ISO 8528-12

Reciprocating internal combustion engine driven alternating current generating sets — Part 12: Emergency power supply to safety services

This document applies to generating sets driven by reciprocating internal combustion (RIC) engines for emergency power supply to safety services. This document applies, for example, to safety equipment in hospitals, high-rise buildings and public gathering places. It establishes the special requirements for the performance, design and maintenance of generating sets used in these applications referred to previously and takes into account the provisions of ISO 8528-1 to ISO 8528-6 and ISO 8528-10[1]. [1] Under preparation. Stage at the time of publication: ISO/FDIS 8528-10:2022.

Groupes électrogènes à courant alternatif entraînés par moteurs alternatifs à combustion interne — Partie 12: Alimentation électrique de secours de services de sécurité

General Information

• Status: Not Published
• ICS: 13.100 - Occupational safety. Industrial hygiene
• ICS: 27.020 - Internal combustion engines
• ICS: 29.160.40 - Generating sets
• Technical Committee: ISO/TC 70 - Internal combustion engines
• Drafting Committee: ISO/TC 70 - Internal combustion engines
• Current Stage: 6000 - International Standard under publication
• Completion Date: 22-Jul-2022

RELATIONS

• Revises: ISO 8528-12:1997 - Reciprocating internal combustion engine driven alternating current generating sets — Part 12: Emergency power supply to safety services
• Effective Date: 06-Jun-2022

Standards Content (sample)

ISO/DISFDIS 8528--12:20232022(E)
ISO TC 70/WG 10
Date: 2022-03-2105-11

Reciprocating internal combustion engine driven alternating current generating sets —

Part 12: Emergency power supply to safety services
FDIS stage
Warning for WDs and CDs

This document is not an ISO International Standard. It is distributed for review and comment. It is subject to

change without notice and may not be referred to as an International Standard.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.

A model manuscript of a draft International Standard (known as “The Rice Model”) is available at

---------------------- Page: 1 ----------------------
ISO/FDIS 8528-12:2022(E)
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part

of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or

mechanical, including photocopying, or posting on the internet or an intranet, without prior written

permission. Permission can be requested from either ISO at the address below or ISO’s member body

in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 8528-12:2022(E)
Contents

Foreword ............................................................................................................................................................. v

1 Scope ....................................................................................................................................................... 1

2 Normative references ....................................................................................................................... 1

3 Terms and definitions ....................................................................................................................... 2

4 Additional regulations and requirements .................................................................................. 3

5 Classification designation ................................................................................................................ 3

5.1 General ................................................................................................................................................... 3

5.2 Typical examples of classification ................................................................................................. 3

6 Generating set design ........................................................................................................................ 4

6.1 Criteria for determining the required power ............................................................................ 4

6.2 Power determination ........................................................................................................................ 4

6.3 Operating limit values....................................................................................................................... 4

7 Additional requirements ................................................................................................................. 6

7.1 Characteristics of batteries and battery charger for auxiliaries and starter .................. 6

7.2 Compressed air starter ..................................................................................................................... 7

7.3 Fuel capacity ........................................................................................................................................ 7

7.4 Ventilation louvers ............................................................................................................................ 7

7.5 Electric power supply........................................................................................................................ 7

7.6 Robustness against vibrations ....................................................................................................... 8

8 Controlgear and switchgear ............................................................................................................ 8

8.1 General ................................................................................................................................................... 8

8.2 Protection, measurement, monitoring and control equipment for the AC generator . 8

8.2.1 AC generator protection equipment ............................................................................................ 8

8.2.2 AC generator measurement and monitoring equipment ...................................................... 8

8.3 Engine measurement and monitoring equipment ................................................................... 8

8.4 Generating set measurement and monitoring equipment .................................................... 9

8.5 Remote signals .................................................................................................................................... 9

9 Test mode .............................................................................................................................................. 9

9.1 Test operation with synchronization to the mains supply ................................................... 9

9.1.1 General ................................................................................................................................................... 9

9.1.2 Gradual power application without switching.......................................................................... 9

9.1.3 Gradual power application with switching ................................................................................ 9

9.1.4 Sudden power application with short time parallel operation ........................................ 10

9.2 Without mains synchronization ................................................................................................. 10

