1、Designation:D327300(Reapproved2005) Designation: D3273 12Standard Test Method forResistance to Growth of Mold on the Surface of InteriorCoatings in an Environmental Chamber1This standard is issued under the fixed designation D3273; the number immediately following the designation indicates the year
2、oforiginal adoption or, in the case of revision, 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.This standard has been approved for use by agencies of the Department
3、 of Defense.1. Scope1.1 This test method describes a small environmental chamber and the conditions of operation to evaluate reproducibly in a4-week period the relative resistance of paint films to surface mold fungi, mildew growth in a severe interior environment. Theapparatus is designed so it can
4、 be easily built or obtained2by any interested party and will duplicate results obtained in a largetropical chamber.1.2 This test method can be used to evaluate the comparative resistance of interior coating to accelerated mildew growth.Performance at a certain rating (in accordance with Test Method
5、 D3274) does not imply any specific period of time for a fungalfree coating. However, a better rated coating nearly always performs better in actual end use.NOTE 1This test method is intended for the accelerated evaluation of an interior coatings resistance to fungal defacement. Use of this test met
6、hodfor evaluating exterior coatings performance has not been validated, nor have the limitations for such use been determined. ShouldIf this test methodis to be used for the testing of an exterior coating system, a precautionary statement regarding interpretation of results as being outside of the s
7、copeofthis test method must be included. Any accelerated weathering (leaching, weathering machine exposure, etc.) should be reported and should also bearreference to the fact that it is beyond the current scope of this test method.1.3 Temperature and humidity must be effectively controlled within th
8、e relatively narrow limits specified in order for thechamber to function reproducibly during the short test period. Severity and rate of mold growth on a film is a function of themoisture content of both the film and the substrate. A relative humidity of 95 to 98%6 3 % at a temperature of 32.5 6 1C
9、(906 2F ) is necessary for test panels to develop rapidly and maintain an adequate moisture level to support mold growth.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of
10、 the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D3274Test Method for Evalu
11、ating Degree of Surface Disfigurement of Paint Films by Fungal or AlgalGrowth, or Soil and Dirt AccumulationE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Significance and U
12、se3.1 An accelerated test for determining the resistance of interior coatings to mold growth is useful in estimating the performanceof coatings designed for use in interior environments that promote mold growth and in evaluating compounds that may inhibit suchgrowth and the aggregate levels for thei
13、r use (see also Note 1).3.2 This test method should preferably be used by persons who have had basic microbiological training.1This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D
14、01.28 on Biodeterioration.Current edition approved Dec.Feb. 1, 2005.2012. Published February 2006.March 2012. Originally approved in 1973. Last previous edition approved in 20002005 asD3273 00 (2006). DOI: 10.1520/D3273-00R05.10.1520/D3273-12.2Additional specifications for construction of a chamber
15、that has been found suitable for this method may be obtained from New Jersey Industrial Controls, P.O. Box 601,Rockaway, NJ 07866.3For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume informa
16、tion, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately dep
17、ict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19
18、428-2959, United States.4. Apparatus4.1 Environmental Chamber, capable of maintaining a relative humidity of 95 to 98%6 3 % at a temperature of 32.5 6 1C(90 6 2F) while providing a continuous inoculation of the surface of exposed panels with mold spores. The chamber should bekept in a room controlle
19、d to 21 to 24C (70 to 75F) no less than 21C (75F) so that heat loss from the cabinet is insignificantand that 9592 to 98 % relative humidity is readily obtained at the test temperature. Alternatively the cabinet must be insulated withsuitable materials to minimize heat loss.4.2 Cabinet, suitable to
