June 2006 DEUTSCHE NORM ICS 23.040.10 D DIN 2460 Steel water pipes and fittings Stahlrohre und Formstücke für Wasserleitungen 10224:2005-12 and DIN EN 10311:2005-08 supersedes DIN 2460:1992-01 DIN EN Together with Document comprises 34 pages Translation by DIN-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text. Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN No reproduction or networking permitted without license from IHS --``,,,,`,``,``,`,``,```````,`,`-`-`,,`,,`,`,,`--- Kowsar San'at Espadana Co. www.KowsarPipe.com Kowsar San'at Espadana Co.
Transcript
June 2006DEUTSCHE NORM
English price group 14No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).
This standard has been prepared by Technical Committee NARD-4 Stahlrohre of the Normenausschuss Rohrleitungen und Dampfkesselanlagen (NARD) (Piping and Boiler Plant Standards Committee). The general requirements for water supply and sewer systems specified by CEN/TC 164 and CEN/TC 165 have been taken into consideration in this revision. The present standard gives requirements for various pipe and fitting designs, depending on the application; these requirements may be included in the technical delivery conditions.
Amendments
This standard*) differs from DIN 2460:1992-01 as follows:
a) Definitions from European Standards have been included.
b) Requirements which are dealt with in DIN EN 10224 and DIN EN 10311 have been deleted.
c) Wall thickness calculations as in DIN 2413-1 (withdrawn) have been included.
d) The standard has been editorially revised.
Previous editions
DIN 2460: 1942-11, 1965-12, 1966-05, 1980-12, 1992-01 DIN 2461: 1942-11, 1965-12, 1966-05
1 Scope
This standard gives design requirements for steel pipe and fittings used in water supply and sewer systems under static and operating conditions.
Although this standard primarily applies to drinking water and sewer systems, it also applies to pipes and fittings used in systems conveying other aqueous media (e.g. raw, process, and cooling waters) as well as seawater, saltwater and brines. It does not, however, apply to domestic installations.
The dimensions of pipes as in this standard are calculated for the allowable operating pressures specified for a given pipeline component as well as the expected external loads. The wall thickness of components made from steels listed in the tables need not be specially calculated if the intended operating pressure does not exceed the appropriate values specified in these tables, or if the thickness is not less than the specified nominal thickness. In all other cases, an appropriate stress-strain analysis is required.
*) This English translation also includes amendments from a Corrigendum to DIN 2460 (DIN 2460 Ber 1) which was published in April 2007. These are shaded grey.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
DIN 1072, Road and foot bridges — Design loads
DIN 2605-1, Steel butt-welding pipe fittings — Elbows and bends with reduced pressure factor
DIN 2605-2, Steel butt-welding pipe fittings — Elbows and bends for use at full service pressure
DIN 2609, Steel butt-welding pipe fittings — Technical delivery conditions
DIN 2615-1, Steel butt-welding pipe fittings —Tees with reduced pressure factor
DIN 2615-2, Steel butt-welding pipe fittings — Tees for use at full service pressure
DIN 2616-1, Steel butt-welding pipe fittings — Eccentric reducers with reduced pressure factor
DIN 2616-2, Steel butt-welding pipe fittings — Reducers for use at full service pressure
DIN 2617, Steel butt-welding pipe fittings — Caps — Dimensions
DIN 2880:1999-01, Application of cement mortar lining for cast iron pipes, steel pipes and fittings
DIN 30670, Polyethylene coatings for steel pipes and fittings — Requirements and testing
DIN 30675-1, External corrosion protection of buried pipes — Corrosion protection systems for steel pipes
DIN 30678, Polypropylene coatings for steel pipes
DIN 50929-3, Probability of corrosion of metallic materials when subject to corrosion from the outside — Buried and underwater pipelines and structural components
DIN EN 10204, Metallic products — Types of inspection documents
DIN EN 10208-1, Steel pipes for pipelines for combustible fluids — Technical delivery conditions — Part 1: Pipes of requirement class A
DIN EN 10208-2, Steel pipes for pipelines for combustible fluids — Technical delivery conditions — Part 2: Pipes of requirement class B
DIN EN 10216 series, Seamless steel tubes for pressure purposes — Technical delivery conditions
DIN EN 10217 series, Welded steel tubes for pressure purposes — Technical delivery conditions
DIN EN 10220, Seamless and welded steel tubes — General tables of dimensions and masses per unit length
DIN EN 10224, Non-alloy steel tubes and fittings for the conveyance of water and other aqueous liquids — Technical delivery conditions
DIN EN 10253-1, Butt-welding pipe fittings — Part 1: Wrought carbon steel for general use and without specific inspection requirements
DIN EN 10298:2005-12, Steel tubes and fittings for onshore and offshore pipelines — Internal linings with cement mortar
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
DIN EN 10311, Joints for the connection of steel tubes and fittings for the conveyance of water and other aqueous liquids
