4.0 Methods
of Test [7]
4.1 General
The following tests should be conducted for each type of
nozzle. Before testing, precise drawings of parts and the assembly
should be submitted together with the appropriate specifications (using
SI units). Tests should be carried out at an ambient temperature of
(20,±5)°C, unless other temperatures are indicated.
4.2 Visual examination
[7.2]
Before testing, nozzles should be examined visually with
respect to the following points:
4.3 Body strength [7.3]
4.3.1 The design load should be measured on ten
automatic nozzles by securely installing each nozzle at room temperature,
in a tensile/compression test machine and applying a force equivalent
to the application of the rated working pressure.
An indicator capable of reading deflection to an accuracy
of 0.01 mm should be used to measure any change in length of the nozzle
between its load bearing points. Movement of the nozzle shank thread
in the threaded bushing of the test machine should be avoided or taken
into account.
The hydraulic pressure and load is then released and the
heat responsive element is then removed by a suitable method. When
the nozzle is at room temperature, a second measurement is to be made
using the indicator.
An increasing mechanical load to the nozzle is then applied
at a rate not exceeding 500 N/minute, until the indicator reading
at the load bearing point initially measured returns to the initial
value achieved under hydrostatic load. The mechanical load necessary
to achieve this should be recorded as the service load. Calculate
the average service load.
4.3.2 The applied load is then progressively increased
at a rate not exceeding 500 N/minute on each of the five specimens
until twice the average service load has been applied. Maintain this
load for 15 ± 5 s.
The load is then removed and any permanent elongation as
defined in 3.6 is recorded.
4.4 Leak resistance and
hydrostatic strength tests (see
3.8
)
[7.4]
4.4.1 Twenty nozzles should be subjected to a
water pressure of twice their rated working pressure, but not less
than 34.5 bar. The pressure is increased from 0 bar to the test pressure,
maintained at twice rated working pressure for a period of 3 min and
then decreased to 0 bar. After the pressure has returned to 0 bar,
it is increased to the minimum operating pressure specified by the
manufacturer in not more than 5 s. This pressure is to be maintained
for 15 s and then increased to rated working pressure and maintained
for 15 s.
4.4.2 Following the test of 4.4.1, the twenty nozzles should
be subjected to an internal hydrostatic pressure of four times the
rated working pressure. The pressure is increased from 0 bar to four
times the rated working pressure and held there for a period of 1
minute. The nozzle under test should not rupture, operate or release
any of its operating parts during the pressure increase nor while
being maintained at four times the rated working pressure for 1 minute.
4.5 Functional test (see
3.5
) [7.5]
4.5.1 Nozzles having nominal release temperatures
less than 78°C, should be heated to activation in an oven. While
being heated, they should be subjected to each of the water pressures
specified in 4.5.3 applied
to their inlet. The temperature of the oven should be increased to
400 ± 20°C in 3 min measured in close proximity to the
nozzle. Nozzles having nominal release temperatures exceeding 78°C
should be heated using a suitable heat source. Heating should continue
until the nozzle has activated.
4.5.2 Eight nozzles should be tested in each normal
mounting position and at pressures equivalent to the minimum operating
pressure, the rated working pressure and the the average operating
pressure. The flowing pressure should be at least 75% of the initial
operating pressure.
4.5.3 If lodgement occurs in the release mechanism
at any operating pressure and mounting position, 24 more nozzles should
be tested in that mounting position and at that pressure. The total
number of nozzles for which lodgement occurs should not exceed 1 in
the 32 tested at that pressure and mounting position.
4.5.4 Lodgement is considered to have occurred
when one or more of the released parts lodge in the discharge assembly
in such a way a to cause the water distribution to be altered after
the period of time specified in 3.5.1.
4.5.5 In order to check the strength of the deflector/orifice
assembly, three nozzles should be submitted to the functional test
in each normal mounting position at 125 percent of the rated working
pressure. The water should be allowed to flow at 125 percent of the
rated working pressure for a period of 15 min.
4.6 Heat responsive element
operating characteristics
4.6.1 Operating temperature test (see
3.3
) [7.6]
Ten nozzles should be heated from room temperature to 20
to 22°C below their nominal release temperature. The rate of increase
of temperature should not exceed 20°C/min and the temperature
should be maintained for 10 min. The temeprature should then be increased
at a rate between 0.4°C/min to 0.7°C/min until the nozzle
operates.
The nominal operating temperature should be ascertained
with equipment having an accuracy of ±0.35% of the nominal
temperature rating or ±0.25°C, whichever is greater.