10 Testing ................................................................................................................................................ 10

10.1 General ................................................................................................................................................ 10

10.2 Installation tests .............................................................................................................................. 11

10.3 Periodic tests .................................................................................................................................... 11

11 Rating plate ....................................................................................................................................... 12

12 Required documentation .............................................................................................................. 12

13 Checklist ............................................................................................................................................. 12

© ISO 2022 – All rights reserved iii
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ISO/FDIS 8528-12:2022(E)

Bibliography .................................................................................................................................................... 15

iv © ISO 2022 – All rights reserved
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ISO/FDIS 8528-12:2022(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the World

Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was revisedprepared by Technical Committee ISO/TC 70, Internal combustion engines.

The

This second edition is a minor revisioncancels and contains only editorial changes. It replaces the first

edition (ISO 8528-12:1997).

The main ), of which it constitutes a minor revision. The changes are as follows:

— adoption into — structure updated according to the current ISO template;
— update of normative references updated;

— deleteprevious Clause 4 and refer to deleted – the symbols based on terms and definitionsused in

ISO 8528-5 now apply;
— division of Clause 7 in sub-clausessplit into subclauses;
removal of — hanging paragraphs inremoved from Clauses 8 and 9;

— modification of values in Table 3 modified based on the values in ISO 8528-5:2022, Table 4.;

— minor editorial changes.
© ISO 2022 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/FDIS 8528-12:2022(E)
A list of all parts in the ISO 8528 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
vi © ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 8528-12:2022(E)
Reciprocating internal combustion engine driven alternating
current generating sets — Part 12: Emergency power supply to
safety services
1 Scope

This document applies to generating sets driven by reciprocating internal -combustion (RIC) engines for

emergency power supply to safety services.

ItThis document applies, for example, to safety equipment in hospitals, high-rise buildings, and public

gathering places etc. This document. It establishes the special requirements for the performance, design

and maintenance of generating sets used in thethese applications referred to abovepreviously and

takingtakes into account the provisions of ISO 8528-1 to ISO 8528-6 and ISO 8528-10.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

ISO 8528--1:2018, Reciprocating internal combustion engine driven alternating current generating sets —

Part 1: ApplicationsApplication, ratings and performance

ISO 8528--2:2018, Reciprocating internal combustion engine driven alternating current generating sets —

Part 2: Engines

ISO 8528--3, Reciprocating internal combustion engine driven alternating current generating sets —

— Part 3: Alternating current generators for generating sets

ISO 8528--4:2005, Reciprocating internal combustion engine driven alternating current generating sets —

Part 4: Controlgear and switchgear

ISO 8528--5:2022, Reciprocating internal combustion engine driven alternating current generating sets —

Part 5: Generating sets

ISO 8528--6:2005, Reciprocating internal combustion engine driven alternating current generating sets —

Part 6: Test methods

ISO 8528-10, Reciprocating internal combustion engine driven alternating current generating sets —

Part 10: Measurement of airborne noise by the enveloping surface method
IEC 60034-1:2017, Rotating electrical machines — Part 1: Rating and performance

IEC 60364-5-56, Low-voltage electrical installations — Part 5-56: Selection and erection of electrical

equipment — Safety services

IEC 60364-IEC 60364-7-710, Low-voltage electrical installations — Part 7-710: Requirements for special

installations and locations — Medical locations
© ISO 2022 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO/FDIS 8528-12:2022(E)

IEC 60601-1, Medical electrical equipment — Part 1: General requirements for basic safety and essential

performance

IEC 60622, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Sealed nickel-

cadmium prismatic rechargeable single cells

IEC 60623, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Vented

nickel-cadmium prismatic rechargeable single cells

IEC 60896--11, Stationary lead-acid batteries — Part 11: Vented types — General requirements and

methods of tests

IEC 60896--21, Stationary lead-acid batteries — Part 21: Valve regulated types — Methods of test

IEC 61951-1, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Secondary

sealed cells and batteries for portable applications — Part 1: Nickel-Cadmium
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 8528-1 to ISO 8528-6 and the

following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
change-overchangeover time
𝒕𝒕
𝐜𝐜𝐜𝐜

time interval from the appearance of a malfunction of the normal electrical power supply system until

the safety services are again connected to the emergency power supply; this connection to the safety

services may be applied in several load steps

Note 1 to entry: This connection to the safety services may be applied in several load steps.

