Sat. sol. 10% Sol. Sol.
Sat. sol. Sat. sol.
R R R R R R R R R R R R R R R
RL N RL R R R R R RL N N R R R R R RL
R R R R R R R R R R R R R R R R R
R R R R R R
R R R R
RL R R R R R R R R R R
- N R R R R - R N N N
RL RL RL R
RL N
R RL - -
RL R R R R R R R R R R R R
R R R
RL R R
Potassium permanganate 20% R R
AT; 15.05.2019 12
Reagent or product Concentration Temperature
20ºC 60ºC Potassium persulfate Potassium sulphate Potassium sulphite Potassium sulphide Copper chloride Copper nitrate Copper sulphate Salicylic acid Sodium benzoate Sodium bicarbonate Sodium bisulfite Sodium bromide Sodium carbonate Sodium cyanide Sodium chlorate Sodium chloride Sodium ferricyanide Sodium ferrocyanide Sodium fluorate Sodium phosphate Sodium hydroxide Sodium hydroxide Sodium hypochlorite Sodium nitrate Sodium nitrite Sodium sulphate Sodium sulphide Sulphurous anhydride Sulphuric acid Sulphuric acid Sulphuric acid (oleum) Sulphuric anhydride Sulphurous acid Tin (II) chloride Tin (IV) chloride Developer Tanic acid Tartaric acid Thionyl chloride Toluene Trichlorethylene Triethanolamine Urea Urine Wines and hard liquor Xiline Zinc carbonate Zinc chloride Zinc oxide Zinc sulphate
Sat. sol. Sat. sol.
Sol. Sol.
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
40% Sol.
15% chlorine Sat. sol. Sat. sol. Sat. sol. Sat. sol. 100% 10% 50%
100% 30%
Sat. sol. Sol. Sat.
Aq. sol. dil. Sol. Sol.
100% 100% 100% Sol. Sol.
100% Sat. sol. Sat. sol. Sat. sol. Sat. sol.
R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R N N R R R R R R N RL N R R R R RL R R R R
R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R N N R R R R R R N N N
RL R R R N R R R R
AT; 15.05.2019 13
Liquids that may be conveyed without pressure (sewage) up to 60ºC by means of HDPE pipes unsubjected to mechanical pressure
Reagent or product Concentration Acetate Acetic acid Water Oxygenated water Adipic acid Alcohol Sulphate Aluminum chloride Aluminum fluoride Aluminum sulphate Ammonia (gas) Ammonia (liquid) Ammonia (solution) Ammonium chloride Ammonium fluoride Ammonium nitrate Ammonium sulphate Ammonium sulphide Ammonium chloride Silver acetate Silver cyanide Silver nitrate Arsenic Barium carbonate Barium chloride Barium hydroxide Barium sulphate Benzoic acid Beer Boric salt Boric acid Hydrobromic acid Hydrobromic acid Buthane (gas) Buthyl alcohols (butanols) Lime carbonate Calcium chlorate Calcium chloride Calcium hydroxide Calcium hypochlorite Calcium nitrate Calcium sulphate Carbonic anhydride Carbonium oxide Hydrocyanic acid Cyclohexanol Hydrocloric acid Hydrocloric acid Monochloroacetic acid Citric acid Dextrin Dioxane Ethanediol (see ethylene glycol) Phenol Iron chloride (II) Iron sulphate (II) Iron chloride (III) Iron nitrate (III) Iron sulphate (III) Hydrofluoric acid Fluorosilicic acid
10%
30%
Sat. sol. 96% Sol.
Sat. sol. Sat. sol. Sat. sol. 100% 100%
Dil. sol. Sat. sol.
Sol. Sat. sol. Sat. sol.
Sol. 90%
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sat. sol. Sat. sol.
50% 100% 100% 100%
Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol. 100% 100% 10%
100% 10%
Aq. sol. dil. Sol.
Sat. sol. Sol.
100%
Sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol.
4% 40%
AT; 15.05.2019 14
Reagent or product Concentration Formaldehyde Formic acid Formic acid Phosphoric acid Glucose Glycerin Ethylene glycol (ethanediol) Glycolic acid Hydroquinine Hydrogen Hydrogen sulphide Milk Lactic acid Beer yeast Magnesium carbonate Magnesium chloride Magnesium hydroxide Magnesium nitrate Maleic acid Molasses Mercury Mercury cyanide Mercury chloride Mercury nitrate Methanol (see methyl alcohol) Methyl alcohol Nickel chloride Nickel nitrate Nickel sulphate Nitric acid Oxalic acid Potassium bicarbonate Potassium bicromate Potassium bisulphate Potassium bisulfite Potassium bromate Potassium bromide Potassium carbonate Potassium cyanide Potassium chlorate Potassium chromate Potassium ferrocyanide Potassium ferrocyanide Potassium fluoride Potassium phosphate Potassium hydroxide Potassium hydroxide Potassium nitrate Potassium perchlorate Potassium permanganate Potassium persulfate Potassium sulphate Potassium sulphide Propionic acid Copper chloride Copper nitrate Copper sulphate Salicylic acid Sodium benzoate Sodium bicarbonate Sodium bisulfite Sodium bromide Sodium carbonate
40% 50%
96% ÷ 100%
50% Sat. sol. 100% 100% Sol.
Sat. sol. 100% 100%
100% Sol.
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Aq. sol. dil. 100%
Sat. sol. Sat. sol.
Sol.
100% Sat. sol. Sat. sol. Sat. sol.
25% Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
10% Sol.
Sat. sol. Sat. sol.
20% Sat. sol. Sat. sol.
Sol. 50%
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
Sol. Sat. sol. Sat. sol.
AT; 15.05.2019 15
Reagent or product Concentration Sodium chlorate Sodium cyanide Sodium ferricyanide / ferrocyanide Sodium fluoride Sodium phosphate Sodium hydroxide Sodium hydroxide Sodium hypochlorite Sodium nitrate Sodium nitrite Sodium sulphate Sodium sulphide Sulphurous anhydride Sulphurous acid Sulphuric acid Sulphuric acid Tin (II) chloride Tin (III) chloride Developer Tannic acid Tartaric acid Urea Urine Wine and hard liquor Zinc carbonate / chloride / oxide / sulphate
Sat. sol. Sat. sol. Sat. sol. Sat. sol. Sat. sol.
40% Sol.
15% chlorine Sat. sol. Sat. sol. Sat. sol. Sat. sol. 100% 30% 10% 50%
Sat. sol. Sat. sol.
Aq. sol. dil. Sol. Sol. Sol.
Sat. sol.
Liquids that may be conveyed without pressure (sewage) up to 20ºC by means of HDPE pipes
unsubjected to mechanical pressure
Reagent or product Concentration Acetaldehyde Acetic acid, glacial acid Acetic anhydride Oxygenated water Acetic acid, starch Starch acid Aniline Benzaldehyde Petrol (aliphatic hydrocarbons) Butyric acid Cyclohexanone Chromic acid Chromic acid Decalin Diothylphthalate Heptane
100% > 96% 100% 90%
100% 100% 100% 100%
100% 100% 20% 50%
100% 100% 100%
Ethanol / Ethyl alcohol Ethyl acetate Hydrofluoric acid Phosphoric acid Phosphorus trichloride Furfuryl alcohol Nicotinic acid Oils, fats and mineral oils Oleic acid Oxygen Picric acid Lead acetate Pyridine Potassium hypochlorite Propionic acid Sulphuric acid Triethanolamine
40% 100% 60% 95%
100% 100%
Dil. sol.
100% 100%
Sat. sol. Sat. sol. 100% Sol.
100% 98% Sol.
