1、Designation: D 7539 10Standard Practice forUsing a Test Chamber for Humidity Conditioning of TestPanels of Pavement Marking Paints1This standard is issued under the fixed designation D 7539; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 Specification D3924 defines a standard environment of23 6 2C and 50 6 5 % relative humidity and fr
3、ee from draftsfor normal conditioning and testing of paint, varnish, lacquer,and related materials. This practice describes a test chamberthat allows for control of relative humidity above the ambientrelative humidity and minimization of air flow for conditioningof test panels at elevated relative h
4、umidity and room tempera-tures.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of t
5、hesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D711 Test Method for No-Pi
6、ck-Up Time of Traffic PaintD1640 Test Methods for Drying, Curing, or Film Formationof Organic Coatings at Room TemperatureD3924 Specification for Environment for Conditioning andTesting Paint, Varnish, Lacquer, and Related MaterialsD7377 Practice for Evaluating the Water Wash-Off Resis-tance of Traf
7、fic Paints using a Water FaucetD7538 Practice for Evaluating the Water Wash-Off Resis-tance of Traffic Paints Using an Atomizing Spray Device2.2 Other Standard:3TT-P-1952E Federal Specification for Paint, Traffic andAirfield Marking, Waterborne (10 July 2007)3. Terminology3.1 Definitions:3.1.1 test
8、chamber, na cabinet or box, preferably made oftransparent, waterproof material, such as clear acrylic plastic,with panel supports and holes (ports) that can be partially tofully opened to mix outside ambient air with humidified air inthe chamber or some other means to provide humidified airwith mini
9、mal air flow.3.1.1.1 DiscussionAlso commonly referred to as a humid-ity box or humidity chamber, as in Federal SpecificationTT-P-1952E.3.1.2 waterborne pavement marking (traffc) paint, nanaqueous paint used for marking pavements.4. Summary of Practice4.1 Atest chamber is described that allows for th
10、e control ofrelative humidity above ambient relative humidity and theminimization of air flow variability at ambient room tempera-tures.5. Significance and Use5.1 The drying rate of organic coatings varies with changesin temperature, air flow, and relative humidity. In particular, thedrying rate of
11、waterborne paints depends on the evaporation ofwater and thus is much more dependent on relative humiditythan are solvent based paints or paints that are 100 % solids.Measurement of the rate of drying of waterborne paints underambient conditions in laboratories cannot be adequately repli-cated witho
12、ut some control of the drying conditions. A testchamber will be described that provides a means of controllingrelative humidity above ambient humidity and minimizing theeffects of air flow variability at ambient room temperatures. Ifdesired, the test chamber without water in it and with ventswide op
13、en can be placed in a temperature and humiditycontrolled room to test dry speed at various temperatures aswell as humidity while using the chamber to minimize theeffect of air flow.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Application
14、s and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved July 1, 2010. Published July 2010.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
15、formation, refer to the standards Document Summary page onthe ASTM website.3Available from General Services Administration, Federal Supply Service,Specification Section, Suite 8100, 470 LEnfant Plaza, SW, Washington DC 20407,http:/www.gsa.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO
16、Box C700, West Conshohocken, PA 19428-2959, United States.5.2 This practice is particularly useful for testing the dryingrate of waterborne pavement marking (traffic) paints where fastdry at elevated ambient humidity is an important feature. Forwaterborne traffic paints, the test chamber can be used
17、 toevaluate dry to no-pick-up (Test Method D711) and waterwash-off resistance (Practices D7377 and D7538) at elevatedambient humidity.6. Apparatus and Equipment6.1 Test ChamberThe required elements of the test cham-ber are listed below. (Manufacturing details and a photographof a suitable test chamb
18、er are shown in Appendix X1.)(1) Manufactured from transparent material to allow forvisual monitoring of relative humidity and dry time testprogress inside of the chamber.(2) Horizontal support for coated test panels within thechamber that is perforated to allow circulation of humidifiedair.(3) A do
19、or in the front of the chamber for taking test panelsin and out of the chamber.(4) Control of relative humidity above the ambient relativehumidity and minimization of air flow.6.2 Hygrometerplaced in the test chamber in full view ofthe operator to monitor the relative humidity inside of thechamber.