The test should be conducted in a water bath for nozzles
or separate glass bulbs having nominal release temperatures less than
or equal to 80°C. A suitable oil should be used for higher-rated
release elements. The liquid bath should be constructed in such a
way that the temperature deviation within the test zone does not exceed
0.5%, or 0.5°C, whichever is greater.
4.6.2 Dynamic heating test (see
3.4
)
4.6.2.1 Plunge test
Tests should be conducted to determine the standard and
worst case orientations as defined in 1.4 and 1.5. Ten additional
plunge test should be performed at both of the identified orientations.
The worst case orientation should be as defined in 3.14.1. The RTI is calculated as
described in 4.6.2.3 and 4.6.2.4 for
each orientation, respectively. The plunge tests are to be conducted
using a brass nozzle mount designed such that the mount or water temperature
rise does not exceed 2°C for the duration of an individual plunge
test up to a response time of 55 s. (The temperature should be measured
by a thermocouple heatsinked and embedded in the mount not more than
8 mm radially outward from the root diameter of the internal thread
or by a thermocouple located in the water at the centre of the nozzle
inlet.) If the response time is greater than 55 s, then the mount
or water temperature in degrees Celsius should not increase more than
0.036 times the response time in seconds for the duration of an individual
plunge test.
The nozzle under test should have 1 to 1.5 wraps of PTFE
sealant tape applied to the nozzle threads. It should be screwed into
a mount to a torque of 15 ± 3 Nm. Each nozzle is to be mounted
on a tunnel test section cover and maintained in a conditioning chamber
to allow the nozzle and cover to reach ambient temperature for a period
of not less than 30 min.
At least 25 ml of water, conditioned to ambient temperature,
should be introduced into the nozzle inlet prior to testing. A time
accurate to ±0.01 s with suitable measuring devices to sense
the time between when the nozzle is plunged into the tunnel and the
time it operates should be utilized to obtain the response time.
A tunnel should be utilized with air flow and temperature
conditionsfootnote at the test section (nozzle
location) selected from the appropriate range of conditions shown
in table 2. To minimize
radiation exchange between the sensing element and the boundaries
confining the flow, the test section of the apparatus should be designed
to limit radiation effects to within ±3% of calculated RTI
valuesfootnote.
Table 2 Plunge Oven Test
Conditions
|
|
Air Temperature ranges 4
|
Velocity ranges 5
|
| Normal
Temperature, ºC
|
Standard
Response, ºC
|
Special
response, ºC
|
Fast
Response, ºC
|
Standard
Response, m/s
|
Special
response, m/s
|
Fast Response
Nozzle, m/s
|
| 57 to
77
|
191 to
203
|
129 to
141
|
129 to
141
|
2.4 to
2.6
|
2.4 to
2.6
|
1.65 to
1.85
|
| 79 to
107
|
282 to
300
|
191 to
203
|
191 to
203
|
2.4 to
2.6
|
2.4 to
2.6
|
1.65 to
1.85
|
| 121 to
149
|
382 to
432
|
282 to
300
|
282 to
300
|
2.4 to
2.6
|
2.4 to
2.6
|
1.65 to
1.85
|
| 163 to
191
|
382 to
432
|
382 to
432
|
382 to
432
|
3.4 to
3.6
|
2.4 to
2.6
|
1.65 to
1.85
|
| 4.The selected air temperature
should be known and maintained constant within the test section
throughout the test section throughout the test to an accuracy of
+/- 1 ºC for the air temperature range of 129 to 141 ºC within the
test section and within +/- 2 ºC for all other air
temperatures.
|
| 5. The selected air velocity
should be known and maintained constant throughout the test to an
accuracy of +/-0.03 m/s fpr velocities of 1.65 to 1.85 and 2.4 to
2.6 m/s and +/-0.04 for velocities 3.4 to 3.6 m/s.
|
The range of permissible tunnel operating conditions is
shown in table 2. The selected
operating condition should be maintained for the duration of the test
with the tolerances as specified by footnotes 10 and 11 in table 2.
4.6.2.2 Determination of Conductivity Factor (C)
[7.6.2.2]
The conductivity factor (C) should be determined using the
prolonged plunge test (see 4.6.2.2.1) or the prolonged exposure ramp
test (see 4.6.2.2.2).
4.6.2.2.1 Prolonged Plunge Test [7.6.2.2.1]
The prolonged plunge test is an iterative process to determine
C and may require up to twenty nozzle samples. A new nozzle sample
must be used for each test in this section even if the sample does
not operate during the prolonged plunge test.