DVGW GW 91), Assessment of soils in terms of the corrosion behaviour of buried pipelines and vessels of unalloyed and low-alloy ferrous materials
DVGW GW 3401), FCM coating for the mechanical protection of polyolefin-coated steel pipes and fittings — Requirements and inspection, field coating and repairs, pipe-laying and corrosion protection
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1 flange flattened, circular pipe or fitting end perpendicular to the pipe or fitting axis, having a circle of equispaced holes for bolts
3.2 flange connection a joint between two flanged components
3.3 spigot end cylindrical end of a pipe or fitting
3.4 socket flared end of a pipe or fitting into which the spigot end of a pipe or fitting is inserted to form a connection between the two components
3.5 axial force-locking joint a connection which is either welded or is formed using a special device or design feature to prevent the connection from being pulled apart when under load
3.6 random length delivery length where the length and tolerance of individual tubes are not defined; however, a length range may be agreed
[DIN EN 10266:2003-12, Term 2.13]
3.7 approximate length delivery length, specified by the purchaser, with a unilateral or a bilateral tolerance as specified in the product standard
[DIN EN 10266:2003-12, Term 2.14]
1) Obtainable from Wirtschafts- und Verlagsgesellschaft Gas und Wasser mbH, Josef-Wirmer-Straße 3, 53123 Bonn, Germany.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
3.8 exact length delivery length, specified by the purchaser, with a restricted unilateral tolerance as specified in the product standard
[DIN EN 10266:2003-12, Term 2.16]
3.9 effective length actual length that a tube contributes when correctly assembled in a run of piping
[DIN EN 10224:2003-07, Term 3.2]
3.10 nominal size DN an alphanumerical designation of size for components of a pipework system, which is used for reference purposes. It comprises the letters DN followed by a dimensionless whole number which is indirectly related to the physical size, in millimetres, of the bore or outside diameter of the end connections
NOTE 1 The number following the letters DN does not represent a measurable value and should not be used for calculation purposes except where specified in the relevant standard.
NOTE 2 In those standards which use the DN designation system, any relationship between DN and component dimensions should be given, e.g. DN/OD or DN/ID.
[DIN EN ISO 6708:1995-09, Term DN]
3.11 allowable maximum operating pressure PMA maximum pressure occurring from time to time, including surge, that a component is capable of withstanding in service
[DIN EN 805:2000-03, Term 3.1.1]
3.12 allowable operating pressure PFA maximum hydrostatic pressure that a component is capable of withstanding continuously in service
NOTE PFA replaces the former designation PN.
[DIN EN 805:2000-03, Term 3.1.2]
3.13 allowable site test pressure PEA maximum hydrostatic pressure that a newly installed component is capable of withstanding for a relatively short duration, in order to ensure the integrity and tightness of the pipeline
[DIN EN 805:2000-03, Term 3.1.3]
4 General
The delivery conditions of DIN EN 10224 or DIN 2609 apply to pipes and fittings as in this standard. Unless otherwise specified in the order, delivered products are to be of steel grade L235 as in DIN EN 10224.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Equivalent steel grades in accordance with the technical delivery conditions of the DIN EN 10208, DIN EN 10216 and DIN EN 10217 standard series2) may also be agreed (see Table A.1) both for pipes and fittings. For fittings, steel grades as in DIN EN 10253-1 and DIN 2609 may also be agreed. Functional requirements for connections are specified in DIN EN 10311. The functional and hygienic integrity of pipes and fittings for conveying drinking water shall be certified; such pipes and fittings are subject to third party inspection.
NOTE In the case of applications covered by the Construction Products Directive, the CE mark may only be applied to pipes supplied in accordance with DIN EN 10224.
In addition to the allowable operating pressure (PFA), the design of buried pipes and fittings takes into account loads due to the soil cover (with cover heights of 0,6 m to 6 m) and traffic loads up to SLW 60 according to DIN 1072.
In the case of pipelines laid above ground, further loads may have to be considered, such as the pipeline’s self weight, the distance between supports, as well as wind and snow loads. Possible internal pressure drops to an absolute pressure of 0,2 bar shall also be taken into account in pipe designs. In addition, pressure surges not exceeding 1 % of the design service life are taken into account.
Further information on design calculations and the support and bedding of steel pipes is given in Annexes B to E.
5 Designation and ordering information
5.1 Designation
Designation (example) of a pipe of nominal size DN 250:
Pipe DIN 2460 — DN 250
Designation (example) of a fitting of nominal size DN 250:
Fitting DIN 2460 — DN 250
5.2 Ordering information
5.2.1 General
When ordering, a differentiation shall be made between the information required in 5.2.2 for pipes, that required in 5.2.3 for fittings, and the additional information according to 5.2.4. Symbols to be used when ordering are listed in Table 1.
