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1、Subjects 444(13, 1424, 1425, 1651, 1655, 1690) Melville, L.I., NY 11747 (in reply, refer to Subject 444.) 1285 Walt Whitman Road August 1 O, 2000 TO: Technical Advisory Panel of Underwriters Laboratories for Communications and Electrical Council of Underwriters Laboratories Inc. Fire Council of Unde
2、rwriters Laboratories Inc. Subscribers to ULs Standards Service for Communications Cables - UL 444 Power-Limited Circuit Cable - UL 13 Cables for Power-Limited Fire-Alarm Circuits - UL 1424 Cables for Non-Power Limited Fire-Alarm Circuits - UL 1425 Optical Fiber Cable - UL 1651 Community Antenna Tel
3、evision Cables - UL 1655 Data Processing Cable - UL 1690 Power Limited Wire and Cable SUBJECT: Report on the June 7, 2000 Meeting of the Technical Advisory Panel of UL for Communications and Power-Limited Wire and Cable - Request for Comments. The following topics were discussed at the meeting: I -
4、Introduction 2 - Fire Test Harmonization Project 3 - UL 910 Research Project, Control Charts, FPRF Tunnel Operators Group 4 - Revised Methodology for Determining Compliance with UL 910 Test 5 - Internet Access to UL Services 6 - Broadband Cable 7 - Circuit Integrity Marking for Fire Alarm Cable 8 -
5、Interchangeability of FEP with Different Material Designations 9 - Polymer Science Expertise 10 - UL Services II - Wire and Cable Fund COMMENTS DUE: September 21,2000 COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services COPYRIGHT Underwriters Laboratories Inc. Licensed
6、by Information Handling Services SUBJECT 444 -2- AUGUST 10,2000 A meeting of the Technical Advisory Panel of UL for Communications and Power-Limited Wire and Cable (TAPCOM) was held on June 7, 2000 at ULs Northbrook Office. The purpose of the meeting was to discuss various topics related to communic
7、ations and power-limited wire and cable. Attached as Appendix A is the Revised Methodology for Determining Compliance with the UL 910 Test. Attached as Appendix B is a list of those who attended the meeting. Attached as Appendix C is a directory of UL staff members to contact for assistance with com
8、munications and power-limited wire and cable issues. Questions regarding interpretation of requirements should be directed to the responsible UL Staff. Please see Appendix D of this bulletin regarding designated responsibility for the subject product categories. Copies of the following presentations
9、 have been sent electronically to attendees (the overview for Broadband Cable, and the research report have not been sent electronically). Additional copies of the following material may be obtained by contacting Laura Schroeppel at ULs Melville Office: The Fire Test Harmonization Project presentati
10、on discussed in Item 2 of this report. The UL 910 Research Project, Cable Control Charts, and the FPRF Tunnel Operators Group presentation discussed in Item 3 of this report. The Internet Access to UL Services presentation discussed in Item 5 of this report. The overview of the new category for Netw
11、ork-Powered Broadband Communications Cables, discussed in Item 6 of this report. The research report titled, ”Investigation of the Influence of the Variation in Test Parameters and Smoke System Modifications on UL 910 Test Results” discussed in Item 3 of this report. * * * * * * The following report
12、 is not intended to be a verbatim transcript of the discussion at the meeting, but is intended to record the significant features of those discussions. 1 - Introduction The chairman explained that this Technical Advisory Panel (TAPCOM) may be converted to an Industry Advisory Group (IAG). The member
13、ship of this TAPCOM would be rolled over into an IAG which will be chaired by Mr. Steve Galan of ULs Melville office. An IAG is typically comprised of producers, users, and suppliers while an Industry Advisory Conference (IAC) is comprised of manufacturers. The chairman also explained that UL is now
14、 developing Standards Technical Panels (STP). STPs will be made up of a balanced group of users, producers, and general interest groups. The STP process will help UL to move forward with ANSI approval of its Standards, and will allow for more input in the early stages of standards development. Addit
15、ional information about the STP process will be distributed by UL in the near future. COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services SUBJECT 444 3- 2 - Fire Test Harmonization Proje
16、ct AUGUST 10,2000 A project was initiated in June of 1998 under the auspices of the National Fire Protection Association (NFPA) Fire Protection Research Foundation (FPRF) to address harmonization of the NFPA 262 (National Fire Protection Association Standard for the Method of Test for Fire and Smoke
17、 Characteristics of Wire and Cable) fire test. A member of the FPRF project Technical Advisory Committee presented an update on the NFPA 262 fire test harmonization project which was completed earlier this year. The laboratories that participated in this harmonization project were Building Research
