ASTM D7358-07

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7358 − 07
StandardTest Method for
Water Content of Paints by Quantitative Calcium Hydride
Reaction Test Kit
This standard is issued under the fixed designation D7358; 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.
1. Scope water in the whole paint sample is manually calculated using
the exact weights of the paint sample and the diluted extract
1.1 This test method describes the determination of the total
sample, if used.
water content of paints using a calcium hydride reaction test
kit, or water content between 2 and 85 % water.
4. Significance and Use
1.2 The values stated in SI units are to be regarded as the
4.1 Although Test Method D4017 is widely used for the
standard. The values given in parentheses are for information
determination of water in paints and related materials, this
only.
method may overcome some of the variability found in the
Karl Fischer method.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4.2 Control of water content is often important in control-
responsibility of the user of this standard to establish appro-
ling the performance of paints, and it is critical in determining
priate safety and health practices and determine the applica-
volatile organic compound (VOC) content when VOC content
bility of regulatory limitations prior to use.
is measured by difference from total volatile matter and water
content as required in certain federal and state regulations.
2. Referenced Documents
2 5. Interferences
2.1 ASTM Standards:
5.1 The following compounds, tested at twice the sample
D1193 Specification for Reagent Water
size,havebeenfoundtoproducenomeasurableresponsetothe
D3925 Practice for Sampling Liquid Paints and Related
calcium hydride reaction test kit and, therefore, cause no
Pigmented Coatings
interference at levels up to 40 %:
D4017 Test Method for Water in Paints and Paint Materials
by Karl Fischer Method
Ethanol
Methanol
E29 Practice for Using Significant Digits in Test Data to
A
Acetone
Determine Conformance with Specifications
Methyl Ethyl Ketone
Tetrahydrofuran
Diethylene Glycol Dimethyl
3. Summary of Test Method
Ether
A
Ethylene Glycol
3.1 A0.25 mLsample is reacted with a specially formulated
Diethylene Glycol
calcium hydride reagent to convert water in the sample to
Dipropylene Glycol
hydrogen gas. The reaction is carried out in a sealed pressure Stearic Acid
2–Ethyl Hexanoic Acid
vessel and the resulting pressure is then measured using a
Lead Oxide (II and III)
specially designed meter programmed to convert gas pressure
Aluminum Oxide (Brockman I)
into water content. The results are displayed in milligrams of
A
0.25 mL sample size program A and B.
water in the reacted sample extract. The actual weight percent
5.2 When using the 5 mL sample size programs, that is,
This test method is under the jurisdiction of ASTM Committee D01 on Paint
programs C, D, or E, ethylene glycol and acids have been
and Related Coatings, Materials, andApplications and is the direct responsibility of
found to produce a positive result in the presence of a small
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
Current edition approved Nov. 1, 2007. Published November 2007. DOI:
amount of water. Ethylene glycol responds at approximately
10.1520/D7358-07.
7 % of the volumetric equivalent.
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
Standards volumeinformation,refertothestandard’sDocumentSummarypageon
the ASTM website. HydroSCOUT User’s Manual.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7358 − 07
6. Apparatus 9. Sampling, Test Specimens, and Test Units
6.1 HydroSCOUT System —A test kit system consisting 9.1 Sample Collection—Take a representative sample of the
of the HydroSCOUT meter, reaction tubes, sampling syringes liquid coatings in accordance with Practice D3925. Mix
and dilution vials. The entire analytical sequence, including thoroughly before taking specimens for individual tests.
sampling, sample dilution, chemical reactions and
10. Preparation
quantification, is available in kit form using pre-dispensed and
encapsulated reagents. An analytical balance is required in
10.1 Preparation—Remove a sampling syringe with cap
order to obtain the most precise results. In addition, a mechani- and a test tube from the kit box. Check the contents to ensure
cal shaker may be necessary to obtain a representative sample.
that all items are present and intact. If a dilution is to be used,
remove a dilution vial and an additional sampling syringe and
7. Reagents and Materials
cap. Remove the screw cap and rubber septum from the tube
and the cap from the dilution vial, if used. Insert one green
7.1 Purity of Reagents—Reagent grade chemicals shall be
water ampule into the top of the polypropylene ampule sleeve
usedinalltests.Allreagentsshallconformtothespecifications
and replace the holder in the tube.
of the Committee on Analytical reagents of the American
Chemical Society, where such specifications are available.
