ASTM C282-10
(Test Method)Standard Test Method for Acid Resistance of Porcelain Enamels (Citric Acid Spot Test)
Standard Test Method for Acid Resistance of Porcelain Enamels (Citric Acid Spot Test)
SIGNIFICANCE AND USE
This test method is intended specifically for testing the porcelain enamel finish on stoves, refrigerators, table tops, sinks and other sanitary ware, laundry appliances, architectural units, etc., where the surface may come in contact with food acids at room temperature.
Citric acid has been chosen as the test medium because it is one of the most common of the food acids and will generally provide a measurable result in its action on porcelain enamel.
SCOPE
1.1 This test method covers a procedure for evaluating porcelain enamels in their resistance to citric acid exposure at room temperature. No attempt is made to categorize porcelain enamels as to their acid-resistance or non acid-resistance properties, since the requirements in the several branches of the industry differ.
1.2 The test method is applicable for ware of various shapes providing they contain a substantially flat area approximately 50 mm in diameter.
1.3 The test method is not applicable to finishes on chemical and hospital ware, which may come in contact with strong mineral acids, nor to cooking utensils, which may come in prolonged contact with hot acid solutions.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:C282 −10
StandardTest Method for
Acid Resistance of Porcelain Enamels
1
(Citric Acid Spot Test)
This standard is issued under the fixed designation C282; 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 U.S. Department of Defense.
INTRODUCTION
The described method furnishes a means of testing and grading glossy porcelain enamels with
respect to their resistance to citric acid at room temperature. Citric acid has been selected because it
is the most common and one of the more severe of the food acids in its action on conventional
porcelain enamels. The degree of etching by a citric acid solution provides a good indication of the
susceptibility of attack of a porcelain enamel coating to common food-based acids.
1. Scope 3. Significance and Use
1.1 This test method covers a procedure for evaluating 3.1 This test method is intended specifically for testing the
porcelain enamels in their resistance to citric acid exposure at porcelain enamel finish on stoves, refrigerators, table tops,
room temperature. No attempt is made to categorize porcelain sinks and other sanitary ware, laundry appliances, architectural
enamels as to their acid-resistance or non acid-resistance units, etc., where the surface may come in contact with food
properties,sincetherequirementsintheseveralbranchesofthe acids at room temperature.
industry differ.
3.2 Citric acid has been chosen as the test medium because
1.2 The test method is applicable for ware of various shapes it is one of the most common of the food acids and will
providing they contain a substantially flat area approximately generally provide a measurable result in its action on porcelain
50 mm in diameter. enamel.
1.3 Thetestmethodisnotapplicabletofinishesonchemical
4. Apparatus
and hospital ware, which may come in contact with strong
4.1 Dropper Bottle, or medicine dropper,
mineral acids, nor to cooking utensils, which may come in
prolonged contact with hot acid solutions.
4.2 WatchGlass,25mmindiameterwithfirepolishededge,
1.4 This standard does not purport to address all of the
4.3 Towel, soft cotton, and
safety concerns, if any, associated with its use. It is the
4.4 Drafting Pencil, conventional graphite, degree 3B.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Reagents and Materials
bility of regulatory limitations prior to use.
5.1 Citric Acid Solution—Dissolve 10 g of anhydrous citric
2. Summary of Test Method
acidcrystals(H C H O )in100mLofwater.Solutionshallbe
3 6 5 7
prepared not more than 48 h prior to use.
2.1 Thetestmethodconsistsofa15minexposureofthetest
surface to a small pool of 10 % citric acid, and an evaluation of
5.2 CleanerSolution—Dissolve10goftrisodiumphosphate
theeffectintermsofthechangeinappearanceandthe“relative
(Na PO ) in 1 L of tap water.
3 4
cleanability” of the surface resulting from the treatment.
6. Sampling
1
This test method is under the jurisdiction ofASTM Committee B08 on Metallic
6.1 The test specimens may be articles of commerce, pieces
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
cut from articles of commerce, or laboratory specimens pre-
Materials for Porcelain Enamel and Ceramic-Metal Systems.
Current edition approved April 1, 2010. Published May 2010. Originally
pared especially for this test.
approvedin1951.Lastpreviouseditionapprovedin2005asC282 – 99(2005).DOI:
NOTE 1—Processing variables in the application and drying and firing
10.1520/C0282-10.
