ISO 14903:2012
(Main)Refrigerating systems and heat pumps — Qualification of tightness of components and joints
Refrigerating systems and heat pumps — Qualification of tightness of components and joints
The requirements contained in ISO 14903:2012 are applicable to joints of maximum DN 50 and components of maximum 5 l and maximum mass of 50 kg. ISO 14903:2012 is intended to describe the qualification procedure for type approval of the tightness of components, joints and parts used in refrigerating systems and heat pumps as described in ISO 5149. It characterizes the joint tightness and stresses met when operating, following the fitting procedure specified by the manufacturer, and specifies the minimal list of necessary information to be provided by the supplier of a component to the person in charge of carrying out this procedure. ISO 14903:2012 specifies the level of tightness of the component, as a whole, and its assembly as specified by the manufacturer. ISO 14903:2012 applies to the hermetically sealed and closed components, joints and parts used in refrigerating installations, including those with seals, whatever their material and their design are. ISO 14903:2012 specifies additional requirements for mechanical joints that can be recognized as hermetically sealed joints.
Systèmes de réfrigération et pompes à chaleur — Qualification de l'étanchéité des composants et des joints
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 14903
First edition
2012-11-01
Refrigerating systems and heat
pumps — Qualification of tightness of
components and joints
Systèmes de réfrigération et pompes à chaleur — Qualification de
l’étanchéité des composants et des joints
Reference number
ISO 14903:2012(E)
©
ISO 2012
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ISO 14903:2012(E)
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ii © ISO 2012 – All rights reserved
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ISO 14903:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and units . 2
5 Test requirements . 3
6 Requirements for hermetically sealed systems . 7
7 Test procedures . 7
7.1 General . 7
7.2 Sampling . 7
7.3 Test temperature . 7
7.4 Tightness test . 8
7.5 Requirements for joints .11
7.6 Pressure temperature vibration tests (PTV) .12
7.7 Operation simulation .20
7.8 Freezing test .20
7.9 Additional pressure test for hermetically sealed joints .22
7.10 Vacuum test .22
7.11 Compatibility screening test .22
7.12 Fatigue test for hermetically sealed joints .25
8 Test report .25
9 Information to the user .25
Annex A (normative) Equivalent tightness control levels .27
Annex B (informative) Test arrangements .33
Bibliography .35
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ISO 14903:2012(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 2.
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 document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14903 was prepared by Technical Committee ISO/TC 86, Refrigeration and air conditioning,
Subcommittee SC 1, Safety and environmental requirements for refrigerating systems.
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ISO 14903:2012(E)
Introduction
This International Standard is intended to describe the qualification procedure for type approval of the
tightness of hermetically sealed and closed components, joints and parts used in refrigerating systems
and heat pumps as described in ISO 5149. The sealed and closed components, joints and parts concerned
are, in particular, fittings, bursting discs, flanged or fitted assemblies.
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INTERNATIONAL STANDARD ISO 14903:2012(E)
Refrigerating systems and heat pumps — Qualification of
tightness of components and joints
1 Scope
The requirements contained in this International Standard are applicable to joints of maximum DN 50
and components of maximum 5 l and maximum mass of 50 kg.
This International Standard is intended to describe the qualification procedure for type approval of the
tightness of components, joints and parts used in refrigerating systems and heat pumps as described
in ISO 5149. It characterizes the joint tightness and stresses met when operating, following the fitting
procedure specified by the manufacturer, and to specify the minimal list of necessary information to be
provided by the supplier of a component to the person in charge of carrying out this procedure.
This International Standard specifies the level of tightness of the component, as a whole, and its assembly
as specified by the manufacturer.
This International Standard applies to the hermetically sealed and closed components, joints and parts
used in refrigerating installations, including those with seals, whatever their material and their design are.
This International Standard specifies additional requirements for mechanical joints that can be
recognized as hermetically sealed joints.
2 Normative references
The following documents in whole or in part are normatively referenced in this document and are
indispensable for its application. For undated references, the latest edition of the referenced document
(including any amendments) applies.