11. Calibration and Standardization
7.2 Purity of Water—Unless otherwise indicated, reference
11.1 The commercially available meter is calibrated at the
to water shall mean reagent water conforming to Specification
factory over the pressure range of 0 to 60 psig. Each time the
D1193, Type II.
meter is turned on, the pressure transducer recalibrates the 0
7.3 Calcium Hydride (20 %) in HI SOL 10—contained in a
psig point. If this changes significantly from the factory set
crushable glass ampule.
point, an error message will be displayed. This error will also
appear if a tube is accidentally inserted into the meter before
7.4 Water—contained in a crushable glass ampule.
the meter is turned on.
7.5 Diethylene Glycol Dimethyl Ether (Diglyme)—2.25 mL
contained in a glass vial.
12. Procedure
12.1 Sample Introduction for Expected Water Content Less
8. Hazards
Than 15 % (No Dilution)—Work the plunger on an empty
8.1 Store ampules in a cool, dry place. Keep away from
sampling syringe a few times to ensure that it slides easily.
heat, sparks, water and open flames.
Place the tip of the syringe into the paint sample to be tested
8.2 See manufacturer’s instructions and Material Safety
andslowlypullbackontheplungeruntilitreachesthestopand
Data Sheet (MSDS) before use.
cannot be pulled further. Remove the syringe from the paint
sample and wipe any excess paint from the outside of the
8.3 The gray ampule in the tube contains calcium hydride,
syringe with a tissue wipe provided with the kit. Cap the
which is a flammable solid and water reactive.
syringe with the cap provided and weigh; record the weight
8.4 Perform test only in a well ventilated area.
(gross sample weight) to the nearest 0.1 mg. Dispense the
8.5 Always wear rubber gloves and safety glasses.
sample into the reaction tube. Recap the syringe without
wiping,reweighit,andrecordthisweight(sampletareweight).
8.6 Take care to ensure that fingers are not cut by glass in
The difference in the two weights becomes the sample weight
the kits. Each ampule should be crushed only once to reduce
(S ) to be used in Eq 1. Replace the rubber septum (hole on
the risk of glass pieces piercing the sides of the tube.
top) by gripping the tube firmly and pressing the septum down
8.7 When venting reaction tube after completion of test,
with the thumb. (NOTE: Do not squeeze the sides of the tube
point tube upright and away from user and bystander.
while inserting the septum.) Replace the screw cap tightly,
8.8 Whenbreakingthegreenwaterampuleaftercompletion turning it until it cannot be turned further. Proceed to step 12.3.
of test, the tube must be shaken vigorously for the full 15
12.2 Sample Introduction for Expected Water Content
seconds to ensure that the water contacting the remaining
Greater Than 15 % (With Dilution)—Work the plunger on an
calcium hydride does not overheat the side of the tube,
empty sampling syringe a few times to ensure that it slides
otherwise tube failure can result.
easily. Place the tip of the syringe into the paint sample to be
tested and slowly pull back on the plunger until it reaches the
stop and cannot be pulled further. Remove the syringe from the
HydroSCOUT is a trademark of the Dexsil Corporation.
5 paint sample and wipe any excess paint from the outside of the
The sole source of supply of this kit known to the committee at this time is
Dexsil Corporation, One Hamden Park Drive, Hamden, CT06517. If you are aware
syringe with a tissue wipe provided with the kit. Cap the
of alternative suppliers, please provide this information to ASTM International
syringe with the cap provided and weigh; record the weight
Headquarters.Your comments will receive careful consideration at a meeting of the
1 (gross sample weight) to the nearest 0.1 mg. Dispense the
responsible technical committee, which you may attend.
sample into the dilution vial containing a premeasured amount
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For sugg
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