ISO TC 20/SC 14

Date:   2002-06-15

ISO DAMD 15389-A

ISO TC 20/SC 14/WG 3

Secretariat:   ANSI

### Space systems -- Flight to ground umbilical {#space-systems-flight-to-ground-umbilical .unnumbered}

AMENDMENT 1: Add Annex A

**Prevention of accidental cross - connection**

###### *Systymes spatiaux -- Ombilicaux bord-sol* {#systymes-spatiaux-ombilicaux-bord-sol .unnumbered}

*AMENDEMENT 1:*

Warning

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######## Contents Page

**Foreword
.............................................................................................................................
iv**

######## A.1 Scope ...................................................................................................\..................... 17

######## A.2 Terms and definitions ................................................................................................. 17

######### A.3 General requirements ................................................................................................. 18

######### A.4 Design requirements ................................................................................................... 18

**A.5 Marking requirements
.................................................................................................
19**

**A.6 Verification
................................................................................................................
21**

####### Table. A.1 Marking colours .......................................................................................\............\... 20

Foreword

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federation of national standards bodies (ISO member bodies). The work of
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Commission (IEC) on all matters of electrotechnical standardization.

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ISO NWIP 14 N 244 was prepared by Technical Committee ISO/TC 20,
*Aircraft and space vehicles*, Subcommittee SC 14, *Space systems and
operations*.

Space systems -- Flight to ground umbilicals

##### AMENDMENT 1: Add Annex A {#amendment-1-add-annex-a .unnumbered}

*Page 16*

*Add the following Annex A*

####### ANNEX A

**(normative)**

**Prevention of accidental cross connection**

**A.1 Scope**

This annex establishes the requirements for umbilicals, connectors, and
couplings located on the same plate to prevent an accidental cross
connection. There are two groups of requirements: design and symbolic.
The design requirements provide the distinctive characteristics of
elements for attaching connectors (threaded connections, flanges, etc.).
The symbolic requirements provide presence of distinctive marking
connectors and couplings (pipelines, cables) by symbols or colour.

Due to launch vehicle and spacecraft assembly specific features,
arrangement of many connectors and couplings in close proximity from
each other is required. During assembly, test, and operation, connectors
and couplings should not to be in a zone of simultaneous service. All
connectors and couplings in this zone shall have a very different design
and be marked to exclude a random error joint.

The accidental cross connection of service lines can result in very
serious and even tragic consequences. For example:

-   supplying other gas or fluids;

-   supplying gas or fluid under other pressure;

-   supplying the electric power with other parameters;

-   supplying an error signal (command).

Therefore, differences in design of connectors and couplings that are
located close to each other should be significant. Such differences can
be both in a design and in marking for identification.

International cooperation in space engineering assumes international
cooperation in designing, manufacturing, and operation. The application
of uniform methods will increase the reliability of space systems by
minimizing the accidental cross connection of connectors and couplings.
The application of unified symbols will promote mutual understanding and
personnel training.

This annex applies to umbilical assemblies connected to pipelines and
equipment cables at a launch complex or to the launch vehicle or
spacecraft. This annex can be used by those participating in the
creation, renovation, modernization, and operation of launch complexes.

**A.2 Terms and definitions**

**A.2.1 factory tests**

refer to ISO 17400:2000

**A.2.2** **flanged connection**

connection, at which halves of electrical or hydraulic connectors are
docked by means of flanges, available on bodies of their halves

**A.2.3 field tests**

refer to ISO 17400:2000

**A.2.4 nipple**

half a hydraulic or gas coupling with an external sealing surface

**A.2.5 threaded connection**

connection, at which halves of electrical or hydraulic connectors are
docked by means of a thread available on bodies of their halves

**A.2.6 union**

half a hydraulic or gas coupling with an internal sealing surface

**A.3 General requirements**

Electrical, and fluid couplings located on a single umbilical carrier
plate ( or carrier) should be designed to prevent the accidental cross
connection of incorrect coupling halves.

This requirement may be implemented through one of the following ways:

a)  usage of a different design;

b)  application of distinctive marking.

The simultaneous use of both methods is recommended.

## A.4 Design requirements {#a.4-design-requirements .unnumbered}

**A.4.1 Threaded connections**

The electrical and fluid connectors and coupling located on one plate
should have different threads.

Threads should be distinguished by:

a)  diameter - not less than by 4 mm;

b)  arrangement - external, internal;

c)  step - not less than by 1,5 mm;

d)  number of threads per unit of measure;

e)  direction -- right of left.

Other features include the following:

a)  guide elements;

b)  fixing elements;

c)  arrangement of nipples and unions, etc.

**A.4.2 Flanged connections**

The electrical and fluid connectors (umbilicals) located on one plate
should have different flanges.

These flanges should be distinguished by one or more of the following:

a)  geometrical configuration (circle, oval, square, triangle, irregular
    polygon, etc.);

b)  flanges thickness;

c)  attachment (perpendicularly or in parallel to plate) orientation;

d)  quantity of attachment;

e)  arrangement of attachment;

f)  type of fastening elements (bolt with a nut, screw, pin, lock);

g)  diameter of threaded elements;

h)  quantity of connectors (couplings) located on a flange;

i)  location of flanges (flanges on both halves of connectors
    (couplings) or only on a part of the pipeline (cable)).

The following types of fastening elements are recommended:

a)  removable bolts or screws;

b)  folding bolts;

c)  locks with different attachment methods.