5.2.2 Required ordering information for pipe
Inquiries and orders for pipe shall contain the following information:
⎯ quantity, e.g. number of pipes, total pipe length;
⎯ designation: “Pipe”;
⎯ standard number: DIN 2460;
2) Pipes as in DIN EN 10217-1 shall comply with grade TR2 requirements.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
EXAMPLE of required ordering information: 3 200 m pipes of nominal size DN 250 in random lengths at the manufacturer’s discretion, in accordance with DIN EN 10224, black, of steel grade L235 according to DIN EN 10224, with inspection certificate 3.1 according to DIN EN 10204:
3 200 m pipe DIN 2460 — DN 250
5.2.3 Required ordering information for fittings
⎯ Quantity;
⎯ designation: “Fitting type”;
⎯ standard number: DIN 2460;
⎯ nominal diameter/nominal size DN;
⎯ wall thickness;
⎯ fitting design: e.g. 90° (elbow);
⎯ fitting type: e.g. 3 D;
⎯ allowable operating pressure;
⎯ fitting, e.g. in accordance with DIN EN 10224 or DIN 2605-2.
EXAMPLE of required ordering information: 5 fittings of nominal size DN 250 with a wall thickness s = 5 mm (5), design 90° (90), design type 3 D (3) in accordance with DIN EN 10224, for an allowable operating pressure of 50 bar (50), with plain ends, black, of steel grade L235 according to DIN EN 10224, with inspection certificate 3.1 according to DIN EN 10204:
5 fittings DIN 2460 — DN 250 — 5 — 90 — 3 — 50 — DIN EN 10224
5.3 Additional ordering information
If no additional information is specified in the order, the pipes and fittings shall be supplied in accordance with the general requirements. Additional ordering information shall be given using the symbols listed in Table 1.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
⎯ test report 2.2 or inspection certificate 3.2 according to DIN EN 10204; no information: inspection certificate 3.1;
⎯ steel grade unless otherwise specified: L235;
⎯ pipe wall thicknesses other than those specified in Tables 2 to 5;
⎯ specification of nondestructive test method for fittings;
⎯ coating, lining; no information: no corrosion protection.
EXAMPLE of additional ordering information: 3 200 m welded pipes of nominal size DN 250 in approximate lengths of 12 m, bevelled for butt welding (V), with cement mortar lining according to DIN EN 10298 (ZM) and polyethylene coating according to DIN 30670 in normal design (PE-n)
3 200 m pipe DIN 2460 — DN 250 — FL 12 — V — ZM — PE-n
EXAMPLE of additional ordering information: 5 fittings of nominal size DN 250 with a wall thickness of 5 mm, design 90° (90), design type 3 D (3) in accordance with DIN 2605-1, for an allowable operating pressure of 50 bar (50), bevelled for butt welding (V) and with cement mortar lining (ZM)
5 fittings DIN 2460 — DN 250 — 5 — 90 — 3 — 50 — V — ZM — DIN 2605-1
6 Pipes
Pipes shall be welded or seamless and shall comply with the requirements of clause 4. Unless otherwise specified, welded pipe will be supplied in steel grade L235 according to DIN EN 10224. The weld area in electrical welded pipes shall be heat treated. Pipe made from other steel grades or in compliance with other standards may also be used. When ordering such pipe, the technical delivery conditions to be agreed shall meet at least the requirements of this standard.
7 Fittings
Fittings shall be welded or seamless and shall comply with the requirements of clause 4.
Steel butt-welding pipe fittings as in DIN 2609 shall meet the requirements laid down in DIN 2605-1 and DIN 2605-2 for elbows and bends, DIN 2615-1 and DIN 2615-2 for tees, DIN 2616-1 and DIN 2616-2 for reducers and DIN 2617 for caps. Unless otherwise specified in the order, fittings are to be supplied with plain ends.
Part 1 of DIN 2615 and DIN 2616, and DIN 2617 cover fittings having the same wall thickness as the pipes specified in Tables 2 to 5. For this reason, these fittings may only be used in applications involving a reduced pressure factor.
Unless otherwise specified in the order, fittings are to be supplied in accordance with Part 2 of the relevant standard (full correlation of utilization).
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The dimensions and tolerances shall be as in the applicable delivery conditions and as specified in 8.2 and 8.3.
8.2 Outside diameter and wall thickness
Tables 2 to 5 give the dimensions of pipes required for different operating pressures and connection types.
Greater wall thicknesses and/or other steel grades may also be agreed for pipes, especially in the case of higher nominal pressures (see also clause 6).
8.3 Lengths
Pipes in accordance with this standard are to be supplied in random lengths within the ranges defined in DIN EN 10224, as shown in Table A.3 of this standard, at the manufacturer’s discretion. Requirements such as a specific length range as in Table A.3 or other requirements regarding length ranges or types of lengths as in Table A.2 shall be specified in the order. In the case of socket pipes, note that the effective length (cf. 3.9) is equal to the ordered length minus the insertion depth.
NOTE The length requirements for socket pipes are specified in 9.4.
9 Joints for pipes and fittings
9.1 General
General functional requirements for joints are described in DIN EN 10311. Specific requirements are specified in 9.2 to 9.6 below.
9.2 Pipe ends
The cut face of pipe ends is to be perpendicular to the pipe axis and free from burrs.
9.2.1 Plain ends
Pipes and fittings are to be supplied with plain ends.
