EN ISO 9906:1999

SLOVENSKI STANDARD
01-december-2000
Rotodynamic pumps - Hydraulic performance acceptance tests - Grades 1 and 2
(ISO 9906:1999)
Rotodynamic pumps - Hydraulic performance acceptance tests - Grades 1 and 2 (ISO
9906:1999)
Kreiselpumpen - Hydraulische Abnahmeprüfung Klassen 1 und 2 (ISO 9906:1999)
Pompes rotodynamiques - Essais de fonctionnement hydraulique pour la réception -
Niveaux 1 et 2 (ISO 9906:1999)
Ta slovenski standard je istoveten z: EN ISO 9906:1999
ICS:
23.080 ýUSDONH Pumps
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 9906
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 1999
ICS 23.080
English version
Rotodynamic pumps - Hydraulic performance acceptance tests -
Grades 1 and 2 (ISO 9906:1999)
Pompes rotodynamiques - Essais de fonctionnement Kreiselpumpen - Hydraulische Abnahmeprüfung Klassen 1
hydraulique pour la réception - Niveaux 1 et 2 (ISO und 2 (ISO 9906:1999)
9906:1999)
This European Standard was approved by CEN on 20 August 1999.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 1999 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9906:1999 E
worldwide for CEN national Members.

Page 2
CORRECTED  2002-05-08
Foreword
This document (ISO 9906:1999) has been prepared by Technical Committee ISO/TC 115
"Pumps" in collaboration with Technical Committee CEN/TC 197 "Pumps", the secretariat of
which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication
of an identical text or by endorsement, at the latest by June 2000, and conflicting national
standards shall be withdrawn at the latest by June 2000.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United
Kingdom.
Endorsement notice
The text of the International Standard ISO 9906:1999 has been approved by CEN as a
European Standard without any modifications.
NOTE Normative references to International Standards are listed in annex ZA (normative).

Page 3
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions
of any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications,
indicated by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 5167-1 1991 Measurement of fluid flow by EN ISO 5167-1 1995
means of pressure differential
devices - Part 1: Orifice plates,
nozzles and Venturi tubes
ISO 5198 1998 Centrifugal, mixed flow and axial EN ISO 5198 1987
pumps - Code for hydraulic
performance tests - Precision class
ISO 8316 1987 Measurement of liquid flow in closed EN ISO 8316 1995
conduits - Method by collection of
the liquid in a volumetric tank
ISO 9104 1991 Measurement of fluid flow in closed EN 29104 1993
conduits - Methods of evaluating the
performance of electromagnetic
flow-meters for liquids
INTERNATIONAL ISO
STANDARD 9906
First edition
1999-12-15
Rotodynamic pumps — Hydraulic
performance acceptance tests — Grades 1
and 2
Pompes rotodynamiques — Essais de fonctionnement hydraulique pour
la réception — Niveaux 1 et 2
A
Reference number
ISO 9906:1999(E)
ISO 9906:1999(E)
Contents
1 Scope .1
2 Normative references .1
3 Terms, definitions and symbols.2
4 Guarantees .8
4.1 Subjects of guarantees .8
4.2 Other conditions of guarantee .8
5 Execution of tests.8
5.1 Subjects of tests .8
5.2 Organization of tests .9
5.3 Test arrangements.11
5.4 Test conditions .13
6 Analysis of test results.17
6.1 Translation of the test results to the guarantee conditions.17
6.2 Measuring uncertainties.18
6.3 Values of tolerance factors.20
6.4 Verification of guarantees.20
6.5 Obtaining specified characteristics .21
7 Measurement of flow rate .22
7.1 Measurement by weighing.22
7.2 Volumetric method .22
7.3 Differential pressure devices.22
7.4 Thin-plate weirs.23
7.5 Velocity area methods.23
©  ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
ii
© ISO
ISO 9906:1999(E)
7.6 Tracers methods. 23
7.7 Other methods . 23
8 Measurement of pump total head . 24
8.1 General . 24
8.2 Definition of the measuring sections . 25
8.3 Water level measurement . 30
8.4 Pressure measurements . 31
9 Measurement of speed of rotation. 34
10 Measurement of pump power input. 35
10.1 General . 35
10.2 Measurement of torque. 35
10.3 Electric power measurements. 35
10.4 Special cases . 35
11 Cavitation tests. 36
11.1 General . 36
11.2 Test installations . 38
11.3 Determination of the NPSH required by the pump. 39
Annex A (normative) Tolerance factors for pumps produced in series with selection made from typical
