CEN/TR 13932:2009

Rotodynamic pumps - Recommendations for fitting of inlet and outlet on piping

This CEN Technical Report lays down stipulations relating to installation conditions for sudden change in section or direction (elbows, tee fittings, junctions) and the most widely used accessories at the inlet and outlet of pumps (valves and fittings) in order to minimise the effect of disturbances in the flow of liquid thereby created upstream and downstream from the pump and on the operation of the pump.
NOTE 1   The recommendations given in this document permit to solve a majority of the most current cases.
These recommendations relate to three aspects of installation:
   the fitting of the pump to pipework by convergent and divergent pipes;
   in the case of elbows, tees and branching, their direction with respect to the axis of the pump;
   the minimum clearances to be adhered to between a disturbing (elbow, valve, etc.) and the mounting flange of the pump.
This document applies to the installation of rot dynamic pumps (centrifugal, mixed flow and axial flow) fitted in piping. It applies to pumps having intake diameters equal to or less than 500 mm. The recommendations may be adapted in agreement with the pump manufacturer for intakes having dimensions exceeding 500 mm or for special applications. This document is not applicable to pumps of which the inlet is located in reservoirs, sumps or tanks and which will be dealt with in a subsequent standard.
The recommendations in this document are only valid under the following conditions:
   Newtonian fluids having a maximum viscosity of 2.10-4 m2/s;
   occluded gas content at pumping temperature and inlet pressure not exceeding 2 % by volume for water and
                4 % for other fluids;
   solids content (small particle size, such as sand) not exceeding 1 % by volume, nor 1 % by weight;
   in piping with diameters D1 and D2 (see Figure 11), flow rate velocity, should be in the following ranges:
   3 m/s to 5 m/s at inlet;
   4 m/s to 10 m/s at outlet.

Kreiselpumpen - Empfehlungen für Rohrleitungsanschlüsse an Ein-und Autrittsstutzen

Pompes rotodynamiques - Recommandations pour les raccordements des tuyauteries d'aspiration et de refoulement

Le présent rapport technique présente des stipulations relatives aux conditions d’installation en cas de
changements soudains de section ou de direction (coudes, raccords en T, raccordements) et aux accessoires les
plus couramment utilisés à l’aspiration et au refoulement des pompes (appareils de robinetterie et raccords) aux
fins de minimiser les effets des perturbations de l’écoulement du liquide qu’ils causent en amont et en aval de la
pompe et sur le fonctionnement de la pompe.
NOTE 1 Les recommandations données dans le présent document permettent de résoudre une majorité des cas les plus
courants.
Ces recommandations portent sur trois aspects de l’installation :
- le raccordement de la pompe à la tuyauterie par convergent et divergent ;
- dans le cas des coudes, des tés et des embranchements, leurs orientations par rapport à l’axe de la pompe ;
- les distances minimales à respecter entre un élément perturbateur (coude, appareils de robinetterie, etc.) et la
bride de raccordement de la pompe.
Le présent document s’applique à l’installation des pompes rotodynamiques (centrifuges, hélico-centrifuges et
hélices) insérées dans une tuyauterie. Il s’applique aux pompes ayant des diamètres d’aspiration inférieurs ou
égaux à 500 mm. Pour les orifices de dimensions supérieures à 500 mm ou pour des applications particulières les
recommandations peuvent être aménagées en accord avec le fabricant de pompes. Le présent document ne
s’applique pas aux pompes qui aspirent dans des réservoirs, fosses, puisards, bassins, cas qui seront traités par
une norme appropriée.
La validité des recommandations du présent document s’entend uniquement pour les conditions suivantes :
- liquides newtoniens ayant une viscosité maximale de 2.10-4 m²/s ;
- teneur en gaz occlus à la température de pompage et à la pression d’aspiration ne dépassant pas 2 % en
volume pour l’eau et 4 % pour les autres liquides ;