9.2.2 Bevelled ends
On agreement, pipes and fittings may also be supplied with bevelled ends as in Figure 1.
9.3 Slip welding joints
On agreement, the pipes may be supplied as shown in Figure 2. The insertion depth “t” and the socket clearance “f” for slip welding joints up to DN 1000 are given in Table 3. The insertion depth and socket clearance for larger nominal sizes are subject to special agreement.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The pipe end designs for socket joints are shown in Figs. 3 and 4. Depending on the design, socket joints may be axially force-locking. The outside diameters of such pipes may vary from the standard outside diameters according to DIN EN 10220. The outside diameter tolerance is ± 0,8 mm over the entire pipe length.
Socket pipes shall be ordered in exact lengths given in Table A.5.
9.5 Couplings
The pipe end designs for coupled pipe are shown in Figs. 5 and 6 (cf. Table 5).
9.6 Other pipe joints
Other pipe joints as in DIN EN 10311 may also be agreed upon. The pipe end design shall be defined in each case.
10 Linings
10.1 Drinking water pipelines
Pipes and fittings for drinking water pipelines shall be lined with cement mortar. The application and quality of factory-applied linings are covered by DIN EN 10298. Technical information is given in DIN 2880.
10.2 Pipelines for other aqueous media
The lining type and design is subject to agreement. For cement mortar linings, the specifications of 10.1 apply by analogy.
11 Coatings
11.1 General requirements
Where pipes are to be supplied with a coating, the coating type and application shall be specified in the order. Steel pipes for buried pipelines shall be protected against corrosion. The application areas and limits of coatings on steel pipe are defined in DIN 30675-1.
As a rule, fittings are to be supplied without a coating, because they are coated or lined after on-site installation.
Where fittings are to be supplied coated, this shall be specified in the order.
11.2 Polyethylene coatings
Polyethylene coatings shall be in accordance with DIN 30670.
11.3 Polypropylene coatings
Polypropylene coatings shall be in accordance with DIN 30678.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
FZM coatings serve as mechanical protection for steel pipes with a polyolefin or duroplastic coating. The requirements for FZM coatings are laid down in DVGW GW 340.
11.5 Other coatings
On special agreement, pipes may also be supplied with other coating types. Coatings not approved for soil category III as in DIN 30675-1 (severely aggressive soils) require an assessment of in-situ corrosion probability and soil classification in accordance with DVGW GW 9 and/or DIN 50929-3.
12 Inspection certificates
Pipes and fittings are to be supplied with an inspection certificate 3.1 as in DIN EN 10204. The following inspection documents as in DIN EN 10204 may also be supplied (cf. Tables 2 to 5):
⎯ test report — 2.2 ;
⎯ inspection certificate — 3.2.
Requirements regarding inspection documents for linings and coatings are to be laid down in the relevant technical delivery conditions.
13 Marking
Pipes and coatings shall be marked in accordance with the relevant standards.
Dimensions in millimetres
a) Type C1 according to DIN EN 10298:2005-12, Annex A or as in DIN 2880:1999-01, Figure 1
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
a Calculated in accordance with Annex C using the following safety factors: S = 1,50 for L235 with inspection certificate 3.1; S = 1,7 for L235 with test report 2.2; S = 1,58 for L355 with inspection certificate 3.1, without any allowance for corrosion and/or wear. As a rule, no corrosion allowance is required for pipes that are both coated and lined. The calculated allowable operating pressure was rounded down to the next lowest pressure stage. The pressure PFA given here applies to pipelines with welded joints, traffic loads up to SLW 60, a cover height over the pipe of 0,6 to 6 m, and a possible internal pressure drop to an absolute pressure of pabs = 0,2 bar.
b Mass per unit length of bare pipe. c Steel grade in accordance with DIN EN 10224.
NOTE Values shaded in grey taken from DIN 2460 Ber 1:2007-04.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
1 000 1 016 10,0 248 130 3 20 32 a Calculated in accordance with Annex C using the following safety factors: S = 1,50 for L235 with inspection certificate 3.1, S = 1,58
for L355 with inspection certificate 3.1, without any allowance for corrosion and/or wear. As a rule, no corrosion allowance is required for pipes that are both coated and lined. The calculated allowable operating pressure was rounded down to the next lowest pressure stage. The pressure PFA given here applies to pipelines with welded joints, traffic loads up to SLW 60, a cover height over the pipe of 0,6 to 6 m, and a possible internal pressure drop to an absolute pressure of pabs = 0,2 bar.
