ISO 8861:1998

INTERNATIONAL ISO
STANDARD 8861
Second edition
1998-05-15
Shipbuilding — Engine-room ventilation in
diesel-engined ships — Design
requirements and basis of calculations
Construction navale — Ventilation du compartiment machines des navires à
moteurs diesels — Exigences de conception et bases de calcul
A
Reference number
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.
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 8861 was prepared by Technical Committee
ISO/TC 8, Ships and marine technology, Subcommittee SC 3, Piping and
machinery.
This second edition cancels and replaces the first edition (ISO 8861:1988),
of which it constitutes a technical revision.
Annex A of this International Standard is for information only.
©  ISO 1998
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
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Printed in Switzerland
ii
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INTERNATIONAL STANDARD  ISO ISO 8861:1998(E)
Shipbuilding — Engine-room ventilation in diesel-engined
ships — Design requirements and basis of calculations
1  Scope
This International Standard specifies design requirements and suitable calculation methods for
the ventilation of the engine room in diesel-engined ships, for normal conditions in all waters.
Annex A provides guidance and good practice in the design of ventilation systems for ships'
engine rooms.
NOTE —  Users of this International Standard should note that, while observing the requirements of the
standard, they should at the same time ensure compliance with such statutory requirements, rules and
regulations as may be applicable to the individual ship concerned.
2  Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the editions indicated were
valid. All standards are subject to revision, and parties to agreements based on this Interna-
tional Standard are encouraged to investigate the possibility of applying the most recent
editions of the standards listed below. Members of IEC and ISO maintain registers of currently
valid International Standards.
Quantities and units — Part 1: Space and time
ISO 31-1:1992, .
ISO 31-3:1992, Quantities and units — Part 3: Mechanics.
ISO 31-4:1992, Quantities and units — Part 4: Heat.
Reciprocating internal combustion engines — Performance — Part 1:
ISO 3046-1:1995,
Standard reference conditions, declarations of power, fuel and lubricating oil consumptions, and
test methods
.
ISO 3258:1976, Air distribution and air diffusion — Vocabulary.
3  Definitions
For the purposes of this International Standard, the definitions given below, together with those
in ISO 31-1, ISO 31-3, ISO 31-4, ISO 3046-1 and ISO 3258, apply.
3.1  engine room: Space containing main propulsion machinery, boiler(s), diesel generator(s)
and major electrical machinery, etc.
©
3.2  ventilation: Provision of air to an enclosed space to meet the needs of the occupants
and/or the requirements of the equipment therein.
: The continuous brake power which the engine manufacturer
3.3 service standard power
declares that an engine is capable of delivering, using only the essential dependent auxiliaries,
between the normal maintenance intervals stated by the manufacturer and under the following
conditions:
a) at a stated speed at the ambient and operating conditions of the engine application;
b) with the declared power adjusted or corrected as determined by the manufacturer to the
stated ambient and operating conditions of the engine application;
c) with the maintenance prescribed by the engine manufacturer being carried out.
[ISO 3046-1:1995]
See A.1 in annex A of ISO 3046-1:1995.
4  Design conditions
The outside ambient air temperature shall be taken as + 35 °C.
Temperature rise from air intake to air passing from the engine room up to the casing entrance
shall be max. 12,5 K.
The capacity of the ventilation plant should be such as to provide comfortable working
conditions in the engine room, to supply the necessary combustion air to the diesel engine(s)
and boiler(s), and to prevent heat-sensitive apparatus from overheating.
In order to meet these requirements, the air should be distributed to all parts of the engine
room, so that pockets of stagnant hot air are avoided. Special considerations should be given to
areas with great heat emission and to all normal working areas, where reasonably fresh and
clean outdoor air should be provided through adjustable inlet devices.
When arranging the air distribution, all normal conditions at sea and in harbour for in-service
machinery shall be taken into account.
5  Airflow calculation
5.1  Total airflow
The total airflow Q to the engine room shall be at least the larger value of the two following
calculations.
