UL 1746 CRD-2012 UL Standard for Safety External Corrosion Protection Systems for Steel Underground Storage Tanks - Section Paragraph Reference Part II Section 20 and Part III Secst.pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared and published by Underwriters Laboratories Inc.(UL). It is normative for the a

2、pplicable UL Product Certification Program(s); however, it is currently notpart of the UL Standard(s) referenced below.Product Category (CCN): EGHXStandard Number: UL 1746Edition Date: January 17, 2007Edition Number: 3Section / Paragraph Reference: Part II Section 20 and Part III Section 24 - Physic

3、alProperties of Materials TestsSubject: Assessment of Alternate Glass FibersDECISION:Part II - Add a clarification under General Sub-Section 20.1:20.1.2 In cases where alternate glass fibers (rovings or mattes) are requested to be used within a FRPmatrix that has previously been evaluated in accorda

4、nce with all applicable requirements in UL 1746, thefollowing steps in 20.1.2.1 to 20.1.2.4 for a comparative analysis shall be used to determine equivalencyand/or the need for additional testing:20.1.2.1. Basic material information (generic type & class, physical properties, dimensions, etc.) shall

5、 beobtained from the manufacturer on the original and alternate component fiber for comparison. If the fibermaterials are in the same generic family with similar properties & dimensions, continue to 20.1.2.2,otherwise, full testing per UL 1746 Sec 20 for short & long term material properties is requ

6、ired.20.1.2.2 Separate production samples of the complete FRP matrix using the same resin, but with originaland alternate glass fibers, shall be evaluated for glass content comparison per the UL 746A Sec 43 AshContent Test. If the glass content of the alternate FRP is within +/- 5% of the original F

7、RP, continue to20.1.2.3, otherwise, full testing per UL1746 Sec 20 for short & long term material properties is required.20.1.2.3 Separate production samples of the FRP matrix using the same resin, but with original andalternate glass fibers, shall be evaluated for flexural strength comparison per t

8、he UL 1746 Par 20.3.1Physical Properties Tests for ASTM D790 Flexural Strength, except 10 samples for each set of materialsbeing compared shall be tested in the as-received and after boiling (in DI water for 24 hrs) conditions.20.1.2.4. If the flexural modulus strength results comparing the original

9、 and alternate(s) of both before &after retention value averages are statistically similar (using a “difference of means” calculation with a 0.10alpha significants level), the alternate glass fiber is accepted as an equivalent without additional testing,otherwise, full testing per UL 1746 Sec 20 for

10、 short & long term material properties is required.Part III - Add a clarification under General Sub-Section 24.1:24.1.2 In cases where alternate glass fibers (rovings or mattes) are requested to be used within a FRPmatrix that has previously been evaluated in accordance with all applicable requireme

11、nts in UL 1746, thefollowing steps in 24.1.2.1 to 24.1.2.4 for a comparative analysis shall be used to determine equivalencyand/or the need for additional testing:UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL24.1.2.1. Basic material informa

12、tion (generic type & class, physical properties, dimensions, etc.) shall beobtained from the manufacturer on the original and alternate component fiber for comparison. If the fibermaterials are in the same generic family with similar properties & dimensions, continue to 24.1.2.2,otherwise, full test

13、ing per 1746 Sec 24 for short & long term material properties is required.24.1.2.2 Separate production samples of the complete FRP matrix using the same resin, but with originaland alternate glass fibers, shall be evaluated for glass content comparison per the UL 746A Sec 43 AshContent Test. If the

14、glass content of the alternate FRP is within +/- 5% of the original FRP, continue to20.1.2.3, otherwise, full testing per 1746 Sec 24 for short & long term material properties is required.24.1.2.3 Separate production samples of the FRP matrix using the same resin, but with original andalternate glas

15、s fibers, shall be evaluated for flexural strength comparison per the UL1746 Par 24.2.3Physical Properties Tests for ASTM D790 Flexural Strength, except 10 samples for each set of materialsbeing compared shall be tested in the as-received and after boiling (in DI water for 24 hrs) conditions.24.1.2.

16、4. If the flexural modulus strength results comparing the original and alternate(s) of both before &after retention value averages are statistically similar (using a “difference of means” calculation with a 0.10alpha significants level), the alternate glass fiber is accepted as an equivalent without

17、 additional testing,otherwise, full testing per 1746 Sec 24 for short & long term material properties is required.RATIONALE FOR DECISION:Since UL1746 Sec 20 and Sec 24 are intended to evaluate the completed FRP matrix (resin & fibers) andnot individual components, the identified analysis sequence an

18、d associated test methods have beenconsistently applied by UL in order to determine the equivalence of alternate glass fibers.The fiber comparison (material type, dimensions and content) is an initial equivalence measure of theoriginal vs alternate fibers within the same FRP matrix. The ASTM D790 Fl

19、exural Strength Test of physicalproperties and Difference of Means statistical analysis of both as-received and after boiling has been thebest way to compare different fibers based on established and accepted industry practice. The highernumber of test samples improves the statistical calculations,

20、and the sample boiling simulates expectedsoftening of the resin in the matrix related to liquid exposures over time.If both the construction and performance measures meet the high level of equivalence, and since theglass is highly resistant to chemical change and the previously tested resins have no

21、t changed, additionaltests are not necessary. This CRD does not apply to alternate resins.Copyright 2012 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorrectness of Certification Requirement Decisions it may issue o

22、r that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of Underwriters Laboratories Inc. inpractically applying the requirements of the standard. They do not represent formal interpretations of thestandard under American National Standards Institute (

23、ANSI) processes. UL shall not be responsible toanyone for the use of or reliance upon Certification Requirement Decisions by anyone. UL shall not incurany obligation or liability for damages, including consequential damages, arising out of or in connectionwith the use or reliance upon Certification Requirement Decisions. The electronic version of theCertification Requirement Decision is the current version and previously printed copies may be outdated.This document is published as a service to ULs certification customersSTANDARD NUMBER: UL 1746 -2-