Centrifugalne črpalke - Priporočila za pritrjevanje dotočnih in odtočnih cevi

General Information

• Status: Published
• Publication Date: 20-Jan-2009
• ICS: 23.080 - Pumps
• Technical Committee: CEN/TC 197 - Pumps
• Drafting Committee: CEN/TC 197 - Pumps
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 21-Jan-2009
• Due Date: 05-Jul-2009
• Completion Date: 21-Jan-2009
• Ref Project: SIST-TP CEN/TR 13932:2009 - Rotodynamic pumps - Recommendations for fitting of inlet and outlet on piping

Relations

• Replaces: CR 13932:2000 - Rotodynamic pumps - Recommendations for fitting of inlet and outlet on piping
• Effective Date: 28-Jan-2009

Overview

CEN/TR 13932:2009 - Rotodynamic pumps: Recommendations for fitting of inlet and outlet on piping - provides practical installation guidance to minimise hydraulic disturbances caused by sudden changes of section or direction (elbows, tees, junctions) and common accessories (valves, filters, check valves) at pump inlets and outlets. It applies to rotodynamic pumps (centrifugal, mixed‑flow and axial‑flow) with intake diameters ≤ 500 mm and covers recommended layouts, clearances and component selection to protect pump performance and reliability.

Key topics and technical requirements

• Scope and applicability
  • Applies to pumps in piping (not to inlets located directly in reservoirs, sumps or tanks).
  • Valid for Newtonian fluids up to viscosity 2·10‑4 m²/s, limited dissolved gas (≤ 2% vol for water, ≤ 4% for other fluids) and solids content ≤ 1% (by volume and weight).
  • Recommended flow velocities: 3–5 m/s at inlet, 4–10 m/s at outlet (limits, not optimal values).
• Convergent / divergent transitions
  • Horizontal convergent: non‑symmetrical with top generating line horizontal; included angle α ≤ 20° (larger angles require special radiused transitions).
  • Vertical convergent: symmetrical, α ≤ 25°.
  • Divergent: symmetrical, recommended α between 7° and 12° to limit energy loss; some non‑symmetrical cases allowed (max 8°).
• Elbows and orientation
  • Preferred large‑radius elbows (3D, R ≥ 1.5·D); small radius (2D, R ≤ D) allowed but less desirable - sharp elbows prohibited.
  • Orientation of inlet elbows affects inlet flow quality and depends on pump inlet type (axial, lateral) and pump specific speed.
• Tees, junctions, valves and fittings
  • Minimum clearances between disruptive fittings and pump flange are specified; full‑bore and clearway valve definitions provided.
  • Guidance on stop, regulating and check valves (references to EN valve standards).

Practical applications

• Use CEN/TR 13932:2009 when designing or reviewing pump piping layouts to:
  • Reduce swirl, velocity unbalance and other inlet disturbances that degrade hydraulic performance.
  • Specify straight lengths, elbow radii and transition angles to lower vibration, noise and cavitation risk.
  • Define minimum clearances and valve types to avoid flow disturbances close to the pump flange.
• Typical users: pump manufacturers, piping and mechanical engineers, plant designers, installation contractors, maintenance teams and consultants involved in industrial water systems, HVAC, process plants and utilities.

Related standards

• References included (examples): EN ISO 9906 (pump acceptance tests), EN valve standards (EN 12334, EN 14341, EN 593, etc.). Consult the Technical Report and pump manufacturer for cases outside the stated limits (intakes > 500 mm or special fluids).

