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A01263038 23 Feb 12

Designation: G85 – 11

Standard Practice for

Modified Salt Spray (Fog) Testing1
This standard is issued under the fixed designation G85; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.

1. Scope D609 Practice for Preparation of Cold-Rolled Steel Panels

1.1 This practice covers and sets forth conditions for five for Testing Paint, Varnish, Conversion Coatings, and
modifications in salt spray (fog) testing for specification Related Coating Products
purposes. These are in chronological order of their develop- D1141 Practice for the Preparation of Substitute Ocean
ment: Water
1.1.1 Annex A1, acetic acid-salt spray test, continuous. D1193 Specification for Reagent Water
1.1.2 Annex A2, cyclic acidified salt spray test. D1654 Test Method for Evaluation of Painted or Coated
1.1.3 Annex A3, seawater acidified test, cyclic (SWAAT). Specimens Subjected to Corrosive Environments
1.1.4 Annex A4, SO2 salt spray test, cyclic. E70 Test Method for pH of Aqueous Solutions With the
1.1.5 Annex A5, dilute electrolyte cyclic fog dry test. Glass Electrode
1.2 This practice does not prescribe the type of modifica- 3. Significance and Use
tion, test specimen or exposure periods to be used for a specific
product, nor the interpretation to be given to the results. 3.1 This practice is applicable to ferrous and nonferrous
1.3 The values stated in SI units are to be regarded as metals; also organic and inorganic coatings. The variations
standard. No other units of measurement are included in this described herein are useful when a different or more corrosive
standard. environment than the salt fog described in Practice B117 is
1.3.1 Exception—Fahrenheit temperature values are given desired.
for information only throughout this practice. 4. Apparatus
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.1 Cabinet:
responsibility of the user of this standard to consult and 4.1.1 The apparatus required for salt spray (fog) testing
establish appropriate safety and health practices and deter- consists of a fog chamber, a salt solution reservoir, a supply of
mine the applicability of regulatory limitations prior to use. suitably conditioned compressed air, one or more atomizing
nozzles, specimen supports, provision for heating the chamber,
2. Referenced Documents and necessary means of control. The size and detailed con-
2.1 ASTM Standards:2 struction of the cabinet are optional, provided the conditions
B117 Practice for Operating Salt Spray (Fog) Apparatus obtained meet the requirements of this practice. The material of
construction shall be such that it will not affect the corrosive-
ness of the fog. Suitable apparatus that may be used to obtain
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion these conditions is described in Appendix X1 of Practice B117
of Metals and is the direct responsibility of Subcommittee G01.05 on Laboratory with necessary modifications described in each annex of this
Corrosion Tests.
Current edition approved May 1, 2011. Published August 2011. Originally practice.
approved in 1985. Last previous edition approved in 2009 as G85–09. DOI: 4.1.2 Design the cabinet so that drops of solution that
10.1520/G0085-11.
2
accumulate on the ceiling or cover of the chamber do not fall
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
on the specimens being tested. Do not return drops of solution
Standards volume information, refer to the standard’s Document Summary page on that fall from the specimens to the solution reservoir for
the ASTM website. respraying.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.

