Ships and marine technology -- Potable water supply on ships and marine structures

ISO 15748-2 applies to the planning, design and configuration of potable water supply systems on ships, stationary or floating marine structures and inland waterway crafts. It serves to determine the quantity of potable water to be carried on board, the capacity of the pressurized reservoirs and water heaters, the pumping capacity, etc.

Navires et techmologie maritime -- Approvisionnement en eau potable sur navires et structures maritimes

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Status
Published
Publication Date
29-May-2002
Current Stage
6060 - International Standard published
Start Date
27-Mar-2002
Completion Date
30-May-2002
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INTERNATIONAL ISO
STANDARD 15748-2
First edition
2002-05-01
Ships and marine technology — Potable
water supply on ships and marine
structures —
Part 2:
Method of calculation
Navires et technologie maritime — Approvisionnement en eau potable sur
navires et structures maritimes —
Partie 2: Méthode de calcul
Reference number
ISO 15748-2:2002(E)
ISO 2002
---------------------- Page: 1 ----------------------
ISO 15748-2:2002(E)
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© ISO 2002

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ii © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
Contents Page

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

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

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

3 Potable water consumption..........................................................................................................................2

4 Potable water storage ...................................................................................................................................2

5 Determination and sizing of system components .....................................................................................2

6 Flow rates .......................................................................................................................................................3

7 Supply pressure.............................................................................................................................................3

8 Generation and maintenance of pressure...................................................................................................3

9 Pipe diameters of distribution lines.............................................................................................................4

10 Hot water requirements.................................................................................................................................5

11 Water heaters .................................................................................................................................................5

12 Circulation lines and circulating pumps .....................................................................................................6

13 Calculation example......................................................................................................................................6

Annex A (informative) Tables and figures with useful information .......................................................................7

Annex B (informative) Form sheets for calculation...............................................................................................18

Annex C (informative) Calculation example ...........................................................................................................22

Annex D (informative) Information concerning the installation of sanitary facilities ........................................38

© ISO 2002 – All rights reserved iii
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ISO 15748-2:2002(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.

The main task of technical committees is to prepare International Standards. 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.

Attention is drawn to the possibility that some of the elements of this part of ISO 15748 may be the subject of

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

ISO 15748-2 was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee SC 3,

Piping and machinery.

ISO 15748 consists of the following parts, under the general title Ships and marine technology — Potable water

supply on ships and marine structures:
— Part 1: Planning and design
— Part 2: Method of calculation
Annexes A, B, C and D of this part of ISO 15748 are for information only.
iv © ISO 2002 – All rights reserved
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INTERNATIONAL STANDARD ISO 15748-2:2002(E)
Ships and marine technology — Potable water supply on ships
and marine structures —
Part 2:
Method of calculation
1 Scope

This part of ISO 15748 applies to the planning, design and configuration of potable water supply systems on ships,

stationary or floating marine structures and inland waterway crafts.

This part of ISO 15748 serves to determine the quantity of potable water to be carried on board, the capacity of the

pressurized reservoirs and water heaters, the pumping capacity, etc.

NOTE In accordance with ISO 15748-1 plastic pipes are permitted but are rarely used at present due to the restrictive

conditions laid down by the classification societies. Pressure losses in plastic pipes have not yet been included in ISO 15748

owing to their limited applicability.
2 Normative references

The following normative documents contain provisions which, through reference in this text, constitute provisions of

this part of ISO 15748. For dated references, subsequent amendments to, or revisions of, any of these publications

do not apply. However, parties to agreements based on this part of ISO 15748 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 65, Carbon steel tubes suitable for screwing in accordance with ISO 7-1

ISO 161-1, Thermoplastics pipes for the conveyance of fluids — Nominal outside diameters and nominal

pressures — Part 1: Metric series
ISO 274, Copper tubes of circular section — Dimensions

ISO 1127, Stainless steel tubes — Dimensions, tolerances and conventional masses per unit length

ISO 4200, Plain end steel tubes, welded and seamless — General tables of dimensions and masses per unit

length

ISO 5620-1, Shipbuilding and marine structures — Filling connection for drinking water tanks — Part 1: General

requirements

ISO 15748-1, Ships and marine technology — Potable water supply on ships and marine structures — Part 1:

Planning and design
© ISO 2002 – All rights reserved 1
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ISO 15748-2:2002(E)
3 Potable water consumption
3.1 General

The consumption of potable water depends on the type of ship, underway time (time the crew and passengers are

embarked), number of potable water dispensing and supply points and the cruising area.

