1、Designation: D 7013 04Standard Guide forNuclear Surface Moisture and Density Gauge CalibrationFacility Setup1This standard is issued under the fixed designation D 7013; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 guide outlines procedures for setup of nuclearmoisture density gauge in shielded, Method A, and unshielded,Method
3、B, configurations.1.2 This guide does not attempt to describe the calibrationtechniques or methods. It is assumed that this guide will beused by persons familiar with the operations of the gauge andin performing proper calibration, service and maintenance.1.3 This guide does not attempt to address m
4、aintenance orservice procedures related to the gauge.1.4 This guide does not purport to address all of the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this guide to establish appropriate safety, andhealth practices and determine the applicability of regula
5、torylimitations prior to use.1.5 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cannot replace education orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this
6、guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should thisdocument be applied without consideration of a projects manyunique aspects. The word “Stan
7、dard” in the title of thisdocument has been approved through ASTM consensus pro-cess.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inpractice D 6026.1.6.1 The method used to specify how data are collected,calculated, or recorded
8、 in this standard is not directly relatedto the accuracy to which the data can be applied in the designor other uses, or both. How one applies the results obtainedusing this standard is beyond its scope.2. Referenced Documents2.1 ASTM Standards:2D 2922 Standard Test Method for Density of Soil andSoi
9、l-Aggregate in Place by Nuclear Methods (ShallowDepth)D 653 Terminology Relating to Rock, Soil and ContainedFluidsD 3740 Standard Practice for Minimum Requirements forAgencies Engaged in the Testing and/or Inspection of Soiland Rock as Used in engineering Design and ConstructionD 6026 Standard Pract
10、ice for Using Significant Digits inGeotechnical Data3. Terminology3.1 For common definitions of terms refer to TerminologyD 6533.2 Definitions of Terms Specific to This Standard:3.2.1 Unshielded Calibration bayAn open area within acalibration facility where the closest wall is a minimum of 1meter (3
11、 ft.) from the spot in which the gauge is beingcalibrated.3.2.2 Shielded Calibration bayAn enclosed area sur-rounded by concrete blocks or walls to protect the gauge beingcalibrated from outside influence and background radiationfrom all gauges in the facility.3.2.3 Shielded Storage BayAn enclosed a
12、rea shielded bywalls to maintain and control radiation background in thefacility and to reduce influences from stored gauges.4. Summary of Method4.1 Nuclear moisture density gauges require proper calibra-tion to ensure measurement repeatability between gauges.Since these gauges contain radioactive i
13、sotopes, influencesfrom the surroundings and other gauges should be controlledduring the calibration process. This guide provides procedures1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.08 on Special and Construc-tion
14、Control Tests.Current edition approved Dec. 1, 2004. Published December 2004.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page ont
15、he ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.to facilities involved in calibration of one or more gauges inshielded and unshielded calibration bays. The goal of thisguide is to insure proper gauge calibration and t
16、o reduceinfluences that would result in field measurement variabilitybetween gauges.5. Significance and Use5.1 Gauge calibration is conducted for the following pur-poses:5.1.1 To ensure gauge measurement repeatability betweengauges5.1.2 To correct for electronic and mechanical changes overtime5.1.3
17、To adjust readings after major service to the gauge5.2 To establish a proper calibration area for gauges5.3 To reduce the chance of improper calibrationNOTE 1The quality of the results produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the e
18、quipment and facilities used. Agencies that meet thecriteria of practice D 3740 are generally considered capable of competentand objective testing/inspection/etc. Users of this standard are cautionedthat compliance with practice D 3740 does not in itself assure a means ofevaluating some of those fac