The nozzle under test should have 1 to 1.5 wraps of PTFE
sealant tape applied to the nozzle threads. It should be screwed into
a mount to a torque of 15 + 3 Nm. Each nozzle is to be mounted on
a tunnel test section cover and maintained in a conditioning chamber
to allow the nozzle and cover to reach ambient temperature for a period
of not less than 30 min. At least 25 ml of water, conditioned to ambient
temperature, should be introduced into the nozzle inlet prior to testing.
A timer accurate to ±0.01 s with suitable measuring
devices to sense the time between when the nozzle is plunged into
the tunnel and the time it operates should be utilized to obtain the
response time.
The mount temperature should be maintained at 20 ±
0.5°C for the duration of each test. The air velocity in the tunnel
test section at the nozzle location should be maintained with ±2%
of the selected velocity. Air temperature should be selected and maintained
during the test as specified in table
3.
Table 3 Plunge Oven
Test Conditions for Conductivity Determinations
| Nominal
nozzle temperature, ºC
|
Oven
temperature, ºC
|
Maximum
variation of air temperature during test, ºC
|
| 57
|
85 to 91
|
± 1.0
|
| 58 to 77
|
124 to 130
|
± 1.5
|
| 78 to 107
|
193 to 201
|
± 3.0
|
| 121 to 149
|
287 to 295
|
± 4.5
|
| 163 to 191
|
402 to 412
|
± 6.0
|
The range of permissible tunnel operating conditions is
shown in table 3. The selected
operating condition should be maintained for the duration of the test
with the tolerances as specified in table
3.
To determine C, the nozzle is immersed in the test stream
at various air velocities for a maximum of 15 minfootnote. Velocities are chosen such that actuation
is bracketed between two successive test velocities. That is, two
velocities must be established such that at the lower velocity (u1)
actuation does not occur in the 15 min test interval. At the next
higher velocity (uh), actuation must occur within the 15
min time limit. If the nozzle does not operate at the highest velocity,
select an air temperature from table
3 for the next temperature rating.
Test velocity selection should insure that:
The test value of C is the average of the values calculated
at the two velocities using the following equation:
where:
|
Δ T
g
|
= |
Actual gas (air) temperature minus the mount temperature (Tm)
in °C. |
|
Δ T
ea
|
= |
Mean liquid bath operating temperature minus the mount temperature
(Tm) in °C. |
|
u |
= |
Actual air velocity
in the test section in m/s. |
The nozzle C value is determined by repeating the bracketing
procedure three times and calculating the numerical average of the
three C values. This nozzle C value is used to calculate all standard
orientation RTI values for determining compliance with 3.14.1.
4.6.2.2.2 Prolonged Exposure Ramp Test [7.6.2.2.2]
The prolonged exposure ramp test for the determination of
the parameter C should be carried out in the test section of a wind
tunnel and with the requirements for the temperature in the nozzle
mount as described for the dynamic heating test. A preconditioning
of the nozzle is not necessary.
Ten samples should be tested of each nozzle type, all nozzles
positioned in standard orientation. The nozzle should be plunged into
an air stream of a constant velocity of 1 m/s ± 10% and an
air temperature at the nominal temperature of the nozzle at the beginning
of the test.
The air temperature should then be increased at a rate of
1 ± 0.25°C/min until the nozzle operates. The air temperature,
velocity and mount temperature should be controlled from the initiation
of the rate of rise and should be measured and recorded at nozzle
operation. The C value is determined using the same equation as in
4.6.2.2.1 as the average of the ten test values.
4.6.2.3 RTI Value Calculation [7.6.2.3]
The equation used to determine the RTI value is a follows:
where:
|
t
r
|
= |
response
time of nozzles in seconds |
|
u
|
= |
Actual air velocity
in the test section of the tunnel in m/s from table 2
|
|
ΔT
ea
|
= |
Mean
liquid bath operating temperature of the nozzle minus the ambient
temperature in °C |
|
ΔT
g
|
= |
Actual
air temperature in the test section minus the ambient temperature
in °C |
|
C |
= |
Conductivity factor as determined
in 4.6.2.2 |
4.6.2.4 Determination of Worst Case Orientation
RTI
The equation used to determine the RTI for the worst case
orientation is as follows:
where:
|
t
r-wc
|
= |
Response
time of the nozzles in seconds for the worst case orientation |
All variables are known at this time per the equation in
paragraph 4.6.2.3 except RTIwc (Response Time Index for
the worst case orientation) which can be solved iteratively per the
above equation.
In the case of fast response nozzles, if a solution for
the worse case orientation RTI is unattainable, plunge testing in
the worst case orientation should be repeated using the plunge test
conditions under Special Response shown in table 2.