performance curves and for pumps with a driver power input less than 10 kW (relevant to series pumps
grade 2) . 42
Annex B (normative) Determination of reduced impeller diameters . 43
Annex C (normative) Friction losses. 44
Annex D (informative) Conversion to SI units. 49
Annex E (informative) Guide for suitable time periods between calibrations of test instruments. 50
Annex F (informative) Costs and repetition of tests. 51
Annex G (informative) Performance correction chart for viscous liquids. 52
Annex H ((informative) NPSHR reduction for pumps handling hydrocarbon liquids and high temperature
water . 55
Annex I (informative) Statistical evaluation of measurement results . 57
Annex J (informative) Pump test sheet. 59
Annex K (informative) Checklist . 60
Bibliography. 61

© ISO
ISO 9906:1999(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 9906 was prepared by Technical Committee ISO/TC 115, Pumps, Subcommittee SC 2,
Methods of measuring and testing.
This first edition of ISO 9906 cancels and replaces ISO 2548:1975 and ISO 3555:1977, which have been combined
and technically revised (see Introduction).
Annexes A, B and C form a normative part of this International Standard. Annexes D to K are for information only.
iv
© ISO
ISO 9906:1999(E)
Introduction
This International Standard combines and replaces the former acceptance test standards ISO 3555:1977
(corresponding to grade 1 of this International Standard) and ISO 2548:1975 (corresponding to grade 2 of this
International Standard), but there is an important change in the verification of guarantees, because the uncertainty
of measurement must not influence the acceptability of a pump and the tolerances are due to constructional
differences only.
New tolerance factors have been introduced to ensure as far as possible that a pump which was acceptable under
the previous International Standards (ISO 2548 and/or ISO 3555) would also be acceptable under this International
Standard.
Contrary to this International Standard, ISO 5198 is not to be understood as an acceptance test code. It gives
guidance for measurements of very high accuracy and for the thermodynamic method for direct measurement of
efficiencies, but it does not recommend verification of guarantees.
Terms used in this International Standard such as “guarantee” or “acceptance” should be understood in a technical
but not in a legal sense. The term “guarantee” therefore specifies values for checking purposes determined in the
contract, but does not say anything about the rights or duties arising, if these values are not reached or fulfilled. The
term “acceptance” does not have any legal meaning here, either. Therefore, an acceptance test carried out
successfully alone does not represent an “acceptance” in the legal sense.

INTERNATIONAL STANDARD  © ISO ISO 9906:1999(E)
Rotodynamic pumps — Hydraulic performance acceptance
tests — Grades 1 and 2
1 Scope
This International Standard specifies hydraulic performance tests for acceptance of rotodynamic pumps (centrifugal,
mixed flow and axial pumps, hereinafter simply designated as “pumps”). It is applicable to pumps of any size and to
any pumped liquids behaving as clean cold water (such as defined in 5.4.5.2). It is neither concerned with the
structural details of the pump nor with the mechanical properties of their components.
This International Standard contains two grades of accuracy of measurement: grade 1 for higher accuracy, and
grade 2 for lower accuracy. These grades include different values for tolerance factors, for allowable fluctuations
and uncertainties of measurement.
For pumps produced in series with selection made from typical performance curves and for pumps a with power
input of less than 10 kW, see annex A for higher tolerance factors.
This International Standard is applicable both to a pump itself without any fittings and to a combination of a pump
associated with all or part of its upstream and/or downstream fittings.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 1438-1, Water flow measurement in open channels using weirs and Venturi flumes — Part 1: Thin-plate weirs.
ISO 2186, Fluid flow in closed conduits — Connections for pressure signal transmissions between primary and
secondary elements.
ISO 3354, Measurement of clean water flow in closed conduits — Velocity-area method using, current-meters in full
conduits and under regular flow conditions.