Rough calculations of the daily potable water requirements should be based on the guide values in Table A.1.

Determination of potable water consumption with respect to the planned/existing dispensing points should be

based on the guide values in Table A.2 for cargo ships and in Table A.3 for passenger ships.

3.2 Potable water requirements of technical equipment

The quantity of potable water required by other technical facilities including air conditioning equipment/plants for air

humidification is to be taken from the information supplied by the manufacturer of the respective facility and added

to the potable water consumption determined in accordance with 3.1.
3.3 Potable water consumption of commissary equipment

The following guide values for water consumption have been determined; detailed values shall be supplied by the

manufacturer. The determined quantity shall be added to the values determined in accordance with 3.1.

 garbage grinders for food disposal = 20 l/min
 dishwashing machines = 3 l/rack up to 8 l/rack
 coffee and tea machines = 18 l/h to 120 l/h
 vegetable peeling and cleaning machines = 5 l/filling
 washing machines = 25 l/kg dry laundry
4 Potable water storage

Potable water storage and potable water distilling plants shall be provided in consultation with the contractor.

5 Determination and sizing of system components
The sizes of system components shall be determined taking into account:
 the pipe material to be used;

 the configuration of the potable water installations (pipelines, fittings, service devices);

 the calculation plans for cold water, hot water and circulation lines.

The sizing of components is calculated based on to the expected volume flow at the time of the maximum water

comsumption = peak flow.

The values and information required for the calculations are listed in Tables A.4 to A.11 and in Figures A.1 to A.4.

The use of the forms supplied in annex B has proved helpful for the calculation process.

2 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
6 Flow rates

In order to prevent flow noises and pressure surges, flow rate limitations should be considered.

NOTE Two examples of flow rate limitation are given below.
Example 1
 2,5 m/s in engine rooms and machinery trunks;
 2,0 m/s in commissary spaces;
 1,4 m/s in accommodation decks;
 1,0 m/s in the hospital and close vicinity;
 1,0 m/s in pump suction lines;
 0,5 m/s in circulating lines.
Example 2
 2,5 m/s for CuNi pipes with DN u 65 (delivery);
 2,0 m/s for CuNi pipes with DN 50 and steel pipes with DN u 65 (delivery);

 1,4 m/s for CuNi pipes with DN u 25 and steel pipes with DN u 32 (delivery); any material pipe with DN u 65

(suction);

 1,0 m/s for pipes with DN u 15 (delivery); any material pipe with DN u 32 (suction);

 0,7 m/s for any material pipe with DN u 15 (suction).
7 Supply pressure

The minimum system supply pressure (pump, water reservoir) is determined by adding the pressure losses due to:

 geodetic differences in altitude;
 pressure losses in the apparati;
 pressure losses from pipe friction and individual resistances;

 minimum flow pressure of 1,5 bar or, following greater demands at the highest dispensing point, plus 10 %.

The pressure losses at the suction side shall be taken into consideration.
8 Generation and maintenance of pressure
8.1 General

Potable water may either be supplied directly, or indirectly, via pressurized water reservoirs. Direct supply is

appropriate if large quantities of potable water per hour are consumed, e.g. on passenger ships. In all other cases

mostly pressurized water reservoirs are used.

The decision as to which method of potable water supply is suitable depends on the peak demand for potable

water and is also influenced by the arrangement, space requirements, weight etc. of the components or component

groups within the entire supply system.
© ISO 2002 – All rights reserved 3
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ISO 15748-2:2002(E)

The limit for deciding between pressurized water reservoirs of direct pump supply lies between 30 m /h and

40 m /h.
Minimum supply pressure in accordance with clause 7 shall be ensured.
The design temperature for the system is 10 °C.
8.2 Pressurized water reservoirs

In order to keep the available quantity of water, i.e. the quantity between pump cut-ins and cut-offs, as great as

possible, and to prevent frequent switchings of the pump, the water stored in the pressurized reservoirs is

sufficiently pre-compressed with air.

