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

ISO 15748-1 applies to the planning, design and configuration of potable water supply systems on ships, stationary or floating marine structures and inland waterway vessels. It specifies the minimum requirements for potable water supply systems to be met in order to protect the potable water and to maintain its quality. ISO 15748-1 also provides hints on components to be used and on laying of the pipelines.

Navires et technologie 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 15748-1
First edition
2002-05-01
Ships and marine technology — Potable
water supply on ships and marine
structures —
Part 1:
Planning and design
Navires et technologie maritime — Approvisionnement en eau potable sur
navires et structures maritimes —
Partie 1: Planification et conception
Reference number
ISO 15748-1:2002(E)
ISO 2002
---------------------- Page: 1 ----------------------
ISO 15748-1:2002(E)
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ii © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
Contents Page

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

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

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

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

4 Capacity requirements..................................................................................................................................5

5 Sanitary requirements...................................................................................................................................5

6 Potable water supply systems .....................................................................................................................6

7 Technical requirements ................................................................................................................................7

8 Pipelines .........................................................................................................................................................7

9 Pipes and pipe dimensions ..........................................................................................................................9

10 Fittings and pipe joints .................................................................................................................................9

11 Fittings............................................................................................................................................................9

12 Protective fittings ........................................................................................................................................10

13 Pumps...........................................................................................................................................................10

14 Potable water tanks.....................................................................................................................................11

15 Potable water heating plants......................................................................................................................13

16 Sterilization of potable water......................................................................................................................16

17 Layout of piping...........................................................................................................................................18

18 Calculation principles .................................................................................................................................21

19 Testing and flushing of pipelines ..............................................................................................................21

Annex A (informative) Explanations........................................................................................................................22

Annex B (informative) Appropriate pipe dimensions ............................................................................................23

Annex C (informative) Inspection and maintenance of filters ..............................................................................25

Bibliography..............................................................................................................................................................26

© ISO 2002 – All rights reserved iii
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ISO 15748-1:2002(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 15748-1 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 and C of this part of ISO 15748 are for information only.
iv © ISO 2002 – All rights reserved
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INTERNATIONAL STANDARD ISO 15748-1:2002(E)
Ships and marine technology — Potable water supply on ships
and marine structures —
Part 1:
Planning and design
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 navigation vessels.

This part of ISO 15748 specifies the minimum requirements for potable water supply systems to be met in order to

protect the potable water and to maintain its quality.
It also provides hints on components to be used and on laying of the pipelines.

NOTE The transfer of potable water and the regulations to be observed are not covered by this part of ISO 15748. The

transfer of potable water is subject to special regulations.
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 7-1, Pipe threads where pressure-tight joints are made on the thread — Part 1: Dimensions, tolerances and

designation
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 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions, tolerances

and designation
ISO 274, Copper tubes of circular section — Dimensions

ISO 426-2, Wrought copper-zinc alloys — Chemical composition and forms of wrought products — Part 2: Leaded

copper-zinc alloys

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

ISO 1635, Wrought copper and copper alloys — Round tubes for general purposes — Mechanical properties

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ISO 15748-1:2002(E)

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 14726-1, Ships and marine technology — Identification colours for the contents of piping systems — Part 1:

Main colours and media

ISO 14726-2 , Ships and marine technology — Identification colours for the contents of piping systems — Part 2:

Additional colours for different media and/or functions

ISO 15748-2, Ships and marine technology — Potable water supply on ships and marine structures — Part 2:

Method of calculation
SOLAS 1974, International Convention for the Safety of Life at Sea, 1974
3 Terms and definitions

For the purposes of this part of ISO 15748, the following terms and definitions apply.

3.1
potable water supply system

system for the generation, treatment, transfer, conveyance, storage, transport and distribution of potable water

3.2
water treatment plant

equipment for treating potable water whilst maintaining potable water properties, e.g. using filters, dosage plants,

ion exchangers, disinfecting plants
3.3
potable water heaters

appliances used to heat potable water without affecting its properties for consumption apart from a change in

temperature, e.g. continuous-flow water heaters, storage heaters
3.4
apparatus

collective term for technical installations making use of and/or transforming potable water