19、tors.6. Apparatus6.1 Calibration reference block(s) as per the requirements ofASTM D 2922 with density certification from the blockmanufacturer6.2 High density concrete blocks 9cm 3 20 cm 3 41 cm(3.59 3 89 3 169) or cinder blocks 20 cm 3 20 cm 3 41 cm(89 3 89 3 169) filled with sand or other fine ag
20、gregatematerials for construction of bay walls6.3 Lead sheet 1 to 6 mm (0.032 to 0.25 inches) thick forlining the bay walls. The exposed surfaces containing leadshould be painted or covered6.4 Plywood of minimum 1.3 cm (0.59) thickness forsecuring lead sheets to the calibration bay walls.7. Method A
21、: Shielded Calibration Bay Setup7.1 Set up a shielded calibration bay if more than one gaugeis going to be calibrated simultaneously, and the space betweengauges being calibrated is less than 10 meter (33 ft). If thegauge in storage bay is less than 7 meters (23 ft) from the areawhere the calibratio
22、n is going to take place, or if the area wheregauges are routinely serviced is less than 10 meters (33 ft) fromthe calibration area. Refer to the Appendix X1 for examples ofshielded calibration bay configurations.NOTE 2Use Method B, if section 7.1 does not fit your calibrationfacility requirements.7
23、.1.1 Determine the number of bays required for calibrationof nuclear gauges. This can be based on the number of gaugescalibrated per year and can vary from one to several bays.7.1.2 The bay inside dimensions should be establishedbased on the bay walls being a minimum of 610 mm (24inches) from the ce
24、nter of calibration blocks and lined with 1mm (0.032 inches) of lead. Smaller inside dimensions can beused if lead sheets thicker than 6 mm (0.25 inch) are used onthe walls. However, under no circumstances should the wallsbe less than 610 mm (24 inches) from center of the gauge.NOTE 3Depending on th
25、eir design, some gauges may be less suscep-tible to wall effect. Lead sheets may not be required, if it is determined thatthe counts inside and outside the bay are equal and that the gauge is notaffected by the walls surrounding the calibration bay.7.1.3 The calibration bay wall thickness should be
26、a mini-mum of 410 mm (16 inches) thick. The walls should beconstructed using high-density concrete blocks or cinderblocks filled with sand or fine aggregate material. Stagger theblocks during wall construction to block gaps and to improvewall integrity.7.1.4 The wall height should be 1.0 to 1.3 mete
27、rs (40 to 50inches)7.1.5 Design and construct the bay such that the opening ofthe bay is not in direct line with the storage bay or the areawhere the gauges are serviced7.1.6 Center the calibration reference block(s) in the bay7.1.7 Once the bays are complete and the calibration blocksare setup, fol
28、low the procedures in section 9 and makeadjustments, if necessary.7.2 Configuration of a Shielded Bay7.2.1 Wall Influence Verification for Shielded CalibrationBay(s)The response to the surrounding walls can varysignificantly for different gauge geometries. For accuratecalibration, influence from the
29、 walls should be eliminated.7.2.1.1 Place a gauge on a calibration reference block7.2.1.2 Take two four minute counts, moisture and density,in Backscatter and 300 mm (12 inch) position and one fourminute counts at all other gauge depths.7.2.1.3 Move the calibration reference block(s) out of thebay,
30、a minimum of 1 meter (3 ft) from any walls and 10 meter(33 ft) from any gauges.7.2.1.4 Repeat step 7.2.1.2 with the same gauge7.2.1.5 The difference between the counts in step 7.2.1.2and 7.2.1.4 for all gauge depths should be less than 61.0 %.Determine the difference by equation Eq 1 and record to 0
31、.1 %Difference 5SLargest Count 2 Smallest CountLargest CountD3 100 (1)7.2.1.6 If the difference in the counts are higher than the 61.0 % limit, increase the inside wall dimensions or the leadliner thickness and repeat the steps in 7.2.1.1-7.2.1.5.7.2.1.7 Repeat this procedure for all model gauges.7.
32、2.2 Reference Standard Count Verification in ShieldedCalibration Bay(s)The size and geometry of gauges willhave an effect on the accuracy of the standard counts. Foraccurate calibration, standard counts taken on top of calibrationreference block(s) should closely match counts taken on theground.7.2.