This test method is based on the Test for Acid Resistance of Porcelain Enamels operations materially affect the degree of attack by the acid on the surface
(Citric Acid Spot Test) Bulletin T-21, of the Porcelain Enamel Institute. of porcelain enamels. Sample specimens used for classification of acid
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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C282−10
resistance must be processed under identical conditions to the commercial TABLE 1 Requirements for Respective Classes of Acid
Resistance
ware they represent.
Classification Requirements
7. Procedure
Class AA No visible stain, and
Pass dry-rubbing test
7.1 Thoroughly wash area to be tested using a soft cotton
Class A Pass blurring-highlight test, and
towel moistened with a warm, 1 % solution of trisodium
Pass wet-rubbing test
phosphate. Rinse in warm, running tap water, and dry with a
Class B Pass blurring-highlight test, and
Fa
...
This 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:C282–99(Reapproved 2005) Designation: C282 – 10
Standard Test Method for
Acid Resistance of Porcelain Enamels
1
(Citric Acid Spot Test)
This standard is issued under the fixed designation C282; 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.
INTRODUCTION
The described method furnishes a means of testing and grading glossy porcelain enamels with
respect to their resistance to citric acid at room temperature. Citric acid has been selected because it
is the most common and one of the more severe of the food acids in its action on conventional
porcelain enamels. The degree of etching by a citric acid solution provides a good indication of the
susceptibility of attack of a porcelain enamel coating to common food-based acids.
1. Scope
1.1 This test method covers a procedure for evaluating porcelain enamels in their resistance to citric acid exposure at room
temperature. No attempt is made to categorize porcelain enamels as to their acid-resistance or non acid-resistance properties, since
the requirements in the several branches of the industry differ.
1.2 The test method is applicable for ware of various shapes providing they contain a substantially flat area approximately 50
mm in diameter.
1.3 The test method is not applicable to finishes on chemical and hospital ware, which may come in contact with strong mineral
acids, nor to cooking utensils, which may come in prolonged contact with hot acid solutions.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Summary of Test Method
2.1 The test method consists of a 15 min exposure of the test surface to a small pool of 10 % citric acid, and an evaluation of
the effect in terms of the change in appearance and the “relative cleanability” of the surface resulting from the treatment.
3. Significance and Use
3.1 This test method is intended specifically for testing the porcelain enamel finish on stoves, refrigerators, table tops, sinks and
other sanitary ware, laundry appliances, architectural units, etc., where the surface may come in contact with food acids at room
temperature.
3.2 Citric acid has been chosen as the test medium because it is one of the most common of the food acids and will generally
provide a measurable result in its action on porcelain enamel.
4. Apparatus
4.1 Dropper Bottle, or medicine dropper,
4.2 Watch Glass, 25 mm in diameter with fire polished edge,
4.3 Towel, soft cotton, and
4.4 Drafting Pencil, conventional graphite, degree 3B.
1
This test method is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
Materials for Porcelain Enamel and Ceramic-Metal Systems.
Current edition approved Sept. 15, 2005. Published September 2005. Originally approved in 1951. Last previous edition approved in 1999 as C282–99. DOI:
10.1520/C0282-99R05.
Current edition approved April 1, 2010. Published May 2010. Originally approved in 1951. Last previous edition approved in 2005 as C282 – 99(2005). DOI:
10.1520/C0282-10.
This test method is based on the Test for Acid Resistance of Porcelain Enamels (Citric Acid Spot Test) Bulletin T-21, of the Porcelain Enamel Institute.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
C282 – 10
5. Reagents and Materials
5.1 Citric Acid Solution—Dissolve 10 g of anhydrous citric acid crystals (H C H O ) in 100 mL of water. Solution shall be
3 6 5 7
prepared not more than 48 h prior to use.
5.2 Cleaner Solution—Dissolve 10 g of trisodium phosphate (Na PO ) in 1 L of tap water.
3 4
6. Sampling
6.1 The test specimens may be articles of commerce, pieces cut from articles of commerce, or laboratory specimens prepared
especially for this test.
NOTE 1—Processing variables in the application and drying and firing operations materially affect the degree of attack by the acid on the surface of
porcelain enamels. Sample specimens us
...
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