4.7 Heat Exposure Test
[7.7]
4.7.1 Glass Bulb Nozzles (see
3.9.1
)
Glass bulb nozzles having nominal release temperatures less
than or equal to 80°C should be heated in a water bath from a
temperature of (20 ± 5)°C to (20 ± 2)°C below
their nominal release temperature. The rate of increase of temperature
should not exceed 20°C/min. High temperature oil, such as silicone
oil should be used for higher temperature rated release elements.
This temperature should 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 lower than the nominal operating temperature, whichever is
lower. Remove the nozzle from the liquid bath and allow it to cool
in air until the gas bubble has formed again. during the cooling period,
the pointed end of the glass bulb (seal end) should be pointing downwards.
This test should be performed four times on each of four nozzles.
4.7.2 All Uncoated Nozzles (see
3.9.2
) [7.7.2]
Twelve uncoated nozzles should be exposed for a period of
90 days to a high ambient temperature that is 11°C below the nominal
rating or at the temperature shown in table 4, whichever is lower, but not less than 49°C. If
the service load is dependent on the service pressure, nozzles should
be tested under the rated working pressure. After exposure, four of
the nozzles should be subjected to the tests specified in 4.4.1, four nozzles to the test
of 4.5.1. two at the minimum
operating pressure and two at the rated working pressure, and four
nozzles to the requirements 3.3.
If a nozzle fails the applicable requirements of a test, eight additional
nozzles should be tested as described above and subjected to the test
in which the failure was recorded. All eight nozzles should comply
with the test requirements.
Table 4 Test Temperatures
for Coated and Uncoated Nozzles
| Values in degrees Celsius
|
| Nominal release
temperature
|
Uncoated nozzle
test temperature
|
Coated nozzle
test temperature
|
| 57–60
|
49
|
49
|
| 61–77
|
52
|
49
|
| 78–107
|
79
|
66
|
| 108–149
|
121
|
107
|
| 150 to 191
|
149
|
149
|
| 192–246
|
191
|
191
|
| 247–302
|
246
|
246
|
| 303–343
|
302
|
302
|
4.7.3 Coated Nozzles (see
3.9.3
) [7.7.3]
In addition to the exposure test of 4.7.2 in an uncoated version, twelve
coated nozzles should be exposed to the test of 4.7.2 using the temperatures
shown in table 4 for coated
nozzles.
The test should be conducted for 90 days. During this period,
the sample should be removed from the oven at intervals of approximately
7 days and allowed to cool for 2 h to 4 h. During this cooling period,
the sample should be examined. After exposure, four of the nozzles
should be subjected to the tests specified in 4.4.1, four nozzles to the test
of 4.5.1; two at the minimum
operating pressure and two at the rated working pressure, and four
nozzles to the requirements of 3.3.
4.8 Thermal Shock Test
for Glass Bulb Nozzles (see
3.10
)
[7.8]
Before starting the test, condition at least 24 nozzles
at room temperature of 20 to 25°C for at least 30 min.
The nozzles should be immersed in a bath of liquid, the
temperature of which should be 10 ± 2°C below the nominal
release temperature of the nozzles. After 5 min, the nozzles are to
be remove from the bath and immersed immediately in another bath of
liquid, with the bulb seal downwards, at a temperature of 10 ±
1°C. Then test the nozzles in accordance with 4.5.1.
4.9 Strength Test for
Release Elements [7.9]
4.9.1 Glass Bulbs (see
3.7.1
) [7.9.1]
At least 15 sample bulbs in the lowest temperature rating
of each bulb type should be positioned individually in a test fixture
using the sprinkler seating parts. Each bulb should then be subjected
to a uniformly increasing force at a rate not exceeding 250 N/s in
the test machine until the bulb fails.
Each test should be conducted with the bulb mounted in new
seating parts. The mounting device may be reinforced externally to
prevent its collapse, but in a manner which does not interfere with
bulb failure.
Record the failure load for each bulb. Calculate the lower
tolerance limit (TL1) for bulb strength. Using the values of service
load recorded in 4.3.1, calculate
the upper tolerance limit (TL2) for the bulb design load. Verify compliance
with 3.7.1.
4.9.2 Fusible Elements (see
3.7.2
)
4.10 Water Flow Test
(see
3.4.1
) [7.10]
The nozzle and a pressure gauge should be mounted on a supply
pipe. The water flow should be measured at pressures ranging from
the minimum operating pressure to the rated working pressure at intervals
of approximately 10% of the service pressure range on two sample nozzles.