ISO 3966, Measurement of fluid flow in closed conduits — Velocity area method using Pitot static tubes.
ISO 4373, Measurement of liquid flow in open channels — Water-level measuring devices.
ISO 5167-1, Measurement of fluid flow by means of pressure differential devices — Part 1: Orifice plates, nozzles
and Venturi tubes inserted in circular cross-section conduits running full.
ISO 5198, Centrifugal, mixed flow and axial pumps — Code for hydraulic performance tests — Precision grade.
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.
ISO 8316, Measurement of liquid flow in closed conduits — Method by collection of the liquid in a volumetric tank.
ISO 9104, Measurement of liquid flow in closed conduits — Methods of evaluating the performance of electro-
magnetic flow-meters for liquids.
© ISO
ISO 9906:1999(E)
IEC 60034-2, Recommendations for rotating electrical machinery (excluding machines for traction vehicles) —
Part 2: Determination of efficiency of rotating electrical machinery.
IEC 60051, Recommendations for direct acting electrical measuring instruments and their accessories.
3 Terms, definitions and symbols
For the purposes of this International Standard, the following terms, definitions and symbols apply.
NOTE 1 The definitions, particularly those given for head and net positive suction head (NPSH), may not be appropriate for
general use in hydrodynamics, and are for the purposes of this International Standard only. Some terms in current use but not
strictly necessary for the use of this International Standard are not defined.
NOTE 2 Table 1 gives an alphabetical list of symbols used, and Table 2 gives a list of subscripts. In this International
Standard all formulae are given in coherent SI units. For conversion of other units to SI units, see annex D.
NOTE 3 In order to avoid any error of interpretation, it is deemed desirable to reproduce the definitions of quantities and units
as given in ISO 31 and to supplement these definitions by some specific information on their use in this International Standard.
3.1
angular velocity
number of radians of a shaft per unit time
w = 2pn
3.2
speed of rotation
number of rotations per unit time
3.3
density
mass per unit volume
3.4
pressure
force per unit area
NOTE In this International Standard all pressures are gauge pressures, i.e. measured with respect to the atmospheric
pressure, except for atmospheric pressure and the vapour pressure which are absolute pressures.
3.5
power
energy transferred per unit time
3.6
Reynolds number
UD
Re =
v
3.7
mass flow rate
external mass flow rate of the pump, i.e. the rate of flow discharged into the pipe from the outlet branch of the pump
NOTE 1 The following losses or abstractions are inherent to the pump:
a) discharge necessary for hydraulic balancing of axial thrust;
b) cooling of bearings of the pump itself;
c) liquid seal to the packing.
© ISO
ISO 9906:1999(E)
NOTE 2 Leakage from the fittings, internal leakage, etc., are not to be reckoned in the rate of flow. On the contrary, all derived
flows for other purposes, such as
 cooling of the motor bearings;
 cooling of a gear box (bearings, oil cooler), etc.
are to be reckoned in the rate of flow.
NOTE 3 Whether and how these flows are to be taken into account depends on the location of their derivation and of the
section of flow-measurement, respectively.
3.8
volume flow rate
outlet volume flow rate has the following value:
q
Q =
r
NOTE In this International Standard the symbol Q may also designate the volume flow rate in any given section. It is the
quotient of the mass flow rate in this section and the density. (The section may be designated by subscripts.)
3.9
mean velocity
mean axial velocity of flow equal to the volume flow rate divided by the pipe cross section area
Q
U =
A
NOTE Attention is drawn to the fact that in this case Q may vary for different reasons across the circuit.
3.10
local velocity
velocity of flow at any point
3.11
head
energy per unit mass of fluid, divided by acceleration due to gravity, g
3.12
reference plane
any horizontal plane used as a datum for height measurement
NOTE For practical reasons it is preferable not to specify an imaginary reference plane.
3.13
height above reference plane
height of the considered point above the reference plane
NOTE Its value is:
 positive, if the considered point is above the reference plane;
 negative, if the considered point is below the reference plane.
See Figures 3 and 4.
© ISO
ISO 9906:1999(E)
3.14
gauge pressure
pressure relative to atmospheric pressure
NOTE 1 Its value is:
 positive, if this pressure is greater than the atmospheric pressure;
 negative, if this pressure is less than the atmospheric pressure.