Keywords: CEN/TR 13932:2009, rotodynamic pumps, pump piping, inlet and outlet, elbows, convergent divergent, valves and fittings, pump installation recommendations.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2009
1DGRPHãþD
SIST CR 13932:2001
&HQWULIXJDOQHþUSDONH3ULSRURþLOD]DSULWUMHYDQMHGRWRþQLKLQRGWRþQLKFHYL
Rotodynamic pumps - Recommendations for fitting of inlet and outlet on piping
Kreiselpumpen - Empfehlungen für Rohrleitungsanschlüsse an Ein-und Autrittstutzen
Pompes rotodynamiques - Recommandations pour les raccordements des tuyauteries
d'aspiration et de refoulement
Ta slovenski standard je istoveten z: CEN/TR 13932:2009
ICS:
23.080 ýUSDONH Pumps
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 13932
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
January 2009
ICS 23.080 Supersedes CR 13932:2000
English Version
Rotodynamic pumps - Recommendations for fitting of inlet and
outlet on piping
Pompes rotodynamiques - Recommandations pour les Kreiselpumpen - Empfehlungen für Rohrleitungsanschlüsse
raccordements des tuyauteries d'aspiration et de an Ein-und Autrittstutzen
refoulement
This Technical Report was approved by CEN on 13 October 2008. It has been drawn up by the Technical Committee CEN/TC 197.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 13932:2009: E
worldwide for CEN national Members.

Contents Page
Foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 6
3 Definitions . 6
4 Minimum installation precautions. 7
4.1 Pipework components . 7
4.1.1 Convergent - divergent pipes . 7
4.1.2 Elbows . 10
4.1.3 Tees . 18
4.1.4 Junctions . 20
4.1.5 Devices to improve flow . 23
4.2 Valves and fittings . 23
4.2.1 Stop valves . 23
4.2.2 Regulating valves . 24
4.2.3 Check valves (according to EN 12334 and EN 14341) . 24
4.2.4 Valve accessories . 24
Bibliography . 25

Foreword
This document (CEN/TR 13932:2009) has been prepared by Technical Committee CEN/TC 197 “Pumps”, the
secretariat of which is held by AFNOR.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes CR 13932:2000.