1
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A01263038 23 Feb 12

G85 – 11
4.1.3 Equip the cabinet with one or more timing devices to form corrosive or inhibitive films. The use of nitric acid
provide for intermittent spraying or periodic introduction of a solution for the chemical cleaning, or passivation, of stainless
gas, or both. steel specimens is permissible when agreed upon between the
4.2 Air Supply: purchaser and the seller. Take care that specimens are not
4.2.1 Make sure the compressed air supply to the nozzle or recontaminated after cleaning by excessive or careless han-
nozzles for atomizing the salt solution is free of oil and dirt and dling.
maintain the air supply between 69 and 172 kPa (10 and 25 5.2.2 Prepare specimens for evaluation of paints and other
psi). organic coatings in accordance with applicable specification(s)
for the material(s) being tested, or as agreed upon between the
NOTE 1—The air supply may be freed of oil and dirt by passing it
through a water scrubber or at least 610 mm (2 ft) of suitable cleaning purchaser and supplier. Otherwise, make sure the test speci-
material such as asbestos, sheep’s wool, or activated alumina. mens consist of steel meeting the requirements of Practice
D609; clean and prepare the specimens for coating in accor-
4.2.2 Temperature in the saturator tower (bubble tower)
dance with applicable procedure of Practice D609.
varies depending on the test method used.
5.2.3 Whenever it is desired to determine the development
4.3 Conditions in Salt-Spray Chamber:
of corrosion from an abraded area in the paint or organic
4.3.1 Temperature—The temperature in the exposure zone
coating, make a scratch or scribed line through the coating with
varies with the test method used. For recommended exposure
a sharp instrument so that the underlying metal is exposed
zone temperatures for the various methods, see the annexes in
before testing. Use the conditions of making the scratch as
this practice. Each set point and its tolerance represents an
defined in Test Method D1654, unless otherwise agreed upon
operational control point for equilibrium conditions at a single
between the purchaser and seller.
location in the cabinet which may not necessarily represent the
5.2.4 Protect the cut edges of plated, coated, or duplex
uniformity of conditions throughout the cabinet. Record the
materials and areas that contain identification marks or that are
temperature within the exposure zone of the closed cabinet at
in contact with the racks or supports with a suitable coating that
least twice a day at least 7 h apart (except on weekends and
is stable under the conditions of the test, such as ceresin wax,
holidays, when the salt spray test is not interrupted for
unless otherwise specified.
exposing, rearranging, or removing test specimens or to check
and replenish the solution in the reservoir). NOTE 4—Should it be desirable to cut test specimens from parts or from
preplated, painted, or otherwise coated-steel sheet, protect the cut edges
NOTE 2—Suitable methods to record the temperature are a continuous by coating them with paint, wax, tape, or other effective media so that the
recording device or a thermometer which can be read from outside the development of preferential attack or a galvanic effect between such edges
closed cabinet. Obtain the recorded temperature with the salt spray and the adjacent plated or otherwise coated-metal surfaces, is prevented.
chamber closed to avoid a false low reading because of wet-bulb effect
when the chamber is open. 6. Salt Solutions
4.3.2 Atomization and Quantity of Fog—Place at least two 6.1 Make the salt solutions by using either synthetic sea salt
clean fog collectors within the exposure zone so that no drops in accordance with Practice D1141 or sodium chloride in
of solution from the test specimens or any other source can be accordance with Practice B117, unless otherwise specified in
collected. Position the collectors in the proximity of the test the appropriate annex. Make-up water shall be distilled or
specimens, one nearest to any nozzle and the other farthest deionized water conforming to Type IV water in Specification
from all nozzles. Make sure that for each 80 cm2 of horizontal- D1193 (except that for this practice, limits for chlorides and
collecting area fog accumulates in each collector from 1.0 to sodium may be ignored).
2.0 mL of solution per hour based on an average run of at least 6.2 Synthetic Sea Salt Solution (see Annex A3)—Make the
16 h continuous spray. salt solution so that it consists of 42 g of synthetic sea salt in
NOTE 3—Suitable collecting devices are glass funnels with the stems accordance with Practice D1141 per litre of solution (see Note
inserted through stoppers into graduated cylinders or crystallizing dishes. 5).
Funnels and dishes with a diameter of 100 mm have an area of about 80 6.3 Sodium Chloride Solution (Except Annex A3 and Annex
cm2. A5):
4.3.3 Direct or baffle the nozzle or nozzles so that none of Prepare the salt solution by dissolving 5 6 1 parts by weight
the spray can impinge directly on the test specimens. of sodium chloride in 95 parts of water conforming to Type IV
water in Specification D1193 (except that for this practice,
5. Test Specimens limits for chlorides and sodium may be ignored) containing not
5.1 Define the type and number of test specimens to be used, more than 200 ppm of total solids (see Note 5). Halides
as well as the criteria for the evaluation of the test results in the (Bromide, Fluoride, and Iodide) other than Chloride shall
specifications covering the material or product being tested or constitute less than 0.1 % by mass of the salt content. Copper
upon mutual agreement between the purchaser and the seller. content shall be less than 0.3 ppm by mass. Sodium chloride
5.2 Preparation of Test Specimens: that has had anti-caking agents added shall not be used because
5.2.1 Clean metallic and metallic-coated specimens. The such agents may act as corrosion inhibitors (see Note 6). See
cleaning method is optional depending on the nature of the Table 1 for a listing of these impurity restrictions. Upon
surface and the contaminants; however, when using a cleaning agreement between the purchaser and the seller, analysis may
method do not include in the contents abrasives other than a be required and limits established for elements or compounds
paste of pure magnesium oxide nor of solvents which may not specified in the chemical composition given above.