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Liquids whose conveyance is not possible by means of HDPE pipes
Reagent or product Concentration Chlorine water
Aqua regia
Liquid bromine
Bromine (dry vapors)
Carbonium sulphide
Carbonium tetrachloride
Dry chlorine (gas)
Chloroform
Methylbenzoic acid
Fluorine
Methylene chloride
Nitric acid
Nitric acid
Nitric acid
Ozone
Sulphuric acid (oleum)
Sulphuric anhydride
Thionyl chloride
Toluene
Trichloroethylene
Xylene
Sat. sol.
HCl/HNO3 = 3/1
100%
100%
100%
100%
100%
100%
Sat. sol.
100%
100%
50%
75%
100%
100%
100%
100%
100%
100%
100%
11. FIRE BEHAVIOR Polyethylene is a combustible product which, in contact with a flame, burns slowly, with a low brightness yellowish flame. The burned product tends to leak melt material. Burning liberates CO, CO2, H2O, along with the usual hydrocarbon burning products; no corrosive gases are liberated. According to norms DIN IEC 707/VDE 0304 T.3. and UL 94, fire behavior is classified as follows: BH 3 - 15 mm/min FH 3 - 15 mm/min UL 94 HB According to ASTM D1929, the self-ignition temperature is 350ºC. The Oxygen Limit Index (OLI) of HDPE is 17.4%, while the burning heat has a value of 46,500 KJ/kg. Smoke opacity is low, ASTM D843 indicates a value of 15. Smoke toxicity is also low. 12. RADIATIONS BEHAVIOR HDPE pipes do not demonstrate contraindications for beta- or gamma-waves emitting water pipes; an example are the descending pipes in nuclear plants.
γ ray, X-ray and electron flux irradiation of HDPE generates reticulation phenomena which, in the absence of oxygen, improve the polymer's strength, solely altering its traction elongation values.
13. STATIC ELECTRICITY HDPE pipes are subjected to electrostatic phenomena due to the high value of material resistivity
(>1018 Ωcm.). As for gas product pipes, solid particles or microdrops present in the flow may lead to static electricity deposits particularly on the pipe metallic parts (flanges, shutters etc.). Earthed piping is subjected to charge deposits, given the environment humidity and the wide piping - soil contact. There are certain particular environment and installation situations (e.g., gas pipe suspended in a dry, ventilated environment, in the presence of easily flammable products), where the importance of the phenomenon needs evaluation. One must take into consideration that a high environmental humidity drastically diminishes the likelihood for electrostatic charge deposits. If interventions must be performed on pipes for conveying combustible gas, we recommend that in maximum safety settings the pipe part being handled to be buried soaked in water with tensioactive additives (e.g., detergents) in order to be kept wet; it should be grounded with a piece of material maintained in a wet state.
AT; 15.05.2019 17
For a subsequent ditch filling one could use the recovery material, which must be well compressed, thus excluding materials impregnated with water, peat, mud, etc. Filling must be performed in a single direction and performed during the morning as much as possible. We recommend that pipe ends be left uncovered for a better performance of subsequent mounting operations. Under special circumstances, layout could be significantly improved (see figure below) by using geotextile materials in order to stabilize the pit bottom (1), the pipe protection (3); the method is also useful to anchor the pipe (preventing it from floating on underground water) (4).
14. ENVIRONMENT INTERACTION The high thermal inertia of VALROM pipes, due to the specific type of polymer used, does not produce any interaction with the environment, as early as the manufacturing stage. Pipings are not subjected to biochemical actions of microorganisms, as are manufactured using materials that cannot provide food support. Laying HDPE pipes in systems with high microbiologic aggresivity, in the presents of rodents or insects, does not generate specific problems, again confirming the product validity. 15. RECOVERY AND REUSE OF POLYETHYLENE USED BY VALROM Polyethylene is a thermoplastic material, therefore, waste derived from the production process lend itself to processing within recycling plants. The high heat of combustion and the quality of its combustion products make polyethylene an interesting material to burn in cremation facilities. 16. TRANSPORT AND STORAGE
A correct transportation of VALROM pipings requires a smooth fixing plan. The load must be secured with stripes and ribbons, in non-metal cages. In binding workpoints, as far as low thickness pipes are concerned, we recommend that binding stress distribution brackets be used. Unloading and potential onsite moves need to be performed with the aid of forklifts, cranes or excavators with a balance. Pipes must be stored in stacks, on a plane, smooth foundations; bundles may be deposited in an inclined posture and leaning against a plane vertical wall; for low thickness types (such as PN 4/6) a horizontal stacking is recommended, for a better protection against deformations. Bars must be stored in stacks on a clean ground (stack height should not exceed 1.5 m for PN 2.5; 3.2; 4-type pipes). May we remind you that correct storage significantly facilitates future piping manipulation tasks. 17. LAYOUT After performing the excavations according to project specifications, the ditch bottom must be leveled with a sand layer. After the pipe is laid out, gaps left between the pipe and the ditch wall shall be filled with selected soil. Where best conditions exist for pipe performance/economy, we recommend that a pit width be preserved equal to the pipe diameter plus 40 cm; also, an adjoining protection area shall be preserved with at least 15 cm of sand above and below the pipe. Fine digging material is allowed over the upper sand layer, in compressed layers around 30 cm thick. (see figure below)
A correct pipe layout allows for best operational results to be obtained.
Layout using geotextile materials
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18. JOINING SYSTEMS
Joining methods of HDPE pipes manufactured by Valrom Industrie are as follows: - butt welding, using fittings such as T-pipes, elbows, adapters, plugs - welding using electroweldable fittings such as bushings (couplings), T-pipes, elbows, adapters,
plugs, intakes with/without a collar (coupling T-pipes) - mechanic coupling using fittings such as T-pipes, elbows, plugs, connectors, - flange joints
The network deployment method depends upon the technical-economical assessment. Note: Both pipes and fittings could be found in the product catalog, sections WaterKIT and GasKIT. Weld joint The joining technique between polyethylene pipes as well as between pipes and fittings is fusion. Specifically, it consists in heating contact surfaces for a certain period of time, under specific pressure and temperature conditions that determine a sufficient amount of melt material on both surfaces. The two surfaces are pressed against each other, so that the melt material combines, forming a single structure. The joining methods for polyethylene parts are butt welding and electrofusion. In order to obtain a safe joint it is IMPORTANT that the individual authorized to perform these types of tasks to observe the welding procedure. Butt welding join During a butt welding process, the ends of two polyethylene pipes are aligned and fastened within a hydraulically driven fixture system that moves the pipe ends one towards another. The butt welding device configuration is as follows:
pipe clamping dies
electrohydraulic unit with electric panel
bracket with thermoplate and mill
adapters
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Butt welding stages are as follows:
• checking pipes and ends to be joined
• fastening the terminal ends of pipes in the fixture system (clamping dies) and correcting the ovality of same
• turning ends to be welded with the circular mill
• clean the pipe surfaces of impurities by wiping them with wipes /cloth soaked in isopropyl alcohol
• installing the thermoplate and keeping the terminal ends of pipes seated on same. The thermoplate seating duration is prescribed in the user manuals of welding devices and depends on pipe dimensions (diameter and thickness)
• removal of thermoplate and bringing the two pipe ends into contact
• the welded joint is released from the clamping dies after cooling
• weld checking
• removal of extra material and weld inspection
• recording the welding parameters Parameters involved in the welding process are:
• preheating, welding and cooling times, in minutes or seconds (specified in the user manuals of welding machines)
• preheating and welding pressures, in bar or MPa
• thermoplate temperature in °C
• geometric dimensions of pipes The welding chart is as follows:
P welding pressure T time Phase 1: heating Phase 2: melting Phase 3: thermoplate withdrawal Phase 4: pressure increase Phase 5: welding Phase 6: cooling
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Parameters Values Units of measure Plate temperature, T
d3 ≤ dn ≤ 250
250 < dn
210 ± 10
225 ± 10
°C
Phase 1 p1 *) 0.18 ± 0.02 N/mm2 (MPa)
t1 Measured until size is reached for bead B1
s
bead width, B1 dn ≤ 180 1 < B1 ≤ 2 mm
180 ≤ dn ≤ 315 2 < B1 ≤ 3
315 < dn 3 < B1 ≤ 4
Phase 2 p2 *) 0.03 ± 0.02 N/mm2 (MPa)
t2 (30 + 0.5 dn) ± 10 s
Phase 3 p3 N/mm2 (MPa) Phase 4 t4 s Phase 5 p5 *) 0.18 ± 0.02 N/mm2 (MPa)
t5 minimum 10 min Phase 6 t6 minimum: 1.5 en
maximum: 20 min. min
*) NOTE: This pressure relies on the outer diameter (dn), pipe thickness (en) and the type of the welding machine. Additional requirements must be met such as:
• checking and calibrating of welding machines
• checking weldings
• markup and registering of welding parameters
• the weather conditions during welding and their influence: the working area where welding is performed must be protected from severe weather conditions: excessive solar radiations, humidity,
wind, ambient work area and pipe temperature must not drop below 5°C. A uniform temperature of pipe wall, according to welding joint, must be preserved in order to achieve correct welding. The area where welding is performed may need protecting (covering) and warming in order to perform pipe conditioning. Where excessive solar radiation is present one shall protect the area where welding is to be performed in advance, in order to allow uneven warmed pipes to equalize their temperature. Under strong winds, the free ends of the pipe must be covered in order to prevent joint cooling during welding.