b Mass per unit length of bare pipe. c Steel grade in accordance with DIN EN 10224. d Taking into consideration on-site conditions during pipe laying, the specified socket clearance (as a function of the maximum possible
outside diameter) should be maintained, taking into account the outside diameter tolerances and permissible ovality. NOTE Values shaded in grey taken from DIN 2460 Ber 1:2007-04.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Table 4 — Dimensions, mass per unit length and allowable operating pressure of welded steel socket pipes
Socket diameter d2
a Insertion
depth t
Mass per unit lengthc
Allowable operating
pressure PFAb
L235d with νN = 1,0
and inspection certificate 3.1
Nominal size
Pipe outside
diameter d1
Fig. 3 Fig. 4
Nominal wall
thicknesssb
Fig. 3 Fig. 4 DN mm mm mm mm mm mm kg/m bar
80 98,0 132 136 3,6 105 138 9,0 40
100 117,5 153 158 3,6 110 143 9,0 40
125 144,7 180 185 4,0 120 153 13,8 40
150 168,3 205 213 4,0 131 162 16,2 40
200 219,1 260 271 4,5 133 169 23,8 40
250 273 314 326 5,0 143 181 33,0 40
300 323,9 368 380 5,6 (6,3)e 150 188 44,0 (49,4) 40 a The tolerance for the socket diameter is ± 0,8 mm.
b Calculated in accordance with Annex C using the following safety factors: S = 1,50 for L235 with inspection certificate 3.1, without any allowance for corrosion and/or wear. As a rule, no corrosion allowance is required for pipes that are both coated and lined. The calculated allowable operating pressure was rounded down to the next lowest pressure stage. The pressure PFA given here applies to pipelines with welded joints, traffic loads up to SLW 60, a cover height over the pipe of 0,6 to 6 m, and a possible internal pressure drop to an absolute pressure of pabs = 0,2 bar.
c Mass per unit length of bare pipe.
d Steel grade in accordance with DIN EN 10224.
e The value in brackets indicates the nominal wall thickness for socket joints according to Fig. 4 for operating pressures up to 40 bar.
NOTE Values shaded in grey taken from DIN 2460 Ber 1:2007-04.
Figure 5 — Rolled groove pipe end
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The method of calculating the external pressure load on buried pipelines described below complies with VdTÜV MB 1063:1978-05 and takes account of the load cases “internal pressure”, “soil loads”, and “traffic loads with and without internal pressure”. This technical rule applies only in cases of conventional pipeline burial with bedding as in Table D.1 that is suitable to the pipe coating.
B.2 Symbols and units
The symbols and units used are listed in Table B.1 below.
Table B.1 — Symbols, design parameters, units
Symbol Design parameter Unit da Pipe outside diameter mm s Wall thickness mm σK Minimum yield strength N/mm2 ν Poisson’s ratio = 0,3 — rm Mean pipe radius mm ri Inner radius mm γ Specific gravity of soil kN/m3 ς Friction angle ° H Cover height over pipe m B Trench width at level of pipe apex m P Internal pressure N/mm2 q1 Soil load kN/m2 A Reduction factor due to soil load — λ Coefficient of soil pressure mm Ψ Impact factor according to DIN EN 1610:1997-10 — pv Traffic load kN/m2 q2 Pressure at pipe apex level increased by impact factor kN/m2 q Total load kN/m2 qo Lateral soil pressure kN/m2 O Ovality % σmax d Compressive stress N/mm2 σmax z Tensile stress (referred to below as “hoop stress”) N/mm2 Pk Critical buckling pressure N/mm2 P1 Effective internal pressure under superimposed load N/mm2 Sk Buckling resistance — S Safety factor — fλ Reduction factor due to soil pressure — λa Active soil pressure coefficient acc. to Rankine —
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The soil load q1 is calculated using the following equation:
q1 = A ⋅ γ ⋅ H (B.1)
ς
ς
tge tg
ABH
BH
⋅−
=⋅−1 (B.2)
For buried pipelines or pipelines or dam pipelines, A = 1.
Depending on the type of soil, the following values apply according to VdTÜV MB 1063:1978-05:
Table B.2 — Specific gravity and friction angle of various soil types
Soil type Friction angle ς(°)
Specific gravity γ (kN/m3)
Moraine gravel, crushed stone, shingle 37 19
Gravel, gravelly sand 33 20
Sand 31 17
Silt 25 18
Loam, drift sheet 22 21
Slush, lean clay 20 20
Loess, loess clay 18 21
Slush, unctuous clay 14 15
Mud, marshy soil, clay 12 17
B.3.2 Traffic loads
The traffic load q2 is calculated using the following equation:
vpq ⋅= ψ2 (B.3)
The traffic load pressure at the level of the pipe apex can be taken from VdTÜV MB 1063:1978-05, Figures 3 and 4. The values were determined for standard vehicles according to DIN 1072 and pipelines buried under paved roads and in open terrain.
B.3.3 Total load
The total load q is the sum of the soil loads and the traffic loads:
21 qqq += (B.4)
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
At the pipeline supports, the lateral soil pressure, which is dependent on the degree of trench backfill compaction, is to be considered. The reduction in the total load acting on the pipeline is taken into account by the coefficient λ. This is 0,5 for a non-compacted backfill and 0,7 in the case of proper compaction.