Q q q
a: = + as calculated according to 5.2 and 5.3 respectively.
c h
Q q
b: = 1,5 x , i.e. the airflow for combustion + 50 %. The total airflow to the engine room
c
shall not be less than the airflow for combustion [engine(s) and boiler(s)] plus 50 %.
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ISO ISO 8861:1998(E)
Combustion air to, and heat emission from, all equipment installed within the casing and funnel
shall not be taken into account.
The calculations shall be based on simultaneous maximum rating of main propulsion diesel
engine(s), diesel generator engine(s), boiler(s) and other machinery under normal sea
conditions, and on a temperature increase of 12,5 K.
The calculations should, to the greatest possible extent, be based on information from the
manufacturers. Guidance values given in this International Standard should be used only when
manufacturers' information is not available.
In order to ensure satisfactory air distribution, combustion air to, and heat emission from, main
propulsion diesel engine(s), diesel generator engine(s), generator(s), boiler(s), and possibly
other machinery with considerable heat emission, shall be calculated separately including other
conditions as necessary.
Spaces separated from the main engine room, such as individual auxiliary engine rooms, boiler
rooms and separator rooms, shall also be calculated separately.
5.2  Airflow for combustion
5.2.1  Sum of airflow for combustion
q
The sum of the airflow for combustion, , shall be calculated, in cubic metres per second, as
c
follows:
q = q + q + q
c dp dg b
where
q
is the airflow for combustion for main propulsion diesel engine(s), in cubic metres
dp
per second (see 5.2.2);
q is the airflow for combustion for diesel generator engine(s), in cubic metres per
dg
second (see 5.2.3);
q is the airflow for combustion for boiler(s), in cubic metres per second (see 5.2.4), if
b
relevant under normal sea conditions.
5.2.2  Airflow for combustion for main propulsion diesel engine(s)
The airflow for combustion for the main propulsion diesel engine(s), q , shall be calculated, in
dp
cubic metres per second, as follows:
×
m
P ad
dp
q =
dp
r
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where
P is the service standard power of the main propulsion diesel engine(s) at maximum
dp
continuous power output, in kilowatts;
m
is the air requirement for combustion for diesel engine(s), in kilograms per kilowatt
ad
second;
NOTE —  Where specific data for m are not available, the following values may be used for
ad
calculation:
m = 0,002 3 kg/(kW�s) for 2-stroke engines,
ad
0,002 0 kg/(kW�s) for 4-stroke engines.
r = 1,13 kg/m (i.e. the density of air, at + 35 °C, 70 RH and 101,3 kPa).
5.2.3  Airflow for combustion for diesel generator engine(s)
The airflow for combustion for diesel generator engine(s), q , shall be calculated, in cubic
dg
metres per second, as follows:
×
m
P ad
dg
q =
dg
r
where
P is the service standard power of the diesel generator engine(s) at maximum power
dg
output, in kilowatts;
m
is the air requirement for diesel engine combustion, in kilograms per kilowatt second;
ad
m
NOTE —  Where specific data for are not available, the following values may be used for
ad
calculation:
m = 0,002 3 kg/(kW�s) for 2-stroke engines,
ad
0,002 0 kg/(kW�s) for 4-stroke engines.
r = 1,13 kg/m (i.e. the density of air, at + 35 °C, 70 % RH and 101,3 kPa).
5.2.4  Airflow for combustion for boilers and thermal fluid heaters
q
The airflow for combustion for boiler(s), , shall be calculated, in cubic metres per second, as
b
follows:
In a case where the total steam capacity of a boiler is known, the following formula is used:
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ISO ISO 8861:1998(E)
××
mm m
sfs af
q =
b
r
In a case where the capacity of a boiler or a thermal fluid heater is known in kilowatts, the
following formula is used:
Q××
mm
fs af
q =
b
r
where
Q is the maximum continuous rating of the boiler(s), in kilowatts;
m is the total steam capacity (maximum continuous rating) of the boiler(s), in kilograms
s
per second;
m
is the fuel
...