18、Establishment (BRE), Loss Prevention Council (LPC), Japan Electric Cable Technology Center (JECTEC), Intertek Testing Services (ITS), and Underwriters Laboratories (UL). The four phases for this project were as follows: Phase I - System Evaluation - A revised version of NFPA 262 was distributed to e
19、ach of the participating laboratories. This revised version included more detailed descriptions of the apparatus, maintenance, and calibration method used for this test. Dimensional, procedural, and control system differences were identified. This resulted in the installation of new duct sections an
20、d smoke systems so that all the tunnels involved in this harmonization project would be physically equivalent to the UL tunnel in Northbrook. Phase II - Calibration Burn Trials using F40 cable (four pair unshielded twisted pair communication cable with PVC jacket and FEP insulation). Phase III - 910
21、ST and Commercial Cable Burn Trials - three tests for each cable. Phase IV - 910ST Verification Burn Trials - six tests per lab. Once phase I was completed and each of the tunnel furnaces were physically harmonized, tests conducted under the remaining phases of the project exhibited a high degree of
22、 agreement between the test labs for peak and average optical density (OD), and for flame spread results. It was then decided that the burning behavior of different cables needed to be checked in this process. The different cable samples used were commercially available cables, and the 91 OST refere
23、nce cable. The 91 OST cable is comprised of PVDF insulation extruded over a solid copper conductor. The commercial cables used were F40 (four pair, unshielded twisted pair, low smoke PVC jacket, FEP insulation), CCl (two pair fire alarm cable, PVC jacket and insulation), CC2 (similar to F40), and CC
24、3 (fiber optic cable, PVC jacket and insulation). The precision of the test results for the cables used was measured in terms of repeatability and reproducibility in accordance with the Standard for Accuracy (Trueness and Precision) of Measurement Methods and Results, IS0 5725. Repeatability is an i
25、ntra-lab assessment, and reproducibility is an inter-lab assessment. In summary, physical harmonization was achieved between the participating test lab tunnels, a revised NFPA 262 standard has been developed and proposed to the NFPA Fire Test Committee, and repeatability and reproducibility data was
26、 generated using the IS0 5725 protocol using five cable constructions and 120 individual tests. COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services SUBJECT 444 -4- AUGUST 10,2000 A Resea
27、rch Advisory Council (RAC), under the FPRF, was established. It is comprised of cable manufacturers and suppliers who meet regularly to discuss issues associated with this test. The Tunnel Operators Group (TOG) within the RAC was also established. The TOG, comprised of the test laboratories who part
28、icipated in the harmonization project, discuss issues such as maintenance, operation, training, and sample preparation. 3 - UL 910 Research Project, Control Charts, FPRF Tunnel Operators Group UL presented information on; a) its internally sponsored UL 910 research project to investigate the influen
29、ce of the variation in test parameters and smoke system modifications on UL 910 test results, b) the control charts for three cable types, and c) the Tunnel Operators Group. a) UL 910 RESEARCH PROJECT - This project was sponsored and conducted by UL to investigate the influence of variations in test
30、 parameters on UL 91 O test results. The UL 910 test method was developed to measure the burning characteristics of electrical cables installed in environmental air handling spaces. The test uses the Steiner Tunnel fire test apparatus to measure flame propagation and optical density of smoke generat
31、ed from cables during a twenty minute fire test. The Standard for Test for Flame-Propagation and Smoke-Density Values for Electrical and Optical-Fiber Cables Used in Spaces Transporting Environmental Air, UL 91 O, requires calibration of the test chamber and related systems with respect to key test
32、parameters. These procedures include verification of the air velocity; determination of the time-temperature profile obtained with the ignition gas burner; and calibration of the smoke measurement system. The objectives of this study were to investigate (i) the influence of test parameters on UL 910
33、 test results, (i) factors that interfere with the smoke measurement; and (iii) methods to reduce the interference in the smoke measurement. The test parameters investigated were the tunnel airflow velocity and the ignition burner gas flow rates. A horizontal smoke system orientation and adjustment