The checking procedures of butt-welded pipes/fittings are performed according to ISO 11414. Electrofusion welding The electrofusion process uses fittings manufactured by injection, with a calibrated electric resistance embedded inside the fitting wall. The electrofusion principle is simple: pipe ends are introduced inside the fitting, then a current is generated which, by means of spires, heats material on both internal fitting surface and external pipe surface. Due to temperature increase and pressure generated between surfaces, the two masses of melt material flow together. Surfaces outside the fusion area are called cold areas. These areas cool down the melt material and balance pressures on the entire circumference. Every fusion area is provided with an indicator developed in the fitting wall and pushed outside during the fusion process. This is the first visual indicator for the completion of the welding process. The standard electrofusion welding stages are as follows:
• checking fittings, pipes and ends to be joined
• examining the correctness of pipe ends cutting
• mark the contact surface or half the fitting length on the ends to be welded
• abrasion of contact surfaces
• cleaning the scraped area and the internal surface of the fitting by wiping it with a cloth soaked in isopropyl alcohol
• re-marking the contact surface
• mounting on the fixture system
AT; 15.05.2019 21
• connecting the fitting to the device
• recording of parameters indicated on the fitting label or reading the barcode with the barcode reader or magnetic card and starting the process
• process stopping takes place automatically
• checking for increased values of indicators
• allowing the assembly to cool down for a minimum time indicated on the fitting label
• releasing the assembly from the fixture system
• monitoring every operating parameter Fittings are stored individually packed in polyethylene bags, in order to protect them against dirt, but a long-term storage allows the additives to migrate on the surface and may affect the joining process. These products could be removed by cleaning with a cloth and an adequate dissolver, e.g. isopropanol. In most cases, pipes are stored outside, which makes their surface dirty, possibly UV-degraded and oxidated to a small extent - this is why a simple cleaning does not suffice; a surface abrasion of 0.1 mm is required for
D≤63 and 0.2 mm for D>63. This shall provide an adequate surface for fusion and, henceforth, joining. A simple grinding with emery is not enough, because an adequate surface cannot be achieved; moreover, particles from the glass paper may remain that can subsequently initiate slow cracking. Electrofusion is accepted worldwide mainly due to being easy to implement, but also easy to trace and monitor. The electrofusion device has the following features:
• identifying the welder by badge
• recording the date, location, fitting data and operating times
• measures ambient conditions and adjusts welding parameters
• reads parameters from the fitting barcode or from the magnetic card
• checks fitting quality by measuring the electric resistance
• monitoring the fusion process and alerts on errors
• prints registered data in order to prove joint quality In order to obtain a safe joint it is IMPORTANT that the individual authorized to perform these types of tasks to observe the welding procedure. One must observe the welding machine instructions of use and occupational health and safety norms. Mechanical joints Compression sealing fittings are used for joining PE pipes for water networks with a rated pressure of 10 bar and a diameter of up to 110 mm. The parts comprising a compression fitting are the following:
A. connection body (PP-B) B. fastening plug C. compression collar D. compression bushing E. O-ring
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Mounting instructions:
Ø 20 ÷Ø 63 Ø 75 ÷Ø 110
1: Cut the pipe perpendicularly and remove burrs. In order to provide an insertion of the O-ring as light as possible, lubricate both the O-ring and the pipe.
1: Cut the pipe perpendicularly using a special cutting device, a band saw or a circular saw. In order to obtain a straight line of cut, it is best to use a guidance part as an aid. Remove burrs and bevel the pipe end in order not to deteriorate the fitting.
2: Unscrew the blue plug from the fitting by 3-4 turns.
2: Unscrew the blue plug from the fitting by 3-4 turns and ensure that the O-ring and the locking bushing are placed as shown in the picture
3: Insert the pipe into the fitting and make sure that it has passed by the O-ring and reached the inside shoulder.
3: Insert the pipe into the fitting until it touches the three fines inside the fitting body.
4: Screw/clamp the plug with the help of spanners 4: Screw/clamp the plug with the help of pipe
spanners.
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Connecting part/Collar plug/Connecting collar
Locate the mounting point and ensure the pipe is smooth, with no pinches or scratches that may affect the fitting
Clamp the part bottom side and join it with the higher side. DO NOT forget to insert the fitting placed in the upper side.
Insert the screws upwards. Screw the nuts and tighten same in a diagonal pattern.
Using a drill press, make a hole in the pipe, ensuring not to touch the collar thread or the fitting.
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The alternative method: 1. Using a white marker (preferred) mark reference lines on the pipe in order to reposition the
collar. 2. Drill the pipe with the drill press and remove the chips. 3. Position the collar by the marked lines. Be careful to align the hole in the collar with the hole
in the pipe 4. Mount the screws with nuts and tighten them in succession, in a diagonal pattern.
19. JOINTS AND SPECIAL PARTS In order a solve various situations encountered in designing and mounting of VALROM pipes, a series of special parts has been developed (curves, T-pipes, adapters, derivations). These parts have been obtained by injection or adhesion to manufactured items, using the properly profiled pipe as reference.
A series of usual fittings (bushings, T-pipes, adapters, elbows, plugs, etc.) shall be presented for smaller diameters, developed using either special plastics or metal (brass, bronze).
TYPICAL SPECIAL PARTS
90 deg. ELBOW PROFILED 90 deg. ELBOW IN SEGMENTS
PROFILED T T IN SEGMENTS
FREE FLANGE BLANK FLANGE
CLAMPING CARD T ADAPTED
CONCENTRIC ADAPTER PLUG
ECCENTRIC ADAPTER ADJUSTABLE COLLAR PLUG
ELECTRIC BUSHING PLUG WITH LOAD
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20. ANCHORING SPECIAL PARTS When welded special parts or special parts with anti-looseness components are used, HDPE pipings do not normally require anchoring systems, as the piping-ground part is adequate to keep them secured in position. Should large cross-section pipes be laid out in low-consistency ground, support these special points using concrete blanket in order to full bind the pipes and relieve same from possible parasite stresses. Force the special part is being subjected to has a value given by:
F = K P S⋅ ⋅ where:
Special parts, like shutters, slide valves, etc. must lay onto a support if having a large mass and
subjected to sudden moves.