3.2
bridging time
𝒕𝒕
𝐁𝐁

minimum time for which the generating station supplies the consumers with electrical power under pre-

determinedpredetermined operating conditions and which corresponds with the rated operating time as

defined in IEC 60601-1

Note 1 to entry: The bridging time corresponds with the rated operating time as defined in IEC 60601-1.

3.3
safety services

equipment for the safety of persons which is installed and kept prepared in case of failure of the usual

electrical power supply system
2 © ISO 2022 – All rights reserved
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ISO/FDIS 8528-12:2022(E)
3.4
consumer power demand

total of all intended demands of the connected consumers, taking into consideration the actual load steps

3.5
power demand for safety services
required power demand to fulfil the safety service requirements
4 Additional regulations and requirements

If special requirements or additional regulations are to be observed, they shall be stated by the customer

and agreed upon between manufacturer and customer.
5 Classification designation
5.1 General

Classification of generating sets for safety services is based on performance class G2 as defined in

ISO 8528-1 and the required change-overchangeover time, t 𝑡𝑡 ,, according to IEC 60364-5-56 and

Table 1.
Table 1 — Classification by change-overchangeover time
Generating sets noNo break shortShort break longLong break
Change- < 15 s
overChangeover 0 < 0,5 s > 15 s
time
Classification 1 2 3 4
5.2 Typical examples of classification
Typical examples of classification as defined in Table 1 are given in Table 2.
Table 2 — Examples
Classification Typical examples
The mains voltage drops below the rated voltage by more than 10 %.
After a change-overchangeover time of 0 s the power for the consumer power
demand for safety services shall be available. The design of the no-break
generating sets depends on the required frequency and voltage deviations.
The mains voltage drops below the rated voltage by more than 10 %.
After a change-overchangeover time of 0,5 s the power for the consumer power
demand for safety services shall be available. The design of the short-break
generation set depends on the required frequency and voltage deviations.
The mains voltage drops below the rated voltage by more than 10 % for a period
longer than 0,5 s.
© ISO 2022 – All rights reserved 3
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ISO/FDIS 8528-12:2022(E)
After a change-overchangeover time of max.maximum 15 s, power for 100 % of
the consumer power demand for safety services shall be available in steps.
The mains voltage drops below the rated voltage by more than 10 % for a period
longer than 0,5 s.
After a change-overchangeover time of max.maximum 15 s, power for 80 % of the
consumer power demand for safety services shall be available in two steps, and
the power for 100 % of the consumer demand shall be available after an
additional 5 s has passed.
6 Generating set design
6.1 Criteria for determining the required power

To ensure a reliable supply of electrical power by the generating set, the generating set manufacturer

shall be informed of the power requirements of the installations to be supplied.

The power requirements shall include short load peaks when switching in electrical installations (e.g.

lifts, pumps, fans, lighting equipment and non-linearnonlinear electrical installations). Where applicable,

e.g.for example for reasons of redundancy, the use of several generating sets operating in parallel maywill

possibly be required.

Since many modern RIC engines are turbocharged, it will be necessary to arrange load acceptance in

several steps.

For load acceptance, the definitions and values laid down in ISO 8528-5:2022, Clause 8.4, Figure 5 and

Figure 6 apply, where the load acceptance capability of the generating set is shown to be dependent on

the brake mean effective pressure of the RIC engine.

If larger steps are used than those recommended in ISO 8528-5:2022, Figure 5 and Figure 6, either

suitable additional measures shall be taken, or the generating set power rating, and, where applicable,

the rotating mass of the flywheel, shall be increased.

The information provided by the check listchecklist in Clause 13 of this document is suggested as

necessaryrecommended for designing the generating set.

Essential equipment of emergency generating sets, such as a cooling system, a fuel system including

storage tank, and a lubrication system etc., shall be provided to ensure the operation of the generating

set for the required period.
The cooling system of the RIC engine shall be self-contained.
6.2 Power determination

ISO 8528-1:2018, Clauses 13 and 14 appliesapply for determining the power requirement.

