Technical specifications for centrifugal pumps - Class III (ISO 9908:1993)

Covers class III requirements for centrifugal pumps or single stage, multistage, horizontal or vertical construction, coupled or closecoupled, with any drive and any installation for general application. Includes design features concerned with installation, maintenance and safety of such pumps including baseplate, coupling and auxiliary piping by excluding the drive, if it is not an integral part of the pump.

Technische Anforderungen für Kreiselpumpen - Klasse III (IS0 9908:1993)

Diese internationale Norm gilt für die Anforderungen der Klasse III an einstufige oder mehrstufige Kreiselpumpen in horizontaler oder vertikaler Bauart (mit Kupplung oder als Blockpumpe) mit beliebigem Antrieb und beliebigem Einbau für allgemeine Zwecke. Diese Internationale Norm schließt Ausführungsmerkmale ein, soweit sie sich auswirken auf Aufstellung, Wartung und Betriebssicherheit der Pumpe, einschließlich Grundplatte, Kupplung und Hilfsrohrleitungen, jedoch ohne Antriebsmaschine, sofern diese nicht Teil der Pumpe ist.

Spécifications techniques pour pompes centrifuges - Classe III (ISO 9908:1993)

1.1 La présente Norme internationale couvre les spécifications de la classe III des pompes centrifuges à un ou à plusieurs étages, de construction verticale ou horizontale (à accouplement normal ou serré), associées à n'importe quel type d'entraînement, dans n'importe quelle installation pour utilisation générale. 1.2 La présente Norme internationale comprend les caractéristiques de conception relatives à l'installation, l'entretien et la sécurité de ce type de pompes, y compris le socle, l'accouplement et les tuyauteries auxiliaires, mais à l'exclusion de la machine d'entraînement, si celle-ci ne fait pas partie intégrante de la pompe. 1.3 Lorsque l'application de la présente Norme internationale est demandée: a) et qu'elle spécifie une conception particulière, des conceptions différentes, répondant à l'esprit de la présente Norme internationale, peuvent être proposées, dans la mesure où la variante est décrite en détail; b) des pompes ne satisfaisant pas à toutes les exigences de la présente Norme internationale peuvent être proposées, dans la mesure où tous les écarts sont indiqués.

Technical specifications for centrifugal pumps - Class III (ISO 9908:1993)

General Information

Publication Date
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
Due Date
Completion Date


Buy Standard

EN ISO 9908:2000
English language
24 pages
sale 10% off
sale 10% off
e-Library read for
1 day

Standards Content (Sample)

SIST EN ISO 9908:2000
Technical specifications for centrifugal pumps - Class III (ISO 9908:1993)
Technical specifications for centrifugal pumps - Class III (ISO 9908:1993)
Technische Anforderungen für Kreiselpumpen - Klasse III (IS0 9908:1993)
Spécifications techniques pour pompes centrifuges - Classe III (ISO 9908:1993)
Ta slovenski standard je istoveten z: EN ISO 9908:1997
23.080 ýUSDONH Pumps
SIST EN ISO 9908:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 9908:2000

---------------------- Page: 2 ----------------------

SIST EN ISO 9908:2000

---------------------- Page: 3 ----------------------

SIST EN ISO 9908:2000

---------------------- Page: 4 ----------------------

SIST EN ISO 9908:2000
First edition
Technical specifications for centrifugal
- Class III
Spkcifications techniques pour pompes centrifuges - Classe 111
Reference number
IS0 9908: 1993(E)

---------------------- Page: 5 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normative references
Definitions .
Design .
Materials .
Shop inspection and tests
Preparation for dispatch
Centrifugal pump - Data sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
........................................ 14
Enquiry, proposal, purchase order
Examples of seal arrangements
Piping arrangements for seals
Check list
Bibliography .
0 IS0 1993
All rights reserved. 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 per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland

---------------------- Page: 6 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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 IS0 9908 was prepared by Technical Committee
lSO/TC 115, Pumps, Sub-Committee SC 1, Dimensions and technical
specifications of pumps.
Annexes A, B and C form an integral part of this International Standard.
Annexes D, E, F and G are for information only.

