fp) Designation: B 117-97 Standard Practice for Operating Salt Spray (Fog) Apparatus* “Thi sana i ised dete fed deson B17; he ober imme flowing the Sesgnon ines the yea of esol ain on he ae of revs, he see fast reason. number in entees ten he er at eapproval A ‘Soerctin eps) inci sn eal cage ce he at rvs apo ‘is tandant has been approved foray agence of he Department of fos 1. Scope 1.1 This practice describes the apparatus, procedure, and conditions required to create and maintain the salt spray (fog) test environment. Suitable apparatus which may be used is deseribed in Appendix XL 112 This practice does not prescribe the type of test speci- men or exposure periods o be used for a specific product, nor the interpretation to be given to the results 1.3 The values stated in SI units are to be regarded as standard. The inch-pound units in parentheses are provided for information and may be approximate. 1.4 This standard does not purpart to address all of the safety concerns, if any, associated with tts use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica~ bility of regulatory limitations prior to se, 2. Referenced Documents 2.1 ASTM Standards: B368 Method for Copper-Aecelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test? 609 Pracice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related Coating Products? D198 Specification for Reagent Water* 1 1684 Tes Method for Evaluation of Painted of Coated ‘Specimens Subjected Corrosive Environments? E70 Test Method for pl! of Aqueous Solutions with the Giass Blectrode* E691 Practice for Conducting an Inerlaboratory Study to Determine the Precision of a Test Method® G85 Practice for Modified Salt Spray (Fog) Testing” "Te raise unser he uinon of ASTM Comainse Gt on Conan of Meas and he de eponaiyof Sabcomter OO1.05 cm Lbarsry Cones Tes Caren adn approved Ap 10 197 Publibed Nowembe 1957. Ongally dana ok of AST Stantands, Vl 0205. 2a Book of ASP Senda, O60 “Iw! Book of STA Steere 1D tna Bok of ASTU Sentry, ol 1505. ‘mud oot of ASA Senden ol 0323 ep AST 10 Bar Hacer C Cnc, PBR Se, 3. Significance and Use 3.1 This practice provides a controlled corrosive environ ment which has been utilized produce relative corrosion resistance information for specimens of metals and coated metals exposed in a given test chamber. 3.2 Prediction of performance in natural environments has seldom been correlated with salt spray resulis when used as stand alone data 3.2.1 Correlation and extrapolation of corrosion perfor- mance based on exposure tothe test environment provided by this practice are not always predictable. 3.22 Correlation and extrapolation should be considered only in cases where appropriate corroborating long-term atmo spheric exposures have been conducted 3.3 The reproducibility of results in the salt spray exposure i highly dependent on the type of specimens tested and the evaluation criteria selected, a8 well as the control of the operating variables. In any testing program, sufficient repli- cates should be included to establish the variability of the results. Variability has been observed when similar specimens are tested in different fog chambers even though the testing conditions are nominally similar and within the ranges speci- fied in this practice. 4. Apparatus 4.1 The apparatus required for salt spray (Fog) exposure consists ofa fog chamber, a salt solution reservoir, a supply of suitably conditioned compressed air, one or more atomizing nozzles, specimen suppors, provision for heating the chamber, and necessary means of contol, The size and detailed con- struction of the apparatus ate optional, provided the conditions obtained meet the requirements ofthis practice. 42 Drops of solution which accumulate on the ceiling or cover of the chamber shall not be permitted to fall on the specimens being exposed. 433 Drops of solution which fall from the specimens shall rot he returned to the solution reservoir for resprayine ‘4.4 Material of construction shall be such that it will not affect the carrosiveness of the fog. 4.5 All water used for this practice shall conform to Type IV water in Specification D 1193 (except that for this practice limats for chlorides and sodium may be ignored). This does not4h 8117 apply to running tap water. All other water will be referred to as reagent grade 5. Test Specimens 5.1 The type and number of test specimens to be used, as well asthe criteria forthe evaluation of the test results, shall be defined in the specifications covering the material or product being exposed or shall be mutually