NOTE 2 All pressures in this International Standard are gauge pressures read from a manometer or similar pressure-sensing
instrument, except atmospheric pressure and the vapour pressure of the liquid, which are expressed as absolute pressures.
3.15
velocity head
kinetic energy per unit mass of the liquid in movement, divided by g:
U
2g
3.16
total head
in any section, the total head is given by:
p U
xx
Hz=+ +
xx
r g 2g
where z is the height of the centre of the cross-section above the reference plane and p is the gauge pressure
related to the centre of the cross-section
NOTE The absolute total head in any section is given by:
p
p U
xxamb
Hz=+ + +
x(abs) x
rrg g 2g
3.17
inlet total head
total head in the inlet section of the pump:
p U
Hz=+ +
r g 2g
3.18
outlet total head
total head in the outlet section of the pump:
p U
Hz=+ +
r g 2g
3.19
pump total head
algebraic difference between the outlet total head H and the inlet total head H
2 1
NOTE 1 If the compressibility is negligible,  .
H = H 2 H
2 1
If the compressibility of the pumped liquid is significant, the density r should be replaced by the mean value:
rr+
r =
m
© ISO
ISO 9906:1999(E)
and the pump total head should be calculated by the formula:
2 2
pp-UU-
21 2 1
Hz=- z+ +
r ⋅g 2g
m
NOTE 2 The mathematically correct symbol would be H .
1-2
3.20
specific energy
energy per unit mass of liquid:
y = gH
3.21
loss of head at inlet
difference between the total head of the liquid at the measuring point and the total head of the liquid in the inlet
section of the pump
3.22
loss of head at outlet
difference between the total head of the liquid in the outlet section of the pump and the total head of the liquid at the
measuring point
3.23
pipe friction loss coefficient
coefficient for the head loss by friction in the pipe
3.24
net positive suction head
NPSH
absolute inlet total head above the head equivalent to the vapour pressure relative to the NPSH datum plane:
-pp
amb v
NPSH=-Hz+
D
r g
NOTE This NPSH relates to the NPSH datum plane, whereas the inlet total head relates to the reference plane.
3.25
NPSH datum plane
horizontal plane through the centre of the circle described by the external points of the
entrance edges of the impeller blades
3.26
NPSH datum plane
plane through the higher centre
NOTE The manufacturer should indicate the position of this plane with respect to precise reference points on the pump.
See Figure 1.
Key
1  NPSH datum plane
Figure 1 — NPSH datum plane
© ISO
ISO 9906:1999(E)
3.27
available NPSH
NPSHA
NPSH available as determined by the conditions of the installation for a specified flow rate
3.28
required NPSH
NPSHR
minimum NPSH given by the manufacturer/supplier for a pump achieving a specified performance at a specified
flow rate, speed and pumped liquid (occurrence of visible cavitation, increase of noise and vibration due to
cavitation, beginning of head or efficiency drop, head or efficiency drop of a given amount, limitation of cavitation
erosion)
3.29
NPSH3
NPSH required for a drop of 3 % of the total head of the first stage of the pump as standard basis for use in
performance curves
3.30
type number
dimensionless quantity calculated at the point of best efficiency which is defined by the following formula:
12/ 12/
2 p nQ¢w Q¢
K = =
34/ 34/
gH y¢()¢
where Q9 is the volume rate of flow per eye and H9 is the head of the first stage
NOTE The type number is to be taken at maximum diameter of the first stage impeller.