The lateral soil pressure can thus be calculated as follows:
qq ⋅+
=λ2
30 i.e. for λ = 1, then q0 = q (B.5)
B.4 Ring stiffness under service conditions
The ovality of pipe under service conditions can be calculated on the basis of the loads:
100221)1(2
32 q
srO ⋅⎟
⎠
⎞⎜⎝
⎛⋅+−
⋅−⋅±= mλλν The maximum permissible pipe ovality is 3 % (B.6)
B.5 Gravity pipelines, non-pressurized pipelines
Under external loads, the compressive stresses are highest on the pipe inside in the area of the supports, while the tensile stress on the pipe interior is highest in the apex and base of the pipe. The maximum tensile and compressive stresses that can occur are calculated as follows:
qs
rq
sr
⋅⎟⎟⎠
⎞⎜⎜⎝
⎛⋅
+−
⋅−⋅−=2
max 213 mm
d λλσ (B.7)
qs
rq
sr
⋅⎟⎟⎠
⎞⎜⎜⎝
⎛⋅
+−
⋅+⋅⋅+
+−=
2
max 213
221 mm
z λλ
λλσ (B.8)
The higher value is to be compared with the yield strength:
Kσσ max=S The safety factor shall be at least 1,1. (B.9)
B.6 Pipe buckling
Buckling resistance is given by the quotient of the critical buckling pressure and the effective internal pressure.
1PP
S kk = Buckling resistance shall be at least 2,5. (B.10)
The critical buckling pressure is to be calculated as follows:
3
2 )1(4000210
⎟⎟⎠
⎞⎜⎜⎝
⎛⋅
−=
mk r
sPν
(B.11)
The effective internal pressure takes account of external compressive forces due to pipe-laying conditions.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The effective internal pressure P1 (in this case, the highest possible internal pressure under operating conditions) is also used for calculating the maximum hoop stress.
This is done using the following equation:
1,121
135,1
221
2
max ⋅⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛⋅
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛⋅
+−
⋅+
+⋅⎟⎟⎠
⎞⎜⎜⎝
⎛⋅⋅
++
−⋅
= qs
rqs
rs
rP mmiz λ
λαλ
λσ (B.13)
where
k
1712,0PP
f⋅=
λα and ( )( )
( )( )2/45tan22
12/45tan1
2
2
ςλ
λς
λ
−°+
+⋅
−−°−
=f (B.14)
The calculated maximum hoop stress shall not exceed the specified minimum yield strength of the material used.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Calculation of wall thicknesses for internal pressure
C.1 General
The calculation method described below complies with DIN 2413-1:1993-10 (withdrawn).
The equations for calculating wall thickness for internal pressure apply to pipes with a circular cross-section where the diameter ratio u = da/di does not exceed 2,0 under predominantly static loading within the temperature range of 0 °C to 120 °C.
C.2 Symbols and units
The symbols and units used are listed in Table C.1 below.
Table C.1 — Symbols, design parameters, units
Symbol Design parameter Unit c = c1 + c2 Allowance on the minimum wall thickness mm c1 Allowance for negative wall thickness tolerance mm
1c′ Negative wall thickness tolerance % c2 Allowance for corrosion and/or wear mm da Pipe outside diameter mm di Pipe inside diameter mm P Design pressure N/mm2 S Required wall thickness including allowances mm sv Minimum thickness excluding allowances mm u = da/di Inside-to-outside diameter ratio —
vN Weld efficiency factor for longitudinal and/or helical welds (utilization of allowable design stress) —
A Elongation ( )oo SL ⋅= 65,5 %
K Strength characteristic N/mm2
S Safety factor — Y = 1/S Degree of yield strength utilization —
zulσ Allowable stress under static loading N/mm2 Secondary symbols ∧ ˆ — ∨ — ⎯ Mean value (e.g. σ = mean stress) —
Minimum value (e.g. p̌ = minimum pressure)
Maximum value (e.g . p = maximum pressure)
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
The required wall thickness is obtained by adding the minimum wall thickness sv according to Table C.2, allowance c1 for the negative wall thickness tolerance and, where applicable, allowance c2 for corrosion and/or wear in the case of pipes without external or internal corrosion protection.
The required wall thickness is thus:
21 ccss ++= v (C.1)
Where the negative wall thickness tolerance 1c′ is given in %, the following holds:
( )1
2 100100
ccss
′−+= v (C.1a)
Table C.2 — Determination of the minimum wall thickness sv
Minimum wall thickness sv Strength K Safety factor S and degree of yield strength utilization Y
mm N/mm2
σ zul = K/S = y · k Ab S Y
≥ 25 % = 20 % = 15 %
1,5 1,6 1,7
0,67 0,63 0,59
Values for pipelines buried in terrain without special additional stresses:
a The strength values specified in the applicable standards, rules, datasheets or specifications are to be used; values are to be interpolated where necessary. For design temperatures < 20 °C the values for 20 °C are to be used.
b Elongation after fracture oo SL ⋅= 65,5 Intermediate values may be linearly interpolated or, in the case of low values,
extrapolated to 15 %.
c Equation (C.2b) is the mathematical transformation of equation (C.2a) and will yield the same result, if da = di + 2 sv.