agreed upon between the purchaser and the seller 6, Preparation of Test Specimens 6.1 Specimens shall be suitably cleaned. The cleaning ‘method shall be optional depending on the nature ofthe surface and the contaminants. Care shall be taken that specimens are not recontaminated after cleaning by excessive or careless handling. {62 Specimens for evaluation of paints and other organic coatings shall be prepared in aceordance with applicable specification(s) for the material(s) being exposed, or as agreed ‘upon between the purchaser and the supplier. Otherwise, the ‘est specimens shall consist of steel meeting the requirements ‘of Practice D 609 and shall be cleaned and prepared for coating ‘in accordance with the applicable procedure of Practice D 609. 63 Specimens coated with paints or nonmetallic coatings shall not be cleaned or handled excessively prior to test. 64 Whenever itis desired to determine the development of | corrosion from an abraded area inthe paint or organie eoating, a scratch or scribed line shall be made through the coating with a sharp instrument so as to expose the underlying metal before testing. The conditions of making the seratch shall be as defined in Test Method D 1654, unless otherwise agreed upon between the purchaser and the seller. 65 Unless otherwise specified, the cut edges of plated, coated, or duplex materials and areas containing identification ‘marks of in contact with the racks or supports shall be protected with a suitable coating stable under the conditions of the practice Nave 1—Shoulditbe desirable to cutest specimens fom parts oe fom preplted, punted, or otherwise coated sel Sheet, he cut cges shall be protected by coating them with pint, wat tape, or other eective media £o thatthe development ofa galvanic eflect between such edges and the ‘Mdjcent plated or otherwise coated metal sraces, i prevented. 7.1 The position of the specimens in the salt spray chamber ‘during the test shall be such thatthe following conditions are met: 7.1.1 Unless otherwise specified, the specimens shall be supported or suspended between 15 and 30° from the vertical and preferably parallel to the principal direction of flow of fog through the chamber, based upon the dominant surface being tested 7.1.2 The specimens shall not contact each other or any ‘metallic material or any material capable of acting as a wick 7.1.3 Bach specimen shall be so placed as to permit free settling of fog on all specimens 7.14 Salt solution fom one specimen shall not drip on any other specimen, [Nore 2-Suitable materia fo the constuction or coating of racks and supports are glist ube, plastic, of suitably coated wood. Bare metal ‘hall nat be ied. Specimens shall preferably be suppor from the bottom orth sie. Sled wooden strip are suitable forthe suppor of fat panels. Suspension fom gs hooks or waxed string may be used as long 88 the spectied posion of the specimens is obtained. if necessary by means of second suppor atte Boom ofthe specimens 8. Salt Solution 8.1 The salt solution shal be prepared by dissolving $ + 1 pars by mass of sodium chloride in 95 parts of water conforming to Type IV waler in Specification D 1193 (except that for this practice limits for chlorides and sodium may be ‘ignored). The salt sed shall be sodium chloride substantially free of nickel and copper and containing on the dry basis not ‘more than 0.1 % of sodium iodide and not more than 0.3 % of total impurities. Some salts contain additives that may act as corrosion inhibitors; careful atention should be given to the ‘chemical content of the salt. Upon agreement between the purchaser and the seller, analysis may be required and limits established for elements or compounds not specified in the chemical composition given above. 8.2 The pH of the salt solution shall be such that when atomized at 35°C (95°F) the collected solution will be in the pH range from 65 to 7.2 (Note 3). Before the solution is atomized it shall be free of suspended solids (Note 4). The pH ‘measurement shall be made at 25°C (77°F) using a suitable lass pHT-sensing electrode, reference electrode, and pH meter system in accordance with ‘Test Method E70 Nore 3—Temperaueaffets the pH ofa sat solution prepare from water sued wih ctbon dione 9 oor temperature an pH ads ‘ent may be made bythe following tree methods (1), When th pH of Salt solution adjusted at room temperature, and stomized af 38°C (0S), the pi ofthe eolleted eouton willbe higher than te onginal solution du othe lst of eafbon done atthe higher temperature. When the pH of