EN 17450-2:2024

SLOVENSKI STANDARD
01-december-2024
Vgrajeni gasilni sistemi - Sistemi s pršečo vodo - 2. del: Zahteve in preskusne
metode za šobe
Fixed firefighting systems - Water mist systems - Part 2: Product characteristics and test
methods for nozzles
Ortsfeste Brandbekämpfungsanlagen - Wassernebelsysteme - Teil 2: Anforderungen
und Prüfverfahren für Düsen
Installations fixes de lutte contre l’incendie - Systèmes à brouillard d’eau - Partie 2 :
Caractéristiques de produit et méthodes d’essai pour les diffuseurs
Ta slovenski standard je istoveten z: EN 17450-2:2024
ICS:
13.220.10 Gašenje požara Fire-fighting
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 17450-2
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 13.220.20
English Version
Fixed firefighting systems - Water mist systems - Part 2:
Product characteristics and test methods for nozzles
Installations fixes de lutte contre l'incendie - Systèmes Ortsfeste Brandbekämpfungsanlagen -
à brouillard d'eau - Partie 2 : Caractéristiques de Wassernebelsysteme - Teil 2: Produkteigenschaften
produit et méthodes d'essai pour les diffuseurs und Prüfverfahren für Düsen
This European Standard was approved by CEN on 1 August 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17450-2:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Product characteristics . 7
4.1 General. 7
4.2 Nominal operating temperature for automatic nozzles . 8
4.3 Thermal response of automatic nozzles . 8
4.4 K-factor . 8
4.5 Function of nozzles . 9
4.5.1 Automatic nozzles . 9
4.5.2 Open nozzles . 9
4.6 Strength of nozzle body and deflector . 9
4.6.1 Mechanical strength test . 9
4.6.2 Hydrostatic strength test . 9
4.6.3 Strength of nozzle deflector and its supporting or moving parts . 9
4.7 Strength of release element of automatic nozzles . 9
4.7.1 General. 9
4.7.2 Automatic nozzles using glass-bulbs . 9
4.7.3 Automatic nozzles using fusible links . 9
4.8 Leak resistance . 10
4.9 Heat exposure for automatic nozzles using glass bulbs . 10
4.10 Resistance against thermal shock for automatic nozzles using glass bulbs . 10
4.11 Resistance against corrosion . 10
4.11.1 Stress corrosion for nozzles with brass parts . 10
4.11.2 Sulphur dioxide corrosion . 10
4.11.3 Salt mist corrosion . 10
4.11.4 Moist air exposure . 11
4.12 Aging test (by heat exposure) for automatic nozzles (optional) . 11
4.13 Resistance against water hammer for automatic nozzles. 11
4.14 Resistance to heat . 11
4.15 Resistance to low temperature for automatic nozzles (optional). 11
4.16 Resistance to vibration . 11
4.17 Resistance to impact . 11
5 Testing, assessment and sampling methods . 12
5.1 General. 12
5.2 Operational tests . 12
5.2.1 Comparison of fire test nozzles with the one used for component testing . 12
5.2.2 Operating temperature of automatic nozzles . 12
5.3 Thermal response tests . 12
5.4 Water flow test . 12
5.5 Function test of nozzles . 12
5.5.1 Function of release element for automatic nozzles . 12
5.5.2 Functional test for open nozzles with blow-off caps . 13
5.5.3 Verification functional test . 13
5.6 Strength of nozzle body and deflector tests . 14
5.6.1 Mechanical strength test . 14
5.6.2 Hydrostatic strength test . 14
5.6.3 Strength of nozzle deflector and its supporting or moving parts test . 14
5.7 Strength of release elements test for automatic nozzles . 14
5.7.1 General . 14
5.7.2 Automatic nozzles using glass bulbs . 15
5.7.3 Automatic nozzles using fusible links . 15
5.8 Leak resistance test . 15
5.9 Heat exposure for automatic nozzles using glass bulbs . 15
5.10 Thermal shock test . 16
5.11 Corrosion tests . 16
5.11.1 General . 16
5.11.2 Stress corrosion . 16
5.11.3 Sulphur dioxide corrosion. 16
5.11.4 Salt mist corrosion . 16
5.11.5 Moist air exposure . 16
5.12 Aging test (by heat exposure) for automatic nozzles (optional) . 17
5.13 Water hammer test . 17
5.14 Heat-resistance test . 18
5.15 Low temperature resistance test for automatic nozzles (optional) . 18
5.16 Vibration test . 18
5.17 Resistance to impact test . 19
6 Documentation and marking . 20
6.1 Product documentation . 20
6.2 Marking . 20
7 Test facilities . 21
7.1 Test facility . 21
7.2 Test report . 21
Annex A (normative) Test apparatus for water flow test . 22
A.1 Single inlet pipe nozzle . 22