C.4 Design pressure
The design pressure p is defined as the internal pressure in a pipeline section, taking into account all operating conditions. To quantify the design pressure, the greater of the values given in Table C.2 under (C.2a) and (C.2b) is to be used.
a) Maximum possible pressure at the safety device plus the pressure due to the difference in height between the safety devices and the lowest point of the pipeline.
b) Fractions of the peak pressure p̂ (maximum possible internal pressure) reached under design operating conditions, including pressure increases due to differences in height, pressure drops and dynamic processes (e.g. pressure surges) give the following:
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
,ˆ00,1 pp = if the effective duration of the peak pressure exceeds 10 % of the design service life.
,ˆ83,0 pp = if the effective duration of the peak pressure does not exceed 1 % of the design service life.
Intermediate values are to be determined by linear interpolation.
C.5 Allowable pressures
This standard uses the following pressure definitions as in EN 805:
PFA PFA is the allowable operating pressure, i.e. the design pressure p according to C.4 of this standard.
This is the maximum hydrostatic pressure, exclusive of surge, that a component can safely withstand in permanent service. PFA supersedes the formerly used allowable nominal pressure PN of a pipeline and can be calculated in accordance with Annex C of this standard.
PMA PMA is the allowable maximum operating pressure, i.e. the maximum internal pressure, including surge, which a component can safely withstand in service.
PMA can be expressed as follows: PMA = PFA ⋅ 1,2
This relationship holds on condition that the effective period of peak pressure action does not exceed 1% of the pipeline’s service life. If this period exceeds 10% of the pipeline’s service life, then PMA = PFA. Intermediate values are to be determined by interpolation.
PMA represents the peak pressure p̂ according to C.4 of this standard.
PEA PEA is the allowable site test pressure, i.e. the maximum hydrostatic pressure that a newly installed component can withstand for a relatively short period, when either fixed above ground level or laid and back-filled underground in order to measure the integrity and leak tightness of the pipe.
PEA can be expressed as follows: PEA = PMA + 5 bar
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Buried pipelines are laid both in traffic areas (e.g. roads, paths or squares) and in open terrain. Since the applicable regulations specify an increased degree of compaction of 97 % Proctor density as the minimum requirement for the first case, these different load cases must be considered, taking the pipe coating into consideration, when laying pipe.
Intensive compaction of the trench backfill, e.g. with a view to subsequent road construction, constitutes an increased load on the pipe coating. As a basic requirement in conventional pipe burial with subsequent compaction, the backfill material must be suitable for compaction. Suitable materials include sand, gravelly sand and sieved, cohesionless or weakly cohesive soil.
D.2 Support
Before lowering the pipe, the trench floor must be prepared to ensure that the pipeline is supported over its entire length; point supports should be avoided because of the associated uneven pressure distribution. Joint holes are to be prepared in a way that the joints can be properly manufactured and tested.
As a rule, the in-situ soil can be used to support the pipe string. However, stony and rocky soils are not suitable for supporting plastic-coated pipe. In such cases, the pipe trench must be deepened and backfilled with a layer of material suitable for compaction (see Table D.1). Unstable soils may require further support measures.
D.3 Bedding
The bedding layer shall be 10 cm thick in the case of DN 250 pipes and 15 cm thick for pipes larger than DN 250. The cover layer should be such that it is at least 30 cm in height after compaction.
Plastic-coated pipes shall be bedded in stone-free material suitable for compaction (see Table D.1).
Table D.1 — Bedding materials for plastic-coated steel pipe
Pipe-laying in traffic areas with increased compaction requirements
Pipe-laying in open terrain with low compaction requirements
Round grain (sand/gravel)
Crushed grain (crushed stone/shingle)
Round grain (sand/gravel)
Crushed grain (crushed stone/shingle)
0 – 4 mm max. 8 mm
0 – 5 mm max. 8 mm
0 – 8 mm max. 16 mm
0 – 5 mm max. 8 mm
NOTE The difference in particle sizes relevant to pipe-laying in traffic areas and open terrain does not correspond to the specifications of DVGW W 400-2.
The data given in the table above refer to commonly-used materials which comply with current technical standards and regulations.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Plastic-coated pipes can also be bedded in other materials which either meet the above requirements or whose suitability has been verified in appropriate bedding tests. For polyethylene-coated pipes with an additional fibre cement mortar lining (FZM), the excavated spoil can be used as bedding material3) provided it is suitable for compaction. The cover height should then be at least three times the maximum particle size of the material in question.
Calculation of unsupported spans in steel pipelines
E.1 General
The allowable deflection of steel pipe shall be calculated for two load cases:
a) Allowable elastic deflection during the transportation, lifting and handling of pipe and, especially, when lowering pipe strings during pipe-laying or, for example, when designing starting pits for a flush-drilling project.
b) Allowable pipe deflection under operating conditions, e.g. in open-trench pipelines, taking account of the required spacing of supports.
E.2 Symbols and units
The symbols and units used are listed in Table E.1 below.