3.31
pump power input
power transmitted to the pump by its driver
3.32
pump power output
mechanical power transferred to the liquid during its passage through the pump:
P = r Q g H = r Q y
u
3.33
driver power input
power absorbed by the pump driver
3.34
pump efficiency
pump power output divided by the pump power input
P
u
h =
P
3.35
overall efficiency
pump power output divided by the driver power input
P
u
h=
gr
P
gr
© ISO
ISO 9906:1999(E)
Table 1 — Alphabetical list of basic Table 2 — List of letters and figures used
letters used as symbols as subscript
Symbol Quantity Unit Subscript Meaning
A Area m 1 inlet
Diameter m 1 inlet measuring section
D '
E Energy J 2 outlet
e Overall uncertainty, relative value % 2' outlet measuring section
f Frequency s , Hz abs absolute
a
g Acceleration due to gravity m/s amb ambient
H Pump total head m D difference, datum
H Losses in terms of head of liquid m f fluid in measuring pipes
J
k Equivalent uniform roughness m G guaranteed
K Type number (pure number) H pump total head
l Length m gr combined motor/pump unit (overall)
m Mass kg m mean
21 21
n Speed of rotation s , min M manometer
NPSH Net positive suction head m n speed of rotation
p Pressure Pa P power
P Power W Q (volume) flow rate
b
q Mass flow rate kg/s sp specified
c
Q Volume flow rate m /s T translated, torque
Re Reynolds number (pure number) u useful
t Tolerance factor, relative value % v vapour (pressure)
t Time s h efficiency
T Torque Nm x at any section
U Mean velocity m/s
v Local velocity m/s
V Volume m
y Specific energy J/kg
z Height above reference plane m
z Difference between NPSH datum m
D
plane (see 3.25) and reference plane
h Efficiency (pure number)
Q Temperature °C
l Pipe friction loss coefficient (pure number)
n Kinematic viscosity m /s
r Density kg/m
w Angular velocity rad/s
a
In principle, the local value of g should be used. Nevertheless,
for grade 2 it is sufficient to use a value of 9,81 m/s . For the
calculation of the local value g = 9,780 3 (1 + 0,005 3 sin j) –
3 · 10 ·z, where j is the latitude and z is the altitude.
b
An optional symbol for mass rate of flow is q .
m
c
An optional symbol for volume rate of flow is q .
v
© ISO
ISO 9906:1999(E)
4 Guarantees
4.1 Subjects of guarantees
One guarantee point shall be defined by a guarantee flow Q and a guarantee head H .
G G
The manufacturer/supplier guarantees that under the specified conditions and at the specified speed (or in some
cases frequency and voltage) the measured H(Q) curve will pass through a range of tolerance (see Table 10 and
Figure 2), surrounding the guarantee point.
Other tolerance ranges (e.g. only given by positive tolerance factors) may be agreed upon in the contract.
In addition, one or more of the following quantities may be guaranteed under the specified conditions and at the
specified speed:
a) the pump efficiency, h , or in the case of overall pump driver unit,
G
at the flow rate which is defined
the combined efficiency, h ;
grG
in 6.4.2 and Figure 2.
}
b) the required net positive suction head (NPSHR) at the guarantee flow;
By special agreement several guarantee points and the appropriate values of efficiency and required net positive
suction head at reduced or increased flow rates may be guaranteed. The maximum power input may be guaranteed
for the guarantee flow or for a range of operation. This, however, may require larger tolerance ranges to be agreed
upon between the purchaser and manufacturer/supplier.
4.2 Other conditions of guarantee
Unless otherwise agreed, the following conditions shall apply to the guaranteed values.
a) Unless the chemical and physical properties of the liquid being pumped are stated, the guarantee points shall
apply to clean cold water (see 5.4.5.2).
b) The relationship between the guarantee values under clean cold water conditions and the likely performance
under other liquid conditions shall be agreed in the contract.
c) Guarantees shall apply only to the pump as tested by the methods and in the test arrangements specified in
this International Standard.
d) The pump manufacturer/supplier shall not be responsible for the specification of the guarantee point.
5 Execution of tests
5.1 Subjects of tests
5.1.1 General
If not otherwise agreed between the manufacturer/supplier and the purchaser, the following shall apply:
a) accuracy according to grade 2;
b) tests shall be carried out on the test stand of the manufacturer's works;
c) the NPSH test is not included.
Any deviations from this shall be agreed between the purchaser and manufacturer/supplier. This should be done as
soon as possible, and should preferably form part of the contract.
Among others, such deviations may be:
 accuracy according to grade 1;
© ISO
ISO 9906:1999(E)
 no negative tolerance factors (see 4.1);
 tolerance factors corresponding to annex A;
 statistical evaluation of measurement results according to annex I;
 tests in a neutral laboratory or on site;
 deviations from the requirements concerning the installation of the pump and the measuring apparatus;
 simulated construction of pumps (e.g. several rotors in same casing);
 a requirement for the NPSH test.