This pre-compression shall be 0,3 bar less than the pump cut-in pressure. The pressure difference between cut-in

and cut-off pressure shall be between 1 bar and 2 bar.
−1 −1

The switching frequency is usually between 6 and 8 switching events h ; however, 12 switching events h shall

not be exceeded.

The required reservoir capacity is to be determined in accordance with Figure A.4.

8.3 Supply pumps
8.3.1 General

The capacity of centrifugal pumps shall be such that when the cut-off pressure is reached the capacity corresponds

to 110 % of the calculated maximum consumption (10 % margin). Reciprocating pumps shall be dimensioned for

120 % to 130 % of the maximum consumption rate determined.

Pumps with flat characteristic curves shall be selected. If several pumps are used, the cut-in and cut-off pressures

of each pump shall be stepped with respect to each other, e.g. 4 bar, 3,5 bar, 3 bar.

Provisions shall be made for quantities of water supplied from continuous-action pumps but remaining unused to

be fed back to the potable water reservoirs.
8.3.2 Pump suction lines

The guide values listed in Table A.4 are valid for steel pipes and do not include losses caused by pipe elbows,

fittings, etc. These losses shall be taken into consideration.
8.3.3 Pump discharge lines

The pump discharge line connects the supply pump with the water reservoir via a shut-off fitting. The nominal width

shall be determined in accordance with Table A.5.
9 Pipe diameters of distribution lines
The pipe diameters shall be determined as follows:

 ascertain the calculation flow at service points of pipe sections (for guide values see Table A.12);

 determine the sum flows for these pipe sections and allocate to the pipes;
 determine the peak flow for these pipe sections in accordance with Figure A.3;

 determine pipe diameters and pressure losses provisionally with the help of Figure A.1; if pressure losses are

too high, larger diameters shall be selected;
4 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)

by means of a more simple procedure by determining nominal widths from Table A.11 on the basis of the

respective maximum flows.
10 Hot water requirements

The volume of hot water to be provided or to be kept in store shall be determined from the peak demand for mixed

water using the following equations:
VV=+V (1)
MC H
H tt−
= (2)
Ct −t
VH=× (3)
HC+
where
V is the mixed water volume;
V is the cold water volume;
V is the hot water volume;
C is the cold water portion;
H is the hot water portion;
t is the mixed water temperature;
t is the cold water temperature;
t is the hot water temperature.
11 Water heaters
11.1 Determination of the necessary water heater volume
a) Continuous-flow water heaters
They shall be sized with respect to the peak demand for hot water.
b) Storage heaters

The size of storage heaters shall be selected so that the peak demand for hot water:

 on passenger ships can be heated in 4 h;
 on other ships can be heated in 2 h.

An additional heating facility which may be required for emergency use or during docking may be smaller in

capacity. For passenger ships, it is recommended that the necessary hot water volume be divided between two or

more water heaters.
The supply of hot water shall also be ensured in port.
© ISO 2002 – All rights reserved 5
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ISO 15748-2:2002(E)
11.2 Guide values for water heater volumes

Guide values for necessary water heater volume (depending on the load/number of persons), heating power and

additional heating are listed in Table A.6.
12 Circulation lines and circulating pumps
12.1 Determination of nominal widths

The nominal widths of circulating lines depend on the nominal widths of the water supply lines. The respective

guide values are listed in Table A.7.

For systems including several circulating lines, installation of restriction fittings in the direction of flow upstream of

the shut-off fitting is recommended.
12.2 Determination of pump delivery flow

The pump delivery flow V required is determined from the total volume V of the water supply and circulating

tot

lines (not including the storage reservoir or water heater capacities) and the number of water circulations per hour

according to the following equation:
Vn=×V (4)
UP tot
where
V is the pump delivery flow, in litres per hour;
n is the number of circulations per hour;

V is the total volume of water supply and circulating lines, expressed in litres.

tot

Circulating the hot water three times per hour is enough to prevent excessive cooling of the water. For the volume

of water per meter of pipe see Tables A.8 to A.10.
12.3 Determining the head of the pump

The head of the pump required, H , is determined from the sum of the pressure losses due to pipe friction and

individual resistances in the longest circulation section plus 40 %.