2
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A01263038 23 Feb 12

G85 – 11
TABLE 1 Maximum Allowable Limits for Impurity Levels in 7.1.2 Do not allow contact of the specimens between each
Sodium Chloride other, between any metallic material, or between any material
Impurity Description Allowable Amount capable of acting as a wick.
Total Impurities #0.3% 7.1.3 Place each specimen so as to permit free settling of fog
Halides (Bromide, Fluoride and Iodide) < 0.1 % on all specimens. A minimum spacing between specimens of
excluding Chloride
Copper < 0.3 ppm 30 mm is recommended.
Anti-caking Agents None Added 7.1.4 Do not permit the salt solution from one specimen to
drip on any other specimen.
7.1.5 It is recommended that placement of replicate speci-
NOTE 5—The specific gravity of salt solution will change with tem-
mens be randomized to avoid possible bias caused by differ-
perature. Table 2 shows salt concentration and density versus temperature
and can be used to determine if the sample measured is within specifica- ence in spray patterns. Individual specimens may also be
tion. The sample to be measured may be a composite sample from rotated daily for the same reason.
multiple fog-collecting devices within a single cabinet, if necessary, to 7.1.6 Suitable materials for the construction or coating of
obtain sufficient solution volume for measurement. racks and supports are glass, rubber, plastic, or suitably coated
Table 23 shows the salt concentration and salt density of 4%, 5%, and wood. Do not use bare metal. Support specimens preferably
6% salt solution between 20 and 40°C. A measurement that falls within the from the bottom or the side. Slotted wooden, laminated plastic,
range between 4 and 6% is acceptable.
It is important to understand the equipment being used to measure
or inert plastic strips are suitable for the support of flat panels.
specific gravity. One common practice for specific gravity measurement is Suspension from glass hooks or waxed string may be used as
the use of a hydrometer. If used, careful attention to the hydrometer type long as the specified position of the specimens is obtained, and,
is important as most are manufactured and calibrated for measurements at if necessary, by means of secondary support at the bottom of
15.6°C. Since salt density is temperature dependent an offset will be the specimens.
necessary to make an accurate measurement at other temperatures. 7.2 Continuity of Test—Unless otherwise specified in the
Contact the hydrometer manufacturer to find the proper offset for the
specifications covering the material or product being tested, the
hydrometer being used.
NOTE 6—A measurable limit for anti-caking agents is not being defined test shall be continuous for the duration of the entire test
as a result of how salt is manufactured. During salt manufacturing, it is period. Continuous operation implies that the chamber be
common practice to create salt slurry from the raw salt mined. A closed except for the short daily interruptions necessary to
crystallization process then captures the pure salt from this slurry. Some inspect, rearrange, or remove test specimens, to check and
naturally occurring anti-caking agents can be formed in this process and replenish the solution in the reservoir, and to make necessary
are not removed from the resultant product. Avoid salt products where recordings as described in 4.3.1, 4.3.2, and Section 9. (See
extra anti-caking agents are added. Additionally, when doing an elemental
Note 8.)
analysis of salt there can be trace elements present that either stand alone
or are part of an anti-caking agent. It is not economically feasible to know NOTE 8—Operations should be so scheduled that the cumulative
where such elements came from due to the long list of possible anti-caking maximum time for these interruptions are held to 60 min or less per day.
agents that would have to be tested. Therefore a salt product that meets the It is recommended to have only one interruption per day if possible. If
impurity, halide, and copper limits with no anti-caking agents added is interruption time is longer that 60 min, it should be noted in the test report.
acceptable. The salt supplier can provide an analysis of the salt with a
7.3 Period of Test—Designate the period of test in accor-
statement indicating that anti-caking agents were not added to the product.
dance with the specifications covering the material or product
6.4 The pH of the salt solutions will vary depending on the being tested or as mutually agreed upon between the purchaser
test method used. Before the solution is atomized, free it of and the seller. Exposure periods of multiples of 24 h are
suspended solids (see Note 7). Take the pH measurements suggested.
electrometrically at 25°C (77°F) using a glass electrode with a 7.4 Cleaning of Tested Specimens—Unless otherwise speci-
saturated potassium chloride bridge in accordance with Test fied in the specifications covering the material or product being
Method E70. tested, at the end of the test, specimens may be gently washed
NOTE 7—The freshly prepared salt solution may be filtered or decanted or dipped in clean running water no warmer than 38°C (100°F)
before it is placed in the reservoir, or the end of the tube leading from the to remove salt deposits from their surface, and then immedi-
solution to the atomizer may be covered with a double layer of cheesecloth ately dried. Dry with a stream of clean, compressed air.
or suitable nonmetallic filter cloth to prevent plugging of the nozzle.
NOTE 9—Drying with compressed air may not be desirable for alumi-
7. Procedure num specimens to be tested for exfoliation corrosion resistance.

7.1 Position of Specimens During Test: 8. Evaluation of Results

7.1.1 Unless otherwise specified, support or suspend the 8.1 Make a careful and immediate examination for the
specimens between 6 and 45° from the vertical, and preferably extent of corrosion of the dry test specimens or for other failure
parallel to the principal direction of horizontal flow of fog as required by the specifications covering the material or
through the chamber, based upon the dominant surface being product being tested or by agreement between the purchaser
tested. Note that test severity increases as angle from the and the seller.
vertical increases.
9. Report
3
“Thermodynamic Properties of the NaCl + H2O system II. Thermodynamic
9.1 Record the following information, unless otherwise
Properties of NaCl(aq), NaCl.2H2O(cr), and Phase Equilibria,” Journal of Physics prescribed in the specifications covering the material or prod-
and Chemistry Reference Data, Vol 21, No. 4, 1992. uct being tested:

3
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A01263038 23 Feb 12

G85 – 11
TABLE 2 Temperature versus Density Data
Density, g/cm3
Temperature, °C (°F) 4% Salt 5% Salt 6% Salt
Concentration Concentration Concentration
20 (68) 1.025758 1.032360 1.038867
21 (69.8) 1.025480 1.032067 1.038560
22 (71.6) 1.025193 1.031766 1.038245
23 (73.4) 1.024899 1.031458 1.037924
24 (75.2) 1.024596 1.031142 1.037596
25 (77) 1.024286 1.030819 1.037261
26 (78.8) 1.023969 1.030489 1.036919
27 (80.6) 1.023643 1.030152 1.036570
28 (82.4) 1.023311 1.029808 1.036215
29 (84.2) 1.022971 1.029457 1.035853
30 (86) 1.022624 1.029099 1.035485
31 (87.8) 1.022270 1.028735 1.035110
32 (89.6) 1.021910 1.028364 1.034729
33 (91.4) 1.021542 1.027986 1.034343
34 (93.2) 1.021168 1.027602 1.033950
35 (95) 1.020787 1.027212 1.033551
36 (96.8) 1.020399 1.026816 1.033146
37 (98.6) 1.020006 1.026413 1.032735
38 (100.4) 1.019605 1.026005 1.032319
39 (102.2) 1.019199 1.025590 1.031897
40 (104) 1.018786 1.025170 1.031469

9.1.1 Type of salt and water used in preparing the salt pH of collected solution. Sample to be measured may be a
solution, composite sample from multiple fog-collecting devices (within
9.1.2 All readings of temperature within the exposure zone one test chamber), if necessary to obtain sufficient solution
of the chamber, volume for measurement. All records of data obtained for
9.1.3 Weekly or daily records, see Note 10, (depending on volume of salt solution collected in millilitres per hour per each
which test annex is being performed) of data obtained from 80 cm2 fog collecting device. (See 4.3.2.)
each fog-collecting device for volume of salt solution collected NOTE 10—Except on Saturday, Sundays, and holidays, when the test is
in millilitres per hour of operation per 80 cm2 of horizontal not interrupted for exposing, rearranging, or removing test specimens or to
collection area. check and replenish the solution in the reservoir(s).
9.1.4 Concentration or specific gravity of collected solution 9.1.7 Type of specimen and its dimensions, or number or
and the temperature of that solution when measured. Follow description of part,
Table 2 for salt concentration and density versus temperature to 9.1.8 Method of cleaning specimens before and after test-
determine that the sample measured is within specification. ing,
Sample to be measured may be a composite sample from 9.1.9 Method of supporting or suspending article in the salt
multiple fog-collecting devices within a single cabinet, if spray chamber,
necessary, to obtain sufficient solution volume for measure- 9.1.10 Description of protection used as required in 5.2.4,
ment. 9.1.11 Exposure period,
9.1.5 pH of collected solution. Sample to be measured may 9.1.12 Interruptions in test, cause and length of time, and
be a composite sample from multiple fog collecting devices 9.1.13 Results of all inspections.
within a single cabinet, if necessary, to obtain sufficient
NOTE 11—It is also advisable to record the concentration or specific
solution volume for measurement.
gravity of any atomized salt solution that has not made contact with the
9.1.6 Weekly or daily records, see Note 10, (depending on test specimen and that was returned to the reservoir.
which test annex is being performed) of data obtained from
fog-collecting devices for concentration or specific gravity at 10. Keywords
23 6 3°C (73 6 5°F) of solution collected (see Note 11) and 10.1 acidic salt spray; corrosion; salt spray

4
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G85 – 11
ANNEXES

(Mandatory Information)

A1. ACETIC ACID-SALT SPRAY (FOG) TESTING

A1.1 Salt Solution A1.3 Conditions in the Salt Spray Chamber

A1.1.1 A sodium chloride solution made in accordance with A1.3.1 Temperature—Maintain the exposure zone of the
6.3. acetic acid-salt spray fog chamber at 35 6 2°C (95 6 3°F).
A1.1.2 Adjust the pH of this solution measured in accor- Each set point and its tolerance represents an operational
dance with Test Method E70 to range from 3.1 to 3.3 by the control point for equilibrium conditions at a single location in
addition of acetic acid. the cabinet which may not necessarily represent the uniformity
NOTE A1.1—The initial solution may be adjusted to pH of 3.0 to 3.1 of conditions throughout the cabinet.
with the expectation that the pH of the collected fog will be within the
specified limits. Base the adjustment of the initial pH for make-up solution NOTE A1.2—This test is particularly applicable to research studies that
upon the requirements to maintain the required pH of the collected have the effect of altering parameters of the electroplating process in
samples. If less than 0.1 or more than 0.3 % of the glacial acetic acid is connection with decorative chromium plating on steel or zinc die-cast base
required to attain the specified pH, the purity of the water or salt, or both as well as for the evaluation of the quality of the product. This is true
may not be satisfactory. because of the normal duration of the test, which may be as brief as 16 h,
but normally runs for 144 to 240 h or more giving ample opportunity for
A1.2 Conditions in Saturator Tower observations at practical intervals of the effects of minor parameter
A1.2.1 Make sure the temperature in the saturator tower changes.
(bubble tower) is 47 6 1°C (117 6 2°F).