Table E.1 — Symbols, design parameters, units
Symbol Design parameter Unit
DA Pipe outside diameter mm
DI Pipe inside diameter mm
E Elastic module, steel (210 000 N/mm2) N/mm2
fzul Allowable deflection mm
IY,Z Second moment of area mm4
L Width between supports m
Q Line load kg/m
S Safety factor (for water pipe 1,5) mm
WY,Z Section modulus, pipe mm3
σzul Allowable stress N/mm2
Rmin Allowable bend radius m
fzul Allowable deflection mm
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
Use the following equation to calculate the allowable elastic bending radius for steel water pipe:
zul
Amin 2 σ
SEDR ⋅⋅=
Use the following equation to calculate the maximum allowable deflection as a function of the pipe length:
22minminzul 4
21 LRRf −⋅−=
E.4 Calculation of unsupported span for operating conditions
The calculation of unsupported spans in pipelines under operating conditions forms part of the stress-strain analysis of a given pipeline. This applies to the bending moments due to line loads, loads due to wind and snow, as well as additional internal and external components which have to be considered in the stress-strain analysis. Local loads at the support points must also be considered. For simple systems or in the context of preliminary planning, calculations may be based on TRR 100.
This calculation is based on the following criteria:
1) Maximum allowable stress
The bending stresses due to unsupported spans are to be superimposed on the longitudinal stresses due to internal pressure. Their allowable level is limited by the strength characteristics of the material used. For pipe steels with a specified minimum yield strength of 235 N/mm² and full utilization of the wall thickness by the internal pressure, TRR 100 specifies the allowable bending stress at room temperature as σzul ≤ 40 N/mm2. If the material’s strength is not fully utilized by the internal pressure, then the maximum allowable stress will be higher.
2) Maximum allowable deflection
Limiting the maximum allowable deflection helps to avoid liquid accumulation, e.g. when emptying a pipeline. For nominal sizes > DN 50, a reference value of fzul ≤ 5 mm has been specified for the maximum allowable deflection.
For the purpose of this calculation, the pipeline is regarded as a continuous beam. Loads of critical interest include the pipeline’s weight (empty and filled) as a distributed line load.
3) Calculation of the second moment of area
( )64
44IA
ZY,DD
I−⋅π
=
4) Calculation of the section modulus
( )A
IAZY, D
DDW
⋅
−⋅π=
32
44
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
DIN 1626:1984-104), Welded circular unalloyed steel tubes subject to special requirements — Technical delivery conditions
DIN 1629:1984-105), Seamless circular unalloyed steel tubes subject to special requirements — Technical delivery conditions
DIN 2413-1:1993-106), Design of steel pressure pipes
DIN EN 545, Ductile iron pipes, fittings, accessories and their joints for water pipelines — Requirements and test methods
DIN EN 805:2000-03, Water supply — Requirements for systems and components outside buildings
DIN EN 1610:1997-10, Construction and testing of drains and sewers
DIN EN 10266:2003-12, Steel tubes, fittings and structural hollow sections — Symbols and definitions of terms for use in product standards
DIN EN 10296-1, Welded circular steel tubes for mechanical and general engineering purposes — Technical delivery conditions — Part 1: Non-alloy and alloy steel tubes
DIN EN 13480-3, Metallic industrial piping — Part 3: Design and calculation
DIN EN ISO 6708:1995-09, Pipework components — Definition and selection of DN (nominal size) (ISO 6708:1995)
ISO 7268, Pipe components — Definition of nominal pressure
DVGW W 400-27), Technische Regeln Wasserverteilungsanlagen (TRWV) — Teil 2: Bau und Prüfung — Arbeitsblatt (Technical rules for water distribution plants — Part 2: Construction and testing — Worksheet)
TRR 1008), Bauvorschriften — Rohrleitungen aus metallischen Werkstoffen (Construction rules — Pipelines of metallic materials)
VdTÜV MB 1063:1978-059), Technische Richtlinie zur statischen Berechnung eingeerdeter Stahlrohre (Code of practice for the structural analysis of buried steel pipes)
4) Superseded by DIN EN 10208-1 (1998-02), DIN EN 10217-1 (2002-08), DIN EN 10224 (2003-07) and DIN EN 10296-1 (2004-02).
5) Superseded by DIN EN 10208-1 (1998-02), DIN EN 10216-1 (2002-08), DIN EN 10224 (2003-07) and DIN EN 10297-1 (2003-06).
6) Superseded by DIN EN 13480-3 (2002-08).
7) Available from: Wirtschafts- und Verlagsgesellschaft Gas und Wasser mbH, Josef-Wirmer-Straße 3, 53123 Bonn, Germany.
8) Available from: Carl Heymanns Verlag KG, Luxemburger Straße 449, 50939 Köln, Germany.
9) Available from: TÜV-Verlag GmbH, Unternehmensgruppe TÜV Rheinland Berlin Brandenburg, Am Grauen Stein, 51105 Köln, Germany.
Copyright Deutsches Institut für Normung e. V. Provided by IHS under license with DIN
Not for Resale, 03/03/2014 12:58:17 MSTNo reproduction or networking permitted without license from IHS