The slight pressure losses due to the circulation flow through the water distributing lines and risers may be

neglected in determining the head of a pump, H .
12.4 Selection of pumps

Once the pump delivery and the required head, H , have been determined, the adequate size of the pump shall

be selected with the help of the pump diagram, which shall be supplied by the manufacturer.

If the operating point determined is between two pump-performance characteristics curves (P1 and P2 see

Figure A.2), selection of the smaller pump is recommended for economic reasons.
13 Calculation example

A calculation example for the application of this part of ISO 15748 including tables and figures shown in annex A

and the sheets shown in annex B, is given in annex C.
6 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
Annex A
(informative)
Tables and figures with useful information

Table A.1 — Guide values for potable water consumption in litre per person/bed and day

Type of ship Group of persons Water consumption when fitted with
embarked
Flushing toilet Vacuum toilet
system system
Seagoing ship Cargo ship Crew/bed 220 l 175 l
Passenger ship Passenger/bed 270 l 225 l
Luxury liner Passenger/bed — 275 l
a a
Ferryboat with cabins Passenger/bed 205 l 160 l
Passenger without bed 100 l 55 l
Ferryboat without cabins Passenger without bed 150 l 105 l
Crew without bed 100 l 55 l
Inland waterway craft Cargo ship Crew/bed Minimum 150 l
Passenger ship with cabins Passenger/crew/bed 220 l 175 l
Passenger ship without Crew/passenger 100 l
cabins
Special-purpose ship Research ship per bed 220 l 175 l
Federal armed forces tender Crew/bed 160 l 110 l
and larger
Federal armed forces – Crew/bed 100 l 55 l
smaller than tender
Fishing vessel Crew/bed Minimum 150 l
Offshore Crew/bed 350 l
No shipboard laundry.
© ISO 2002 – All rights reserved 7
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ISO 15748-2:2002(E)
Table A.2 — Guide values for cargo ships water consumption
at different service points per person and day
Consumption
Service point Frequency of use Consumption
per use
Total quantity of water Cold water Hot water
l per day
l/day l/day l/day
Wall-hung/pedestal 2 6 × 12 5 7
wash basin
Shower base 60 2 × 120 50 70
Flushing W.C. 10 6 × 60 60 —
Vacuum W.C. 1,2 6 × 8 8 —
b c c
Urinal 3 5 × 15 15 —
Galley area — — 20 8 12
b d
Laundry — — 38 15 23
Cleaning — — 5 2 3
At a hot water inlet temperature of 60 °C.

If non-potable water is used the consumption of potable water decreases accordingly.

The use of the urinals reduces the use of the WCs.
Consumption of appliances with hot water connections.
Table A.3 — Guide values for passenger ships water consumption
at different service points per person and day
Consumption Frequency of
Service point Consumption
per use use
Total quantity of
Cold water
Hot water
water
l per day l/day l/day l/day
Wall-hung/pedestal wash basin 2,5 8 × 20 8 12
Shower base 60 2 × 120 50 70
Bath tub 150 1 × 150 60 90
Flushing W.C. 10 6 × 60 60 —
Vacuum W.C. 1,2 6 × 8 8 —
b c c
Urinal 3 5 × 15 15 —
Galley dining rooms — — 25 10 15
Laundry — — 75 to 100 30 to 40 45 to 60
Cleaning — — 20 8 12
Shower and swimming pool — — 10 — —
Fresh water for swimming pool — — 10 — —
Whirlpool — — 60 — —
Sauna 60 1 × 60 — —
At a hot water inlet temperature of 60 °C.

If non-potable water is used the consumption of potable water decreases accordingly.

