1、Designation: F 2420 05Standard Test Method forDetermining Relative Humidity on the Surface of ConcreteFloor Slabs Using Relative Humidity Probe Measurementand Insulated Hood1This standard is issued under the fixed designation F 2420; the number immediately following the designation indicates the yea
2、r 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the quantitative determination
3、of percent relative humidity above the surface of concrete floorslabs for field or laboratory tests.1.2 The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the use
4、r of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Some specificwarnings are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2E 104 Practices for Maintaining Constant Relative Humid-ity by Mea
5、ns of Aqueous SolutionsF 2170 Test Method for Determining Relative Humidity inConcrete Floor Slabs Using In-Situ ProbesNOTE 1For additional references, see A1.2.2.2 Other Standards:Resilient Floor Covering Institute, Recommended WorkPractices for the Removal of Resilient Floor Coverings3U.S. Departm
6、ent of Housing and Urban Development,Lead-Based Paint: Interim Guidelines for Hazard Iden-tification and Abatement in Public and Indian Housing43. Terminology3.1 Definitions:3.1.1 dew pointdew point temperature is the temperatureat which air becomes saturated when cooled with no furtheraddition of m
7、oisture or change of pressure. Condensation canoccur when moist air is cooled to its dew point and below.3.1.2 relative humidityratio of the amount of water vaporactually in the air compared to the amount of water vaporrequired for saturation at that particular temperature andpressure expressed as a
8、 percentage.3.1.3 service temperature and relative humidityaverageambient air temperature and relative humidity that typicallywill be found in the buildings occupied spaces during normaluse.4. Summary of Test Method4.1 This test method covers a procedure where a purposely-made thermally insulated ho
9、od is placed on and sealed to thesurface of a concrete floor slab. An entrapped and imperviousair pocket or chamber is formed directly above and in contactwith the surface of the bare floor slab. Through a lined accesshole in the hood, a humidity probe can be inserted to measurethe relative humidity
10、 (RH), temperature, and dew point withinthe air pocket.4.2 Methods of probe calibration and factors affectingequilibration are described in Section 8.4.3 The basis of this test is to use a Humidity Probe todetermine the relative humidity, temperature and dew point ofan air pocket within the air cham
11、ber formed under a thermallyinsulated hood sealed to the floor surface. This air chambershall be located directly above the bare and clean surface of theconcrete floor slab. Sufficient time as outlined under 10.1.6 and10.1.7 should be allowed for moisture, humidity and tempera-ture equilibrium to be
12、come established between the pocket ofair and the floor slab before relative humidity readings aretaken.4.4 An example of a suitable hood is illustrated in Figs. 1-3.Calculation of the insulation value of the hood is shown inA1.3.1This test method is under the jurisdiction ofASTM Committee F06 on Re
13、silientFloor Coverings and is the direct responsibility of Subcommittee F06.40 onPractices.Current edition approved Feb. 1, 2005. Published March 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan
14、dards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the Resilient Floor Covering Institute, 401 E. Jefferson Street,Suite 102, Rockville, MD 20850, 4Available from the U.S. Department of Housing and Urban Development, 4517th Street SW, Washington
15、, DC 20410.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 Moisture permeating from concrete floor slabs affectsthe performance of flooring systems such as resilient, wood,textile floor coverings and resino
16、us coatings. Manufacturers ofsuch systems generally require humidity/moisture testing beperformed before installation over concrete floor slabs. Themeasurement of relative humidity (RH) directly above theporous surfaces of a floor slab is one such method.5.2 Excessive moisture in or emitting from fl
17、oor slabs afterinstallation can cause floor covering system failures such asdelamination, bonding failure, deterioration of finish flooringand coatings, and microbial growth.5.3 The surface RH Hood (relative humidity) test method isintended to quantify the relative humidity condition that existsat t
18、he surface of a floor slab to which a floor covering orcoating shall be applied. Results indicate moisture contentconditions at the time of the test, as moisture movement withinthe slab is dynamic. SeeA1.4 for reference to some methods ofdetermining moisture/humidity levels in a concrete slab.6. App
19、aratus6.1 Humidity Probe and Digital MeterProbes shall haverelative humidity and temperature sensors, cylindrical in shapeand have an external diameter of less than 0.75 in. (20 mm). Itis essential that the probe be designed so that it can be sealedwithin an access hole when positioned in the hood.