21. WATER HAMMER A phenomenon occurring in hydraulic networks is hammering - rise of pressure due to velocity variations of the liquid being conveyed; this velocity variation occurs due a quick handling of shutters and slide valves. If not strictly controlled, this phenomenon might lead to severe perturbations and faults. The usage of VALROM HDPE pipes obviously diminishes this drawback; specifically, the low pipe elastic modulus reduces drastically the pressure points, thus protecting the entire installation.
The maximum overpressure occurs when the tap shutting time τ is lower or equal to the perturbation propagation time on the tap - pool - tap route (2L).
τ =2L
c
The maximum pressure value could be computed, with a good degree of approximation, with the help of Allevi's formula:
c =C
1+E
s
p
ε⋅
D
S
i
[m/s]
C = perturbation propagation speed [m/s]
Cs = sound speed in water 15°C = 1,420 m/s
ε = water elastic modulus 2 x 108 Kgf/m2 Ep = HDPE elastic modulus .9 x 108 Kgf/m2 DI = internal pipe diameter [m] S = pipe wall thickness [m]
F = force exerted on part [Kgf] K = shape coefficient P = maximum test pressure [Kgf/cm2] S = cross-section area of special part
subjected to force [cm2]
K:1 plugs, adapters, T
K:1.4 elbows at 90°
K:0.7 elbows at 45°
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Compute the perturbation propagation speed; the ∆h overpressure value is given by:
Values computed for ∆h are 3-5 times smaller, in average, than values obtained for steel pipes. 22. RESISTANCE AGAINST CRACK PROPAGATION
23. PIPELINES IN SEISMIC AREAS
Crack propagation is a phenomenon that, due to its occurrence in metal structures (pipes and plates), also needed to be examined in the field of plastic pipes. The classic study is performed with the help of the Robertson test, consisting in a controlled breach in a gas-pressurized pipe wall and measuring the propagation length. One of the essential problems of this test is the breach formation difficulty: one end of the test pipe (adequately profiled and notched) is subjected to a calibrated energy blow. Since breach begins, the installation point
must be cooled down to roughly -110°C, using liquid nitrogen. The test is deemed as passed whether the breach length is smaller or equal to 5.5 times the pipe diameter. VALROM pipes comply with testing limits without any problems.
VALROM pipes are very well suited for usage in seismic areas due to special mechanical features of HDPE, that demonstrate optimum response to stresses occurred during a seismic event. Besides maintaining network continuity, easily subjected to detachment due to plugged assemblies, there is also a trend to diminish significantly the unavoidable hammering occurring within pipes. Tests performed on specifically "monitored" models confirmed these performances within
seismic events of 7° degrees on the RICHTER scale and IX degrees on the MERCALLI scale, when serious damages occur in earthed piping.
∆h =c
gV0
[mH2O] where:
c = perturbation propagation speed [m/s] V0 = water speed in the pipe [m/s] g = acceleration of gravity [m/s2]
beater
structure
notch for breach formation
(-110 deg. C)
sealing bed
pipe sample
framework
Accele
ration
[cm
/s]
Time [s] Recording a seismic phenomenon
AT; 15.05.2019 27
24. RESISTANCE TO ABRASION VALROM HDPE pipes also prove the outstanding features of this polymer in the case of conveying
liquids containing abrasive particles. The low elastic modulus, toughness, low roughness, hydrophobicity, the low friction coefficient, the high chemical inertia allow excellent, highly technically and economically efficient conveyance of liquids and abrasive muds. Accelerated tests, performed in extreme conditions, have proven that the HDPE piping lifetime is 4 to 10/15 times larger as related to pipes made of steel and concrete materials.
Thus, designing and managing the abrasive liquids conveying systems becomes feasible by using the VALROM pipes low weight, flexibility and corrosion resistance to the maximum extent.
The high workability of this material allows, as soon as the critical points of facility have been identified, special parts to be built with an optimum shape in order to diminish wear and facilitate replacement. Low mass, self-cleaning and lack of roughness demonstrated by these pipes considerably simplifies possible maintenance tasks, with notable savings both in the technical domain and in time. These features recommend VALROM pipes for usage in mining and dredging facilities, as well as in all fields where abrasion-resistant materials are needed.
25. BURIED PIPELINES SUBJECTED TO LOADS HDPE pipes are almost completely buried; is layout is being performed according to usual procedures, no crushing issues occur (especially for pressurized pipes). As for pipes mounted closer to surface, with a large value of the diameter/thickness ratio, checking of performance under external load is required, which results in determining the adequate thickness.
A ground of 2100 Kg/m3 volume mass
and a friction angle of 22.5° is taken for reference.
1 m cover for Φ < 600 mm and 1.5 m
cover for Φ > 600 mm, allows traffic of 12
tonnes max.; 2.0 m cover for Φ > 600 allows for 20 tonnes traffic (see adjoining table).
Φ < 600 mm Φ > 600 mm 12 tonnes 1.0 m 1.5 m 20 tonnes 1.5 m 2.0 m
ABRASION RESISTANCE
DU
RA
TIO
N
HDPE GRES PVC Fe Centrifuge cement
GRP. Cement amiante
MATERIALS
AT; 15.05.2019 28
Various layout and working conditions require a crushing verification. You should remember that PE, like any other elastic material, demonstrates a viscoelastic mechanical behavior connected to stress value, duration and working temperature. Whilst "traditional" materials demonstrate mechanical properties easily schematized with rigid (e.g., ceramic) or elastic (e.g., metals) models, PE is definable using a more complex model (see adjoining figure) bringing together the pure elastic deformation component (1), the fully reversible delayed deformation (2) and the irreversible permanent deformation (3). Starting from this model, one could correctly attack and define the mechanical features of these polymers and prefabricates of same.
Modelul comportamentuluivascoelastic
26. CALCULUS OF CRUSHING VALROM, due to accumulated experience, uses the IMHOFF-GAUBE-ROTTNER method, which allows safe calculation of the pipe deformation in time based on pipe and pit dimensions, as well as ground and load type.
An analogy to metallic materials is possible if performance of the latter is considered under high temperature stress, e.g., cauldron or chemical reactors. Examining the crushing phenomenon, one remarks the pipe wall flexibility and an interesting phenomenon comes into attention: the notable ground participation to piping performance. Whilst a "traditional" pipe supports a load placed above, the HDPE pipe discharges a notable load fraction on the adjoining ground. Thus, pipes with significantly different mechanical features may have
equivalent, if not higher, final performances.
The viscoelastic behavior model
PIPE TYPE
GROUND TYPE
PIT TYPE
TRAFFIC TYPE
UNDERGROUND WATER
PIPE LOAD DUE TO GROUND
PIPE LOAD DUE TO TRAFFIC
PIPE LOAD DUE TO WATER
TOTAL PIPE LOAD
PIPE STRESS
DEFORMATION
MATERIAL CHARACTERISTICS
ENVIRONMENT CONDITIONS
CALCULUS MODEL
OK STOP
Calculus to check the crushing of earthed HDPE pipes (the IMHOFF-GAUBE-ROTTNER method)
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A HDPE pipe Φ..........x s..........PN.......... Diameter D=..........cm Thickness s=........…cm B Ditch width B=..........cm Cover height H=...........cm H/B=..........