---------------------- Page: 7 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
This International Standard is the third of a set dealing with technical
specifications of centrifugal pumps; they are designated as Classes I, II
and III. Class I (see IS0 9905) comprises the most severe and Class III
(this International Standard) the least severe requirements. For require-
ments for Class II centrifugal pumps, see IS0 5199.
The selection of the class to be used is made in accordance with the
technical requirements for the application for which the pump is intended.
The class chosen is to be agreed between purchaser and
The safety requirements of the field of application are furthermore to be
taken into account.
However, it is not possible to standardize the class of technical require-
ments for centrifugal pumps for a certain field of application, because each
field of application comprises different requirements. All classes (I, II and
Ill) can be used in accordance with the different requirements of the pump
application. It may happen that pumps built in accordance with Classes I,
II and III may work beside each other in one plant.
Further text covering specific applications or industry requirements are
dealt with later in separate standards.
Criteria for the selection of a pump of the required class for a certain ap-
plication may be based on:
- reliability,
- operating conditions,
- environmental conditions.
Throughout this International Standard, text written in bold letters indi-
cates where a decision may be required by the purchaser, or where
agreement is required between the purchaser and manufacturer/supplier.

---------------------- Page: 8 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
Technical specifications for centrifugal pumps -
Class Ill
Members of IEC and IS0 maintain registers of cur-
1 Scope
rently valid International Standards.
I SO 76: 1987, Rolling bearings - Static load ratings.
1 .l This International Standard covers Class III re-
quirements for centrifugal pumps of single stage,
IS0 281 :I 990, Rolling bearings - Dynamic load
multistage, horizontal or vertical construction (coupled
r-a tings and rating life.
or close-coupled) with any drive and any installation
for general application.
IS0 2372: 1974, Mechanical vibration of machines
with operating speeds from IO to 200 rev/s - Basis
for specifying evaluation standards.
1.2 This International Standard includes design fea-
tures concerned with installation, maintenance and
IS0 2548:1973, Centrifugal, mixed flow and axial
safety of such pumps including baseplate, coupling
- Code for acceptance tests - Class C (It is
and auxiliary piping but excluding the driver, if it is not
planned to combine IS0 2548 with IS0 3555 during
an integral part of the pump.
their next revision to create a new International Stan-
1.3 Where the application of this International Stan-
IS0 3069:1974, End suction centrifugal pumps - Di-
dard has been called for:
mensions of cavities for mechanical seals and for soft
a) and requires a specific design feature, alternative
designs may be offered which meet the intent of
IS0 3555:1977, Centrifugal, mixed flow and axial
this International Standard provided that the
- Code for acceptance tests - Class B (It is
alternative is described in detail.
planned to combine IS0 3555 with IS0 2548 during
their next revision to create a new International Stan-
b) pumps not complying with all requirements of this
International Standard may be offered for con-
sideration, provided that all deviations are stated.
IS0 7005-I :I 992, Metallic flanges - Part 7: Steel
IS0 7005-2:1988, Metallic flanges - Part 2: Cast iron
2 Normative references
The following standards contain provisions which,
IS0 7005-3:1988, Metallic flanges - Part 3: Copper
through reference in this text, constitute provisions
alloy and composite flanges.
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All standards
1) Technical specifications for ten trifugal
IS0 9905:- ,
are subject to revision, and parties to agreements
pumps - Class 1.
based on this International Standard are encouraged
to investigate the possibility of applying the most re-
cent editions of the standards indicated below.
1) To be published.