EXAMPLE
 distillation and sterilization apparatus;
 large-scale cooking equipment, dosage plant;
 pressurized water reservoirs, water heaters;

 dishwashers, coffee machines, as well as devices of all kinds forming part of the potable water system or connected

temporarily or permanently to it, except for supply and circulating pumps.
3.5
water
collective term for all types of water used for water supply
1) To be published
2 © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
3.6
raw water
untreated water
NOTE Raw water and sea water are considered equivalent.
3.7
freshwater

water originally intended for human consumption and use on board as potable water but also used for certain

technical purposes and for sanitary-hygienic needs
3.8
potable water

water suitable for human consumption and use in compliance with the quality requirements laid down in the

applicable statutory provisions, defined in this part of ISO 15748 as:
a) water from a central public potable water supply;

b) water converted from sea water by evaporation at temperatures exceeding 80 °C;

c) water converted from sea water by evaporation at temperatures below 80 °C, and which has additionally been

sterilized;
d) water generated by reverse osmosis;
e) hot potable water heated in suitable water heaters.
3.9
cold water
cold potable water at temperatures between 5 °C and 25 °C
NOTE The upper temperature limit may be higher e.g. in the tropics.
3.10
hot water
hot potable water at temperatures between 50 °C and 90 °C, usually up to 60 °C
3.11
mixed water
hot and cold potable water mixed by means of a mixer tap
3.12
potable water line
pipeline exclusively carrying potable water
3.13
supply line
entire potable water pipeline system downstream of the discharge (supply) pump
3.14
water main

section of piping between the discharge pump and the point where the cold water line branches off from the line

leading to the central water heater
3.15
distribution line
section of the supply line downstream of the watermain
3.16
ring line

distribution line providing bidirectional water supply by way of loop-type installation

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ISO 15748-1:2002(E)
3.17
hot-water ring line

distribution line for unidirectional supply only with water circulation by means of a circulating pump to feed back

unused hot water to the water heater
3.18
circulating line

section of the cold/hot-water ring line without dispensing point, via which unused cold water is fed back to the

suction side of the supply pump or unused hot water is fed back to the water heater

3.19
trunk line
riser
vertical section of the supply line branching off from a distribution line
NOTE Deck lines and dispensing lines branch off from trunk lines.
3.20
deck line
section of the supply line branching off from the trunk line within one deck
3.21
service line
single feed line
section of the supply line leading from the deck line to the consumer
3.22
pump discharge line
discharge line downstream of the discharge outlet of a pump
3.23
pump return line
line through which water is fed to the pump
3.24
service fitting/outlet fitting

fitting for shutting off, releasing and controlling the volume flow at the end of a supply line, the outlet side thereof

being in accordance with the service function, e.g. equipment valve, outlet valve, flush valve, mixer tap

3.25
safety fitting

fitting to protect system parts against inadmissible pressure and temperature transgressions, e.g. safety valves

3.26
protective fitting

fitting to protect the water characteristics in the piping system, e.g. vacuum breakers in connection with non-return

valves, pipe disconnectors
3.27
filter
device for extraction of solid matter from potable water
3.28
calculation flow
assumed flow at the service fitting taken as calculation basis:
 
VV=+V 2
Rmin 0
4 © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
where
V is the calculation flow, expressed in litres per second;
V is the minimum flow, expressed in litres per second;
min
V is the peak flow, expressed in litres per second.
3.29
sum flow

sum of the calculation flows for all water-consuming units served via one cross-section

3.30
peak flow

flow decisive for hydraulic calculation, taking into consideration probable simultaneous water withdrawals during

operation
3.31
closed continuous flow heater

water heater resistant to pressure wherein the water is heated whilst passing the heater, with or without storage

3.32
open storage heater

pressureless water heater, heating and storing water in a container which is part of the storage heater

4 Capacity requirements

On ships, marine structures and inland waterway craft, pure potable water shall always be available in sufficient

quantity. The potable water supply system shall be sized and designed accordingly.

Depending on needs, sufficiently sized potable water storage tanks and/or plants for the conversion of sea water to

potable water shall be provided.

Any accommodation areas on ships and marine structures that are not provided with a dispensing facility from a

central potable water supply shall be equipped with a sufficiently sized potable water container.

5 Sanitary requirements
5.1 Potable water

The quality of the potable water shall be such that its consumption and use will not affect human health, particularly

as far as pathogenic microorganisms are concerned; i.e. potable water
 shall be free of pathogenic microorganisms;
 shall be as sterile as possible;

 should be palatable (it shall be colourless, clear, cool, odourless and acceptable with respect to taste);

 may only contain traces of dissolved minerals.

As far as health considerations are concerned, the potable water characteristics shall comply with the potable

water regulations stated by the authorized national governmental bodies.
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ISO 15748-1:2002(E)
5.2 Protection of the potable water, maintenance of the potable water quality

5.2.1 Potable water supply systems shall be fitted with a means of sterilizing water transferred from land-based

facilities or water stored on board for a prolonged period of time.

5.2.2 It is not permissible to connect potable water lines to lines or facilities carrying water which is not potable

(e.g. cooling freshwater lines); there shall be a hygienically reliable separation between these lines, which may be

achieved, e.g.
 by means of a free air line;

 by means of an indirect connection via the storage units (water supply via a free air line);

 by means of a pipe disconnector;
 by means of a back flow preventer.