G q ground load on a pipe ring 1 cm long
C B D = q =..........Kgf / cmg ⋅ ⋅ ⋅γ
H qT load due to street traffic 1. P load on piping
nT
2/ cm2
πΗ2= =P Kgf..........
n = ground coefficient, n = 3 compact, n = 6 uncompressed sand T = max. wheel load........Kgf (see table) H = pipe cover..........cm
2. qT load on a pipe ring 1 cm long
1,5 P Bm = qT⋅ ⋅ .......... /Kgf cm
Bm = average pit width..........cm I Total load qC on a pipe ring 1 cm long q + qT = qC..........Kgf/cm L Wall stress
qC/2s = σt =..........Kgf/cm2
M Material elastic modulus ET as a function of T(°C), work and the placement foreseen duration ET = ..........Kgf/cm2 N Pipe diameter deformation
D-s = mean diameter = .........cm O Maximum allowed deformation
D max⋅ =0 05, δ
P Deformation
0,005q
EcmC
T
⋅ ⋅
= =
D
s
3
δ ..........
Q Comparison between δ and δmax (δ < δmax)
For values δ > δmax, switching to a larger thickness pipe, or using an adequate protection is required.
Class Total load Kgf
Total load on wheel
Kgf Max. traffic
600,000 100,000
Average traffic 450,000 300,000
75,000 50,000
Min. traffic 120,000 80,000
20,000 20,000
Self-opening 30,000 10,000
C Ground
Type ........with γ =..........Kgf/cm3
D Working temperature 20°C
E Operating period predicted 50 years F Determining the Cg coefficient from MARSTON's diagram Cg=..........
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BENDING ELASTIC MODULUS
(E - t - σ 20σ 20σ 20σ 20°C)
Ela
stic m
od
ulu
s E
(M
Pa)
AT; 15.05.2019 31
rap
ort
ul H
/B
rapo
rtul H
/B
coeficient Cg
coeficient Cg
MARSTON'S DIAGRAM a) ground with no cohesion = 1.7 b) ground with rolling stones/sand = 1.9 c) damp/clay-bearing ground = 2.0 d) compact clay = 2.1 e) compact hydrosaturated clay = 2.2
a) b) c) d) e)
Coefficient C
H/B
ra
tio
H/B
ratio
AT; 15.05.2019 32
27. THERMAL EXPANSION A feature of plastics - and of HDPE as well - is a high value of the linear expansion
coefficient (αt) as related to traditional materials used in manufacturing pipes (15 - 20 times larger
than αt in metals). Unearthed piping exposed to large thermal variations the thermal expansion phenomenon needs to be examined. As for earthed pipes, except for particular situations, once the layout thermal fixture has been performed, the thermal expansion issue is negligible, The length variation calculus for HDPE pipes manufactured by VALROM is performed using the classic formula:
∆ ∆L = Ttα ⋅ ⋅L
where: ∆L = length variation L = pipe length
αt = conventional expansion coefficient 2 x 10-4 K-1
used to devise the nomogram L/∆T/∆L attached (page 34).
Once the maximum allowed length variation
has been calculated in design circumstances, a better method shall have to be chosen in order to compensate this situation. The most convenient system, that deals with most situations, is using the expansion joints; there are three kinds of expansion joints: with elastic connection, steady AND collar. The elastic connection joint unloads axial and angular movements on an rubber-like component, simultaneously demonstrating high flexibility and hydraulic sealing
Elongations are not large. The steady joint allows large elongations, yet is more sensitive than other types, being less used for this reason.
Imbinare de dilatare cu manson
Bushing joints are similar to steady joints, yet are simpler and less expensive, distributing the useful length on a higher amount of sections, better and often more economic solving the pipe motion issues; applicable to pipes of diameters up to
Φ500 PN 4. Some situations require the pipe to be locked, as generated forces are absorbed by the pipes and the environment.
This is why a structure calculus is required using same values of polymer mechanical features as in working conditions. The pipe segment flush between two margins is deemed as a bar under maximum load; the critical presoflexure length must be checked.
where: LK = pipe length [mm]
de = Φe pipe [mm]
di = Φi pipe [mm]
αT = thermal expansion coefficient = 2 x 10-4 K-1 ∆T = thermal jump
Lde di
TK = ⋅
+0 354
2 2
, πα Τ ∆
Expansion connection joint
Expansion bushing joints
AT; 15.05.2019 33
Nomogram ∆∆∆∆T / L / ∆∆∆∆L for PE pipes
CLAMPING AND SUPPORTING COLLARS
L = pipe length [mm]
∆I = length variation [mm]
∆T = temperature difference [°C]
δ = linear expansion
coefficient [mm/m°C]
It is more preferable, in certain situations, to perform compensation by means of an expansion arm or an expansion circle.
A) Compensation using an expansion arm
B) Compensation using an expansion circle
H L≈ ⋅ ⋅26 Φ ∆
∆L= length variation [mm]
Φ = external pipe diameter [mm]
H = arm length [mm]
HL
≈ ⋅ ⋅262
Φ∆
Note: B > ∆L, ∆L = ∆L1 + ∆L2 We recommend that the fixed
point be introduced mid-turn.
SUSTINERE
FIXARE
SUPPORT
CLAMPING
AT; 15.05.2019 34
Compute σ, read E; if the value of FMX is larger than .2%, therefore the distance between brackets must be diminished.
B) Clamped pipe with evenly distributed load
FPL
EJMX =
3
185
FMX = Maximum allowable sag [m] P = Total load = = Pipe weight + transported liquid + overweight [kgf/m] L = Distance between brackets [m] J = Pipe moment of inertia E = Material elastic modulus [MPa] c = Distance from neutral axis [m]
FPL
EJMX =
3
384
The E module is being read from the E/t/σ graph,
where σ is determined by: σ =⋅
⋅P L c
J8
EJ
PLFMX
384
3
=
28. SUSPENDED PIPING As for external or underground gallery installations, supporting HDPE pipes may be performed using a continuous support or a discrete support (using adjustment collars). We recommend in both cases be inserted an antifriction synthetic material pillow between pipe and support (e.g. PE).
The continuous support must embrace the pipe for at least 90/120°, as long as there is no stress concentration on the pipe.
As for support using separate brackets, the maximum gap between them could be checked as a function of the support type being used,
A) perfectly flush at one end and clamped at the other B) clamped at both ends The maximum inflection sag could be used for reference and is normally considered allowable if taking values of .2% in 10 years. Time factor has been included since this is a viscoelastic material, that demonstrates a time-related mechanical behavior.
The E module is being read from the E/t/σ graph, where σ is determined by: σ =⋅
⋅P L c
J8
A) The pipe flush at one end is clamped at the other, demonstrating an evenly distributed load
Fmax
Fmax
AT; 15.05.2019 35
Inte
r-axes d
ista
nce
of bra
cke
ts [cm
]
Ela
stic m
odulu
s E
(M
Pa)
The HDPE flexion flow module f (δ,δ,δ,δ, t ) for T= 20 ºC Inter-axes distance of brackets for overhead HDPE Class PN 2.5 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
Compute σ, read E; if the value of FMX is larger than 0.2%, therefore the distance between brackets must be diminished.