A.2 Calculation . 22
Annex B (informative) Water distribution test. 24
B.1 Apparatus . 24
B.2 Procedure . 24
Annex C (normative) Corrosion tests . 26
C.1 Stress corrosion test for brass nozzles . 26
C.1.1 Reagents . 26
C.1.2 Apparatus . 26
C.1.3 Procedure . 26
C.2 Post exposure flowing test (if required) . 26
C.2.1 Automatic nozzles . 26
C.2.2 Open nozzles . 26
C.3 Sulphur dioxide corrosion test . 26
C.3.1 General . 26
C.3.2 Reagents . 27
C.3.3 Apparatus . 27
C.3.4 Procedure . 27
C.3.4.1 General. 27
C.3.4.2 Automatic nozzles . 27
C.3.4.3 Open nozzles . 27
C.4 Salt mist corrosion test . 28
C.4.1 Reagents . 28
C.4.2 Apparatus . 28
C.4.3 Procedure . 29
C.5 Moist air atmosphere test . 29
Annex D (normative) Thermal response tests . 30
D.1 Test setup. 30
D.2 Prolonged exposure ramp test . 30
D.3 Plunge test . 31
Annex E (normative) Strength of water mist body and deflector tests . 33
Annex F (normative) Test to determine operating temperatures . 35
F.1 Apparatus . 35
F.2 Procedure . 35
Bibliography . 37

European foreword
This document (EN 17450-2:2024) has been prepared by Technical Committee CEN/TC 191 “Fixed
firefighting systems”, the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
EN 17450, Fixed firefighting systems — Water mist systems, consists of the following parts:
— Part 1: Product characteristics and test methods for strainer and filter components
— Part 2: Product characteristics and test methods for nozzles
— Part 3: Product characteristics and test methods for check valves
— Part 4: Product characteristics and test methods for control deluge valves and actuators
— Part 5: Product characteristics and test methods for pressure switches
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Under preparation.
1 Scope
This document specifies product characteristics and test methods of open nozzles and automatic nozzles
for use in water mist systems.
NOTE All pressure data in this document are given as gauge pressures in bar .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 12259-1, Fixed firefighting systems — Components for sprinkler and water spray systems — Part 1:
Sprinklers
EN 14972 (all parts), Fixed firefighting systems — Water mist systems
EN 60751, Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 14972-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
nozzle filter element
element that collects the particles
EXAMPLE A mesh.
3.2
nominal cross section (size)
calculated cross section on basis of the nominal diameter
3.3
pressure loss
differential pressure between inlet and outlet of the filter
3.4
operating pressure
constant or time-dependent pressure at a nozzle during discharge
3.5
stand-by pressure
pressure in the pipework at a closed automatic nozzle, prior to the activation of the nozzle
Note 1 to entry: This can be static pressure or flowing pressure.

2 5
bar = 10 Pa.
Note 2 to entry: This can be higher or lower than the operating pressure.
3.6
maximum stand-by pressure
highest pressure to which the installed nozzle is exposed, due to the effects of the pressure maintenance
device and head of water
Note 1 to entry: Specified by the manufacturer.
3.7
minimum stand-by pressure
lowest pressure to which the installed nozzle is exposed, due to the effects of the pressure maintenance
device and head of water
Note 1 to entry: Specified by the manufacturer.
3.8
maximum operating pressure
highest pressure at the nozzle inlet while operating
Note 1 to entry: Specified by the manufacturer.
3.9
minimum operating pressure
lowest pressure at the nozzle inlet while operating
Note 1 to entry: Specified by the manufacturer.
3.10
release element
part of a nozzle which activates the discharge of the nozzle after thermal or other activation method
3.11
response time index
RTI
1/2 1/2
measure of the thermal sensitivity of the nozzle expressed in (meters seconds) (m s)
3.12
conductivity factor
C-Factor
measure of the conductance between the nozzles heat responsive element and the water filled fitting,
1/2 1/2
expressed in (meters/second) (m/s)
4 Product characteristics
4.1 General
The nozzles used in water mist fire protection systems shall be representative of production nozzles and
shall pass all of the applicable requirements specified in this document.