---------------------- Page: 9 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
b) data sheet (see annex A);
3 Definitions
c) this International Standard;
For the purposes of this International Standard, the
definitions given in IS0 9905 and the following defi-
d) other standards to which reference is made in the
nitions apply.
order (or enquiry if no order is placed).
3.1 rated conditions: Conditions (driver excluded)
that define the (guarantee) point necessary to meet
4.1 .I Characteristic curve
all defined operating conditions, taking into account
any necessary margins. The characteristic curve shall indicate the allowable
operating range of the pump.
NOTE 1 This definition differs slightly from that given in
IS0 9905.
4.1.2 Net positive suction head (NPSH)
3.2 rated driver output: The maximum permissible
The NPSHR shall be based on cold water as specified
driver power output under site operating conditions.
in IS0 2548 and IS0 3555. The NPSHA must exceed
NPSHR by a margin of at least 0,5 m. The basis for
3.3 pressure-temperature rating: Relationship be-
use in performance curves is that NPSH correspond-
tween pressure and temperature given in the form of
ing to a drop of 3 % of the total head of the first stage
a graph (see figure 1).
of the pump (NPSH3).
4 Design
4.1.3 Installation
4.1 General
The pumps should preferably be suitable for outdoor
installation under normal environmental conditions. If
Whenever the documents include contradicting tech
they are suitable only for indoor installation this infor-
nical requirements, they apply in the following se
mation shall be clearly stated in the manufacturer/
supplier’s documentation.
For outdoor installation, the range of environmental
a) purchase order (or enquiry if no order is placed
(see annex B); conditions shall be specified by the purchaser.
Basic design
20" c Operating Temperature
Figure 1 - Relationship between temperature and press

---------------------- Page: 10 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
output rating covering the power requirements at any
4.2 Prime movers
operating conditions of the impeller diameter in-
stalled, no extra margins are required.
4.2.1 Defined operating conditions
Prime movers required as driver for coupled pumps 4.2.2 Undefined operating conditions
shall have power output ratings at least equal to the
Prime movers as drivers for close-coupled pumps
percentage of rated pump power input given in
figure 2 for the range of 1 kW to 100 kW. For pump shall have power output ratings covering the power
power input outside this range, the percentage is requirements at any operating conditions of the
to be agreed upon between manufacturer/sup- impeller diameter installed. These conditions elimin-
plier and purchaser. Where the prime mover has an ate the need for extra margins.
085 1
5 10 50 100
Pump power input at rated conditions
Figure 2 - Driver output percentage of rated pump power required in the range 1 kW to 100 kW

---------------------- Page: 11 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
gle operating point at rated speed (k 5 %) and rated
4.3 Critical speed, balance and vibration
flow (+ 5 %) when operating without cavitation.
4.3.1 Critical speed
Pumps with a special impeller, for example a single
channel impeller, may exceed the limits given in
Under operating conditions, the actual first lateral
table 1. In such case the pump manufacturer/supplier
critical speed of the rotor when coupled to the drive
should indicate this in his offer.
agreed upon shall be at least IO % above the maxi-
mum allowable continuous speed including the trip
speed of a turbine-driven pump. For vertical lineshaft Vertical lineshaft pumps
pumps, a flexible shaft is permitted.
a) Vibration readings shall be taken on the top flange
4.3.2 Balance and vibration of the driver mount on vertical lineshaft pumps
with rigid couplings and near to the top pump
bearing on vertical pumps with flexible couplings. Horizontal pumps
b) Vibration limits for both rolling and sleeve bearing
Unfiltered vibration shall not exceed the vibration se-
verity limits given in table 1 when measured on the pumps shall not exceed a velocity of 7,l mm/s
rms during shop test at rated speed (k 5 %), and
manufacturer/supplier’s test facilities. These values
are measured radially at the bearing housing at a sin- rated flow (+ 5 %) operating without cavitation.
Table 1 - Limits of vibration severity for horizontal pumps with multivane impellers
Maximum rms values of the vibration velocity for the shaft centreline height h, 1) 2)
Speed of rotation y1
h, > 225 mm
min-1 h, g 225 mm
n < 1 800
Z8 415
1 800 < n < 4 500
415 7,l
1) Based on IS0 2372.