Complex load per length unit [Kgf/m]
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Inter-axes distance of brackets for overhead HDPE Class PN 3.2 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
Inter-axes distance of brackets for overhead HDPE Class PN 4 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
Inte
r-a
xe
s d
ista
nce o
f bra
ckets
[cm
] In
ter-
axes d
ista
nce
of bra
cke
ts [cm
]
Total load per length unit [Kgf/m]
Total load per length unit [Kgf/m]
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Inter-axes distance of brackets for overhead HDPE Class PN 6 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
Inter-axes distance of brackets for overhead HDPE Class PN 10 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
Inte
r-axes d
ista
nce
of b
rackets
[cm
] In
ter-
axes d
ista
nce
of bra
cke
ts [cm
]
Total load per length unit [Kgf/m]
Total load per length unit [Kgf/m]
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Inter-axes distance of brackets for overhead HDPE Class PN 16 pipes with:
Maximum sag: = 20/00 of inter-axes distance between brackets T = 20 ºC T = 10 years
30. PIPE BENDING
The flexibility of HDPE pipes allow immediate solving of design, mounting and layout issues, otherwise difficult if other materials are used. This feature requires maximum operational safety, next to a layout period smaller than in other materials (e.g., metals).
In assessing allowable bends one could identify two typical situations as a function of the Φpipe/wall thickness ratio:
1. Φ/s >= 25 valid for PN 2.5 - 3.2 - 4
2. Φ/s < 25 valid for PN 6 - 10 - 16
29. SEWAGE PIPELINES UNDER PRESSURE Civil and industrial sewage systems require high efficiency and conveyance safety (similar to those of pressure networks) due to large quantities and loads of used water. These performances are difficult to achieve, on one hand, with pipe products commonly used, whereas studying and designing cannot be performed in the field with refined special discharge collection and treatment systems without a simultaneous total operational safety of piping being used. Collection of polluting and concentrated discharges in specific directions facilitates an increase in the environment contamination risk potential; therefore, using products and technologies fully guaranteeing a complete sealing of collection networks is of utmost importance. The VALROM HDPE pipes fully comply with these requirements, allowing optimum design and deployment of civil and industrial pressurized sewage networks.
Low roughness of internal surfaces (ε = 0.03), given by the cutting-edge production technology, is preserved in time by PE chemical inertia. This guarantees a hydraulic performance consistent in time, while the high abrasion resistance allows large flow speeds of the liquids being conveyed.
Total load per length unit [Kgf/m]
Inte
r-axes d
ista
nce
of bra
cke
ts [cm
]
AT; 15.05.2019 39
As for pipes used in sewage, assume the situation of a wall under presoflexion that requires a radius
of curvature of 20°, In this case, the radius of curvature is computed using one of the formulas A) and B).
A) Rs
PF
T=
Φ2
112,
B) RPN
PF
T=100Φ
Note: The simplified formula B) is more commonly used.
where: Rε = radius of curvature [mm]
ΦT = outer pipe diameter [mm]
PN = pipe rated pressure [bar]
s = pipe wall thickness [mm]
As for pipes used in pressurized networks, an assessment of pipe wall elongation ε is required.
Said elongation, which is normally (mounting at 20°C) limited to 2%, leads to a radius of
curvature of Rε:
R T
εε
=Φ
2
where: Rε = radius of curvature [mm]
ΦT = outer pipe diameter [mm]
ε = reference elongation [%]
The radius of curvature also depends on the PE pipe mounting temperature
An easily workable option is using the following table:
T [°C] SDR 33 SDR26 SDR 17/SDR17.6
SDR 11
Radius of curvature R
20 ≥ 40 ΦT ≥ 30 ΦT ≥ 30 ΦT ≥ 30 ΦT
10 ≥ 70 ΦT ≥ 55 ΦT ≥ 45 ΦT ≥ 45 ΦT
0 ≥ 100 ΦT ≥ 75 ΦT ≥ 65 ΦT ≥ 65 ΦT
31. PIPE TOWING
The remarkable flexibility, low weight and unbreakability of VALROM HDPE pipes allow ordinary, simple layout methods of traditional systems to be used. It is also possible to use prefabrication techniques on site and tow prepared segments to the layout location. Pipes, even notably long ones (100 m and longer) are easily towable, since they glide very easily on the ground. Towage is facilitated by rolls or flowing "blankets" in order to protect pipes from soil irregularities.
Special situation require that traction stresses be evaluated, in order to accurately determine the
length of towable pipe. The calculus is based on comparing the maximum allowable tractions stress (σadm),
adjusted by a safety coefficient, with σT computed based on foreseen stresses. The important items are: duration of continuous stress, working temperature and draining modalities.
A computing method valid in most cases uses the following procedure: computing the towage force for a horizontal pipe.
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T[deg. C]
Time
The value of σT shall be compared against σadm. In order to determine σadm one could use the graph
(t, T, σ) below; if a duration (t) of the traction stress is defined and an average working temperature (T) of the
pipe is assessed, the value of σadm could be determined.
We often use σadm ≈ 0.5σ graph in order to compensate uncertainties connected with effective pipe
stress. If σT > σadm, the part length is reduced or traction conditions are improved, if possible,
Surface type µ static µ dynamic PE/compact ground 0.50 0.30
PE/clean asphalt 0.45 0.25 PE/blanket 0.50 0.40
PE/iron 0.45 0.35
32. TRACTION TESTS Pipe are moved with the help of operating machines and forklifts.
For towage, the pipe is clamped by the ends using "soft" materials (nylon and polyester straps) and towed at a speed which, related to the pipe dimensions, may reach 100 mm/min when gliding.
In special usage situations (e.g., relining), when size becomes an issue it is essential to use a pulling head connected inside the piping by means of a cylinder plug (as an example).
The amount and sizing of plugs and holes are calculated according to the limit compression and material cutting resistance values.
If limits σc and σt have not been observed, an intervention on connection sizing is required. We recommend that a consistent speed be preserved during the towage operations.
where: σT = traction stress [N/mm2] F = traction force [N] A = pipe wall cross-section area [mm2] Ks = safety coefficient to evaluate based on
layout conditions
COMPRESSION CHECK
σ c
F
Z D s=
⋅ ⋅
2/10 mmNc =≤σ at 20°C 1h
σc = compression load [N/mm2] F = stress [N] Z = no. of holes D = holes diameter [mm] s = wall thickness [mm]
CUTTING CHECK
σ t
F
Z b s=
⋅ ⋅ ⋅2
σ t N mm=≤ 4 2/ at 20°C 1h
σt = cutting load [N/mm2] F = stress [N] Z = no. of holes b = distance from hole to pipe border [mm]
F P L= ⋅ ⋅ µ
where: F = towage force [N] P = unit pipe weight
[N/mm] ≈ Kg/m x 102
µ = the friction coefficient L = pipe length [mm]
σ TsF K
A=
⋅
Str
ess σ
[N
/mm
2 ]
Pulling heads
AT; 15.05.2019 41
33. REHABILITATION OF PIPES BY LINING Modifications of urban structures and field concur to a fast ageing of the legacy service networks which, either by an increase of demand, or by decay of performance, often become insufficient. The phenomenon expands in aqueducts, sewage and gas pipes, where severe drawbacks are observed due to faults and high losses.
HDPE pipes, aside from being usable in most cases for the rehabilitation of installations, is also fit, in various conditions, for interesting solutions to reuse old service routes. The classic "relining" operation is effected by inserting HDPE pipes in old pipes or in legacy seats; due to their high resistance and flexibility, these could be easily laid out even on considerable lengths. Optimum operation is possible when the internal cavity diameter is 10% larger than the outer diameter of inserted piping. This approach reduces service downtimes and eliminates possible annoyances, with a low impact on means and people traffic as well as on onsite cleanliness. Once the pipe chosen, the procedure consists in preparing the pit in the insertion and pulling areas, towing the pipe, e.g., by means of a tractor head. Parts could be prepared on lengths of several hundred meters, depending on working characteristics.