5.2.3 Potable water dispensing points where a backflow of water is possible shall be secured by means of

protective fittings in accordance with 3.26.

5.2.4 Any material, auxiliary material or protective coating used shall be safe from a hygienic and physiological

point of view, and shall be sufficiently resistant to any physical, chemical or corrosive stress to be anticipated. It

shall not release any substances which may influence the digestibility, taste, smell or colour of the potable water. If

applicable, the coating shall comply with the requirements of national authorities.

Pressurized components shall not be negatively influenced by water temperatures of up to 90 °C. For service

fittings the maximum temperature is 70 °C.

5.2.5 Internal corrosion shall be prevented as far as possible by selecting and using materials that are suitable

for potable water (cold or hot) and that are compatible with each other.

5.2.6 Compressed-air cushions directly contacting the water surface inside the pressurized reservoir shall not

impair the quality of the potable water.

5.2.7 Plastics and other non-metallic materials shall conform to the requirements and recommendations

concerning the suitability of these materials to potable water, stated by the authorized national bodies.

6 Potable water supply systems

A potable water supply system includes all facilities, piping and apparatus serving to transfer, store, treat, transport

or dispense potable water. Also included in this definition are facilities serving to produce potable water, e.g.

distillation from sea water.

If the potable water is conveyed through apparatus and facilities that will impair its alimentary quality as defined by

the regulations, the potable water system terminates at the assigned safety fitting. The following components may

be included in potable water supply systems:
 potable water tanks;
 transfer, operating and service lines;
 pumps;
 pressurized water reservoirs;
 potable water heaters;
6 © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
 potable water treatment plants;
 potable water distillation plants;
 fittings (shut-off, safety, protection and supply or outlet fittings);

 measuring and control devices. Figure 1 shows an example of realization of a potable water supply system.

7 Technical requirements
7.1 Associated regulations

In planning the installation of potable water supply systems, the following regulations and directives shall be

observed:

 rules for classification and construction of seagoing ships stated by the relevant classification society;

 technical rules given by a marine employer's liability insurance (if applicable);

 nationally-stated requirements concerning potable water systems.
7.2 Identification marking

Fittings and appliances shall be marked legibly and permanently with the manufacturer's designation or name in

order to readily provide identification of the product at any time. The marking shall comply with the applicable

regulations.
7.3 Pressure and temperature

7.3.1 For safety reasons all components shall be designed to sustain the same working pressures; this pressure

shall comply with the highest set pressure of a safety valve within the system.

7.3.2 Pressure surges and drops occurring during operation shall not exceed the applicable limits (see

ISO 15748-2). This, and the admissible flow rates, shall be taken into consideration when selecting the fittings.

7.3.3 Temperature increases in cold water pipes shall be prevented by suitable means; see explanations in

annex A.

7.3.4 The water temperature in hot water pipes shall be at least 50 °C; see explanations in annex A.

8 Pipelines
8.1 Air pipes, filling pipes and overflow pipes

For air pipes, filling pipes and overflow pipes see the requirements of the relevant classification society. The filling

connection for drinking water tanks shall be in accordance with ISO 5620-1.
8.2 Sounding pipes

For sanitary reasons, sounding pipes for operational gauging in potable water tanks are not permitted. To check

the level, fluid level gauges or devices for measuring tank contents shall be installed.

© ISO 2002 – All rights reserved 7
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ISO 15748-1:2002(E)
Key 9 Potable water supply pump
1 Accommodation area with showers/W.C. 10 Pressure tank
2 Commissary area 11 Technical load
3 Engine room 12 Pipe disconnector
4 Shower/W.C. 13 Sterilization
5 Filling connection for potable water tanks (see ISO 5620-1) 14 Water heater
6 Potable water generator 15 Heating medium
7 Drinking water tank 16 Cold water circulating pump
8 Sea chest 17 Hot water circulating pump

Figure 1 — Example of a potable water supply system on a ship with four superstructure decks

8 © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
9 Pipes and pipe dimensions

For potable water piping systems the pipes and pipe dimensions given in Tables B.1 to B.3 may be used taking the

installation and operating instructions, and the respective regulations devised by the cognizant authorities into

consideration.
10 Fittings and pipe joints
10.1 Fittings and flanged joints

Taking installation and operating instructions into consideration, the fittings and flanged joints to be selected for the

pipes listed in Tables B.1 to B.3 may be used without special proof of suitability.

10.2 Threaded joints
Whitworth threads shall conform to ISO 7-1.

Threads conforming to ISO 228-1 may only be used if the sealing effect is achieved by a gasket being pressed

between the front face of the bell connection and a collar on the externally threaded section.