20、RelativeHumidity Probes should have an accuracy level within 63%from 25 to 98 % relative humidity, and be obtained from amanufacturer having a NIST or equivalent traceable calibrationprocedure. RH Probes should be calibrated at 90 % relativehumidity or higher, in addition to lower humidity levels6.2
21、 An insulated impermeable box or hood shall be manu-factured from rigid thermal insulation type material (forexample, expanded polystyrene (EPS) or similar). The hoodsdesign shall include a recessed pocket that creates an isolatedair chamber directly above the concrete surface. The hoodsdesign must
22、permit it to be sealed to the concrete surfaceduring testing. The hood should have a maximum insulationU-value of 1.0 W/(m2K). The air chamber should be lined orcoated with a suitable vapor barrier material such as PVC so asto isolate the air pocket from the humidity and fluctuations intemperature o
23、f the air outside the hood. (See Figs. 1-3 forillustration of an example of a suitable apparatus.) The hoodsinsulated air chamber shall have a minimum area of between30 and 40 in.2(200 and 260 cm2) with a minimum depth of0.25 in. (6.3 mm) positioned and directly above and exposed tothe surface. This
24、 central area of air chamber shall be ofsufficient dimensions to allow unrestricted movement of theentrapped air around the sensor end of the RH probe when it isin position within the hood. Provision shall be made so that theRH probe is sealed when positioned in the hood. It is essentialthat when th
25、e hood is sealed to the floor that readings can betaken without breaking the seal and releasing the air in the testchamber. To avoid equipment being left on site unattended, thehood should be designed so that the probe may be removedfrom the hood, and the access hole plugged while the hood isleft se
26、aled to the floor.7. Hazards7.1 Silica and Asbestos WarningDo not sand, dry sweep,drill, saw, bead blast, or mechanically chip or pulverizeexisting resilient flooring, backing, lining felt, paint, asphalticcutback adhesives, or other adhesives. These products maycontain asbestos fibers or crystallin
27、e silica.Avoid creating dust.Inhalation of such dust is a cancer and respiratory tract hazard.Smoking by individuals exposed to asbestos fibers greatlyincreases the risk of serious bodily harm. Unless positivelycertain that the product is non-asbestos-containing material,presume that it contains asb
28、estos. Regulations may require thatthe material be tested to determine asbestos content. TheResilient Floor Covering Institutes (RFCI) recommendedwork practices for removal of existing resilient floor coveringsshould be consulted for a defined set of instructions addressedto the task of removing all
29、 resilient floor covering structures.Various federal, state, and local government laws have regula-tions covering the removal of asbestos-containing materials. Ifconsidering the removal of resilient flooring or asphalticNOTEFig. 1 not to scale.FIG. 1 Typical RH Hood Showing Air ChamberNOTEFig. 2 not
30、 to scale.FIG. 2 Typical RH Hood Showing RH Probe Positioned in HoodNOTEFig. 3 not to scale.FIG. 3 Diagram of Typical RH HoodF2420052cutback adhesive that contains or presumes to contain asbes-tos, review and comply with the applicable regulations.7.2 Lead WarningCertain paints may contain lead. Exp
31、o-sure to excessive amounts of lead dust presents a health hazard.Refer to applicable federal, state, and local laws and guidelinesfor hazard identification and abatement of lead-based paintpublished by the U.S. Department of Housing and UrbanDevelopment regarding appropriate methods for identifying
32、lead-based paint and removing such paint, and any licensing,certification, and training requirements for persons performinglead abatement work.8. Calibration8.1 Relative Humidity Probes should be manufactured withNIST or equivalent traceable calibration procedures and havedocumentation available sta
33、ting the range of calibration and theaccuracy over that range. Probes shall be calibrated at 90 %relative humidity or higher, in addition to lower humiditylevels, and have an accuracy level within 63 % between 25and 98 % relative humidity.8.2 Probes should be checked for calibration and if found tob
34、e outside tolerance: (a) those suitable should be recalibrated,and (b) those not suitable for recalibration should be disposed.RH probes should not be used when found to be outsidecalibration tolerances.8.3 Probes should be recalibrated on a periodic basis (atleast annually). Calibration checking an