34、of the air gap between the bottom glass plate and the glass holder assembly in the smoke system assembly were also investigated to determine their influence on the measurement on smoke optical density. The tunnel air velocities used were nominally, 236, 243, and 247 ft/min. The gas flows were set to
35、 obtain nominal rates of 4.6, 4.9, and 5.2 CFM. In these tests, measurements included pre- and post- test photo-detector signals, smoke obscuration, flame propagation and system control parameters. The potential build-up of static smoke in the standoff tubes of the smoke measurement system was also
36、monitored. The cable tests were conducted on 4 pair copper conductor (designated as 4 pair, or F40), and 24 fiber optical fiber (designated as fiber) cables. Repeat tests were conducted to obtain a representative average value for flame propagation, and peak and average optical density. COPYRIGHT Un
37、derwriters Laboratories Inc. Licensed by Information Handling Services COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services SUBJECT 444 -5- AUGUST 10,2000 The findings of the UL 910 research project are summarized as follows: Influence of Test Parameters Variations in t
38、unnel air flow velocity and burner gas flow rate did not have a significant influence on flame propagation results. Optical density measurements were lower for higher air flow velocities. Optical density measurements were lower at reduced gas flows. The two cables tested had different sensitivities
39、of their optical results as a function of the air and gas flows. A model was developed to account for variation in optical density from the combined change in tunnel airflow velocity and ignition gas flow rate. The model was correlated to fire test results. The tunnel air flow system and gas flow de
40、livery system were able to provide control of the inlet air pressure and gas flow rate with a standard deviation of approximately one percent from test to test. Factors That Mav Interfere With Smoke Measurement The amount of smoke observed in the upper standoff tube for all tests using the vertical
41、smoke orientation ranged from 0.25 to 2.0 in. as measured from the junction of the standoff tube with the exhaust duct. Most of the tests generated smoke heights of 0.5 in. or less. This smoke height was not constant and varied with the burning of the cable sample. Further, the smoke was dynamic and
42、 appeared to be a result of fluid dynamics in the exhaust and smoke measurement system. There was no static build-up of smoke in the standoff tubes. There was no observed smoke in the lower standoff tube. Particulate deposits on the smoke system bottom glass plate can have an influence on optical de
43、nsity results. A maximum drift of 2.4 percent was observed in the smoke system clear beam signal, resulting in a maximum, potential change of 0.01 in peak and average optical density calculations. Methods To Reduce the Interference In the Smoke Measurement Tests were conducted with the smoke system
44、in the vertical orientation (standard) and in the horizontal orientation. The tests with the horizontal orientation were conducted to investigate the benefit in eliminating the possible interference in the smoke measurement by particulate deposits. However, the horizontal orientation of the smoke sy
45、stem resulted in lower measured smoke obscuration. This may be due to stratification of smoke in the exhaust duct as a result of the location of the test sample in the tunnel furnace. Increasing the air gap reduced the occurrence of particulate deposits on the bottom glass plate. However, this induc
46、ed a higher airflow into the standoff tubes and lowered the optical density results. COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services COPYRIGHT Underwriters Laboratories Inc. Licensed by Information Handling Services SUBJECT 444 -6- AUGUST 10,2000 Cable ID 910ST - p
47、recolor F40 24 Fiber Subsequent testing has shown that particulate can be reduced by periodic cleaning of the exhaust duct section before the smoke measurement system. Number of Avg Max Std Dev Max Avg POD Std Dev POD Avg AOD Std Dev AOD tests Flame Flame Propagation Propagation (fi) (ft) 19 1.6 0.3
48、7 0.28 0.067 0.1 o 0.01 7 21 0.8 0.50 0.31 0.037 0.09 0.01 2 8 2.0 0.50 0.44 0.033 0.20 0.01 1 Follow up actions are in progress to improve the stability of the gas flow rate and to improve the measurement of the air flow rate. With respect to the particulate deposits, periodic cleaning of the exhau
49、st duct and the introduction of a small amount of airflow across the bottom glass plate have been instituted to keep the particulates from being deposited. The airflow across the bottom glass plate does not influence peak or average optical density. b) CONTROL CHARTS - UL is in the process of developing UL 910 control charts for the newly constructed south tunnel on three different reference cables. These include the 910ST cable described in the standard, as well as the F40 cable and a 24 fiber optical fiber cable. A summary of the data obtained to date is provided in the following table