---------------------- Page: 12 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E) External bolting
4.4 Pressure-containing parts
Bolts or studs that connect pressure-containing parts
4.4.1 Pressure-temperature rating
shall be selected to be adequate for the maximum
allowable working pressure and for normal tightening
The pressure limit (maximum allowable working
pressure) of the pump at the most severe operating
defined by the
conditions shall be clearly
manufacturer/supplier. In no case may the rated
4.5 Branches (nozzles) and miscellaneous
pressure of the pump (casing and cover, including
shaft seal housing and gland follower/end plate) ex-
ceed that of the pump flanges.
NOTE 2 For the purpose of this International Standard
the terms branch and nozzle are synonymous.
The basic design pressure of the pump shall be a
gauge pressure of at least 6 bar*) at 20 OC when made
4.5.1 Type and size
of cast iron, ductile iron, carbon steel or stainless
Type and size of fluid connections shall be stated in
the manufacturer/supplier’s document.
For materials the tensile requirements of which do not
permit the 6 bar rating, the pressure-temperature rat-
4.5.2 Closures
ing shall be adjusted according to the stress-
temperature rating for the material and shall be clearly
Vent, pressure-gauge and drain openings shall be fit-
stated by the manufacturer/supplier.
ted with removable closures adequate to contain the
Low head pumps may have a lower pressure-
maximum allowable working pressures and of ma-
temperature rating if this is clearly stated by the
terial suitable for the pumped liquid.
manufacturer/supplier on the nameplate and data
4.6 External forces and moments on
branches (inlet and outlet)
4.4.2 Wall thickness
The manufacturer/supplier shall provide details of al-
Pressure casings including the shaft seal housing and
lowable external forces and moments on branches on
gland end plate shall be of such thickness as will be
suitable for containing pressure and limiting distortion
under the maximum allowable working pressure at
4.7 Branch (nozzle) flanges
operating temperature.
The casing shall also be suitable for the hydrostatic
If circular flanges are used the flange envelope shall
test pressure (see clause 6) at ambient temperature.
be of a size to enable flanges as specified in
IS0 7005-1, IS0 7005-2 and IS0 7005-3 to be used.
If the pump manufacturer/supplier’s standard pat-
4.4.3 Materials
tern entails a flange thickness and a diameter
greater than that of the rating specified, the
The materials used for pressure-containing parts shall
heavier flange may be supplied if requested by the
depend on the liquid pumped and the application of
manufacturer/supplier, but it shall be faced and
the pump (see clause 5).
drilled as specified above.
4.4.4 Mechanical features
Bolt holes shall straddle the centreline. Dismantli
4.8 Impellers
The pump should be designed to permit necessary
4.8.1 Impeller design
dismantling for spare part replacement without dis-
turbing inlet and outlet connections. If the design is
Impellers of closed, semi-open or open designs may
such that dismantling will cause some disturbance,
be selected according to the application.
then it should be so stated.
4.8.2 Securing of impellers Casing gaskets
Impellers shail be secured against circumferential and
Casing gaskets shall be of a design suitable for the
axial movement when rotating in the intended direc-
rated operating conditions and for hydrostatic test
tion of rotation. Attention shall be drawn to the secure
conditions at ambient temperature.
2) 1 bar = 0,l MPa

---------------------- Page: 13 ----------------------

SIST EN ISO 9908:2000
IS0 9908:1993(E)
attachment of impeller in either direction of close- 4.10.6 Axial movement
coupled pumps.
Axial movement of the rotor permitted by the
bearings shall not adversely affect the performance
4.9 Running clearance
of the mechanical seal.
When establishing running clearances between sta-
4.1 I Bearings
tionary and moving parts, consideration shall be given
to operating conditions and properties of the material
4.11.1 General
(such as hardness and gall resistance) used for these
parts. Clearances shall be sized to prevent contact
Rolling bearings of standard design are normally to be
under operating conditions, and material combinations
selected to minimize the risk of seizure and erosion.
4.11.2 Rolling bearing life
4.10 Shafts and shaft sleeves
Rolling bearings shall be selected and rated in ac-
cordance with IS0 76 and IS0 281; the “basic rating
4.10.1 General
life (L,,)” shall be at least 10 000 h when operating
within the allowable operating range.
Shafts shall be of ample size and stiffness to:
4.11.3 Lubrication
a) transmit the prime mover rated power;
The operating instructions shall include information on
b) minimize unsatisfactory packing or seal perform-
the type and amount of lubricant to be used and the
frequency of application.
c) minimize wear and the risk of seizure;
4.11.4 Bearing housing design
d) take due consideration of the method of starting
The bearing housing shall be designed to prevent the
and inertia loading involved.
ingress of contaminants and the escape of the

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.