In one series of tests, the pressure should be increased from zero
to each value and, in the next series, the pressure shall be decreased
from the rated pressure to each value. The flow constant, K, should
be averaged from each series of readings, i.e., increasing pressure
and decreasing pressure. During the test, pressures should be corrected
for differences in height between the gauge and the outlet orifice
of the nozzle.
4.11 Water Distribution
and Droplet Size Tests
4.11.1 Water Distribution (see
3.4.2
)
The tests should be conducted in a test chamber of minimum
dimensions 7 m x 7 m or 300% of the maximum design area being tested,
whichever is greater. For standard automatic nozzles, install a single
open nozzle and then four open nozzles of the same type arranged in
a square, at maximum spacings specified by the manufacturer, on piping
prepared for this purpose. For pilot type nozzles, install a single
nozzle and then the maximum number of slave nozzles at their maximum
spacings, specified in the Manufacturer Design and Installation Instructions.
The distance between the ceiling and the distribution plate
should be 50 mm for upright nozzles and 275 mm for pendent nozzles.
For nozzles without distribution plates, the distances shall be measured
from the ceiling to the highest nozzle outlet.
Recessed, flush and concealed type nozzles should be mounted
in a false ceiling of dimensions not less than 6 m x 6 m and arranged
symmetrically in the test chamber. The nozzles should be fitted directly
into the horizontal pipework by means of “T" or elbow fittings.
The water discharge distribution in the protected area below
a single nozzle and between the multiple nozzles should be collected
and measured by means of square measuring containers nominally 300
mm on a side. The distance between the nozzles and the upper edge
of the measuring containers should be the maximum specified by the
manufacturer. The measuring containers should be positioned centrally,
beneath the single nozzle and beneath the multiple nozzles.
The nozzles should be discharged both at the minimum operating
and rated working pressures specified by the manufacturer and the
minimum and maximum installation heights specified by the manufacturer.
The water should be collected for at least 10 min to assist
in characterizing nozzle performance.
4.11.2 Water Droplet Size (see
3.4.3
)
The mean water droplet diameters. velocities, droplet size
distribution, number density and volume flux should be determined
at both the minimum and maximum flow rates specified by the manufacturer.
Once the data is gathered, the method of the “Standard Practice
for Determining Data Criteria and Processing for Liquid Drop Size
Analysis" (ASTM E799-92) will be used to determine the appropriate
sample size, class size widths, characteristic drop sizes and measured
dispersion of the drop size distribution. This data should be taken
at various points within the spray distribution as described in 3.4.3.
4.12 Corrosion Test
[7.12]
4.12.1 Stress Corrosion
Test for Brass Nozzle Parts (see
3.11.1
)
Five nozzles should be subjected to the following aqueous
ammonia test. The inlet of each nozzle should be sealed with a nonreactive
cap, e.g., plastic.
The samples are degreased and exposed for 10 days to a moist
ammonia-air mixture in a glass container of volume 0.02 ± 0.01
m3.
An aqueous ammonia solution, having a density of 0.94 g/cm3, should be maintained in the bottom of the container, approximately
40 mm below the bottom of the samples. A volume of aqueous ammonia
solution corresponding to 0.01 ml per cubic centimetre of the volume
of the container will give approximately the following atmospheric
concentrations: 35% ammonia, 5% water vapour, and 60% air. The inlet
of each sample should be sealed with a nonreactive cap, e.g. plastic.
The moist ammonia-air mixture should be maintained as closely
as possible at atmospheric pressure, with the temperature maintained
at 34 ± 2°C. Provision should be made for venting the chamber
via a capillary tube to avoid the build-up of pressure. Specimens
should be shielded from condensate drippage.
After exposure, rinse and dry the nozzles, and conduct a
detailed examination. If a crack, delamination or failure of any operating
part is observed, the nozzle(s) should be subjected to a leak resistance
test at the rated pressure for 1 min and to the functional test at
the minimum flowing pressure (see 3.1.5).
Nozzles showing cracking, delamination or failure of any
non-operating part should not show evidence of separation of permanently
attached parts when subjected to flowing water at the rated working
pressure for 30 min.
4.12.2 Stress-Corrosion
Cracking of Stainless Steel Nozzle Parts (see
3.11.1
)
4.12.2.1 Five samples are to be degreased prior
to being exposed to the magnesium chloride solution.
4.12.2.2 Parts used in nozzles are to be place
in a 500-millilitre flask that is fitted with a thermometer and a
wet condenser approximately 760 mm long. the flask is to be filled
approximately one-half full with 42% by weight magnesium chloride
solution, placed on a thermostatically-controlled electrically heated
mantel, and maintained at a boiling temperature of 150 ± 1°C.