10.3 Welded, soldered or bonded joints

10.3.1 Steel pipes may only be welded on condition that the internal protective coating remain undamaged.

Brazed joints on steel pipes are only permissible if they are executed conformant with the instructions issued by the

manufacturer of the solder [the development of hard zinc layers with reduced corrosion resistance in the soldering

area (heat affected zone) shall be pointed out].
10.3.2 Copper tubes shall only be welded if their wall thickness is W 1 mm.

10.3.3 Stainless steel pipes shall be worked in accordance with the manufacturer's recommendations.

10.3.4 For the fabrication of CuNiFe pipes see available national standards or the manufacturer's recommen-

dations.
10.3.5 PVC pipes shall be bonded and shall not be welded.

10.3.6 For welded joints of high-density and low-density polyethylene pipes (PE-HD and PE-LD) see available

national standards or the manufacturer's recommendations.
10.3.7 Brazing and soldering compounds shall not contain lead.
11 Fittings
11.1 General

Sanitary fittings for supply lines shall conform to the requirements of national authorities (if applicable).

11.2 Water-saving fittings

The fittings to be used shall be exclusively of the water-saving kind and, where appropriate, flow restrictors shall be

installed.
© ISO 2002 – All rights reserved 9
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ISO 15748-1:2002(E)
11.3 Non-return valves

Fittings for cold and heated potable water shall have a common outlet only if this outlet cannot be closed or if

crossing over of the warm potable water into the cold water line is prevented by means of adequate functional

parts; these may be approved non-return valves.
11.4 Protection against scalding

To prevent scalding, hot water showers should be fitted with safety devices (e.g. thermostatic mixer taps) limiting

the temperature of the heated water or the mixed water to 45 °C.
11.5 Materials

The following materials may be regarded as safe with respect to sanitary considerations and corrosion resistance.

Other materials may only be used if they are of identical or better quality than the ones listed:

 wrought and cast stainless steels;
 materials such as CuSn10, CuPb5Sn5Zn5 and GKCuZn40Pb;
 materials specified in ISO 426-2, namely CuZn38Pb2.
11.6 Lubricants
Lubricants shall be suitable for potable water supply systems.
12 Protective fittings

Potable water supply systems shall be fitted with approved non-return valves downstream of the supply pump or

water reservoir in order to prevent water from flowing back into the potable water tank.

Only protective fittings carrying the test lable of the national approving authority shall be used (if applicable).

13 Pumps
13.1 Self-priming pumps

Self-priming pumps shall be installed if the potable water tank is located below the installation level of the supply

pump.
13.2 Pump capacity

Dimensioning of the pump capacity shall be such that there is still sufficient flow pressure despite maximum water

consumption (for determination of the peak consumption see 8.3 of ISO 15748-2:—).

For projects with high peak consumption rates (e.g. passenger ships, marine structures) installation of two or more

supply pumps is recommended.
13.3 Circulating pumps

Circulating pumps shall be installed if reasons given in 17.2.7 or in A.2 are to be considered.

10 © ISO 2002 – All rights reserved
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ISO 15748-1:2002(E)
13.4 Filters

Filters shall be installed in the suction line of the supply pump in order to clear the potable water of undissolved

matter. They shall comply with requirements of the national authorities, if available, and shall undergo minimum

maintenance in accordance with annex C.
13.5 Shut-off fittings and pressure gauges

Shut-off fittings and pressure gauges shall be fitted upstream of the intake as well as downstream of the discharge

of the supply pumps.
13.6 Controllable non-return valves

With pumps switched in parallel, these valves shall be furnished on the discharge side.

14 Potable water tanks
14.1 General requirements

Potable water tanks may be a part of the ship's structure with minimum required framing (except double-bottom

tanks, fore-peak and aft-peak tanks) or be installed as separate (inserted) tanks. Tanks, which are part of the ship's

structure shall not have a common bulkhead (ceiling, deck) with tanks destined for other media.

Tanks shall be made of corrosion-resistant steel or shall have an anticorrosive coating. Steel water tanks shall be

protected against corrosion by a galvanic or varnished coating.

Zinc coating shall not have flaws. Surfaces that come into contact with water shall not have even refurbished flaws.

Surfaces shall be free of any residues such as zinc oxide or soldering flux and meet the requirements laid down in

5.2.4.

On sea-going vessels and marine structures, it is recommended that two potable water tanks be installed for good

reliability of the water supply system.

Potable water tanks shall be disposed in the rooms that have no sources of heat emission and dirt. In exceptional

cases if, for technical reasons, it is found impossible to satisfy this requirement, it is admissible to place them in

rooms with heat emission, but then effective action for water protection against heating shall be taken.

Potable water storage tanks shall have tightly closable hand-holes for repair and cleaning.

Hand-holes shall be set and constructed i
...

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