A2. CYCLIC ACIDIFIED SALT FOG TESTING

A2.1 Salt Solution A2.3.3 Cabinet—Equip the chamber with a timing device
A2.1.1 Use a sodium chloride solution made in accordance that can be used for the following 6-h repetitive cycles: 3⁄4-h
with 6.3. spray; 2-h dry-air purge; and 31⁄4-h soak at high relative
A2.1.2 Adjust the pH of this solution to range from 2.8 to humidity.
3.0 by the addition of acetic acid. A2.3.4 Purge—Purging of the fog atmosphere immediately
after spraying is the most unique feature of this test. Dry all
A2.2 Conditions in Saturator Tower
droplets of water on the specimens and dry the corrosion
A2.2.1 Make sure the temperature in the saturator tower products so that they are of a white, rather than a damp gray
(bubble tower) is 57 6 1°C (135 6 2°F). appearance. Perform this by electrically switching the air-flow
A2.3 Conditions in Salt-Spray Chamber to bypass the saturator tower and aspirator nozzle and allowing
it to enter directly into the test chamber for 120 min at an angle
A2.3.1 Temperature—Maintain the temperature in the ex-
that sweeps the fog out of the peaked lid of the cabinet. This
posure zone of the salt spray chamber at 49 6 2°C (120 6
reduces the relative humidity from 40 to 7 %, depending on the
3°F).
climatic conditions of the ambient air. After purging, the
A2.3.2 Humidity—Although the humidity limits for opti-
mum test conditions have not been determined, operate the salt specimens remain in the closed cabinet until the next spray
spray chamber under wet bottom conditions (that is, make sure cycle. Since most testing requires a wet bottom, the humidity
an inch or so of water is present in the bottom of the box) for gradually increases from 65 to 95 % during this period.
most testing. This ensures that the interior of the box does not A2.3.5 Atomization and Quantity of Fog—Collect the fog in
become dry, a condition that decreases corrosion rate. (The dry a special continuous spray run of at least 16 h periodically
bottom is recommended, however, for testing 2000-series between test runs. Determine the proper consumption of
aluminum alloys and paint coatings that require a less aggres- solution by monitoring solution level in the collection devices.
sive environment.)4

4
Personal communication, Alcoa Technical Center, New Kensington, PA.

5
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G85 – 11

A3. ACIDIFIED SYNTHETIC SEA WATER (FOG) TESTING

A3.1 Salt Solution NOTE A3.1—This test is particularly applicable to production control of
exfoliation-resistant heat treatments for the 2000, 5000, and 7000-series
A3.1.1 Use a synthetic sea salt solution made in accordance aluminum alloys.5 It is also applicable to developmental studies of varying
with 6.2, with the addition of 10 mL of glacial acetic acid per heat treatment parameters to determine effect on corrosion behavior. For
litre of solution. this purpose, a temperature of 49°C (120°F) is recommended for the
A3.1.2 Adjust the pH of the salt solution between 2.8 and exposure zone. For testing organic coatings on various metallic substrates,
3.0. an exposure zone temperature of 24 to 35°C (75 to 95°F) may be used
since temperatures in excess of 35°C frequently result in paint blistering.
A3.2 Conditions in Saturator Tower—Make sure the tem- A3.3.2 Humidity—Although the humidity limits for opti-
perature in the saturator tower (bubble tower) is 47 6 1°C mum test conditions have not been determined, results of an
(1176 2°F) if cabinet temperature is 35°C (95°F); and 57 6 interlaboratory testing program indicate that it is necessary to
1°C (135 6 2°F) if cabinet temperature is 49°C (120°F). operate under wet bottom conditions (that is, an inch or so of
water should always be present in the bottom of the box). This
A3.3 Conditions in Salt Spray Chamber ensures that the interior of the box does not become dry, a
A3.3.1 Temperature—The temperature in the exposure zone condition that will decrease the corrosion rate.
of the salt spray chamber may vary to suit the material being A3.3.3 Cabinet—Equip the cabinet with a timing device
tested. The specifications that cover the material or product that can be used for the following cycle: 30-min spray followed
being tested define the temperature or the temperature may be by 90-min soak at above 98 % relative humidity.
mutually agreed upon between the purchaser and the seller. See
Note A3.1 for recommended exposure zone temperatures for 5
Ketcham, S. J., and Jeffrey, P. W., “Localized Corrosion-Cause of Metal
some materials. Failure,” ASTM STP 516, ASTM, 1973, pp. 273–302.