the salt solution is adjusted at room therefor necessary to adjust itbelow 6.35 the cllested mizing at 35°C (O5°F) will meet the pH limits of 6.510 712 Take about a SOsmL sample ofthe salt solution a prepared at room temperate, bol gently fer 30s, ool, and determine he pH. When the 1H ofthe salt solution i adjusted 1 6.5 to 7.2 by this procedure, the pH ‘ofthe atomized and collected solution at 33°C (98°F) will eome within this range (2) Heating the st slurin boing and eootng to 35°C (95°F) and ‘maintaining tar 38°C (@3°F) for approximately $8 b before adjusting the pH produces soli the pH of which doesnot materially change when Homized at 38°C (OS°F) (2) Heating the water om whic the slt solution sprpared to 35°C (95°F orakove io expel carbon dioxide and adjusting the pH of the salt Solution within the limits 65 t9 72 produces solution the pH of which does not maternally change when uomized at 38°C (5°P) ‘Note 4—The fresh prepared salt solution may be filtered or decented before iis place in te raservor or heen ofthe abe leading Tom the Solution tothe atomizer maybe covered wih a double layer of cheesecloth to prevent plugging ofthe nozzle [Nore 5—The pH canbe adjusted by additions of die ACS reagent mide hydrochonc aed or slum hydroxide solutions, 9. Air Supply 9.1 The compressed air supply to the nozzle or nozzles for atomizing the salt solution shall be free of oil and dirt (Note 6) and maintained between 69 and 172 KPalm? (10 and 25 psi) [Nowe 6—The ae supply may be fred fom oll and dit by pasing i Yhrouph 2 wate scrbter or atleast 610 mm (2) of suitable cleaningqh 8417 rater such a sep woo} exces, slag woo! activated akin, (Commercial caidge fiters which inclde en expirtion rmsicuor my alsa be sed 10, Conditions in the Salt Spray Chamber 10.1 Temperature—The exposure zone of the salt spray chamber shall be maintained at 35+ 1.1 ~ 17°C. (95 +2~3°F), The temperature within the exposure zone of ‘the closed cabinet shall be recorded atleast twice a day a least, 7 hapant (except on Saturdays, Sundays, and holidays when the salt spray testis not interrupted for exposing, rearranging, o ‘removing test specimens of to check and replenish the solution inthe reservoir) Nore 7—A sutble method to record the temperature is by a contin ‘ous recording device or by a themmometer which canbe read from ouside the closed cabinet The recorded temperature must be cbained with the ssltspay chamber closed o wrod false low reading because of wet-buld tifect when the chamber is ope, 102 Atomization and Quantity of Fog— As least two clean fog collectors shall be so placed within the exposure zone that rno drops of solution from the test specimens or any other source shall be collected. The collectors shall be placed in the proximity of the test specimens, one nearest to any nozzle and the other farthest from all nozzles. The fog shall be such that for each 80 em: (12.4 in.”) of horizontal collecting area there will be collected in each collector from 1.0 to 2.0 mL. of solution per hour based on an average run of at least 16 h (Note 8). The sodium chloride concentration ofthe collected solution shall be 5 1 mass % (Note 9). The pH of the collected solution shall be 6.5 to 7.2. The pH measurement shall be made as described in 8.2 (Note 3) [Nort 8Suitblecolletng devices are glass or plastic funnels wih the stems inserted through stopers ino graduated cylinders, of erst Ting dishes. Fuels and dishes with 2 ameter of 10cm (3.94 in) have an area of about 8D cm (124 in Nott 9A solution having a specific gravity of 1.0255 to 1.0400 at 25°C TTF) wil mest the conesntaton requirement. The sodium lode concentration may also be determined using a suitable salinity meter (for example, wing 4 sodium ion-selective glass eletede) oe ‘olonnetnclly a8 follows. Dilute $ ml ofthe eolleted Solution to 100 tml with distilled water and mix thoroughly pipet a 10s aliguot i an ‘vapocting dish or easseroe; 24440 ml of distilled water and I mL of 1% potassium chromate solution (chlorde-tree) and trate with 0.1.8 silver irate souton tothe ist pearance ofa permanent red coloration, { sotion thet require between 4 ond S| mL of 0.1 8 alver nate {olution will meet the concentration requirements 10.3 The nozzle or nozzles shall be so directed or baffled that none of the spray can impinge directly on the test specimens, 11, Continuity of Exposure 11,1 Unless otherwise speeified in the specifications cover- ing the material or product being tested, the test shall be continuous for the duration of the entire test period. Continue ‘ous operation implies that the chamber be closed and the spray reser of tet auton ry be deg by «laa ening group oF ay Se purchaed tom uaa of at abe a an Seer ‘operating continuously except for the short daily imerruptions necessary 10 inspect, rearrange, or remove test specimens, 10 check and replenish the solution in the reservoir, and to make necessary recordings as deseribed in Section 10. Operations shall be so scheduled that these interruptions aze held to a 12, Period of Exposure 12.1 The period of exposure shall be as designated by the specifications covering the material ar product being ested oF as mutually agreed upon between the purchaser and the seller, Note 10—Recommended exposure periods are to be a8 agreed upon ‘ersen the purchaser an the seller, but expose periods of multiples of 2a h are sugges. 13, Cleaning of Tested Specimens 13.1 Unless otherwise specified in the specifications cover- ing the material or product being tested, specimens shall be treated as follows at the end of the test 13.1 The specimens shall be earefully removed 13.2 Specimens may be gently washed or dipped in clean running water not warmer than 38°C (100°F) t0 remove salt deposits from their surface, and then immediately dried. 14, Evaluation of Results 14.1 A careful and immediate examination shall be made as required by the specifications covering the material or product being tested or by agreement between the purchaser end the seller. 15, Records and Reports 15.1 The following information shall be recorded, unless ‘otherwise prescribed in the specifications covering the material ‘or product being tested 15.1.1 Type of salt and water used in preparing the salt solution, 15.1.2 All readings of temperature within the exposure zone ‘of the chamber, 15.13 Daily records of data obtained from cach foge collecting device including the following 15.13.1 Volume of salt solution collected in mililiues per hour per 80 em? (12.4 in), 15.1.3.2 Concentration or specific gravity at 35°C (95°F) of solution collected, and 15.1.3.3 pH of collected solution 15.2 Type of specimen and its dimensions, or number or deseription of pers, 15.3 Method of cleaning specimens before and after resting, 15.4 Method of supporting or suspending article in the salt spray chamber, 15.5 Description of protection used as required in 65, 15.6 Exposure period, 15.7 Interruptions in exposure, cause, and length and 15.8 Results of all inspections [Nore 1I—tF any ofthe atomized salt solution which has not contacted the test specimens ig retuied 1 the reservoir ts adsble wo teed the concentration or specie gravity ofthis solution aoqh 8117 16. Keywords 16.1 controlled corrosive envizenment; corrosive condie tions; determining mass loss; salt spray (fog) exposure APPENDIXES (Nonmandatory Information) 1X1. CONSTRUCTION OF APPARATUS XL Cabinets XIALE Standard salt spray cabinets are available from several suppliers, but certain pertinent accessories are required before they will function according to this practice and provide consistent control for duplication of results. ‘XILL2 The salt spray cabinet consists ofthe basie chamber, fan air-saturator tower, a salt solution reservoir, atomizing nozzles, specimen supports, provisions for heating the cham- ber, and suitable controls for maintaining the desired tempera- ture, X11.3 Accessories such as a suitable adjustable baflle or central fog tower, automatic level control for the salt reservoir, ‘and automatic level control for the airsaturator tower are pertinent parts of the apparatus X14 The size and shape of the cabinet shall be such that the atomization and quantity of collected solution is within the limits of this practice, XILLS The chamber shall be made of suitably inert mate- rials such as plastic, glass, o stone, or constructed of metal and lined with impervious plastics, rubber, or epoxy-type materials or equivalent XI.L6 All piping that contacts the salt solution o¢ spray should be of inert materials such as plastic. Vent piping should be of sufficient size so that a minimum of back pressure exists and should be installed so that no solution is trapped. The exposed end of the vent pipe should be shielded from extreme air currents that may cause fluctuation of pressure or vacuum in the cabinet X12 Temperature Control X1.2.1 The maintenance of temperature within the salt chamber can be accomplished by several methods. It is {generally desirable to control the temperature ofthe surround- ings of the salt spray chamber and to maintain it as stable as possible. This may be