20、accommodate the desired number of test panels typically at least panels, typically a minimum oftwenty-five 75 by 100-mm (3 by 4-in.) panelspanels under these test conditions can be constructed as follows (Fig. 1):4.2.1 Tank, polypropylene or polyethylene or gas, with an offset shoulder at the top ri
21、m is used as the chamber.4The minimumrecommended tank size is 46 by 46 by 61 cm (18 by 18 by 24 in.). A pitched top with straight sides should be constructed outof acrylic plastic so moisture condensation will run down the sides and be recirculated instead of dripping onto the panels. Theminimum rec
22、ommended tank size is 46 by 46 by 61 cm (18 by 18 by 24 in.).Apitched top with straight sides should be constructedout of acrylic plastic so moisture condensation will run down the sides and be recirculated instead of dripping onto the panels. Apitched top is not necessary if the chamber is incubate
23、d in a temperature-controlled warm room that is maintained at 3.25 6 1C(90 6 2F) which prevents condensation on the interior panel surfaces.4.2.2 Heating Coil,5,6installed in the bottom of the chamber by water tight connections through the end wall. The heater shouldbe sized to allow reasonable reco
24、very time and uniform heating of the water when the chamber is opened and closed to place or4Tanks of this type available in dimensions approximating 69 by 46 by 46 cm (27 by 18 by 18 in. ) are available from laboratory supply companies. Nalgene tanks havebeen found suitable.5The sole source of supp
25、ly of a78-mm (0.315-in.) diameter inconel sheathed heater, Model STRI (STRI-1248/120), known to the committee at this time is OmegaEngineering, Inc., One Omega Drive, Stamford, CT 06907, 8008484286. .6If you are aware of alternative suppliers, please provide this information to ASTM International He
26、adquarters. Your comments will receive careful consideration at ameeting of the responsible committee, which you may attend.6Complete units may also be purchased through New Jersey Industrial Controls.FIG. 1 Environmental Cabinet AssemblyD3273 122inspect samples.7It is so placed that it is immersed
27、when there are 50 to 75 mm (2 to 3 in.) of water in the bottom of the chamber.The temperature in the chamber should be monitored and controlled by placing a suitable thermocouple or RTDIt is so placed thatit is immersed when there are 50 to 75 mm (2 to 3 in.) of water in the bottom of the chamber. A
28、 heating coil is not necessary ifthe chamber is incubated in a temperature-controlled warm room that is maintained at 3.25 6 1C(906 2F) . The temperaturein the chamber should be monitored and controlled by placing a suitable thermocouple or RTD8in an area near the test panels.The temperature can be
29、displayed and controlled by a solid state proportional controller.94.2.3 Tray, stainless steel, aluminum or plastic, approximately 25 mm (1 in.) smaller than the inside dimensions of the chamberand 25 to 75 mm (1 to 3 in.) deep with a non-corrodible metal10mesh bottom should be supported 25 mm (1 in
30、.) above the waterlevel and centered in the chamber. One layer of fine plastic or fiberglass screen may be placed over the metal mesh, if needed forholding soil.NOTE 2It has been found that eliminating the plastic screen helps improve water vapor transfer into soil, and maintain active fungal cultur
31、es.4.2.4 Series of Wood, Glass, or Fiberglass Reinforced Plastic Bars, suspended across the width of the chamber at a height andspacing that allows the use of test panels 75 by 100 mm (3 by 4 in.), hung vertically, with approximately 75-mm (3-in.) clearanceabove the inoculated soil with a suitable m
32、ethod of fastening. Screw eyes are used with the wooden panels while a wire frame,plastic cable ties or a large clip is used with the gypsum board panels. Other support systems may be utilized.NOTE 3Other angles of exposure may be used but may alter the rate and severity of mold growth.4.3 Psychrome
33、ter, for measuring relative humidity in the test area. , for measuring relative humidity in the test area. Atemperature/humidity datalogger may also be used if the accuracy of the relative humidity sensor is 63%.5. Reagents and Materials5.1 SoilA good quality greenhouse-grade potting soil, suitable
34、for plant propagation, containing 25% peat moss. pH of thesoil should fall from 5.5 to 7.6. Do not allow soil to become compacted. A good quality greenhouse-grade potting soil, suitablefor plant propagation, containing 25 % peat moss. The pH range of the soil should fall from 5.5 to 7.0. Do not allo
35、w soil to becomecompacted. Additional peat moss can be added to lower the pH into the required range.5.2 Cultures:5.2.1 Aureobasidium pullulans,6,11ATCC 93485.2.2 Aspergillus niger,6,11ATCC 62755.2.3 Penicillium,6,11Sp. 12667 or ATCC 98495.3 Test Panels:5.3.1 Ponderosa Pine (Pinus ponderosa Laws) Sa