A4. SALT/SO2 SPRAY (FOG) TESTING

A4.1 This test consists of spraying salt fog with introduc- A4.4.2.3 Timer.
tion of SO2 gas directly into the chamber periodically. A4.4.2.4 Two-way solenoid valve fabricated of materials
A4.2 Salt Solution inert to SO2 gas.
A4.2.1 Define the salt solution by using the specifications A4.4.2.5 Tubing and fittings for SO2 line of materials inert
covering the material or product being tested or upon mutual to SO2 gas. A schematic of the SO2 line is shown in Fig. A4.1.
agreement between the purchaser and the seller. NOTE A4.1—It is highly desirable to have the SO2 gas introduced into
A4.2.2 If synthetic sea salt is specified, prepare it in the chamber in such a way that a uniform dispersion throughout the
accordance with 6.2. interior will result. If the cabinet is equipped with a central dispersion
A4.2.3 If sodium chloride is specified, prepare it in accor- tower, holes can be drilled in the poly(methyl methacrylate) (PMMA)
dance with 6.3. baffle at the top of the tower so that the gas comes out of eight uniformly
spaced ports. There are undoubtedly other means for accomplishing a
A4.3 Conditions in Saturator Tower uniform dispersion of the gas. However, avoid introducing the gas into the
A4.3.1 Make sure the temperature in the saturator tower chamber through one or two tubes at the side.
(bubble tower) is 47 6 1°C (117 6 2°F). A4.4.3 The pH of the collected solution shall range from 2.5
A4.4 Conditions in the Salt Spray Chamber to 3.2.
A4.4.1 Temperature—Maintain the exposure zone of the A4.4.4 Cycle—Define the cycle to be used by using the
salt spray chamber at 35 6 2°C (95 6 3°F). specifications covering the material or product being tested or
A4.4.2 SO2 Gas—Equipment and materials required for upon mutual agreement between the purchaser and the seller.
addition of SO2 to cabinet are as follows: Examples of some possible cycles are as follows:
A4.4.2.1 Cylinder of SO2 gas. A4.4.4.1 Constant spray with introduction of SO2 gas for 1
A4.4.2.2 Flowmeter capable of measuring SO2 gas flow of h 4 3 a day (every 6 h).
1 cm3/min·ft3 of cabinet volume (35 cm3/min·m3); also con- A4.4.4.2 1⁄2-h salt spray, 1⁄2-h SO2, 2-h soak.
structed of materials inert to SO2 gas.

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FIG. A4.1 Schematic of SO2 Line into Salt Fog Cabinet

A5. DILUTE ELECTROLYTE CYCLIC FOG/DRY TEST

A5.1 This test consists of cycles of 1-h dry-off and 1-h fog. A5.3.4 Dry-Off Temperature—The temperature throughout
The electrolyte is a solution of sodium chloride and ammonium the exposure zone shall reach and remain at 35 6 1.5°C (95 6
sulfate, and is much more dilute than traditional salt fog. The 3°F) within 3⁄4-h of switching from the fog period to the dry
fog is performed at room temperature, while the dry-off is at period.
elevated temperature. In addition, the spray atomizing air is not A5.3.4.1 The dry-off is achieved by purging the chamber
saturated with water. with fresh air, such that within 3⁄4-h all visible moisture is dried
NOTE A5.1—This test is particularly applicable to paints on steel.
off of the specimens.

A5.2 Salt Solutions A5.4 Cabinet Modifications—In order to achieve the tem-
A5.2.1 Prepare an electrolyte solution of 0.05 % sodium perature changes specified in this annex, modifications or
chloride and 0.35 % ammonium sulfate by mass. The water additions to Practice B117 apparatus may be required. These
and sodium chloride shall meet the purity requirements of may include:
Section 6. The ammonium sulfate shall contain not more than A5.4.1 Exposure chamber,
0.3 % total impurities. A5.4.2 Temperature controls,
A5.4.3 Air flow apparatus,
A5.3 Conditions in the Salt Fog Chamber A5.4.4 Insulation, and
A5.3.1 Wet/Dry Cycle—The cycle consists of 1-h fog fol- A5.4.5 Means for conditioning the heated air in the chamber
lowed by 1-h dry-off. or water in the jacket.
NOTE A5.2—Experience indicates that longer cycle times can produce A5.4.6 Consult the cabinet manufacturer for any additional
slower degradation. information or suggestions, or both.
A5.3.2 Fog Temperature—During the fog period, no heat-
A5.5 Saturation Tower—This test does not use humidified
ing is applied to the cabinet. The fog exposure is at ambient
air. Use one of the following methods to avoid humidifying the
room temperature and conditions.
air:
NOTE A5.3— Ambient conditions shall be an indoor atmosphere with A5.5.1 Empty the saturation tower and ensure that the tower
no unusual pollution other than that arising from the test camber. Such
conditions shall be controlled to a temperature of 24 6 3°C (75 6 6°F)
heaters are turned off, or
and a relative humidity below 75 %. Different room temperatures can give A5.5.2 Arrange the spray plumbing so that the atomizing air
different results. does not go through the saturation tower, but goes directly to
the spray nozzle.
A5.3.3 The pH of the collected solution shall range between
5.0 and 5.4 (see 4.3.2 and 6.4). NOTE A5.4—The cycling from wet to dry subjects the specimens to a