20、This hygrometer should be accurate within 63%relative humidity and provide a range from at least 20 to 100 %relative humidity.6.3 Thermometerto record air temperature.6.4 Anemometer/Wind Meter (optional)to confirm airflow inside the chamber is “minimal” (below 0.02 m/s).6.5 Other apparatus and equip
21、ment specified in the chosendrying rate test procedure.7. Reagents7.1 Waterto provide humid air for mixing with ambientair in the test chamber.8. Procedure8.1 Preparation of Test Chamber Type Described in Appen-dix X1:8.1.1 Cover the bottom of the chamber with water or placewater soaked cloth or pap
22、er rags below the panel support withwater.8.1.2 Close all ports and the door and allow equilibration tothe maximum relative humidity allowed by the tolerances ofthe chamber.8.1.3 Establish the desired relative humidity by opening andclosing the ports on the sides of the chamber, preferably so thatth
23、e size of the port openings are about the same on both sidesof the chamber to equalize the air circulation in the chamber.The relative humidity in the test chamber will stabilize once theport openings are established. Occasional slight adjustments inthe side port openings may be required if the ambi
24、ent humidityin the room changes significantly during testing.8.1.4 Target test relative humidity must be above the ambi-ent humidity in the room. It is best to use the chamber in aconditioned room at a controlled temperature (23 6 2C) andhumidity (50 6 5 % relative humidity) as described in Speci-fi
25、cation D3924.8.2 Calibration and StandardizationWhen using the testchamber to determine drying rates, the initial rate test shouldinclude a reference paint of known performance to determinethe relative drying rates of test paints and to gauge the effect ofambient room temperature and relative humidi
26、ty on the dryingrates for that test period.8.3 Using the Test Chamber for Determining Drying Rates:8.3.1 Prepare a test stripe as described in the chosen dryingrate procedure at the wet film thickness as specified by thatprocedure.8.3.2 Record the time of application or use a timer.8.3.3 Immediately
27、 place the panel with the wet film in thecenter of the panel support. The ports on the sides of the testchamber must be adjusted promptly and frequently to regainthe desired relative humidity within 65 % relative humidity.8.3.4 A second panel can be prepared and tested in thechamber at the same time
28、. In order to be able to test the secondpanel after the same elapsed time as the first panel, it isnecessary to allow sufficient time between test panel prepara-tions. Record the time of application of the second panel andimmediately place the panel next to the first panel near thecenter of the pane
29、l support. Testing of more than two panels atone time will introduce more variability in results due to poorercontrol of drying conditions.8.3.5 At regular intervals, test the dry time of the test filmsin accordance with the procedures specified in Test MethodD711 (no-pick-up) and Practices D7377 an
30、d D7538 (waterwash-off resistance) or other desired method. All interestedparties shall agree on the time intervals at which panels areremoved from the chamber for testing.9. Report9.1 Report the relative humidity and temperature inside thetest chamber and relative humidity outside of the test chamb
31、er.10. Keywords10.1 drying rate or drying time; dry through; no-pick-up;relative humidity; test chamber; washout resistance; water-borne traffic paintD7539102APPENDIXES(Nonmandatory Information)X1. TEST CHAMBER CONSTRUCTION ( see Fig. X1.1 for example)X1.1 The test chamber shall consist of a basic b
32、ox, aperforated panel support, a waterproof bottom to hold water orsome other means to provide saturated air inside the chamber,and holes (ports) that can be opened partially to fully to allowambient air to mix with the saturated air or some other meansto allow the operator to control the relative h
33、umidity inside ofthe chamber.X1.2 Place the hygrometer in the chamber so that it is infull view of the operator. This hygrometer should be accuratewithin 63 % relative humidity and provide a range from atleast 20 to 100 % relative humidity.X1.3 The chamber should be made of a transparent,waterproof
34、material such as clear acrylic plastic. The clearplastic should be38 in. thick. The joints should be water tight.X1.4 The panel support and any interior parts should bemade of corrosion-resistant materials.X2. TYPES OF CONSTRUCTIONX2.1 Fig. X2.1 (1a and 1b) are typical engineering draw-ings for fron
35、t and side views of a suitable test chamber.FIG. X1.1 Test ChamberD7539103FIG. X2.1 Testing Chamber Drawing Figure 1aD7539104FIG. X2.1 Testing Chamber Drawing Figure 1b (continued)D7539105ASTM International takes no position respecting the validity of any patent rights asserted in connection with an
36、y item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical
37、 committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration a
38、t a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor
39、Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7539106