Inserting operations could be performed within a minimum time: a Φ400 mm pipe could be inserted at a speed of 1,5/3 m/min with no problems whatsoever. If required, dot-shaped pits could be drilled in succession for possible fixture systems. The cavity between the new pipe and the legacy sewage could be refilled with water and sand. During traction, we do not recommend that traction stresses be exceeded that generate elongations larger than 3 - 4%. INSERTING A CONTINUOUS PIPE INSERTING A PIPE OF BARS 34. UNDERWATER PIPES Installing underwater pipes, especially in a marine environment, due to its aggresiveness and presence of difficult static and dynamic situations, finds an optimum resolution in HDPE pipes. Experiences effected for over 20 years on underwater pipes confirm the excellent performances of same, operated under harsh conditions. One could assert, with utmost objectivity, that this material is particularly used for this type of installations. Given the complete PE immunity as related to the marine environment, the main issue of underwater pipes consists in defining actual dynamic situations, as real layout and work conditions are deemed difficult to foresee and often need to be taken into account using statistic assessments. The viscoelastic behavior of PE, along with great safety in operating the joints are key elements contributing to the increase of the operational safety range of these installations. Layout speed and simplicity are also important items that confirm the technical-economical validity of choosing HDPE. Due to the floating phase of these pipes, floating check issues arise, subsequently followed by clamping checks.
FLOATING CHECK Due to its specific weight of 950 kgf/m3, HDPE demonstrates a push towards water surface. Since the pipe floats, one must check:
( )P P P P C Stub lichidtransportat accesorii s= + + ⋅ <
.
with 115 1 20, ,≤ ≤Cs and
( )S volumtub volumaccesorii apa= + ⋅γ
γwater = 1,000 Kgf/m3 (freshwater)
γwater = 1,030 Kgf/m3 (sea water) The calculus is applied per length unit or per pipeline module.
AT; 15.05.2019 42
CHECKING ANCHORING As for pipelines laid out on seabed, anchoring must be calculated in order to prevent the pipeline to move under the action of particular operational situations (e.g., air bubbles) or due to external stresses exerted by lateral currents. Pushing exerted by same currents is calculated in the extreme scenario when their direction is perpendicular on the pipeline: These values shall require further adaptation to maximum risk circumstances. Anchoring needs to be evenly distributed along the pipe, in order to avoid excessive flexion stresses. Anchoring is comprised of prefabricated blanket half-rings, mounted on the pipe using rods and anchors. In order to avoid pipe deteriorations, as well as anchoring slippage, one interposes rubber or polypropylene tissue stripes between the block and the pipe during the centering operations. During centering operations effected by pulling/pushing (works needs to be performed at speeds that may exceed 10 m/min), pipe slippage on the ground must be cared for and facilitated, in order to avoid abrasions and overstress. Immersion is done by drowning the pipe; there are higher flexion stresses occurring during pipe lowering, due to the "S" shape the pipe assumes. One must check the material compatibility of the traction and flexion stresses; if needed, use (floating) accessories in order to rectify layout conditions. Pipeline protection is possible in particular situations by clonging the pipe in the previously dredged trench. These difficult applications highlight the features of VALROM HDPE pipes: flexibility, low weight, resistance and maneuverability. 35. PRESSURE TESTING The pressure test is made according to NP 133-2013 “Norms regarding the design, execution and exploitation of the water supply and sewerage systems of the localities” and in compliance with SR EN 805:2000 – “Water supply. Requirements for systems and components outside buildings” The tests are performed on lengths of 300m up to a maximum of 500m. The section to be tested must be secured against displacement; the height of the filling over the ridge of the pipes shall be at least 1m. The filling will be carried out over the entire length of the pipe, except at the joint’s areas to be left free for observing any water leakage. First of all, the ventilation valves located at the highest points, have to be opened. Filling the testing sectors with water has to be done from the bottom end. When the water leaking is airless, the aeration valves shall be closed. For closing the sectors one will use secured caps and not valves. The filling pieces of pipes, the drains, aerators and the pressure gauge pipes shall be moulded on these caps. The internal pressure depends on the temperature. From this reason the tests have to be made on chilly weather (in the morning) and the water temperature shall not exceed 23°C. Prior to pressurizing the pipe one will wait the temperature equalization between pipe and water. Establishing the system test pressure (STP) according to SR EN 805. MDP = the maximum design pressure, as it is established by the designer, including the water hammer pressure and the future developments, with:
• MDP is MDPa when the water hammer pressure was established by appreciation;
• MDP is MDPc when the water hammer pressure was calculated; case of water hammer pressure established by appreciation: the lowest value from STP = MDPa x 1.5 or,
S V K= ⋅ ⋅0 052 2, Φ where:
S = pipeline push [kg/m] V = current speed [m/s]
Φ = pipe diameter [m] K = anchoring shape coefficient
K = 0.6 for anchoring on rings K = 0.9 for anchoring on cuboids
The anchor used shall have to meet the following:
ZS
F> where
Z = anchoring used [kg/m] S = lateral current push [kg/m] F = pipeline/seabed friction coefficient
F = 0.1 (slimy bottom)
F = 0.3 (sandy bottom)
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STP = MDPa + 500 kPa the water hammer pressure established by appreciation should not be less than 200kPa; case of the calculated water hammer pressure: STP = MDPc + 100kPa.
Note: Take care that the maximum pressure applied on the pipe should be 1.5 x PN. Testing the network (section) includes:
Preliminary testing phase, that includes a relaxation stage (aimed at avoiding erroneous results in the main testing phase);
Pressure drop test; Main testing phase;
Preliminary testing phase (performed according to EN 805 A27.3) with the purpose of allowing the volume of flexible network (section) pipes to be increased under pressure, prior to the main test. After filling and aeration, the pressure must be set and maintained at the atmospheric one for at least 60
minutes, taking care of avoiding any entry of air. After this relaxation time, the pressure must be increased fast and uniform (less than 10 minutes) to the network testing pressure (STP). Pumping continuous or discontinuous, maintaining this STP for 30 minutes one has to check during this time the network (section) to detect obvious water losses. Leave an additional 1 hour without pumping, while the pipe network flows viscoelastic. One measures the residual pressure at the end of this test. If the pressure dropped by more than 30% of the STP, the preliminary phase has to be stopped and the pressure returned to the atmospheric one. After which one examines the test conditions (influence of temperature, water loss index ...). Do not resume the test procedure until after a minimum of 60 minutes of relaxation. Pressure drop test (performed according to EN 805 A27.4) The results of the main testing phase can be taken into consideration only if the volume of the contained air is small enough in the tested network (section). The method provides a fast removing a volume of water (ΔV) from the pipe and checking the pressure drop (Δp). From the prepared network (section), at the pressure measured in the end of the preliminary test (if passed), a well measured quantity of water (ΔV) is removed fast until the pressure drops with 10-15% from STP. This measured ΔV has to be compared with the calculated ΔVmax as in the relationship below. If ΔV (removed) ≤ ΔVmax the network is well, otherwise it should be repaired and the entire test resumed.