The parts are to be unassembled, that is, not contained in a nozzle
assembly. The exposure is to last for 500 hours.
4.12.2.3 After exposure period, the test samples
are to be removed from the boiling magnesium chloride solution and
rinsed in deionized water.
4.12.2.4 The test samples are then to be examined
using a microscope having a magnification of 25X for any cracking,
delamination, or other degradation as a result of the test exposure.
Test samples exhibiting degradation are to be tested as described
in 4.12.5.5 or 4.12.5.6,
as applicable. test samples not exhibiting degradation are considered
acceptable without further test.
4.12.2.5 Operating parts exhibiting degradation
are to be further tested as follows. Five new sets of parts are to
be assembled in nozzle frames made of materials that do not alter
the corrosive effects of the magnesium chloride solution on the stainless
steel parts. These test samples are to be degreased and subjected
to the magnesium chloride solution exposure specified in paragraph 4.12.5.2. following the exposure,
the test samples should withstand, without leakage, a hydrostatic
test pressure equal to the rated working pressure for 1 minute and
then be subjected to the functional test at the minimum operating
pressure in accordance with 4.5.1.
4.12.2.6 Non-operating parts exhibiting degradation
are to be further tested as follows. Five new sets of parts are to
be assembled in nozzle frames made of materials that do not alter
the corrosive effects of the magnesium chloride solution on the stainless
steel parts. These test samples are to be degreased and subjected
to the magnesium chloride solution exposure specified in paragraph 4.12.5.1. Following the exposure,
the test samples should withstand a flowing pressure equal to the
rated working pressure for 30 minutes without separation of permanently
attached parts.
4.12.3 Sulphur Dioxide
Corrosion Test (see
3.11.2
and
3.14.2
)
Ten nozzles should be subjected to the following sulphur
dioxide corrosion test. The inlet of each sample should be sealed
with a nonreactive cap, e.g. plastic.
The test equipment should consist of a 5 litre vessel (instead
of a 5 litre vessel, other volumes up to 15 litre may be used in which
case the quantities of chemicals given below shall be increased in
proportion) made of heat-resistant glass, with a corrosion-resistant
lid of such a shape as to prevent condensate dripping on the nozzles.
The vessel should be electrically heated through the base, and provided
with a cooling coil around the side walls. A temperature sensor placed
centrally 160 mm ± 20 mm above the bottom of the vessel should
regulate the heating so that the temperature inside the glass vessel
is 45°C ± 3°C. During the test, water should flow through
the cooling coil at a sufficient rate to keep the temperature of the
discharge water below 30°C. This combination of heating and cooling
should encourage condensation on the surfaces of the nozzles. The
sample nozzles should be shielded from condensate drippage.
The nozzles to be tested should be suspended in their normal
mounting position under the lid inside the vessel and subjected to
a corrosive sulphur dioxide atmosphere for 8 days. The corrosive atmosphere
should be obtained by introducing a solution made up by dissolving
20 g of sodium thiosulphate (Na2S2O3H2O) crystals in 500 ml of water.
For at least six days of the 8-day exposure period, 20 ml
of dilute sulphuric acid consisting of 156 ml of normal H2SO4 (0.5 mol/liter) diluted with 844 ml of water should be added
at a constant rate. After 8 days, the nozzles should be removed form
the container and allowed to dry for 4 to 7 days at a temperature
not exceeding 35°C with a relative humidity not greater than 70%.
After the drying period. five nozzles should be subjected
to a functional test at the minimum operating pressure in accordance
with 4.5.1 and five nozzles
should be subjected to the dynamic heating test in accordance with 3.14.2.
4.12.4 Salt Spray
Corrosion Test (see
3.11.3
and
3.14.2
) [7.12.3]
4.12.4.1 Nozzles Intended for Normal Atmospheres
Ten nozzles should be exposed to a salt spray within a fog
chamber. The inlet of each sample should be sealed with a nonreactive
cap, e.g. plastic.
During the corrosive exposure, the inlet thread orifice
is to be sealed by a plastic cap after the nozzles have been filled
with deionized water. The salt solution should be a 20% by mass sodium
chloride solution in distilled water. The pH should be between 6.5
and 3.2 and the density between 1.126 g/ml and 1.157 g/ml when atomized
at 35°C. Suitable means of controlling the atmosphere in the chamber
should be provided. The specimens should be supported in their normal
operating position and exposed to the salt spray (fog) in a chamber
having a volume of at least 0.43 m3 in which the exposure
zone shall be maintained at a temperature of 35 ± 2°C.