accomplished by placing the apparatus ‘in 8 constant-temperature room, but may also be achieved by surrounding the basic chamber ofa jacket containing water oF air at a controlled temperature. X1.2.2 The use of immersion heaters in an internal salt solution reservoir or of heaters within the chamber is detrimen- tal where heat losses are appreciable, because of solution ‘evaporation and radiant heat on the specimens. X13 Spray Nozzles X1.3.1 Satisfactory nozzles may be made of hard rubber, plastic, or other inert materials. The most commonly used type is made of plastic, Nozzles calibrated for air consumption and TABLE X1.1 Operating Characteristics of Typical Spray Nozzle “Sonor Ari, am"mmn ——Soufon consonaton con — eat Ar Pes. fr Presse S018 255 ats 36200 a 36 % 19 35 Ms 3 es oD a0 a Fox ~ Sauion Sn Uns ensamgton, mt ee T1935 31538 Foo sud ar — a bs ds 36 “em Ze arm Aaa 2 i 2s 33 mo fam Som oro feta zee Ms 0 Teepe ae solution-atomized are available. The operating characteristics ‘ofa typical nozzle are given in Table X11 X1.32 It can readily be seen that air consumption is relatively stable atthe pressures normally used, but a marked reduction in solution sprayed occurs ifthe evel ofthe solution is allowed to drop appreciably during the test. Thus, the level of the solution in the salt reservoir must be maintained automatically to ensure uniform fog delivery during the test.® 7X13. If the nozzle selected does not atomize the salt solution into uniform droplets, it will be necessary to direct the spray ata afte or wal to pick up the larger drops and prevent them from impinging on the test specimens. Pending a com- plete understanding of air-pressure effects, et. itis important that the nozzle selected shall produce the desired condition when operated at the air pressure selected. Nozzles are not necessarily located atone end, but may be placed in the center and can aso be directed vertically up through a suitable tower. X14 Air for Atomization X14.1 The air used for atomization must be free of grease, oil, and dirt before use by passing through well-maintained filters. Room air may be compressed, heated, humidified, and washed in a water-sealed rotary pump, ifthe temperature of the water is suitably controlled. Otherwise cleaned air may be Introduced into the bottom ofa tower filed with wate, through 1 porous stone or multiple nozzles. The evel ofthe water must be maintained automaticaly to ensure adequate humidification, A chamber operated in accordance with this method and Appendix X1 will have a relative humidity between 95 and 98%. Since salt solutions from 2 to 6% will give the same results (though for uniformity the limits ae set at 4 t0 6 6), it is preferable to saturate the air at temperatures well above theqb a7 Pychamber temperature as insurance of a wet fog. Table X1.2 shows the temperatures, at different pressures, that are required —z rs Nore 10—Angle of lid. 9010 125" [Thermometer and theastat for controlling eater (tem No.8) in base 2--Automae wate leveling device 3 Humdtying tower ‘Automate tomperture regulator for contrling heater (Item No. 5) 5—Immersion hese, nowrsting 6A let, lip opines, Tir abe to speny nozzle Heater in bese 9-Hinged top, rally operated, or countertaanced 1o-Beackats for rds suppering specimens, testable 1 Intema resenoit |2_-Spray nezle above reserve, suitably designed located, ad balled 1BA~Sproy nozale housed in dispersion fower located preferably in center of cabinet (typical examples) 15—Water sel 14—Combiaton drain and exhaust, Exhaust opposite sdeoftest space fom spray nozle (tem 12), bu preferably in combination with drain, waste tea, and forced daft waste pipe (tems 161, and 19), 16—Contplte spaatonbetwsen forced drat waste pie (lem 17) and combination dain and exhaust Items 14 and 19) to avoid undesirable suetion or back pressure 17 Forced rat waste pipe 1k —Automatic leveling device fr reservoit 19 Waste tap 20—Air space or water jacket 31 Test able o ck, el Below rot area [Nowe 2-—This gure shows he various components iacluling alternate arangemens of the sproynozses and solution reservoir FIG. x1.1 Typical Salt Spray Cabinetabe Nore 1—The controls are the sume, in general as for the smaller laboratory type cabinet (Fig 1-1), bu are sized to care forthe larger cae, The chamber bas te following feature: ‘Angle of celling. 