Annex K shows a checklist of items where agreement between the purchaser and manufacturer/supplier is
recommended.
5.1.2 Contractual tests — Fulfilment of the guarantee
The tests are intended to ascertain the performance of the pump and to compare this with the manufac-
turer’s/supplier's guarantee.
The nominated guarantee for any quantity shall be deemed to have been met if, when tested according to this
International Standard, the measured performance fails within the tolerance specified for the particular quantity (see
clause 6).
When NPSHR is to be guaranteed, the type of test shall be specified (see 11.1.2).
When a number of identical pumps are to be purchased, the number of pumps to be tested shall be agreed between
the purchaser and manufacturer/supplier.
5.1.3 Additional checks
During the test, it may be noted if the behaviour of the pump is satisfactory in respect of the temperature of
1)
packings and bearings, of leakage of air or water, of acoustic emission and of vibrations .
5.2 Organization of tests
5.2.1 General
Both, purchaser and manufacturer/supplier shall be entitled to witness these tests.
5.2.2 Location of tests
5.2.2.1 Works tests
Performance tests should preferably be carried out at the manufacturer’s works, or at a place to be mutually agreed
between the manufacturer/supplier and the purchaser.
5.2.2.2 Site tests
Special agreement is necessary for performance tests on site providing all the requirements of this International
Standard can be satisfied. It is, however, recognised that the conditions at most sites often preclude full compliance
with this International Standard. In these instances site performance tests may still be acceptable providing the
parties have agreed how allowance is made for the inaccuracies which will inevitably result from departure from the
specified requirement.
1)  Special International Standards for pumps are under study in ISO/TC 115.
© ISO
ISO 9906:1999(E)
5.2.3 Date of testing
The date of testing shall be mutually agreed by the manufacturer/supplier and the purchaser.
5.2.4 Staff
Accurate measurements depend not only on the quality of the measuring instruments used but also on the ability
and skill of the persons operating and reading the measuring devices during the tests. The staff entrusted with
effecting the measurements shall be selected just as carefully as the instruments to be used in the test.
Specialists with adequate experience in measuring operations in general shall be charged with operating and
reading complicated measuring apparatus. Reading simple measuring devices may be entrusted to such helpers
who (upon prior instruction) can be assumed to effect the readings with proper care and the accuracy required.
A test supervisor possessing adequate experience in measuring operations shall be mutually appointed. Normally,
when the test is carried out at the manufacturer's works, the test supervisor is a staff member of the pump
manufacturer.
During the tests all persons charged with effecting the measurements are subordinated to the chief of tests, who
conducts and supervises the measurements, reports on test conditions and the results of the tests and then drafts
the test report. All questions arising in connection with the measurements and their execution are subject to his
decision.
The parties concerned shall provide all assistance that the chief of tests considers necessary.
5.2.5 State of pump
When tests are not carried out in the manufacturer's works, opportunity shall be allowed for preliminary adjustments
by both manufacturer and installer.
5.2.6 Test programme
The programme and procedure to be followed in the test shall be prepared by the test supervisor and submitted to
both manufacturer/supplier and purchaser in ample time for consideration and agreement.
Only the guaranteed operational data (see 4.1) shall form the basis of the test, other data determined by
measurement during the tests shall have merely an indicative (informative) function and it shall be so stated if they
are included in the programme.
5.2.7 Testing equipment
When deciding on the measuring procedure, the measuring and recording apparatus required shall be specified at
the same time.
The test supervisor shall be responsible for checking the correct installation of the apparatus and its proper
functioning.
All of the measuring apparatus shall be covered by reports showing by calibration or by comparison with other ISO
or IEC standards that it complies with the requirement of 6.2. These reports shall be presented if required.
Guidance for suitable period between calibrations of test instruments is given in annex E.
5.2.8 Records
All test records and record charts shall be initialled by the test supervisor and by the representatives of both the
manufacturer/supplier and purchaser if present, each of whom shall be provided with a copy of all records and
charts.