The temperature should be recorded at least once per day, at least
7 hours apart (except weekends and holidays when the chamber normally
would not be opened). Salt solution should be supplied from a recirculating
reservoir through air-aspirating nozzles, at a pressure between 0.7
bar (0.07 MPa) and 1.7 bar (0.17 MPa). Salt solution runoff from exposed
samples should be collected and should not return to the reservoir
for recirculation. The sample nozzles should be shielded from condensate
drippage.
Fog should be collected from at least two points in the
exposure zone to determine the rate of application and salt concentration.
The fog should be such that for each 80 cm2 of collection
area, 1 ml to 2 ml of solution should be collected per hour over a
16 hours period and the salt concentration shall be 20 ± 1%
by mass.
The nozzles should withstand exposure to the salt for a
period of 10 days. After this period, the nozzles should be removed
from the fog chamber and allowed to dry for 4 to 7 days at a temperature
of 20 to 25°C in an atmosphere having a relative humidity not
greater than 70%. Following the drying period, five nozzles should
be submitted to the functional test at the minimum operating pressure
in accordance with 4.5.1 and
five nozzles should be subjected to the dynamic heating test in accordance
with 3.14.2.
4.12.4.2 Nozzles Intended for Corrosive Atmospheres
[7.12.3.2]
Five nozzles should be subjected to the tests specified
in 4.12.3.1 except that
the duration of the salt spray exposure shall be extended from 10
days to 30 days.
4.12.5 Moist Air Exposure
Test (see
3.11.4
and
3.14.2
) [7.12.4]
Ten nozzles should be exposed to a high temperature-humidity
atmosphere consisting of a relative humidity of 98% ± 2% and
a temperature of 95°C ± 4°C. The nozzles are to be
installed on a pipe manifold containing deionized water. The entire
manifold is to be placed in the high temperature humidity enclosure
for 90 days. After this period, the nozzles should be removed from
the temperature-humidity enclosure and allowed to dry for 4-7 days
at a temperature of 25 ± 5°C in an atmosphere having a
relative humidity of not greater than 70%. Following the drying period,
five nozzles should be functionally tested at the minimum operating
pressure in accordance with 4.5.1 and
five nozzles should be subjected to the dynamic heating test in accordance
with 3.14.2.
At the manufacturer's option, additional samples may be
furnished for this test to provide early evidence of failure. The
additional samples may be removed from the test chamber at 30-day
intervals for testing.
4.13 Nozzle Coating
Tests [7.13]
4.13.1 Evaporation Test (see
3.12.1
) [7.13.1]
A 50 cm3 sample of wax or bitumen should be placed
in a metal or glass cylindrical container, having a flat bottom, an
internal diameter of 55 mm and an internal height of 35 mm. The container,
without lid, should be placed in an automatically controlled electric,
constant ambient temperature oven with air circulation. The temperature
in the oven should be controlled at 16°C below the nominal release
temperature of the nozzle, but at not less than 50°C. The sample
should be weighed before and after 90 days exposure to determine any
loss of volatile matter; the sample should meet the requirements of
3.12.1.
4.13.2 Low-Temperature Test (see
3.12.2
) [7.13.2]
Five nozzles, coated by normal production methods, whether
with wax, bitumen or a metallic coating, should be subjected to a
temperature of -10°C for a period of 24 hours. On removal from
the low-temperature cabinet, the nozzles should be exposed to normal
ambient temperature for a least 30 min before examination of the coating
to the requirements of 3.12.2.
4.14 Heat-Resistance
Test (see
3.15
) [7.14]
One nozzle body should be heated in an oven at 800°C
for a period of 15 min, with the nozzle in its normal installed position.
The nozzle body should then be removed, holding it by the threaded
inlet, and should be promptly immersed in a water bath at a temperature
of approximately 15°C. It should meet the requirements of 3.15.
4.15 Water-Hammer Test
(see
3.13
) [7.15]
Five nozzles should be connected, in their normal operating
position, to the test equipment. After purging the air from the nozzles
and the test equipment, 3,000 cycles of pressure varying from 4 ±
2 bar ((0.4 ± 0.2)MPa) to twice the rated working pressure
should be generated. The pressure should be raised from 4 bar to twice
the rated working pressure at a rate of 60 ± 10 bar/s. At least
30 cycles of pressure per minute should be generated. The pressure
should be measured with an electrical pressure transducer.
Visually examine each nozzle for leakage during the test.
After the test, each nozzle should meet the leakage resistance requirement
of 3.8.1 and the functional
requirements of 3.5.1 at the
minimum operating pressure.
4.16 Vibration Test
(see
3.16
) [7.16]
4.16.1 Five nozzles should be fixed vertically
to a vibration table. They should be subjected at room temperature
to sinusoidal vibrations. The direction of vibration should be along
the axis of the connecting thread.