6.3 Operating limit values

The operating limits shall at least meet the requirements of performance class G2 as in ISO 8528-5:2022.

Special requirements for the limit values are given in ISO 8528-5:2022, Table 4.

The transient operating limits generally apply asgiven in ISO 8528-5:2022, Table 4 generally apply.

Classifications given in Table 2 are listed in Table 3.
Table 3 — Special requirements for examples given in Table 2
4 © ISO 2022 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/FDIS 8528-12:2022(E)
Classification
Parameter Symbol Unit Reference
1 2 3 4
Frequency ISO 8528-5:2022, AMC
δf δ𝑓𝑓
% AMC ≤ 5 ≤ 4
a a
droop Clause 3.1.26 AMC
Steady-state
ISO 8528-5:2022,
β 𝛽𝛽
frequency % AMC AMC ≤ 1,5 ≤ 0,5
f f
Clause 3.1.23
band
Transient
frequency −
ISO 8528-5:2022,
dyn
deviation % AMC AMC -−10 -−10
Clause 3.2
δ𝑓𝑓
from rated dyn
frequency
Steady-state
ISO 8528-5:2022,
voltage % AMC AMC ≤ ± 2,5 ≤ ± 1
Clause 3.1.28
∆𝑈𝑈
deviation
dyn
Transient
− % +20 +10
ISO 8528-5:2022,
dyn
voltage AMC AMC
Clause 3.2
+ % -−15 -−10
deviation ∆𝑈𝑈
dyn
∆𝑈𝑈
dyn
u ,de
ISO 8528-5:2022,
s Clause 3.2
Voltage t
u ,in
AMC AMC 4 4
recovery time
𝑡𝑡 s ISO 8528-5:2022,
u,de
Clause 3.2
𝑡𝑡
u,in
Unbalanced c c c c
33 33 33 33
IEC 60034-1:2017,
II/
load current 2 N 1
7.2.3 d d b,d d
15 15 15 15
ratio
Total voltage
IEC 60034-1:2017,
k e
harmonic u % AMC AMC – 5
9.11
distortion
NOTE All other values are given in ISO 8528-5.
AMC Agreementagreement between a.c.AC generating set manufacturer and customer.
See also definition in IEC 60034-1:2017, 7.2.3.
For generating sets with ratings above 300 kVA.
For generating sets with ratings below 300 kVA.

This applies also to the voltage between conductors and the neutral conductor under linear and symmetrical loading.

Table 3 (continued)
Classification
Parameter Symbol Unit Reference
1 2 3 4
© ISO 2022 – All rights reserved 5
---------------------- Page: 11 ------------------
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 8528-12
ISO/TC 70
Reciprocating internal combustion
Secretariat: SAC
engine driven alternating current
Voting begins on:
2022-05-26 generating sets —
Voting terminates on:
Part 12:
2022-07-21
Emergency power supply to safety
services
Groupes électrogènes à courant alternatif entraînés par moteurs
alternatifs à combustion interne —
Partie 12: Alimentation électrique de secours de services de sécurité
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 8528-12:2022(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/FDIS 8528-12:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 8528-12:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 S c op e ................................................................................................................................................................................................................................. 1

2 Nor m at i ve r ef er enc e s ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 2

4 Additional regulations and requirements ............................................................................................................................... 2

5 Classification designation ..........................................................................................................................................................................2

5 .1 G ener a l ........................................................................................................................................................................................................... 2

5.2 T ypical examples of classification ......................................................................................................................................... 3

6 G enerating set design .....................................................................................................................................................................................3

6.1 C riteria for determining the required power ............................................................................................................. 3

6 . 2 Power de t er m i n at ion ........................................................................................................................................................................ 4

6.3 O perating limit values ...................................................................................................................................................................... 4

7 A dd it ion a l r e qu i r ement s ............................................................................................................................................................................5

7.1 C haracteristics of batteries and battery charger for auxiliaries and starter ................................. 5

7.2 C ompressed air starter ................................................................................................................................................................... 5

7.3 F uel capacity ............................................................................................................................................................................................. 6