All nozzles with orifice diameters less than 2,5 mm shall be equipped with a nozzle filter. The size of the
nozzle filter element shall be at least 1,5 times the nominal cross section area of the sum of the orifices
behind the filter itself. The filter shall not have a bigger mesh size, i.e. grade of filtration, than 80 % of the
smallest nozzle orifice diameter behind the filter itself.
Nozzle types tested in accordance with this document shall be the same as those that have successfully
passed the fire tests according to the relevant part of the EN 14972 series.
The nozzles shall be compared according to 5.2.1.
As an optional test the water distribution can be tested according to Annex B.
4.2 Nominal operating temperature for automatic nozzles
The nominal operating temperatures of automatic nozzles are given in Table 1. The glass bulb liquid or
the yoke arm(s) of automatic nozzles shall be colour coded according to Table 1.
The nominal operating temperature shall be according to 5.2.2.
Table 1 — Nominal operating temperatures and colour codes
Glass bulbs Fusible links
Nominal operating Liquid colour Nominal operating Yoke arm(s)
temperature code temperature within range colour code
°C  °C
57 orange 57 to 77 uncoloured
68 red 80 to 107 white
79 yellow 121 to 149 blue
93 green 163 to 191 red
100 green 204 to 246 green
121 blue 260 to 302 orange
141 blue 320 to 343 black
163 mauve – –
182 mauve – –
204 black – –
227 black – –
260 black – –
286 black – –
343 black – –
4.3 Thermal response of automatic nozzles
The RTI value shall be verified with tests according to 5.3. In the most unfavourable orientation the
average RTI values shall not exceed 250 % of the average RTI values in the standard orientation.
4.4 K-factor
All K-factors shall vary less than ± 5 % from manufacturer specifications when tested in accordance with
5.4.
4.5 Function of nozzles
4.5.1 Automatic nozzles
For automatic nozzles, when tested in accordance with 5.5.1, the water mist nozzle shall open and within
5 s of release of the release element shall operate as intended. Any lodgement of released parts shall be
cleared within 60 s of the release of the release element.
For nozzles with deflectors or separate/moving parts for the development of a spray, when tested in
accordance with 5.5.1, the deflector and its supporting parts shall operate as intended.
4.5.2 Open nozzles
For open nozzles with blow-off caps, when tested in accordance with 5.5.2, the cap shall fully release
within 5 s and not impede the discharge at any time.
4.6 Strength of nozzle body and deflector
4.6.1 Mechanical strength test
When tested in accordance with 5.6.1, the water mist nozzle body shall not show permanent elongation
of more than 0,2 % in relation to the distance between the load bearing parts at the end of the test.
If the testing of this requirement is not applicable due to the design of the nozzle, the nozzle shall be
pressure tested according to 4.6.2.
4.6.2 Hydrostatic strength test
This test shall only be applied when the test under 4.6.1 is not applicable.
When tested in accordance with 5.6.2, the water mist nozzle body shall not show leakage or permanent
elongation of more than 0,2 % in relation to the distance between the load bearing parts at the end of the
test.
4.6.3 Strength of nozzle deflector and its supporting or moving parts
For nozzles with deflectors (or other protruding parts which impinge upon the water discharge and alter
the spray pattern, or moving parts regardless of their position), when tested in accordance with 5.6.3, the
water mist nozzle deflector and its supporting or moving parts shall not be damaged or deformed and
shall remain intact.
4.7 Strength of release element of automatic nozzles
4.7.1 General
The testing of release elements shall be done as described in 4.7.2 and 4.7.3.
4.7.2 Automatic nozzles using glass-bulbs
The design lower tolerance limit of bulb strength according to EN 12259-1 (0,99 confidence for 99 % of
samples) shall be greater than twice the design upper tolerance limit of the bulb/nozzle assembly load
including the highest calculated water pressure on nozzle. Nozzles shall be tested and comply with the
requirements described in 5.7.2.
4.7.3 Automatic nozzles using fusible links
For each design, fusible heat-responsive elements in the lowest temperature rating shall demonstrate
their ability to sustain the design load when tested in accordance with 5.7.3.