Introduction
The inlet and outlet piping of a pump almost always includes peculiarities or accessories (changes of cross-
sectional area, elbows, connections, valves, filters, check valves, etc.). Particularly in the case of inlet piping, flow
disturbances such as swirl, unbalance in the distribution of velocities and pressures and sudden variations in
velocity are harmful to the hydraulic performance of the pump, its mechanical behaviour and its reliability.
This document cannot attempt to cover the almost infinite range of disturbances that may be encountered as well
as all their types, geometries and possible combinations. In cases that are not dealt with below, the layout of the
piping should be determined by mutual agreement between the parties in keeping with the spirit or a certain
number of principles:
 straight lengths indicated in this document are adequate values in most cases but it is always beneficial, from a
purely hydraulic point of view, to increase them. The optimum length is usually the result of a cost-benefit
trade-off.
 the most hazardous disturbances are those which create a swirling flow as a result of several changes of
direction in various planes, this swirl always takes a very long time to settle down, or disturbances which create
a very marked unbalanced flow due to a sudden change in cross-sectional area.
 generally speaking, the higher the specific speed of a pump, the more sensitive it is to feed conditions. For this
reason, especially strict requirements should be imposed in the case of an axial-flow pump.
In fact, the correct operation of a rotodynamic pump is closely linked to the features of the piping system in which it
is fitted. The noise level of this system as well as any vibrations originating from turbulence or hydraulic shocks also
depend on its layout as well as the choice and arrangement of components such as valves, filters, convergent
pipes, divergent pipes, etc.
The following recommendations are intended to reduce the risk of incorrect operation of the pump and the system
as far as possible. Under no circumstances can they guarantee perfect operation for several reasons:
 the need to make allowance for economic considerations which very often imposes deviation from the ideal
arrangement and the risk of incorrect operation which this involves increases the greater such deviation
becomes.
 the extremely complex influence on the recommended values of several factors which cannot be described in
detail without complicating the implementation of these recommendations excessively. This is the reason why
somewhat wide "average" values have been adopted even though they may sometimes lead to excessive
precautions which may still sometimes nevertheless be inadequate.
The main factors in question are as follows:
 the type of pump (centrifugal, mixed flow, axial flow);
 the size and speed of the pump;
 the margin between the available "NPSHA" and the "NPSHR" required by the pump;
 the characteristics of the liquid (nature, viscosity, presence of dissolved gas or solids in suspension, etc.);
 the flow rate of the liquid.
The last two factors have a very marked effect on the behaviour of the system and on the measures to be taken in
order to limit unwanted conditions.
1 Scope
This CEN Technical Report lays down stipulations relating to installation conditions for sudden change in section or
direction (elbows, tee fittings, junctions) and the most widely used accessories at the inlet and outlet of pumps
(valves and fittings) in order to minimise the effect of disturbances in the flow of liquid thereby created upstream
and downstream from the pump and on the operation of the pump.
NOTE 1 The recommendations given in this document permit to solve a majority of the most current cases.
These recommendations relate to three aspects of installation:
 the fitting of the pump to pipework by convergent and divergent pipes;
 in the case of elbows, tees and branching, their direction with respect to the axis of the pump;
 the minimum clearances to be adhered to between a disturbing (elbow, valve, etc.) and the mounting flange of
the pump.
This document applies to the installation of rot dynamic pumps (centrifugal, mixed flow and axial flow) fitted in
piping. It applies to pumps having intake diameters equal to or less than 500 mm. The recommendations may be
adapted in agreement with the pump manufacturer for intakes having dimensions exceeding 500 mm or for special
applications. This document is not applicable to pumps of which the inlet is located in reservoirs, sumps or tanks
and which will be dealt with in a subsequent standard.
The recommendations in this document are only valid under the following conditions:
4 2
-
 Newtonian fluids having a maximum viscosity of 2.10 m /s;
 occluded gas content at pumping temperature and inlet pressure not exceeding 2 % by volume for water and
4 % for other fluids;
 solids content (small particle size, such as sand) not exceeding 1 % by volume, nor 1 % by weight;
 in piping with diameters D and D (see Figure 11), flow rate velocity, should be in the following ranges:
1 2
 3 m/s to 5 m/s at inlet;
 4 m/s to 10 m/s at outlet.
NOTE 2 These flow rate velocity values are not optimal; they are limits which are not to be exceeded unless special
precautions are taken.
NOTE 3 In all cases where these limits are exceeded, it is essential that the pipework design engineer consults the pump
manufacturer before finalizing the installation drawings.
Even if conditions are well within the stated limits, it is highly advisable to adopt this approach sufficiently early to allow any
modifications requested by the manufacturer to be made.
Many difficulties experienced in a pumping system actually originate from errors in the design and/or production of piping.
2 Normative references
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.
EN 593, Industrial valves ― Metallic butterfly valves
EN 736-1:1995, Valves ― Terminology ― Part 1: Definitions of types of valves
EN 736-3:2008, Valves ― Terminology ― Part 3: Definition of terms
EN 1171, Industrial valves ― Cast iron gate valves
EN 1983, Industrial valves ― Steel ball valves
EN 1984, Industrial valves ― Steel gate valves
EN 12334, Industrial valves ― Cast iron check valves
EN 13397, Industrial valves ― Diaphragm valves made of metallic materials
EN 13709, Industrial valves ― Steel globe and globe stop and check valves
EN 13789, Industrial valves ― Cast iron globe valves
EN 14341, Industrial valves ― Steel check valves
EN ISO 9906, Rotodynamic pumps ― Hydraulic performance acceptance tests ― Grades 1 and 2 (ISO
9906:1999)
ISO 7194, Measurement of fluid flow in closed conduits ― Velocity-area methods of flow measurement in swirling
or asymmetric flow conditions in circular ducts by means of current-meters or Pitot static tubes
3 Definitions
For the purposes of this document, the definitions of EN 736-1:1995 apply, and also the following which are in
accordance with EN 736-3:2008.
3.1
full bore valves
valve with a flow section equal to or greater than 80 % of the section corresponding to the nominal inside diameter
of the body end port
NOTE The nominal inside diameter of the body end for the particular valve type is specified in the corresponding product or
fitness for purpose standard.
3.2
clearway valve
valve designed to have an unobstructed flow way to pass a theoretical sphere having a diameter not less than the
body end port nominal inside diameter
NOTE The nominal inside diameter of the body end for the particular valve type is specified in the corresponding product or
fitness for purpose standard.
3.3 reduced bore valve
valve with a flow section equal to or greater than 36 % of the section corresponding to the port nominal inside
diameter of the body end port and which does not correspond to the full bore valve
NOTE The nominal inside diameter of the body end for the particular valve type is specified in the corresponding product or
fitness for purpose standard.
4 Minimum installation precautions
4.1 Pipework components
4.1.1 Convergent - divergent pipes
4.1.1.1 Convergent transition section
4.1.1.1.1 Horizontal installation
For a horizontal installation, the configuration of the convergent transition section is usually non-symmetrical. Its top
generating line should then be horizontal, so as to avoid the formation of pockets of air or gas. The angle (α)
should not exceed 20° (see Figure 1).
When the angle exceeds 20°, the fitting of the convergent to the pump intake should be made by means of a
transition zone with a radius of at least ¼ of the pump inlet diameter.
However, when the degassing is carried out on the upstream side of the convergent transition section continuously:
 either naturally; or
 by means of a suitable device.
It will be possible to use a symmetrical convergent transition section as described in Clause 4.1.1.1.2.