1)
ISO 5149-1:— , Refrigerating systems and heat pumps — Safety and environmental requirements — Part 1:
Definitions, classification and selection criteria
2)
ISO 5149-2:— , Refrigerating systems and heat pumps — Safety and environmental requirements — Part 2:
Design, construction, testing, marking and documentation
EN 13134, Brazing — Procedure approval
ISO 13971:2012, Refrigerating systems and heat pumps — Flexible pipe elements, vibration isolators,
expansion joints and non-metallic tubes — Requirements, design and installation
EN 12693, Refrigerating systems and heat pumps — Safety and environmental requirements — Positive
displacement refrigerant compressors
ISO 175, Plastics — Methods of test for the determination of the effects of immersion in liquid chemicals
IEC 60068-2-64:1993, Environmental testing — Part 2: Test methods — Test Fh: Vibration, broad-band
random (digital control) and guidance
IEC 60335-2-34, Household and similar electrical appliances — Safety — Part 2-34: Particular requirements
for motor-compressors
1) To be published.
2) To be published.
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ISO 14903:2012(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5149-1:— and the following apply.
3.1
mass flow per year
q
m
value of the leak mass flow rate
NOTE It is expressed in grams per year.
3.2
volume flow rate
Q
value of the leak volume flow rate
NOTE It is expressed in pascal cubic metres per second.
3.3
hermetically sealed system
system in which all refrigerant containing parts are made tight by welding, brazing or a similar
permanent connection which may include capped valves and capped service ports that allow proper
repair or disposal and which have a tested tightness control level of less than 3 grams per year under a
pressure of at least a quarter of the maximum allowable pressure
NOTE Sealed systems as defined in ISO 5149-1:— are equal to hermetically sealed systems.
3.4
product family
group of products that have the same function, same technology, and same material for each functional
part and sealing materials, produced according to the same specification but of a different size
3.5
permanent joints
means joints which cannot be disconnected except by destructive methods
3.6
reusable joint
joint other than permanent joint that can be disconnected without destructive manner
NOTE In some cases the tube is used as sealing material (e.g. flared joint). Sealing component may be replaced.
3.7
same base material
material belonging to the same group as follows:
— steel group
— aluminium and aluminium alloy group, and
— copper group
NOTE Subgroups of these material groups are considered to be same base materials (see EN 14276-2).
4 Symbols and units
The symbols and units used in this International Standard are given in Table 1.
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ISO 14903:2012(E)
Table 1 — Symbols and units
Symbol Description Unit
Percentage deviation of the minimum and maximum torque from the
DK average of the minimum and maximum torque, (K – K )/(K +
rel o,max o,min o,min
K )
o,max
f Frequency of vibrations Hz
K Average torques of the respective joint standard
o,ave
Required maximum torques of the respective joint standard, if specified.
K
o,max
Otherwise, the maximum torque values supplied by the manufacturer
Required minimum torques of the respective joint standard, if specified.
K
o,min
Otherwise, the minimum torque values supplied by the manufacturer
L Length of tube mm
n Number of cycles in temperature and in pressure (method 1)
n Number of cycles in temperature and in pressure(method 2)
1
n Number of cycles in pressure
2
n Number of cycles in vibration
3
n Total number of cycles in temperature and in pressure
total
N Number of samples
P Tightness test pressure bar
P Maximal pressure of cycle bar
max
P Minimal pressure of cycle bar
min
PS Maximal allowable pressure bar
P Nominal set pressure of the device bar
set
3
Q volume flow rate Pa m /s
q mass flow per year g/year
m
s Vibration displacement (peak to peak value) mm
T Maximal temperature of cycle °C
max
T Minimal temperature of cycle °C
min
Θ Mass flow rate kg/s
5 Test requirements
The required tests to be applied to the body of the component and to the joint used in refrigerating
systems and heat pumps are given in Tables 2 and 3.
Figure 1 illustrates the principle of a component and a joint and the corresponding requirements shall
conform to Table 2 or Table 3.
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ISO 14903:2012(E)
According to Table 2
According to Table 2
According to Table 3
Key
1 joint
2 component body
3 pipe
4 component body joint
5 extension pipe
Figure 1 — Principle: component body-joint
All component types and joints types shall be tested.
When a component is connected with different types of joints, one of these joints shall be tested with
the component according to Table 2. The other possible types of joints shall be tested independently
according to Table 3.