90 0 125" Heavy insulated ovter panels 2-Alr space 3-Low-watt density heaters, or steam coils 4 Singe- or double, ill-opening door (efrgerstion type), with inward sloping doe sill Ss Miewing windows (toner chamber vent ‘-tnner chamber drain Duct boards on for FIG. X1.2 Walkin Chamber, 1.5 by 24 m (5 by 8 f) and Upward to affset the cooling effect of expansion to atmospheric pressure X14.2 Experience has shown that most uniform spray chamber atmospheres are obtained by increasing the atomizing air temperature sufficiently to offset heat losses, except those ‘that can be replaced otherwise at very low-temperature gradi- ents, X1S Types of Construction X1.5.1 A modem laboratory cabinet is shown in Fig. X1.1 Walk-in chambers are usually constructed with a sloping X2. USE OF THE SALT SPRAY X2.1_ This practice is primarily used for process qualifiea- tion and quality acceptance. Regarding any new applications it js essential to correlate the results of this practice with actual field exposure results, X2.2. The sat spray has been used to a considerable extent {or the purpose of comparing different materials or finishes. IL, should be noted there is usually not a direct relation between. salt spray (fog) resistance and resistance to corrosion in other ‘media, because the chemistry of the reactions, including the formation of films and their protective value, frequently varies greatly with the precise conditions encountered. Informed personnel are aware of the erratic composition of basic alloys, the possibility of wide variations in quality and thickness of plated items produced on the same racks atthe same time, and the consequent need for a mathematical determination of the 7 TABLE X1.2 Temperature and Pressure Requirements for Operation of Tost at 95°F Th Presta a mr eo now 6 a 7% Tae Bosra pa 6 a Solution FIG. X13 Typleal Spray Nozzle ceiling. Suitably located and directed spray nozzles avoid ceiling accumulation and drip. Nozzles may be located at the ceiling, o 0.91 m (3 N) from the floor directed upward at 30 19 {60° over a passageway. The number of nozzles depends on type ‘and capacity and is related to the area of the test space. An II 10 19 L (3 to Segal) reservoir is required within the chamber, with the level controlled. The major features of « walk-in type cabinet, which differs significantly from the laboratory type, are illustrated in Fig. X12. Construction of a plastic nozzle, such as is furnished by several suppliers, is shown in Fig. X13 (POG) TEST IN RESEARCH number of specimens required to constitute an adequate sample for test purposes. [n this connection itis well to point out that Practice BIT is not applicable to the study or testing of decorative chromium plate (nickel-chromium) on steel or on zinc-base die castings or of cadmium plate on steel. For this purpose Method B 368 and Practice G 85 are available, which are also considered by some to be superior for comparison of chemically teated aluminum (chromated, phosphated, or an- odized), although final conclusions regarding the validity of test results related to service experience have not been reached, Practice B 117 and Practice G 85 are considered to be most useful in estimating the relative behavior of closely related ‘materials in marine atmospheres, since it simulates the basic conditions with some acceleration due to either wetness or temperature, or bothe qh e117 1X3. EVALUATION OF CORROSIVE CONDITIONS X3.1. General—This appendix covers test panels and pro- ‘cedures for evaluating the corrosive conditions within a salt spray cabinet. The procedure involves the exposure of steel test panels and the determination oftheir mass losses in a specified Period of time. This may be done monthly or more frequently to ensure consistent operation overtime. It is also useful for correlating the corrosive conditions among different cabinets X32. Test Panels—The required test panels, 76 by 127 by 08 mm (3.0 by 5.0 by .0315 in.), are made from SAE 1008 ‘commercial-grade cold-rolled carbon steel (UNS G10080). X33. Preparation of Panels Before Testing—Clean panels before testing by degreasing only, so thatthe surfaces are free of dir, oil, or other foreign matter that could influence the test results. After cleaning, weigh each panel on an analytical balance to the nearest 1,0 mg and record the mass. X34. Positioning of Test Panels—Place a minimum of two weighed panels in the cabinet, withthe 127-mm (5.0 in.) length supported 30° from vertical Place the panels in the proximity of the condensate collectors. (See Section 6.) X3.5 Duration of Test Expose panels o the salt fog for 48 to 168 b, X36 Cleaning of Test Panels After Exposure—After re= moval of the panels from the cabinet, rinse each panel immediately with running