4.16.2 The nozzles should be vibrated continuously
from 5 Hz to 40 Hz at a maximum rate of 5 min/octave and an amplitude
of 1 mm (1/2 peak-to-peak value). If one or more resonant points are
detected, the nozzles after coming to 40 Hz, should be vibrated at
each of these resonant frequencies for 120 hours/number of resonances.
If no resonances are detected, the vibration from 5 Hz to 40 Hz should
be continued for 120 hours.
4.16.3 The nozzle should then be subjected to
the leakage test in accordance with 3.8.1 and the functional test in accordance with 3.5.1 at the minimum operating pressure.
4.17 Impact Test (see
3.17
) [7.17]
Five nozzles should be tested by dropping a mass onto the
nozzle along the axial centreline of waterway. The kinetic energy
of the dropped mass at the point of impact should be equivalent to
a mass equal to that of the test nozzle dropped from a height 1 m.
See Figure 2. The mass is
to be prevented from impacting more than once upon each sample.
Figure 2 Impact Test Apparatus
Following the test a visual examination of each nozzle shall
show no signs of fracture, deformation, or other deficiency. If none
is detected, the nozzles should be subjected top the leak resistance
test, described in 4.4.1.
Following the leakage test, each sample should meet the functional
test requirement of 4.5.1 at
a pressure equal to the minimum flowing pressure.
4.18 Lateral Discharge
Test (see
3.18
) [7.19]
Water is to be discharged from a spray nozzle at the minimum
operating and rated working pressure. A second automatic nozzle located
at the minimum distance specified by the manufacturer is mounted on
a pipe parallel to the pipe discharging water.
The nozzle orifices or distribution plates (if used), are
to be placed 550 mm, 356 mm and 152 mm below a flat smooth ceiling
for three separate tests, respectively at each test pressure. The
top of a square pan measuring 305 mm square and 102 mm deep is to
be positioned 152 mm below the heat responsive element for each test.
The pan is filled with 0.47 litres of heptane. After ignition the
automatic nozzle is to operate before the heptane is consumed.
4.19 30 Day Leakage
Test (see
3.19
) [7.20]
Five nozzles are to be installed on a water filled test
line maintained under a constant pressure of twice the rated working
pressure for 30 days at an ambient temperature of (20 ± 5°C).
The nozzles should be inspected visually at least weekly
for leakage. Following completion of this 30 day test, all samples
should meet the leak resistance requirements specified in 3.2.4 and should exhibit no evidence
of distortion or other mechanical damage.
4.20 Vacuum Test (see
3.20
) [7.21]
Three nozzles should be subjected to a vacuum of 460 mm
of mercury applied to a nozzle inlet for 1 min at an ambient temperature
of (20 ± 5°C). Following this test, each sample should
be examined to verify that no distortion or mechanical damage has
occurred and then should meet the leak resistance requirements specified
in 4.4.1.
4.21 Clogging Test (see
3.22
) [7.28]
4.21.1 The water flow rate of an open water mist
nozzle with its strainer or filter should be measured at its rated
working pressure. The nozzle and strainer or filter should then be
installed in test apparatus described in Figure 3 and subjected to 30 minutes
of continuous flow at rated working pressure using contaminated water
which has been prepared in accordance with 4.21.3.
Figure 3 Clogging test apparatus
4.21.2 Immediately following the 30 minutes of
continuous flow with contaminated water, the flow rate of the nozzle
and strainer or filter should be measured at rated working pressure.
No removal, cleaning or flushing of the nozzle, filter or strainer
is permitted during the test.
4.21.3 The water used during the 30 minutes of
continuous flow at rated working pressure specified in 4.21.1 should
consist of 60 litres of tap water into which has been mixed 1.58 kilograms
of contaminants which sieve as described in table 6. The solution should be
continuously agitated during the test.
Table 6 Contaminant for the
Contaminated Water Cycling Test
| SIEVE DESIGNATION
*
|
NOMINAL SIEVE OPENING,
MM
|
GRAMS OF CONTAMINANT (± 5
PERCENT)
|
| PIPE
SCALE
|
TOP SOIL
|
SAND
|
| No.
25
|
0.706
|
—
|
456
|
200
|
| No.
50
|
0.297
|
82
|
82
|
327
|
| No.
100
|
0.150
|
84
|
6
|
89
|
| No.
200
|
0.074
|
81
|
—
|
21
|
| No.
325
|
0.043
|
153
|
—
|
3
|
|
|
TOTAL
|
400
|
544
|
640
|
|