7.4 Vent i l at ion lou ver s .............................................................................................................................................................................. 6

7.5 E lectric power supply ....................................................................................................................................................................... 6

7.6 R obustness against vibrations ................................................................................................................................................. 6

8 C ontrolgear and switchgear ....................................................................................................................................................................7

8 .1 G ener a l ........................................................................................................................................................................................................... 7

8.2 P rotection, measurement, monitoring and control equipment for the AC generator ............. 7

8.2.1 AC generator protection equipment .................................................................................................................. 7

8.2.2 A C generator measurement and monitoring equipment ................................................................ 7

8.3 E ngine measurement and monitoring equipment .................................................................................................. 7

8.4 G enerating set measurement and monitoring equipment ............................................................................... 7

8 . 5 R emot e s i g n a l s ........................................................................................................................................................................................ 7

9 Te s t mo de ..................................................................................................................................................................................................................... 8

9.1 T est operation with synchronization to the mains supply ............................................................................. 8

9.1.1 G ener a l ........................................................................................................................................................................................ 8

9.1.2 Gradual power application without switching ........................................................................................ 8

9.1.3 Gradual power application with switching ................................................................................................ 8

9.1.4 Sudden power application with short time parallel operation ................................................. 8

9.2 W ithout mains synchronization ............................................................................................................................................. 9

10 Te s t i n g............................................................................................................................................................................................................................. 9

10 .1 G ener a l ........................................................................................................................................................................................................... 9

10 . 2 I n s t a l l at ion t e s t s ................................................................................................................................................................................... 9

10 . 3 Per io d ic t e s t s ......................................................................................................................................................................................... 10

11 R at i n g pl at e.............................................................................................................................................................................................................10

12 R e qu i r e d do c u ment at ion .........................................................................................................................................................................10

13 C heck l i s t ....................................................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................12

iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/FDIS 8528-12:2022(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 70, Internal combustion engines.

This second edition cancels and replaces the first edition (ISO 8528-12:1997), of which it constitutes a

minor revision. The changes are as follows:
— structure updated according to the current ISO template;
— normative references updated;
— previous Clause 4 deleted – the symbols used in ISO 8528-5 now apply;
— Clause 7 split into subclauses;
— hanging paragraphs removed from Clauses 8 and 9;
— values in Table 3 modified based on the values in ISO 8528-5:2022, Table 4;
— minor editorial changes.
A list of all parts in the ISO 8528 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 8528-12:2022(E)
Reciprocating internal combustion engine driven
alternating current generating sets —
Part 12:
Emergency power supply to safety services
1 S cope

This document applies to generating sets driven by reciprocating internal combustion (RIC) engines for

emergency power supply to safety services.

This document applies, for example, to safety equipment in hospitals, high-rise buildings and public

gathering places. It establishes the special requirements for the performance, design and maintenance

of generating sets used in these applications referred to previously and takes into account the provisions

of ISO 8528-1 to ISO 8528-6 and ISO 8528-10.
2 Normat ive references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

ISO 8528-1:2018, Reciprocating internal combustion engine driven alternating current generating sets —

Part 1: Application, ratings and performance

ISO 8528-2:2018, Reciprocating internal combustion engine driven alternating current generating sets —

Part 2: Engines

ISO 8528-3, Reciprocating internal combustion engine driven alternating current generating sets — Part

3: Alternating current generators for generating sets

ISO 8528-4:2005, Reciprocating internal combustion engine driven alternating current generating sets —

Part 4: Controlgear and switchgear

ISO 8528-5:2022, Reciprocating internal combustion engine driven alternating current generating sets —

Part 5: Generating sets

ISO 8528-6:2005, Reciprocating internal combustion engine driven alternating current generating sets —

Part 6: Test methods

IEC 60364-7-710, Low-voltage electrical installations — Part 7-710: Requirements for special installations

and locations — Medical locations

IEC 60622, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Sealed

nickel-cadmium prismatic rechargeable single cells

IEC 60623, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Vented

nickel-cadmium prismatic rechargeable single cells

IEC 60896-11, Stationary lead-acid batteries — Part 11: Vented types — General requirements and

methods of tests

IEC 60896-21, Stationary lead-acid batteries — Part 21: Valve regulated types — Methods of test

© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/FDIS 8528-12:2022(E)

IEC 61951-1, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Secondary

sealed cells and batteries for portable applications — Part 1: Nickel-Cadmium
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 8528-1 to ISO 8528-6 and the

following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
changeover time

time interval from the appearance of a malfunction of the normal electrical power supply system until

the safety services are again connected to the emergency power supply

Note 1 to entry: This connection to the safety services may be applied in several load steps.