The use of the urinals reduces the use of the WCs.
If bath tubs and showers are provided, one use per day shall be anticipated.
Additional quantity of water per user and day.
8 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
Table A.4 — Pump suction lines, nominal widths and maximum pipe lengths
l/s 0,5 0,67 0,83 1,0 1,2 1,3 1,5 1,8 2,1 2,8 4,2 5,5 7,0 8,3
Pump delivery
flow
m/h 1,8 2,4 3,0 3,6 4,2 4,8 5,4 6,6 7,5 10 15 20 25 30
Nominal width DN 25 32 40 50 65 80 100
Suction lift m Length of pipe line (m)
0 120 80 105 80 210 140 280 210 140 120 130 100 120 105
1 100 70 90 70 180 120 240 180 120 100 110 85 95 90
2 85 55 75 55 150 100 200 150 100 85 90 70 75 70
3 70 45 60 45 120 80 160 120 80 75 70 60 55 45
Table A.5 — Pump pressure lines, nominal widths
l/s 0,5 0,67 0,83 1,0 1,2 1,3 1,5 1,8 2,1 2,8 4,2 5,5 7,0 8,3
Pump delivery
flow
m/h 1,8 2,4 3,0 3,6 4,2 4,8 5,4 6,6 7,5 10 15 20 25 30
Nominal DN width 20 25 32 40 50 65 80

Table A.6 — Guide values for water heater volumes, heating power and additional heating

Heating-up time Additional
Number of Water heater Heating Quantity in l of mixed water
from heating
persons volume power of 40 °C to be produced in
10 °C to 65 °C power
l kW min 1 h 2 h kW
1 to 10 200 15 51 660 1 030 8
300 10 115 680 930 5
11 to 20 400 30 51 1 320 2 060 15
650 20 125 1 440 1 940 10
21 to 30 650 40 62 1 940 2 920 20
1 000 20 192 1 960 2 450 10
31 to 50 1 000 40 96 2 450 3 440 20
1 500 25 230 2 820 3 440 13
51 to 75 1 000 80 48 3 440 5 400 40
1 500 60 96 3 680 5 160 30
2 000 40 192 3 930 4 910 20
76 to 100 2 000 80 96 4 910 6 880 40
3 000 40 288 5 400 6 380 20
101 to 150 3 000 100 115 6 880 9 330 50
5 000 40 480 8 350 9 330 20
151 to 200 3 000 160 72 8 350 12 280 60
5 000 100 192 9 820 12 280 50
201 to 300 5 000 200 96 12 280 17 200 60
7 000 150 179 14 000 17 690 50
301 to 500 7 000 300 90 17 690 25 060 70
10 000 200 192 19 650 24 570 60
501 to 700 7 000 400 67 20 140 29 970 80
10 000 300 128 22 110 29 480 70
701 to 1 000 10 000 550 70 28 250 41 770 100

NOTE 1 As a rule, single water heaters with more than 3 000 l capacity are not used. For greater hot water demands, two or more water

heaters of appropriate size, or continuous-flow heaters are provided.
NOTE 2 For every size of number of persons two possible decisions are shown.

NOTE 3 The column “Additional heating power” takes into consideration the hot water supply to be ensured in port (see 11.1).

© ISO 2002 – All rights reserved 9
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ISO 15748-2:2002(E)
Table A.7 — Guide values for nominal widths of circulating lines
Water supply line nominal width DN Circulating line nominal width DN
12 12
15 12
20 12
25 12
32 12
40 20
50 20
65 25
80 25
100 32

NOTE The value given in Tables A.8 to A.10 are valid for those pipes included in ISO 15748-1.