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range of solution concentrations varying from very dilute during the fog special continuous spray run of at least 16 h, performed
period to very concentrated just before the water dries off completely. Do between test runs. The regular spray periods of 1 h are not long
not saturate the atomizing air with water, because the purpose of saturation
enough for collecting sufficient fog to make accurate determi-
is to help keep the solution at a fixed concentration.
nations of deposition rate. See 4.3.2 for instructions on fog
A5.6 Atomization and Quantity of Fog—Collect the fog in a collection.

APPENDIXES

(Nonmandatory Information)

X1. SYNOPSIS TEXT CORRELATING WITH Annex A1

X1.1 “Spray” (Fog) Solution operational control point for equilibrium conditions at a single
X1.1.1 5 6 1 parts by mass of Sodium Chloride in 95 parts location in the cabinet which may not necessarily represent the
by mass of Specification D1193 Type IV water. Adjust pH of uniformity of conditions throughout the cabinet.
solution from 3.1 to 3.3 by the addition of glacial acetic acid. X1.1.3 Fog at a rate of 1.0 to 2.0 mL/h per 80 cm2 of
(See Fig. X1.1.) horizontal collection area.
X1.1.2 Maintain the exposure zone temperature at 35 6 2°C
(95 6 3°F). Each set point and its tolerance represents an

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Reprinted with permission.
FIG. X1.1 Continuous Acetic Acid-Salt Spray (Fog) Testing

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X2. SYNOPSIS TEXT CORRELATING WITH Annex A2

X2.1 “Spray” (Fog) Solution for equilibrium conditions at a single location in the cabinet
X2.1.1 5 6 1 parts by mass of Sodium Chloride in 95 parts which may not necessarily represent the uniformity of condi-
by mass of Specification D1193 Type IV water. Adjust pH of tions throughout the cabinet.
solution from 2.8 to 3.0 by the addition of glacial acetic acid. X2.1.3 Fog at a rate of 1.0 to 2.0 mL/h per 80 cm2 of
(See Fig. X2.1.) horizontal collection area, based on a separate continuous fog
X2.1.2 Exposure zone temperature to be held at 49 6 2°C cycle of at least 16 h.
(120 6 3°F). Operate with wet bottom condition. Saturate/ X2.1.4 The test is 6-h repetitive cycles: 3⁄4 –h spray; 2-h
Bubble/Humidifying Tower at 57 6 1°C (135 6 2°F). Each set dry-air purge; and 31⁄4 –h soak at high relative humidity.
point and its tolerance represents an operational control point

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Reprinted with permission.
FIG. X2.1 Cyclic Acidified Salt Fog Testing

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X3. SYNOPSIS TEXT CORRELATING WITH Annex A3

X3.1 “Spray” (Fog) Solution sents an operational control point for equilibrium conditions at
X3.1.1 42 g of synthetic sea salt and 10 mL of glacial acetic a single location in the cabinet which may not necessarily
acid per litre of solution using Specification D1193 Type IV represent the uniformity of conditions throughout the cabinet.
water. Adjust the pH of solution to between 2.8 and 3.0. X3.1.3 Fog at a rate of 1.0 to 2.0 mL/h per 80 cm2 of
Practice D1141 states that, to adjust pH, use 10% Sodium horizontal collection area, based on a separate continuous fog
Hydroxide (NaOH) solution. (See Fig. X3.1.) cycle of at least 16 h.
X3.1.2 Exposure zone temperature may vary to suit material X3.1.4 The cycle is 2 h repetitive cycles: 1⁄2-h spray with
and ranges from 24 to 49 6 2°C (75 to 120 6 3°F), with wet 1 ⁄2-h soak at or above 98 % relative humidity.
1
bottom configuration. Each set point and its tolerance repre-

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Reprinted with permission.
FIG. X3.1 Cyclic Acidified Synthetic Sea Water (Fog) Testing