3.2
bridging time

minimum time for which the generating station supplies the consumers with electrical power under

predetermined operating conditions

Note 1 to entry: The bridging time corresponds with the rated operating time as defined in IEC 60601-1.

3.3
safety services

equipment for the safety of persons which is installed and kept prepared in case of failure of the usual

electrical power supply system
3.4
consumer power demand

total of all intended demands of the connected consumers, taking into consideration the actual load

steps
3.5
power demand for safety services
required power demand to fulfil the safety service requirements
4 A dditional regulations and requirements

If special requirements or additional regulations are to be observed, they shall be stated by the

customer and agreed upon between manufacturer and customer.
5 Classification designation
5.1 General

Classification of generating sets for safety services is based on performance class G2 as defined in

ISO 8528-1 and the required changeover time, t , according to IEC 60364-5-56 and Table 1.

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ISO/FDIS 8528-12:2022(E)
Table 1 — Classification by changeover time
Generating sets No break Short break Long break
Changeover time 0 < 0,5 s < 15 s > 15 s
Classification 1 2 3 4
5.2 Typical examples of classification
Typical examples of classification as defined in Table 1 are given in Table 2.
Table 2 — Examples
Classification Typical examples
The mains voltage drops below the rated voltage by more than 10 %.
After a changeover time of 0 s the power for the consumer power demand for safe-

ty services shall be available. The design of the no-break generating sets depends

on the required frequency and voltage deviations.
The mains voltage drops below the rated voltage by more than 10 %.
After a changeover time of 0,5 s the power for the consumer power demand for
safety services shall be available. The design of the short-break generation set
depends on the required frequency and voltage deviations.
The mains voltage drops below the rated voltage by more than 10 % for a period
longer than 0,5 s.
After a changeover time of maximum 15 s, power for 100 % of the consumer power
demand for safety services shall be available in steps.
The mains voltage drops below the rated voltage by more than 10 % for a period
longer than 0,5 s.
After a changeover time of maximum 15 s, power for 80 % of the consumer power

demand for safety services shall be available in two steps, and the power for 100 %

of the consumer demand shall be available after an additional 5 s has passed.
6 Gener ating set design
6.1 Crit eria for determining the required power

To ensure a reliable supply of electrical power by the generating set, the generating set manufacturer

shall be informed of the power requirements of the installations to be supplied.

The power requirements shall include short load peaks when switching in electrical installations (e.g.

lifts, pumps, fans, lighting equipment and nonlinear electrical installations). Where applicable, for

example for reasons of redundancy, the use of several generating sets operating in parallel will possibly

be required.

Since many modern RIC engines are turbocharged, it will be necessary to arrange load acceptance in

several steps.

For load acceptance, the definitions and values laid down in ISO 8528-5:2022, 8.4, Figure 5 and Figure 6

apply, where the load acceptance capability of the generating set is shown to be dependent on the brake

mean effective pressure of the RIC engine.

If larger steps are used than those recommended in ISO 8528-5:2022, Figure 5 and Figure 6, either

suitable additional measures shall be taken or the generating set power rating and, where applicable,

the rotating mass of the flywheel shall be increased.

The information provided by the checklist in Clause 13 is recommended for designing the generating

set.
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ISO/FDIS 8528-12:2022(E)

Essential equipment of emergency generating sets, such as a cooling system, a fuel system including

storage tank and a lubrication system, shall be provided to ensure the operation of the generating set

for the required period.
The cooling system of the RIC engine shall be self-contained.
6.2 Power determinati on
ISO 8528-1:2018, Clauses 13 and 14 apply for determining the power requirement.
6.3 Oper ating limit values
The operating limits shall at least meet the requirements of per
...