35、d recalibration may berequired on a more frequent basis where probes are exposed toenvironmental conditions that could affect measurement accu-racy.8.4 On-Site Performance Calibration Check:8.4.1 Check probe calibration within 30 days before use bythe following procedure:8.4.2 Calibration Check Proc
36、edure (for on-site checkingonly)Saturated salt solutions: Use prepared saturated saltsolutions in accordance with Practices E 104. Follow probemanufacturers recommended procedure for exposing probesto this solution. Record the as-found relative humidity and thenominal relative humidity of the salt s
37、olutions. If the as-foundRH differs from the nominal RH by more than 63 % the probeshould be recalibrated before use.NOTE 2Initial Calibration or recalibration by end-users using satu-rated salt solutions in accordance with Practices E 104 is not recom-mended due to difficulties of maintaining suffi
38、ciently accurate referencestandards. Checking with salt solutions is an acceptable method ofassessing probes on-site performance.8.4.3 If calibration checking reveals the probe output differsby more than 63 %, recalibrate the probe before use.9. Conditioning9.1 Concrete floor slabs shall be at servi
39、ce temperature andthe occupied air space above the floor slab shall be at servicetemperature and relative humidity expected under normal usefor at least 48 h prior to the hood placements. If this is notpossible then the test should be conducted with conditions at 756 10F (24 6 5C) and relative humid
40、ity of 50 6 10 %. Allartificial aids used to accelerate drying should be turned off atleast 96 h before hoods may be sealed on the concrete surface.10. Procedure10.1 Number of Tests and Locations:10.1.1 Perform three tests for the first 1000 ft2(93 m2) andat least one additional test for each additi
41、onal 1000 ft2(93 m2).Select test locations to provide information about moisturedistribution across the entire concrete floor slab, especiallyareas of potential high moisture. For slabs on-grade andbelow-grade, include test locations in the center of the floorand areas close to exterior walls. Choos
42、e areas that aresusceptible to high moisture when placing hood.10.1.2 Prior to placement of the RH hoods the actual testarea shall be clean and free of any foreign substances. Onlyclean bare concrete surfaces shall be exposed to the airchamber underneath the hood.10.1.3 Where covered floor slabs are
43、 being tested, allcovering materials, adhesive residue, curing compound, seal-ers, paints, etc., shall be removed to expose an area of cleanbare concrete for testing using the RH Hood method. Removalof any existing floor covering or adhesive shall be accom-plished using approved OSHA work practices.
44、 For removal ofany existing flooring or adhesives strictly observe Section 7and any other appropriate safety and health practices. Thecleaned test area should be exposed to conditions specified in9.1 for a period of at least 24 h prior to starting the test.10.1.4 Seal the insulated hood firmly to th
45、e floor with asuitable preformed butyl/sealant adhesive or similar. Thesealant used should be of a type that does not give off anyemissions that could affect the relative humidity readings in thehood. Place seal/stopper in probe hole.10.1.5 Allow a period of at least 72 h to elapse after sealingthe
46、hood to the floor so as to achieve moisture equilibrium inthe air pocket under the hood before taking readings.510.1.6 This test method is not suitable for areas that havesurface applied vapor barriers or curing compounds that cannotbe removed or cleaned off sufficiently to allow vapor flowthrough t
47、he surface of the slab. For very thick floor slabconstruction, (for example, 8 in. and over), and low porosityslabs or slabs with certain types of power floated low emissionsurface finishes it may take considerably longer than 72 h toreach moisture equilibrium. Should these conditions existwhere a c
48、onsiderable amount of additional time may berequired for the satisfactory performance of this test because ofthe low porosity surface or slow vapor movement in the slab,or both, then Test Method F 2170 (below surface in situ RH)should be considered as a more suitable test method underthese circumsta
49、nces.10.1.7 Possible edge effect6(see A1.6).10.1.8 Readings are taken by removing stopper from probeaccess hole in hood, this should be done quickly to ensure thatno air escapes from, or enters, the air pocket under the hood.10.1.9 Insert the humidity probe into hole so that its sensorprotrudes into the center air chamber, and is sealed in positionduring acclimation, and taking of readings.5Equilibrium could be assumed when two consecutive readings taken at 24-hintervals show no change.6To minimize the risk of possible edge effect on thick slabs and por