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X4. CONSTANT SPRAY (FOG) WITH INTRODUCTION OF SO2 GAS FOR 1 H FOUR TIMES A DAY (EVERY 6 H)
(SYNOPSIS TEXT CORRELATING WITH Annex A4)

X4.1 “Spray” (Fog) Solution X4.1.3 Fog at a rate of 1.0 to 2.0 mL/h per 80 cm2 of
X4.1.1 Either 1) 5 parts of NaCl by mass in 95 parts by mass horizontal collection area, based on a separate continuous fog
of Specification D1193 Type IV water, or 2) 42 g of synthetic cycle of at least 16 h.
sea salt in accordance with Practice D1141 per litre of solution. X4.1.4 pH 2.5 to 3.2 of collected solution.
Practice D1141 states that to adjust pH use 10% Sodium X4.1.5 The test is a 6-h repetitive cycle: Constant salt fog
Hydroxide (NaOH) solution. (See Fig. X4.1.) with SO2 gas introduction for the last 1 h of each 6 h cycle. SO2
X4.1.2 Exposure zone temperature to be held constant at 35 gas flow is 1 cm3/min-ft3(35 cm3/min-m3) of chamber volume.
6 2°C (95 6 3°F). Each set point and its tolerance represents
X4.1.6 The SO2 gas is injected into the chamber by a gas
an operational control point for equilibrium conditions at a
single location in the cabinet which may not necessarily dispersion ring or other means to aid a uniform dispersion of
represent the uniformity of conditions throughout the cabinet. gas throughout the chamber.

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Reprinted with permission.
FIG. X4.1 Cyclic Salt/SO2 Spray (Fog) Testing (Example X4.1.1)

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X5. 3 H REPETITIVE CYCLE: 1⁄2-H SPRAY, 1⁄2-H SO2, AND 2-H SOAK
(SYNOPSIS TEXT CORRELATING WITH Annex A4)

X5.1 “Spray” (Fog) Solution X5.1.3 Fog at a rate of 1.0 to 2.0 mL/h per 80 cm2 of
X5.1.1 Either 1) 5 parts of NaCl by mass in 95 parts by mass horizontal collection area, based on a separate continuous fog
of Specification D1193 Type IV water, or 2) 42 g of synthetic cycle of at least 16 h.
sea salt in accordance with Practice D1141 per litre of solution. X5.1.4 pH 2.5 to 3.2 of collected solution.
Practice D1141 states that to adjust pH use 10% Sodium X5.1.5 The test is 3 h repetitive cycles: 1⁄2-h (fog) spray;
Hydroxide (NaOH) solution. (See Fig. X5.1.) 1⁄2-h SO ; and 2-h soak. SO gas flow is 1 cm3/min-ft3(35
2 2
X5.1.2 Exposure zone temperature to be held constant at 35 cm3/min-m3) of chamber volume.
6 2°C (95 6 3°F). Each set point and its tolerance represents
X5.1.6 The SO2 gas is injected into the chamber by a gas
an operational control point for equilibrium conditions at a
single location in the cabinet which may not necessarily dispersion ring or other means to aid a uniform dispersion of
represent the uniformity of conditions throughout the cabinet. gas throughout the chamber.

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Reprinted with permission.
FIG. X5.1 Cyclic Salt/SO2 Spray (Fog) Testing (Example X5.1.1)

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X6. 2 H REPETITIVE CYCLE: 1–H SPRAY AND 1–H DRY OFF

(SYNOPSIS TEXT CORRELATING WITH Annex A5)

X6.1 “Spray” (Fog) Solution visible moisture is dried off the specimens. Each set point and
X6.1.1 0.05 % sodium chloride and 0.35 % ammonium its tolerance represents an operational control point for equi-
sulfate by mass in Specification D1193 Type IV water. (See librium conditions at a single location in the cabinet which may
Fig. X6.1.) not necessarily represent the uniformity of conditions through-
X6.1.2 The test is 2–h repetitive cycles: 1-h spray with out the cabinet.
exposure zone temperature at ambient room temperature of 24 X6.1.3 Spray fog atmosphere at a rate of 1.0 to 2.0 mL/h per
6 3°C (75 6 6°F); and 1–h dry off at 35 6 2°C (95 6 3°F). 80 cm2 of horizontal collection area, based on a separate
The dry off temperature must reach and remain at 35 6 2°C (95 continuous fog cycle of at least 16 h. The spray atomizing air
6 3°F) within 3⁄4-h of switching from spray. The dry off is is not saturated with water.
achieved by purging with fresh air such that within 3⁄4-h all X6.1.4 pH 5.0 to 5.4 of collected solution.

NOTE 1—Dashed chart lines indicate temperature tolerance limits.

NOTE 2—Temperature changes illustrated are pictorial representations only and are not based on actual tests.
NOTE 3—Reprinted with permission.
FIG. X6.1 Dilute Electrolyte Cyclic Fog/Dry Test

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