33、2.1 Place the gauge on its reference standard block ontop of the calibration reference block which is to be used forgauge standardization.7.2.2.2 Take a total of 20 minute standardization count. Forexample, average of 20 one minute counts, average of 5 fourminute counts, etc.7.2.2.3 Record the moist
34、ure and density count7.2.2.4 Remove the calibration reference block from thecalibration bayD70130427.2.2.5 Place the gauge on its reference standard block insafe position in the middle of the bay on the floor7.2.2.6 Take a total of 20 minute standardization count7.2.2.7 Record the moisture and densi
35、ty counts7.2.2.8 Compare the counts in step 7.2.2.3-7.2.2.7. Thedifference in counts as calculated by equation 1 should be lessthan or equal to 6 2.0 % for moisture standard and 6 1.0 % fordensity standard.7.2.2.9 If the differences exceed the limits given in 7.2.2.8,expand the bay dimensions, apply
36、 correction factors for thecounts taken on top of the calibration reference block(s) or takethe standard counts on the ground. It is important that thissection is repeated for each gauge model.7.2.3 Between Bay Cross Talk VerificationSufficientshielding should be provided between adjacent shielded c
37、ali-bration bays in order to eliminate influence from each bay.Bays should be setup to eliminate influence from gauges beingcalibrated in adjacent bays.7.2.3.1 Place one gauge in each bay. Place the gauges ontheir reference standard block in the safe position on top of thecalibration reference block
38、(s).7.2.3.2 Take a total of 20 minute count with each gauge ineach bay.7.2.3.3 Record the counts for both moisture and density forboth gauges7.2.3.4 Remove one of the gauges from the bay and place itin the storage bay7.2.3.5 With the second gauge still remaining in the calibra-tion bay and without m
39、oving the gauge, take a second 20minute standard count.7.2.3.6 Record the moisture and density counts7.2.3.7 Compare the average of the 20 minute counts in step7.2.3.6 to counts for the same gauge in step 7.2.3.3.7.2.3.8 The difference in the counts in step 7.2.3.7 should beless than or equal to 6 1
40、.0 % for density and 62.0 % formoisture.7.2.3.9 If this difference is larger than the limits in 7.2.3.8,increase the wall thickness between the bays or add to thethickness of the lead sheet liners.7.2.3.10 Repeat the steps of this section for each set ofadjacent bays to verify that cross talk betwee
41、n bays has beeneliminated7.2.3.11 Repeat this section for each gauge model or con-duct this test using gauges with plastic top shells and the largestradioactive sources.NOTE 4Do not use the calibration bay to store gauges. Increasednumber of gauges in one bay can affect the calibration accuracy of g
42、augesin the adjacent bays.7.2.4 Follow block manufacturers procedures to completethe gauge calibration8. Shielded Storage Bay Setup8.1 Setup a shielded storage bay if more than five gauges areroutinely stored at a distance of 7 meters (23 ft) or less from thearea where gauge calibration is to take p
43、lace. If five or lessgauges are routinely stored in the storage area, concrete wallsare not necessary. However, gauges should be stored in theirshipping cases, while calibrating other gauges. Refer to theAppendix X1 for examples of shielded storage bay configura-tions.8.1.1 The storage bay should no
44、t be setup directly under orover the area where gauges are to be calibrated.8.1.2 Stagger the blocks during wall construction to blockgaps and to improve wall integrity.8.1.3 If more than five gauges are routinely stored in thestorage bay, build a wall made from high density concrete orcinder blocks
45、 filled with sand or fine aggregate material.8.1.4 The wall thickness for the storage bay should be aminimum of 410 mm (16 inches). The wall should completelysurround the area where the gauges are planned to be stored. Ifgauges are stored on shelves that are elevated from the floor,the height of the
46、 wall should be a minimum of 0.5 meter (20inch) above the height of the shelves on which gauges arestored.NOTE 5Additional requirements might be necessary in order to meetState and Federal licensing regulations. These requirements might include,lockable doors to limit access and appropriate caution
47、signs. Users shouldcheck their materials license requirements and check with their regulatoryagency when building storage bays for nuclear gauges.9. Method B: Configuration of an Unshielded Bay9.1 The area where the gauges are stored and are beingworked on should be at least 10 meters (33 ft) away f
48、rom thearea where the calibration reference block(s) are placed forcalibration.9.2 If more than 5 gauges are stored in the storage, eitherremove the extra gauges and place 20 meters (66 ft) awaywhile calibrating the gauges or build a shielded storage bayaccording to Method A.9.3 If more than one gau
49、ge is being calibrated simulta-neously, place the calibration reference block(s) a minimum of10 meters (33 ft) away from each other.9.4 Follow block manufacturers procedures to complete thegauge calibration.10. General Care10.1 Clean calibration reference block(s) periodically usingblock manufacturers recommendations10.2 Monitor the background readings in your calibrationarea. Backgrounds taken should not vary by more than 63.0 % from the average of the four previous backgroundcounts. If background counts have increased above the 63.0 % limit, identify the reason and make t