The electrical connectors (except the requirements previously specified)
should differ by the following:

a)  pins quantity;

b)  geometrical configuration of pins combination;

c)  pins diameter;

d)  arrangement of pin -- aperture a pair.

**A.5** **Marking requirements**

**A.5.1 General requirements**

Marking by figures, letters or symbols and colour is recommended. See
subclause A.5.3.

Halves of connectors and couplings and also pipelines and cables
attached to them are to have identical marking.

Marking is put directly on both halves of connectors and couplings and
on the pipelines and cables attached to them.

Marking may be by a mechanical method by a painting.

When it is impossible to mark both halves of connectors and couplings or
pipelines and the cables directly, one half should have a label marker.
In this case, places for label attachment are provided on halves of
connectors and coupling (pipelines and cables).

On vacuum pipelines, an inscription \"vacuum\" is made except marking.

**A.5.2 Marking figures and letters**

The marking content should be indicated on the schemes and drawings. The
figures and letters size should be not less than 5 mm. The marking shall
be clear and precise to preclude an error in reading and understanding.

**A.5.3 Marking by symbols**

The marking symbols indicates danger, which can arise with cable
(pipeline) damage (for example, high pressure, poisonous substances,
etc.).

The values of the marking symbols should correspond to the International
Standards guidelines or as specified on the schemes and drawings. In all
cases, the symbols be explained in the operation and maintenance
documentation.

The symbol size should be 15 mm minimum.

The symbol colour should be black or white depending on a background.
Placing symbols inside equilateral triangle with the size of the side
not less than 24 mm. The colour of the triangle background should be
yellow.

Symbol tracing should be clear and precise to avoid an error in
understanding.

**A.5.4 Marking by colour**

Colour marking should indicate the following:

a)  the function (application) of a connection (unit A power supply,
    bottles, charging control, tank fill and drain, tanks
    pressurization, fire suppression, etc);

b)  the value of dangerous characteristic (more than 250 V, more than 4
    MPa, etc);

c)  the fluid and gas type (combustible gases (including liquefied);
    noncombustible gases; inert gases; air; combustible fluids; water;
    fire suppression products; mixes, etc);

d)  the particular fluid or gas (oxygen, hydrogen, kerosene, helium,
    nitrogen, compressed air, etc);

In the case where the use of a colour symbol is required for marking
bands (loops), the following will apply:

a)  a symbol size should be 15 mm minimum;

b)  lines thickness should be 5 mm minimum;

c)  colour should correspond to a function, characteristic, type, etc.

d)  width of a band should be 5 mm minimum.

If it is necessary to identify several characteristics, add one or more
bands. The first band should be the function, followed by additional
bands with a description.

Additional bands corresponding to other characteristics may be added to
basic colour bands.

The distance between additional bands and also from an edge of a basic
band is 5 mm minimum.

When using cables with colour isolation, the colour of the isolation
shall correspond to a function colour.

When using painted pipes, their colour shall correspond with the
function colour.

When applying additional bands, black or white lines that are 1-mm thick
should be applied to the edges of colours that are similar (e.g.,
red/orange) or the same.

Marking colour is used according to table A.1.

####### Table A.1 -- Marking colours

+-------------------------------------------------+----------+---------+
| **Function (group of fluids), dangerous         | **       | **Addit |
| characteristic**                                | Colour** | ional** |
|                                                 |          |         |
|                                                 |          | **      |
|                                                 |          | instruc |
|                                                 |          | tions** |
+-------------------------------------------------+----------+---------+
| Water                                           | Green    |         |
+-------------------------------------------------+----------+---------+
| Air                                             | Blue     |         |
+-------------------------------------------------+----------+---------+
| Combustible gases                               | Yellow   | Letter  |
|                                                 |          | "C"     |
+-------------------------------------------------+----------+---------+
| Incombustible gases                             | Yellow   |         |
+-------------------------------------------------+----------+---------+
| Combustible fluids                              | Brown    | Letter  |
|                                                 |          | "C"     |
+-------------------------------------------------+----------+---------+
| Fire- and explosion danger                      | Red      |         |
+-------------------------------------------------+----------+---------+
| Toxicity, ability to call an asthma, chemical   | Yellow   |         |
| burns, high pressure, steep vacuum              |          |         |
+-------------------------------------------------+----------+---------+

**A.6 Verification**

# A.6.1 General {#a.6.1-general .unnumbered}

The verification of proper connection may be implemented in three stages
(phases):

a\) verification of the connector and coupling on the part of a vehicle;

b\) verification of the connector and coupling on the part of ground
support equipment;

c\) verification of the umbilical in a connected state.

###### A.6.2 Electrical connectors {#a.6.2-electrical-connectors .unnumbered}

The verification of electrical connectors is performed by a current of
minimum voltage and frequency, used on the launch vehicle. This is
performed during factory and independent tests.

###### A.6.3 Fluid coupling {#a.6.3-fluid-coupling .unnumbered}

The verification of fluid coupling is performed by leak testing with a
fluid according to this International Standard at a minimum pressure
used on the launch vehicle. This is performed during factory and field
tests.

###### A.6.4 Umbilical {#a.6.4-umbilical .unnumbered}

The verification of an umbilical is performed pursuant to subclauses
A.6.2 and A.6.3 with the plates connected or their simulators. Pressure
and voltage are supplied to umbilicals at first sequentially and then to
all connectors simultaneously. This is performed during all the stages
of tests according to ISO 17400.

###### A.6.5 Unsatisfactory results {#a.6.5-unsatisfactory-results .unnumbered}

If the results of the verification are unsatisfactory, the defective
umbilicals are replaced and retested.