4.8 Leak resistance
When tested in accordance with 5.8, nozzles shall show no sign of leakage. In addition these tested nozzles
shall function as intended when tested subsequently in accordance with 5.5.3.
4.9 Heat exposure for automatic nozzles using glass bulbs
There shall be no damage to the glass bulb when automatic nozzles are tested in accordance with 5.9.
4.10 Resistance against thermal shock for automatic nozzles using glass bulbs
For automatic glass bulb water mist nozzles, when tested in accordance with 5.10, the glass bulbs shall
remain intact after being cooled in the water bath. The nozzles shall meet the requirements of 4.5 after
being cooled in the water bath.
4.11 Resistance against corrosion
4.11.1 Stress corrosion for nozzles with brass parts
Nozzles shall be tested in accordance with 5.11.2.1. The corrosion tests are described in Annex C.
After exposure the nozzles shall show no evidence of cracks, delamination or failure of an operating part.
In the case that any nozzles show evidence of cracking, delamination or failure of an operating part:
— Automatic nozzles shall show no visible evidence of leakage when subjected to the leak resistance
test described in 5.8. The nozzles shall operate in such a way that the waterway is cleared; any
lodgements shall be ignored, when subjected to a function test in accordance with 5.5.3. The nozzles
shall show no evidence of separation of permanently attached parts, when subjected to a flowing
pressure test in accordance with C.2.
— Open nozzles shall show no evidence of separation of permanently attached parts, when subjected
to a flowing pressure test in accordance with C.2.
4.11.2 Sulphur dioxide corrosion
Nozzles shall be subjected to a sulphur dioxide corrosion test in accordance with 5.11.3. The corrosion
tests are described in Annex C.
After exposure, when subjected to a function test in accordance with 5.5.3 the automatic nozzle shall
operate such that the waterway is cleared; any lodgements shall be disregarded.
Those nozzles which show evidence of corrosive attack or failure of a non-operating part shall show no
visible evidence of separation of permanently attached parts when subjected to the flowing test described
in 5.4 and the K-factor shall vary less than ± 5 % to the results from 4.4.
4.11.3 Salt mist corrosion
Nozzles shall be subjected to a salt mist corrosion test in accordance with 5.11.4. The corrosion tests are
described in Annex C.
After exposure, when subjected to a function test in accordance with 5.5.3 the automatic nozzles shall
operate such that the waterway is cleared; lodgements shall be disregarded.
Those nozzles which show evidence of corrosive attack or failure of a non-operating part shall show no
visible evidence of separation of permanently attached parts when subjected to the flowing test described
in 5.4 and the K-factor shall vary less than ± 5 %.
4.11.4 Moist air exposure
Nozzles shall be subjected to moist air exposure in accordance with 5.11.5. The corrosion tests are
described in Annex C.
After exposure, when automatic nozzles subjected to a function test in accordance with 5.5.3 the
automatic nozzle shall operate such that the waterway is cleared; lodgements shall be disregarded.
Those nozzles which show evidence of corrosive attack or failure of a non-operating part shall show no
visible evidence of separation of permanently attached parts when subjected to the flowing test described
in 5.4 and the K-factor shall vary less than ± 5 %.
4.12 Aging test (by heat exposure) for automatic nozzles (optional)
As an optional test, water mist nozzles can be tested according to 5.12.
When tested in accordance with 5.12 the water mist nozzles shall not operate during the exposure period.
When subjected to the additional tests specified in 5.12, the water mist nozzles shall meet the following
requirements:
a) when tested in accordance with 5.5.3, the water mist nozzles shall operate such that the waterway is
cleared; any lodgements shall be disregarded;
b) when tested in accordance with Annex F, the water mist nozzles shall conform to the requirements
specified in 5.2.2;
c) when tested in accordance with 5.8, the water mist nozzles shall conform to the requirements
specified in 4.8.
4.13 Resistance against water hammer for automatic nozzles
When tested in accordance with 5.13 the automatic nozzles shall show no visible evidence of damage.
4.14 Resistance to heat
When tested in accordance with 5.14, the water mist nozzle body, deflector and its supporting parts shall
show no significant deformation or breakage.
NOTE For automatic nozzles, this test is executed without release elements.
4.15 Resistance to low temperature for automatic nozzles (optional)
When tested in accordance with 5.15, the water mist nozzle shall not operate and shall show no signs of
damage.