Table A.8 — Water volume in steel pipes
Water volume in l/m in
Nominal
Stainless steel
width
Unalloyed steel pipes in accordance with pipes in
accordance with
ISO 65 ISO 4200 ISO 1127
DN Medium series Heavy series Seamless Welded
0,030 0,019 — — —
0,061 0,047 — — —
10 0,123 0,102 0,145 0,145 0,154
12 — — — — —
15 0,201 0,172 0,235 0,235 0,257
0,366 0,327 0,391 0,412 0,441
25 0,581 0,515 0,638 0,693 0,731
32 1,012 0,924 1,087 1,122 1,207
40 1,372 1,269 1,459 1,500 1,598
2,206 2,067 2,333 2,437 2,561
65 3,718 3,536 3,882 3,948 4,015
80 5,128 4,927 5,346 5,434 5,581
100 8,709 8,413 9,009 9,144 9,348
10 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
Table A.9 — Water volume in copper pipes
Water volume in l/m in pipes of
Nominal width
SF-Cu in accordance with CuNiFe dimensions in accordance with
ISO 274 ISO 274
6 0,028 0,050
8 0,038 0,079
10 0,064 —
12 0,133 0,154
0,227 0,254
20 0,380 0,380
25 0,531 0,573
0,908 0,962
1,195 1,353
50 1,963 2,290
65 4,077 4,072
80 5,668 5,675
100 8,332 8,332
Table A.10 — Water volume in plastic pipes
Water volume in l/m in
Nominal
Polybutene Polypropylene
width
Polyethylene pipes Polyvinylchlorid pipes
pipes pipes
PB PE-LD PE-HD PE-X PP PVC-C PVC-U
DN Outside diameters in accordance with ISO 161-1
0,032 0,028 0,032 0,032 0,028 0,045 —
0,055 0,050 0,055 0,055 0,072 0,066 0,079
10 0,121 0,088 0,121 0,106 0,113 0,121 0,145
12 — 0,137 — 0,163 0,177 0,186 —
15 0,206 0,216 0,201 0,254 — 0,296 0,227
0,327 0,353 0,327 0,423 0,290 0,483 0,353
25 0,531 0,556 0,531 0,661 0,452 0,755 0,581
32 0,835 0,866 0,835 1,029 1,122 1,182 1,018
40 1,307 1,385 1,307 1,633 1,590 1,886 1,425
2,075 1,963 2,075 2,324 2,290 2,697 2,256
63 4,254 4,208 2,942 3,339 3,421 3,848 3,610
80 6,362 5,437 4,254 5,001 5,542 5,728 5,204
100 8,203 — 8,203 8,107 9,161 9,297 7,760

To facilitate the decision as to appropriate nominal widths of pipes, Table A.11 lists nominal pipe widths and

respective pressure differential R as functions of flow rates for selected peak flows . This interdependence of the

individual factors is based on the diagram presented in Figure A.1.
© ISO 2002 – All rights reserved 11
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ISO 15748-2:2002(E)
a e
Peak flow, V , in l/s Hospital and close vicinity
b f
Internal pipe diameter, d , in mm Accommodation data
c g
Pressure differential, R (the pressure differences include Commissary spaces
losses in elbows, branches, valves, etc.) h
Machinery spaces and trunk
Flow rate, v, in m/s

Figure A.1 — Nomogram for determination of nominal pipe widths and pressure differentials for given peak

flows and flow rates for copper and stainless steel pipelines
12 © ISO 2002 – All rights reserved
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ISO 15748-2:2002(E)
The values listed in Table 11 are rounded up/down.

Table A.11 — Peak flows, nominal widths, pressure differentials for copper and stainless steel pipelines

Peak flow Flow rate v
V m/s
1 1,4 2 2,5
Nominal Pressure Nominal Pressure Nominal Pressure Nominal Pressure
width differential width differential width differential width differential
l/s
R R R R
DN mbar/m DN mbar/m DN mbar/m DN mbar/m
0,2 15 20,0 12 50 10 125 10 220
0,3 20 14,0 15 36 12 95 12 170
0,45 25 11,0 20 27 15 70 15 130
0,7 32 8,0 25 20 20 52 20 95
1,0 40 6,0 32 15 25 40 25 75
1,5 40/50 4,8 40 11,5 32 30 32 55
2,25 50 3,5 50 8,6 40 23 32 42
3,5 65 2,6 65 6,5 50 16,5 40 30
5,25 80 1,9 65 4,7 65 12 50 23
8,0 100 1,5 80 3,7 65 9,5 65 17

NOTE The pressure differentials mentioned include losses occurring at elbows, branchings, valves, etc. Pressure differentials due to

pipe friction are only very small over a temperature range of up to 60 °C; this alteration of the pressure differential is negligible.

© ISO 2002 – All rights reserved 13
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ISO 15748-2:2002(E)

Table A.12 — Guide values for minimum flow pressures and calculation flow of standard potable water

service points

Minimum flow Type of potable water service point Calculation flow for withdrawal of

pressure
Mixed water Cold or heated
potable water only
  
V V V
minFl R R R
bar cold warm l/s
l/s l/s
Output valves
0,5 — — 0,30
without bubbler ...............
...

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