36、pwood Panels, 12.7 mm (12 , approximately 13 mm (12 in.) thick, 75 by 100mm (3 by 4 in.), free of excessive resins, knots, growth rings or other abnormalities, surfaced smooth on four sides. Wood shallbe kiln dried after sawing to avoid infestation of wood-rotting fungi, and any wood showing evidenc
37、e of such infestation shall beeliminated as test material. Wood shall be weighed after conditioning at room temperature in a dry room to 15 % moisture content.Calculated weight shall fall between 365 and 425 kg/m3(6.0 and 7.0 g/in.3). Panels containing heartwood areas should not be usedas they will
38、inhibit mold growth under test conditions.5.3.2 Gypsum Board Panels, 12.7 mm (12 in. ) thick, 75 by 100 mm (3 by 4 in.). , 13 to 25 mm (12 to 1 in.) thick, 75 by 100mm (3 by 4 in.).5.3.3 Other Substrates such as Drawdown Paper, Tongue Depressors, Glass, etc., may be used as agreed upon by the partie
39、sinvolved. However, when comparing the relative performance of various coatings, the substrates must be the same in order for theresults to be meaningful. Also, when When using substrates that are not themselves susceptible to attack (like glass), use anothertype of positive growth control must be u
40、sed rather than the uncoated panel as specified in 7.2.6. Preparation of Apparatus6.1 Place greenhouse soil in the tray in the cabinet and add water to the tank chamber to the desired depth. Allow the cabinetto equilibrate for 24 h before inoculating the soil with the specified mold suspensions.6.2
41、Prepare mold slants of all three cultures and ageincubate 10 to 14 days or purchase prepared mold slants9of all threecultures.days. Prepare mold suspensions from each type of mold slant by the following procedure: Add one drop of 25 % nonionicsurfactant12solution to 95 to 100 mL sterile deionized or
42、 distilled water and shake. gently mix. Pipet 5 mL of this solution ontoeach of the mold slants. Scrub the surface of the slant with a sterile cotton swab or sterile glass rod to remove as much spore and7For a 46 by 46 by 61-cm (18 by 18 by 24-in.) tank, a 250-watt heater is recommended. For a 61 by
43、 61 by 91-mm (24 by 24 by 36-in.) tank, an 800-watt heater isrecommended.8A grounded 1.5 mm (116) or 2.4 mm (332-in.) “J” type stainless thermocouple gives good response for this application.9A Eurotherm Model 91 controlling the heater via solid state relay has demonstrated that it can be calibrated
44、 and provide calibratable, accurate, and reliable performance.10150-mesh 316 stainless screen gives a high percentage of open area and will not allow dirt to contaminate the water.11The sole source of supply of the cultures can be obtained from American Type Culture Collection, P.O. Box 1549, Manass
45、as, VA 20108. Cultures can be maintainedon malt agar or potato dextrose agar. Prepared slants can be obtained from microbiological supply companies.12Octyl phenol ethoxylates, 910 mole EO, have been found suitable.D3273 123mycelial growth as possible without digging up the surface of the agar. Pour
46、the water from the scrubbed slant back into thesurfactant-sterile water mixture for dilution. Shake gently for 15 to 20 min to break up clumps of mold. Use a pipet to distributethe mold suspensions evenly over the surface of the greenhouse soil in the tray in the cabinet.6.3 Allow two weeks of conti
47、nuous operation for the mold to sporulate and equilibrate with the environment before starting atest. It should not be necessary to recontaminate continually re-inoculate the chamber of panels soil after sufficient microorganismgrowth has built up inbeen established. If the soil, if the chamber is m
48、aintained in continuous operation, a tray of soil can producemold spores for many months, but should be replaced with a fresh inoculated soil twice per year.6.4 Viability of the mold growth in the cabinet can be checked by placing several malt agar or potato dextrose agar plates,13open and face up,
49、at several locations on the panel support rods. After 1 h, cover plates and place in incubator at 32.5 6 1C (906 2F) for 35 to 7 days. If an incubator is not available, leave the covered plates in the cabinet. Mold growth should bemedium-heavy to heavy and cover the complete surface of the agar plate.7. Procedure7.1 Preparation of Test PanelsWear disposable plastic or equivalent gloves or utilize other techniques when handling panelsto avoid fingerprints. Prepare triplicate panels by applying two coats of the material under test to b