⋅+⋅∆⋅⋅=∆
EEV
RWe
DpV
12,1
max [dm3]
ΔVmax - the permissible loss of water [litres] V - the volume of the tested pipe network [litres] Δp - the admissible pressure drop [kPa] Ew - elasticity modulus of water [kPa] = 2.1 x 106 kPa Ew = 2.07x106 kPa at 10°C Ew = 2.15x106 kPa at 20°C D - interior pipe diameter [m] e - the pipe wall thickness [m] ER - bending elasticity modulus provided by Valrom [kPa] 1.2 - correction factor (i.e. for the admissible residual air) during the main testing phase. Main testing phase (performed according to EN 805 A27.5) The viscoelastic pipe flow generated by the STP is interrupted by the pressure drop test. Dropping fast the internal pressure leads to a pipe contraction. The main testing phase records the increase of internal pressure due to this contraction in a 30 minutes period (period of this phase). The main testing phase is acomplished if the pressure curve shows an upward trend and in no case a downward trend over that time. If a downward trend over this 30-minute period appears, then this should indicate a liquid loss in the network. In the case of uncertainty, the main test phase is prolonged to a total of 90 minutes. In this case the pressure drop is limited to 25 kPa starting from the maximum value reached in the contraction phase. If the pressure drops by more than 25 kPa, the test is considered unsatisfactory.
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One has to correct any defect discovered at the network and repeat the test. Repetition of the main testing phase can only be accomplished following the complete procedure (preliminary stage - including the 60min relaxation - and the pressure drop test). Important! The water loss at an end-to-end weld joint may indicate an imminent failure. After the water loss has been observed at the weld joint, the section of the pipeline will be depressed immediately.
36. MALFUNCTIONS AND REPAIRS
Due to HDPE features, the are no material-specific failures.
Failures may occur in specific situations such as:
damages caused by excavators
welding failures
defective mounting of fittings
In order to limit wrong excavation maneuvers and for a correct identification of the network path, install a warning tape with metal tracing wire about 30 cm above the pipes.
Since most defects occur due to mounting failures, tightness and pressure tests are performed before covering the network.
Should a failure occur, the remedy consists in the following:
identifying the correct damage area
isolating the area
uncovering the area to allow intervention
repairing the damage
the checking tests and maneuvers in order to recommission the installation required by network type, according to standard procedures and technical norms, e.g. ventilation of gas pipelines
restoring the area
Repairs are performed on dry, clean pipes.
Accidental damage effecting over a limited area could be remedied by mounting mechanical collars, electro-weldable plugs.
Extended damage is repaired by replacing the affected part with a trunk that can be connected in various ways:
butt welding
flanges
mixed: butt welding and flanges
electro-weldable plugs
mechanical bushings
References
ISO 11414:1996 : Plastics pipes and fittings -Preparation of polyethylene (PE) pipe/pipe or pipe/fitting test piece assemblies by butt fusion
Fitting mounting instructions by Irritec
Operating instructions for MSA 350 edited by Georg Fischer
Operating instructions for Delta welding machines by Ritmo Plastinc Welding Technologie
Einar Grann-Meyer : Polyethylene Pipes in applied engineering
37. MECHANICAL PROCESSING OF PE
Similar to most plastic materials, HDPE possesses a low conductibility coefficient (0.45 W/m°K) and
a low specific cutting force (≈ 100 N/mm2). These characteristics recommend a high operating speed, low advance and small upper exfoliation angle, in order to optimize bringing scrapings and enamel to the working temperature. Insufficient cooling of the working tool leads to melting of scrapings and hindering the removal of same, with the immediate consequence of a decrease in the part's superficial finish. On the other side, overheating may lead to burns, resulting in material deterioration. We recommend that an air jet be directed on the tools in most cases; thus, scrapings get cooler and become easily removed. High speed tools meet various working requirements and are comparable with tools made of more loose alloys.
AT; 15.05.2019 45
38. PAINTING If usual procedures are used, painting HDPE pipes is extremely difficult. Special superficial treatment operations are required and these measures have to be taken into account. 39. FUSION Due to its high chemical inertia, adhesion of HDPE is actually difficult. It requires special adhesives which are difficult to procure. Using "contact" adhesives and preparing surfaces to adhere allows a discrete layer and film adhesion; it not an efficient operation. 40. HEAD LOSSES FOR WATER VALROM pipes belong to the "extremely smooth" range of pipes, a characteristic given by the
production technology. The roughness coefficient ε is fundamental for computing a network's hydraulic performances. Due to its consistent value in time, it is very helpful in designing and demonstrates high safety;
calculus refinement is high due to real values assumed by ε, which values do not worsen in time. Good hydraulic performance leads to an improvement of a service network's global performances, with a subsequent increase of the technical and economical system efficiency. Calculus of load losses is effected by means of the DARCY-WEISBACH formula:
HD
V
gL= ⋅ ⋅
λ 2
2
where the value of λ is computed using COLEBROOK's formula, well suited for an automated
calculus:
12
2 51
3 715λ λ
ε= − +
Log
R De
,
,
WORKING HDPE PIPES WITH THE HELP OF EDGED TOOLS
INDICATIVE PARAMETERS Drilling
γ = rake angle 3° ÷ 5°
β = addendum angle 60° ÷ 90°
v = cutting speed 50 ÷ 150 m/min
s = feed rate 0.1 ÷ 0.5 mm/rotation
Turning
γ = rake angle 0° ÷ 15°
β = bottom rake angle 5° ÷ 15°
v = cutting speed 100 ÷ 250 m/min
s = feed rate 0.2 ÷ 0.5 mm/rotation
Milling
γ = rake angle < 15° v = cutting speed < 1,000 m/min Cutting
γ = rake angle 0° ÷ 5°
M = amount of teeth 2 ÷ 4 teeth/cm
v = cutting speed 600 ÷ 1,500 m/min
s = feed rate 0.5 ÷ 6 mm/rotation
AT; 15.05.2019 46
where: H = head loss [mCA]
λ = hydraulic resistance factor D = internal pipe diameter [m] V = velocity of liquid being lead [m/s] g = acceleration of gravity [m/s2] L = pipe length [mm]
ε = roughness coefficient .007 mm
Re = Reynolds' number = (V x D) / ν Alternatively, one could use MOODY's diagram where values
assumed by λ, Reynolds' number and
relative roughness ε / D could be read.
T°C ν x 10-6
5 1.520 10 1.308 12 1.240 15 1.142 16 1.109 20 1.007 25 0.857
ν = kinematic viscosity [m2/s]
DIAGRAM T/ν
AT; 15.05.2019 47
γ
DV •=Re
MOODY'S DIAGRAM
REYNOLDS' NUMBER Re
Curves of relative roughness ε/D between .000001 and .050
ε= size of superficial roughness [cm]
D = internal pipe diameter [cm]
RE
YN
OLD
S' N
UM
BE
R R
=
Pipeline or Values of ε [cm]
cover type (new) Interval Protection val.
Brass .00015 .00015
Copper .00015 .00015
Cement .03 - .3 .012 Unprotected cast iron .012 - .06 .024 Cast iron covered in asphalt .006 - .018 .012 Cast iron covered in cement .00024 .00024
Cast iron covered in bitumen .00024 .00024
Centrifuged cast iron .0003 .0003
Galvanized iron .006 - .024 .015 Welded iron .003 - .009 .006 Commercial welded steel .003 - .009 .006
Riveted steel .09 - .9 .18 HDPE pipe - aqueducts - sewages
.0023 .0007 .003
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Coated steel pipe
PE pipe
41. LAYOUT COST Comparison has been performed between pressurized pipes demonstrating dimensional analogies and comparable installation modalities (e.g., welding), removing mechanically or plug joined products; the coated steel pipe is used as reference. Costs analysis has been performed on various parameters, taking the following factors into account:
• pipe cost
• transportation
• deployment
• special parts
• welding
• unforeseeable situations
• cathode protection Layout was assumed in the extraurban area.
LAYOUT COST
DN
VALROM INDUSTRIE S.R.L., Bucharest, 28 Preciziei Blvd., sector 6 tel: 021.317.38.00, fax: 0372.89.94.45
UN
IT L
AY
OU
T C
OS
T