The evaluation of the test results shall be made as far as possible while the tests are in progress and, in any case,
before the installation and instrumentation are dismantled in order that suspect measurements can be repeated
without delay.
© ISO
ISO 9906:1999(E)
5.2.9 Test report
After scrutiny, the test results shall be summarized in a report which is signed by the test supervisor alone, or
together, by him and representatives of the manufacturer/supplier and of the purchaser.
All parties specified in the contract shall receive a copy of the report.
The test report should contain the following information:
a) place and date of acceptance test;
b) manufacturer's name, type of pump, serial number, and possibly year of construction;
c) impeller diameter, blade angle or other impeller identifications;
d) guaranteed characteristics, operational conditions during the acceptance test;
e) specification of the pump's driver;
f) sketch of test arrangement, diameters of measuring sections, description of the test procedure and the
measuring apparatus used including calibration data;
g) readings;
h) evaluation and analysis of test results;
i) conclusions:
 comparison of the test results and the guaranteed quantities,
 determination of action taken in connection with any special agreements that were made,
 recommendation whether the pump can be accepted or should be rejected and under what conditions (if
the guarantees are not fully satisfied the final decision whether the pump can be accepted or not is up to
the purchaser),
 statements arising out of action taken in connection with any special agreements that were made.
A pump test sheet is given for guidance in annex J.
5.3 Test arrangements
5.3.1 General
The conditions necessary to ensure satisfactory measurement of the characteristics of operation are defined in this
subclause, taking into account the accuracy required for tests of grades 1 and 2.
NOTE 1 The performance of a pump in a given test arrangement, however accurately measured, cannot be assumed to be a
correspondingly accurate indication of its performance in another arrangement.
NOTE 2 Recommendations and general guidance about suitable pipe arrangements to ensure satisfactory measurements are
given in clauses 7 and 8 and, if necessary, they can be used in conjunction with the International Standards on measurement
of flow rates in closed conduits concerning the different methods (see clause 7).
5.3.2 Standard test arrangements
The best measuring conditions are obtained when, in the measuring sections, the flow has
 an axially symmetrical velocity distribution;
 a uniform static pressure distribution;
 freedom from swirl induced by the installation.
© ISO
ISO 9906:1999(E)
For grades 1 and 2, verification is not required as it is not possible, in practice, entirely to meet these requirements.
It is possible to prevent a very poor velocity distribution or swirl by avoiding any bend or a combination of bends,
any expansion or any discontinuity in the transverse profile in the vicinity (less than four diameters) of the
measuring section.
Generally the effect of the inlet flow conditions increases with the type number K of the pump. When K . 1,2 it is
recommended to simulate the site conditions.
It is recommended that for standard test arrangements leading from reservoirs with a free surface or from large
stilling vessels in a closed circuit, the inlet straight length L shall be determined by the expression: L/D = K 1 5,
where D is the pipe diameter. This is especially valid for grade 1 tests.
This expression is also valid for an arrangement that includes, at a distance L upstream, a simple right-angle bend
that is not fitted with guide vanes. Under these conditions, flow straighteners are not necessary in the pipe between
the bend and the pump. However, in a closed circuit where there is neither a reservoir nor a stilling vessel
immediately upstream of the pump, it is necessary to ensure that the flow into the pump is free from swirl induced
by the installation and has a normal symmetrical velocity distribution.
Significant swirl can be avoided by
 careful design of the test circuit upstream of the measuring section;
 judicious use of a flow straightener;
 suitable arrangement of the pressure tappings to minimize their influence on the measurement.
It is recommended not to install a throttle valve in the suction pipe (see 5.4.4). Nevertheless, if this cannot be
avoided, for instance for cavitation tests, the straight pipe length between the valve and the pump inlet should be in
conformity with the requirements of 11.2.2.
5.3.3 Simulated test arrangements
When from the reasons given above it is agreed to test a pump under simulated site conditions, it is important that
at the inlet of the simulated circuit the flow should as far as possible be free from significant swirl induced by the
installation and have a symmetrical velocity distribution. All necessary provisions shall be made to ensure these
conditions are achieved.
If necessary, for grade 1 tests the velocity distribution of the flow into the simulated circuit shall be determined by
careful Pitot tube traverses, in order to establ
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