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ISO 14903:2012(E)
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Table 2 — Requirements for the body of the component
Tests to be carried out
Tightness test PTV test Operation simu- Freezing test Chemical com- Vacuum test Additional test for hermetically
Description of the components (includ-
7.4 (pressure lation 7.8 patibility with 7.10 sealed joints
ing valves)
temperature 7.7 materials
Pressure test Fatigue test
vibration) 7.11
7.9 7.12
7.6
Component bodies having only YES NO NO NO NO NO NO NO
permanent body joints: brazing and weld-
ing
Identical base materials
a
Components having permanent body YES YES NO NO NO NO NO NO
joints : brazing and welding
Different base materials
Component bodies having other YES YES NO YES YES YES YES YES
permanent body joints: e.g. glue, if operating if non-metallic
permanent compression fittings, temperature parts
expansion joints below 0 °C
Component bodies with YES YES YES YES YES YES Not Not
non-permanent body joints if any external if operating if non-metallic applicable applicable
stems, shaft temperature parts
seals or below 0 °C
removable or
replaceable
parts
YES
YES
Capped valves and capped service ports if operating
YES YES YES if non-metallic YES YES YES
for hermetically sealed systems temperature
parts
below 0 °C
YES
Not Not Not
Safety valves YES YES NO NO if non-metallic
applicable applicable applicable
parts
Flexible piping Test according to ISO 13971:2012
As an exception compressors that comply with the requirements of EN 12693 or IEC 60335-2-34 only need to be subjected to the following test:
— joints connecting to other parts of the refrigerating systems;
— chemical compatibility test for all gaskets (sight glass,etc.).
NOTE Another qualification for this chemical compatibility done according to another standard is equivalent.
a
PTV tests are not required if the destructive and non-destructive tests in EN 13134 are carried out.
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ISO 14903:2012(E)
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Table 3 — Requirements for the joining of components
Requirements
PTV test Additional test for hermeti-
Chemical com-
Tightness (pressure Operation cally sealed joints
Description of the joints and parts
Freezing test patibility with Vacuum test
test temperature simulation
7.8 materials 7.10
Pressure test Fatigue test
7.4 vibration) 7.7
7.11
7.9 7.12
7.6
Permanent piping joints: brazing and
welding YES NO NO NO NO NO NO NO
Identical base materials
Permanent piping joints: brazing and
welding YES YES NO NO NO NO NO NO
Different base materials
Other permanent piping joints: e.g.
glue, permanent compression fittings, YES YES NO YES YES YES YES YES
expansion joints
YES, if sealing Not Not
Non-permanent piping joints YES YES YES YES YES
material applicable applicable
Not Not
Gaskets and sealing NO NO NO NO YES NO
applicable applicable
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ISO 14903:2012(E)
6 Requirements for hermetically sealed systems
Hermetically sealed systems shall be constructed with components that have a tightness control level
qualified according to A.1 or A.2, or that comply with Table 3. These components and joints shall be
submitted to the relevant tests as specified in Tables 2 and 3.
7 Test procedures
7.1 General
The test characteristics to be applied to the components, joints and parts shall pass the qualification test
for type approval of the tightness. The test procedures are shown in Figure 2.
Figure 2 — Test procedure
7.2 Sampling
The largest, the smallest and any random samples in between of the product family shall be submitted
to the test as required in Table 2 or Table 3. The samples used for pressure temperature vibration test
(7.6) and for operation simulation (7.7) shall be the same. For each of the tests described in 7.8, 7.9, 7.10,
7.11, 712, different samples may be used.
7.3 Test temperature
The test temperature (ambient and gas) shall be between 15 °C and 35 °C, unless otherwise specified as
the test conditions.
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ISO 14903:2012(E)
7.4 Tightness test
7.4.1 General
The tightness of components and joints shall be tested.
For pressure relief devices, P = 0,9 × P +0/-2%
set
For all other components and joints P = PS +0/-2% (PS = maximum allowable pressure)
Q ≤ requirements for actual tightness control level A1 – A2
(hermetically sealed components) or B1 – B2 for all other
components
The maximum required tightness control levels are specified for Helium at 10 bar and + 20 °C as a reference.
The actual tightness control levels can be calculated (e.g. other test fluids or pressures) by using the
stated calculation formulas (see Annex A).
The maximum tightness control depends on the size of the tested component or joint. Tightness control
levels are specified in accordance with the joints used in Table 4. These are levels for each individual joint.