tap water to remove salt, and rinse in reagent grade water (see Specifieation D 1193, Type IV), (Chemically clean each panel for 10 min a 20 to 25°C in a fresh solution prepared as follows: ‘Mx 1000 kof roe apg 1.1) wan 000 mL r= ‘pent rae water (01198, Type IV) an ee 10 gf hexareing fre ene Ar carn, fine each pel wth agent rate ‘eter (ype) andy 68 3). X37. Determining Mass Loss—Immediately after drying, determine the mass loss by reweighing and subtracting panel mass after exposure from its original mass X3.7.1 Data generated in the interlaboratory study using this method are available from ASTM as a Research Report? X38 Precision and Bias—Steel Panel Test 23.8.1 An interlaboratory test program using three different sets of UNS G10080 stet panels, 76 by 127 by 0.8 mm (3.0 by 5.0 by .0315 in.) has shown that the repeatability of the mass loss of the steel panels, that is, the consistency in mass loss * avalbe fom ASTM Headgure. Roques RR No GI-103, results that may be expected when replicate panels are run simultaneously in a salt spray cabinet, is dependent upon ‘exposure time and the panel lot or source. The interlaboratory program yielded repeatability standard deviations, 5,» from. which 95% repeatability limits, r, were calculated as follows (oe Practice E 691): ra2es, oa The values of S, andr are reported in Table X3.1. Note that {the corrosion rate of steel inthis environment is approximately ‘constant over the exposure interval and that the ratio of the standard deviation to the average mass loss, the coefficient of variation, Cy, varies between $ and 10% with a weighted average of 7.4% and an r of +21 % of the average mass loss X3.8.2 This interlaboratory program also produced results ‘on the reproducibility of results, that is, the consistency of mass loss results in tests in different laboratories or in different ccabineis in the same facility. This program yielded reproduc ibility standard deviations S, from which 95 % reproducibility limits, R were calculated as follows (See Practice E 691): R= 285, 032) ‘The values of Sy and & are reported in Table X3.2, Note that the ratio of standard deviation to the average mass loss, the ccoeflcient of variation, Cv, varies between 8 10 18% with a weighted average of 12.7 % and an R of 36 % of the average ‘mass loss, X3.83 The mass loss of steel in this salt spray practice is dependent upon the area of steel exposed, the temperature, time of exposure, salt solution make up and purity, pH, spray conditions, and the metallurgy of the steel. The procedure in Appendix X3 for measuring the corrosvity of neutral salt spray cabinets with steel panels has no bias because the value of corrosivity of the salt spray is defined only in terms of this practice. TABLE X3.1 Repeatability Statistics Nore ‘ferent salt spay abies in est programy; Ce = Save coeticient of variation, and, ‘deviations -—Hased om two replicates in every test run, No. = number of 95 Yo repeatbility Limits, repeatability standard aesas TO" So ng No ori os dose 720 ome ort sur son 728 Om Pt tse 2sooe = o2tee «Get oeame 2 * “eo Grmr bom Str ore 10 ra se agee boas as oa 10 ~ see 2auoe tebe Gs Ome 10 ee “Sass oss 808 ota 's Gre i570 ese bat 2mm 8 Gre 168300 oases age Orme Sqb a7 TABLE X3.2 Reproducibility Statistics [Nore_1-No, = number of diferent salt spray cabinets in test program; R= 95 % eeproduibity limits, g: Co = Syavg,coeficient of variation, and Sy = reply standard deviation visios LOG i” ogg ok ye oe Ur bboy ee tems Ge Boog sass eters te samy Sem fom ome to me Mowe teas Nise 868) 10 se wes ses Oaume Hoo asss1B oestrous ten ome ‘ne Aenean Society Tesrg ane Matas aes no poston respecting he akc of any atom riohsasened in connection sah any tam mandoned in ths tarda. Users fs sand ae cress aised tat eterno fh Yat fay i) Dato fan and tne ak of igen sac hs, a ry Der own espana iss stance suc o oven at any tn ye reszonsb lca commie nc mst be rove every fe yar ns Ltnatronsnd eter approved or aman Your Carmen ae ried efron a sanded rr ara sees ‘and shoud be aacrosso 0 ASTM Haass. Your comment wi eae cr consent 2 eating of he response ‘Ethical comma, when you ray etn i you fa at your commons hve ot faved a ar Peon Yu SNA ane Your ‘owe krown tothe ASTI Comite on Sarda a Oe acess Shown below ms sandars i conyatiaby ASTM. 100 Bar Harr Dive POBox CTO. West Conshohocken, PA 184282050, Unto Sats naicual ett (sgl or mate copies) o Uns Sandrd ay be eared by caacing ASTM athe above aaess st 610-332 995 (prone), 5108325555 (an, a sercegvasn. og fal er ou the ASTM websto (weasonI)