Following examination, when subjected to a function test in accordance 5.5.3, the water mist nozzle shall
operate in such a way that the waterway is cleared; any lodgements shall be disregarded.
4.16 Resistance to vibration
When tested in accordance with 5.16, the water mist nozzles shall be able to withstand the effects of
vibration without deterioration of their performance characteristics.
4.17 Resistance to impact
When tested in accordance with 5.17, the water mist nozzles shall show no signs of damage.
5 Testing, assessment and sampling methods
5.1 General
The tests are conducted at a temperature of (20 ± 10) °C unless specified otherwise.
The tolerance of all test parameters is ± 5 % unless specified otherwise.
Water mist nozzles shall be checked for obvious defects before testing.
5.2 Operational tests
5.2.1 Comparison of fire test nozzles with the one used for component testing
This test relates to the requirements specified in 4.1.
The dimensional drawings shall be identical for the test samples for fire tests and component tests, e.g.
nozzle angles, drill sizes, etc.
The K-factor from samples taken from fire test shall be determined according to 5.4 and shall vary less
than ± 5 % from manufacturer specifications.
5.2.2 Operating temperature of automatic nozzles
When tested in accordance with Annex F, the water mist nozzles shall operate within a temperature range
of:

TT± 0,,035×+0 62 °C (1)
( )

where
T is the nominal operating temperature in °C.
5.3 Thermal response tests
The thermal response of the automatic nozzles shall be tested in accordance with Annex D. Five nozzles
shall be tested according to D.2 and five nozzles shall be tested according to D.3.
5.4 Water flow test
The K-factor shall be tested in accordance with Annex A.
A total of 5 samples shall be tested.
5.5 Function test of nozzles
5.5.1 Function of release element for automatic nozzles
The nozzle shall be mounted as intended. The test pressure shall be applied as described in Table 2. Heat
in excess of the nozzle’s operating temperature shall be applied until the nozzle is activated.
NOTE Typically the heat applied is in excess of 400 °C.
Continue heating until the water mist nozzle has operated. The water shall be discharged until any
lodgement has been cleared.
If the nozzle does not operate within the first 3 min after commencement of heat exposure the test has
failed. Further investigation shall be made by the manufacturer on why the test failed.
Test every water mist nozzle type and size at the pressure specified in Table 2. At least 11 water mist
nozzles of each temperature rating shall be tested.
Table 2 — Functional Test Parameters
Test pressure Minimum quantity Minimum for each Maximum failure
operating rate
tested
temperature
bar
a b
Minimum stand-by pressure 8 3 1 per 12
b
Minimum operating pressure 8 4 1 per 32
b
Maximum operating pressure 8 4 1 per 32
a
If the minimum stand-by pressure not declared by the manufacturer, (0,35 ± 0,05) bar shall be applied.
b
Should one of the minimum quantity tested nozzles per pressure stage fail, more nozzles may be tested
to meet the maximum failure rate.
The flowing pressure after operation shall be at least 75 % of the initial test pressure. Measure the oven
temperature local to the water mist nozzle.
Lodgement, being a failure, shall be deemed to have occurred when one or more of the released parts
lodge in the deflector frame assembly in such a way as to cause the spray pattern to be significantly
impeded for a period of more than 1 min.
5.5.2 Functional test for open nozzles with blow-off caps
Subject 2 water mist nozzles and blow-off cap assemblies to 75 % of the minimum operating pressure.
The pressure shall be fully applied immediately. The time needed to build up the pressure shall be
recorded. Check that the blow-off cap is fully released in all cases.
5.5.3 Verification functional test
The nozzle shall be mounted as intended. The test pressure shall be applied as described in Table 3. Heat
in excess of the nozzle’s operating temperature shall be applied until the nozzle is activated.
NOTE Typically the heat applied is in excess of 400 °C.
Continue heating until the water mist nozzle has operated.
If the nozzle does not operate within the first 3 min after commencement of heat exposure the test is
failed. Further investigation shall be made by the manufacturer on why the test failed.
Table 3 — Secondary Functional Test Parameters
Test pressure Minimum quantity Maximum
tested lodgement rate
bar
a
Minimum stand-by pressure According to test Disregard
procedures
a
If the minimum stand-by pressure is not declared by the manufacturer,
(0,35 ± 0,05) bar shall be applied.
5.6 Strength of nozzle body and deflector tests
5.6.1 Mechanical strength test
The service load shall be specified by the manufacturer. The service load shall be verified by the test
laboratory according to Annex E.