Table 4 — Tightness control level according to joints nominal diameter
Nominal diameter Tightness control
Joints
(DN) levels
Hermetically sealed joints ≤ 50 A1
Closed joints ≤ 50 B1
Tightness control levels are specified in accordance with the components used in Table 5. These levels
are for each individual component.
Table 5 — Tightness control level according to components volume
Component volume Tightness con-
Components
l trol levels
0 up to 1,0 A1
Hermetically sealed
components
> 1,0 A2
Closed components 0 up to 2,0 B1
> 2,0 up to 5,0 B2
The required tightness control level is stated in Table 6. The manufacturer can choose a more stringent
tightness control level if adequate.
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ISO 14903:2012(E)
Table 6 — Equivalence of test gas flow according to tightness control levels
Helium reference Equivalent
Equivalent air leak
Component Tightness control leak iso-butane leak
(Q )
air-ref
type level (Q ) (q )
he-ref mR600a
+20 °C, 10 bar
+20 °C, 10 bar +20 °C, 10 bar
3 3
Pa.m /s Pa.m /s g/yr
-7 -7
A1 ≤ 7,5 × 10 ≤ 8 × 10 ≤ 1,5
Hermetically sealed
-6 -7
A2 ≤ 1 × 10 ≤ 11 × 10 ≤ 2,0
-6 -7
Closed B1 ≤ 1 × 10 ≤ 11 ×v10 ≤ 2,0
-6 -6
B2 ≤ 2 × 10 ≤ 2,1 × 10 ≤ 4,0
NOTE The equivalent iso-butane leak is calculated as gas. At +20 °C and 10 bar iso-butane is in the liquid
phase. See R600a in Table A.1.
7.4.2 Tightness control level
NOTE EN 1779 gives guidance on the criteria for method and technique selection.
7.4.2.1 Test method
The tightness control level of joints and components shown in Figure 3 shall be measured by an
integration measure method, i.e. the sum of all leaks.
It is preferable to use tracer gas method.
NOTE 1 For further details on tracer gas method, see EN 13185:2001, Clause 10.
Tracer gas is admitted to the internal volume of the object and it is collected and tested in a vacuum chamber.
The following procedure shall be carried out to measure the tightness control level:
— connect the vacuum chamber to the detector;
— connect the component to the trace gas pressure generator (in the vacuum chamber); see Figure 3 below;
— close the vacuum box and start the leak detector (and if it is needed add a vacuum pump);
— calibrate and adjust the leak detector in accordance with the manufacturer’s instructions using a
calibration leak (if required the leak shall be “standard”);
— measure the background signal in the vacuum box and the component without helium pressure;
— adjust the test pressure in the component;
— measure the leak signal of the component;
— evacuate air from inside the component with a vacuum pump;
— fill the component with tracer gas and adjust test pressure;
NOTE 2 This signal is the total flow of the tracer gas from the component measured by the leak detector.
— calculate the total leakage rate, such as:
qS×−()R 1 101325
CL LL
q = ××
G
SR− cp
CL CL
where
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ISO 14903:2012(E)
q is the total leakage rate, in pascals cubic metres per second;
G
q is the leakage rate of the calibration leak in pascals cubic metres per second (pure tracer
CL
gas);
S is the leak signal;
L
S is the signal generated by the calibration leak;
CL
R , R are the background signal associated with signal S and S , respectively;
L CL L CL
c is the volume fraction of the tracer gas in the gas mixture;
p is the total pressure in the auxiliary enclosure, in pascals.
NOTE 3 The calculation is detailed in EN 13185:2001, 9.2.6
If joints and/or components are tested together, the total level shall fulfil the most stringent tightness
control level of the individual joint or component.
Key
1 tracer gas (PS)
2 vacuum
3 vacuum
4 mass spectrometric leak detector
5 test object
6 calibrated leak
Figure 3 — Principle of tightness control — Tracer gas
7.4.2.2 Alternative test methods
Two alternative methods may be applied.
— Alternative method 1:
The control by pressure technique by accumulation can be a method to measure the leak rate of the
component.
NOTE 1 For details on the pressure technique by accumulation, see EN 13185:2001, 10.4.1.
— Alternative method 2:
Bubble test methods shown in Figure 4 can be acceptable for tightness control level B only, provided that
the method is capable of measuring the actual leakage rate.
NOTE 2 The bubble test method is detailed in EN 1593.