Key
1 Direction of fluid flow
2 Diameter of the pipework inlet
3 Diameter of the pump inlet
Figure 1 — Non-symmetrical convergent transition section
NOTE In some cases, particularly when the pump incorporates an inducer, it is not recommended fitting a convergent
transition section to the pump inlet. In this case, the inlet pipeline near the pump should be studied jointly between the pump
manufacturer and those responsible for the installation.
4.1.1.1.2 Vertical installation
The configuration of the convergent transition section is symmetrical for a vertical installation (see Figure 2). The
included angle (α) should not exceed 25°.

Key
1 Direction of fluid flow
2 Diameter of the pipework inlet
3 Diameter of the pump inlet
Figure 2 —Symmetrical convergent transition section
4.1.1.2 Divergent transition section
The configuration of the divergent transition section is usually symmetrical, irrespective of the installation (see
Figure 3).
Key
1 Direction of fluid flow
2 Diameter of the pump outlet
3 Diameter of the pipework outlet
Figure 3 — Symmetrical divergent transition section
The include angle (α) for a divergent transition sections is recommended to be between 7° and 12° to avoid
excessive energy losses.
In some special cases, "on-line" pumps for example, the non-symmetrical configuration of the divergent may be
permitted with a maximum angle of 8° (see Figure 4).

Key
1 Direction of fluid flow
2 Diameter of pump
3 Diameter of pipework
Figure 4 — Non-symetrical divergent transition section
4.1.2 Elbows
4.1.2.1 Shapes of elbows
4.1.2.1.1 Standardised elbows
This document only applies to standardised elbows of which there are two types:
 small-radius elbows referred to as 2 D: R ≤ D; and
 preferably, large-radius elbows referred to as 3 D: R ≤ 1,5 D.
R is the bending radius; and
D is the diameter of the piping (inside or outside diameter as appropriate).

Figure 5 — Dimensions of standardised elbows
The use of large-radius elbows is strongly recommended, particularly in inlet piping, or for D ≥ 100 mm.
4.1.2.1.2 Angle of elbows
The following sub-clauses make provision for 90° elbows that are the most commonly encountered.
If an elbow having an angle α < 90° is used, reference should be made to the rules stated for 90° elbows by
multiplying the stipulated lengths by α/90 .
If an elbow having an angle α > 90° is used, such elbows are comparable to 90° elbows.
4.1.2.1.3 Other shapes of elbows
Sharp elbows without a bend radius are to be prohibited (except those with fins that are mentioned below).
Segmented elbows, if they have at least five segments, may be likened to standardised elbows.
Other shapes of elbows (convergent elbows, elbows with guide fins, etc.) should be the subject of an agreement
b
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