NOTE The service load is the load which the manufacturer specifies as applied load on the release element
(while being assembled in the nozzle).
Apply a load progressively at a rate not exceeding 5 000 N/min until twice the measured service load has
been reached.
If the load cannot be applied in a mechanical way, it shall be applied via water pressure. Taking the
documentation into account, the water pressure needed inside the nozzle can be calculated with
Formula (2).
F
p 2× (2)
A
where
p is the water pressure in Pa;
F is the measured service load in N;
A is the area of the bulb seat in m .
This load shall be maintained for (15 ± 5) s.
Remove the load and measure any permanent elongation of the water mist nozzle body.
5.6.2 Hydrostatic strength test
Taking the documentation into account, apply water pressure inside the nozzle calculated with
Formula (3).
F
p 2× (3)
A
where
p is the water pressure in Pa;
F is the measured service load in N;
A is the area of the bulb seat in m .
This pressure shall be maintained for 5 min then remove the pressure.
5.6.3 Strength of nozzle deflector and its supporting or moving parts test
Three nozzles shall be individually tested in their intended mounting position with water flowing at
125 % of the maximum operating pressure, for a period of at least 15 min.
5.7 Strength of release elements test for automatic nozzles
5.7.1 General
These tests shall be conducted at an ambient temperature of (20 ± 5) °C.
=
=
5.7.2 Automatic nozzles using glass bulbs
The bulb strength shall be measured by utilizing a compression testing machine to apply a steadily
increasing load until the bulb fractures.
This test shall be conducted with at least 55 sample bulbs in the lowest temperature rating of each bulb
type positioned in their seating parts used in the nozzle or equivalent seats and subjected to a uniformly
increasing force at a rate not exceeding 275 N/s in the test machine or at a rate that deflects the bulb
0,50 mm per minute whichever measurement is convenient for the test apparatus being used. For
calculation only the 50 lowest bulb strength values are used.
The crush force shall be recorded for each bulb, and the average crush force shall be calculated.
5.7.3 Automatic nozzles using fusible links
Fusible release elements shall be subjected to loads in excess of the maximum design load L , which
d
produce failure within and after 1 000 h. At least 10 samples shall be subjected to different loads up to
15 times the maximum design load. Abnormal failures which are not related to evaluation of the fusible
material shall be rejected. A full logarithmic regression analysis using the method of least squares shall
be performed. From the analysis, the maximum design load shall be calculated using the load causing
failure at 1 h, L , and the load causing failure at 1000 h, L , according to Formula (4).
o m
1,02 L
m
L ≤ (4)
d
L
o
where
L is the maximum design load, [N];
d
L is the load causing failure at 1 h, [N];
o
L is the load causing failure at 1 000 h, [N].
m
5.8 Leak resistance test
4 nozzles shall be subjected to this leak resistance test. The pressure shall be increased from 0 bar to
1,5 times of the maximum operating pressure, maintained for a period of 10 min, and then decreased to
0 bar.
Examine the water mist nozzle for evidence of leakage during the test.
5.9 Heat exposure for automatic nozzles using glass bulbs
Glass bulb nozzles shall be heated in a liquid bath. The liquid bath shall be at a temperature of (20 ± 5) °C
when the nozzles are submerged. Then the bath shall be heated to a temperature of (20 ± 2) °C below the
nominal operating temperature of the nozzles. The rate of increase of temperature shall not exceed
20 °C/min. Water shall be used for nozzles having a temperature rating not greater than 93 °C. An oil or
glycerine having a flash point exceeding the test temperature shall be used for higher temperature rated
nozzles.
This temperature shall then be increased at a rate of 1 °C/min to the temperature at which the gas bubble
dissolves, or to a temperature 5 °C less than the lower limit of the operating temperature range,
whichever is lower. The nozzle shall be removed from the liquid bath and cooled in air until the gas bubble
forms again. During the cooling period, the pointed end of the glass bulb (seal end) shall be pointing
downwards. This test shall be performed 4 times on each of 4 nozzles.
5.10 Thermal shock test
Before starting the test, a minimum of 4 nozzles of the highest glass bulb temperature specified by the
manufacturer shall be conditioned at a temperature of (20 ± 5) °C for at least 30 min.
These nozzles shall be heated to (10 ± 2) °C below their lower tolerance operating temperature. The
lowe
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