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ISO 14903:2012(E)
The accuracy of the selected method shall be verified and be in compliance with the requirements for
actual tightness control level. If this method is used, the following requirements shall be applied:
— the test object shall be subjected to an internal air pressure = PS (maximum allowable pressure);
reduced pressure is not acceptable,
— the test object shall be totally immersed in water at a temperature of at least 35 °C,
— the test object shall be exposed to atmospheric pressure,
— the test shall be performed at normal ambient temperature,
— the period of time between bubbles leaving the test object shall be more than 60 s.
Key
1 water
2 test object
3 air pressure (PS)
Figure 4 — Principle of tightness control — Bubble method
7.5 Requirements for joints
7.5.1 General conditions
7.5.1.1 Test samples
All joints tested shall be tested in the same form as the final part received by the customer.
All joints shall to be submitted to the tests as indicated in Table 3.
7.5.1.2 Torque
Tube joints shall be tested both at the minimum torque K and the maximum torque K defined in Table 7.
min max
Table 7 — Torque for the test, K and K
min max
Torque deviation K K
min max
DK ≥ 20 % K K
rel o,min o,max
DK < 20 % 0,8 × K 1,2 × K
rel o,ave o,ave
7.5.1.3 Reusable joint
If the joints to be tested are reusable, the following steps shall be taken before the test:
a) fit the joints to tubes to be connected and tighten the joints to the maximum torque K
max
specified in Table 7,
b) loosen the joints and take the tubes completely apart,
c) repeat a) and b) four more times.
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ISO 14903:2012(E)
7.5.1.4 Requirements for hermetically sealed joints
The joint shall not be opened without the use of special tools.
NOTE Special tools are those other than screwdrivers, parallel wrenches, simple gripping tools, etc.
The joint shall not be reusable without replacing the sealing material in normal use. In case the sealing
material is the tube and the tube is deformed during the sealing process, the deformed part of the tube
shall not be reusable for sealing purposes.
7.6 Pressure temperature vibration tests (PTV)
7.6.1 General
For pressure temperature vibration tests, 7.6.4 or 7.6.5 shall be applied.
The components or joints shall comply with one of the two methods described in 7.6.4 and 7.6.5 for
combined cycle testing in order to qualify the tightness control level.
7.6.2 Samples
For the combined cycle test, the number of samples is determined based on tightness control level
according to Table 8.
Table 8 — Test parameters
Tightness control level Number of samples
A1, B1 3
A2, B2 2
7.6.3 Test method
7.6.3.1 Equipment
Test equipment shall be composed of:
a) a regulated enclosure for environment tests, able to maintain temperatures varying regularly
between T and T ;
min max
b) a pressure device, connected to the joints, capable of producing pressures that vary between
P and P ;
min max
c) a vibration generator, to make the specified frequency and amplitude;
d) a pressure control system capable of controlling the pressure with an accuracy of ± 5%;
e) a temperature control system capable of controlling the temperature inside of the test enclosure
with an accuracy of ± 5 K;
f) a thermocouple capable of monitoring the temperature (T , T ) of the component or joint
max min
submitted to the test.
The temperature sensor shall be adhered to the surface of the sample on the item with the biggest
mass concentration of the pressure bearing part in order to ensure that the sample has reached
the defined temperature values. Where the pressure bearing part is made from metallic and
non-metallic materials, the sensor shall be fixed on the non-metallic material.
The sensor can be fixed to the sample by soldering or with adhesives, whichever is more appropriate,
depending on the material of the sample.
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ISO 14903:2012(E)
Another method proven to have the same performance as the thermocouple can be applied;
g) a cycle counter of temperature and pressure;
h) test equipment to perform tightness test according to 7.4.
7.6.3.2 Test arrangements
The test samples shall be mounted as shown in Annex B in accordance with the number of joints to be
tested and with the dimension of the climatic enclosure in which the tests are carried out.
The tube section shall have a diameter and dimensional tolerances such as specified by the manufacturer
of the joint.
The assembly of the joints on the tube shall be carried out following the fitting instructions of the
manufacturer.
For pressure tests, one end of a tube shall be connected to the pressure generator, the other end shall be
tightly closed.
7.6.4 Method 1 — Combined pressure temperature cycle test with integrated vibration test
7.6.4.1 General
The samples (joints fitted on a tube) shall be submitted to a defined number n of cycles of temperature
and pressure, between maximal values (T , P ) and minimal val
...
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