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									                 COE Installation Quality Bulletin
Installation Quality Bulletin Number: 08-02

To: QTI / C.O. Operations Representatives / Design Engineering
Representatives / Quality Managers / Field Engineering
Representatives / AMC Representatives / All Contracted
Installation Service Suppliers

           Date: Wednesday, April 2, 2008
           From: QWEST Installation Quality Assurance

   Subject: Modification to Existing Central Office Firestopping
     Policy and Procedure per 3M Engineering Judgment




Action Required:
 YES:         NO:
Description of Bulletin:
The purpose of this Bulletin is to update the existing cable hole fire-stopping requirements
associated with the use of the 3M intumescent (CS195+) composite fire-stopping sheets per a
recent ruling by the 3M Company Engineering Judgment.

Qwest follows approved fire stopping arrangements based on the appropriate UL listed fire
stopping assemblies. Currently, TP 77350 “typical” sketches in Chapter 4 depicting firestopped
floor penetrations have illustrated the placement of both a top and bottom steel cover attached to
the penetration (along with the the application of the CS195+ composite fire-stopping sheet and
3M intumescent putty bead around the cable bundle perimeter) to maintain the Underwriter’s
Laboratories (UL) two-hour Fire (F) and 1-1/2 hour temperature transmission (T) ratings (refer to
Figure 1).




                                           Figure 1

This practice of retaining the bottom steel plate cover and the intumescent sheet (CS195+)
is now obsolete for floor penetrations.
3M System No. F-B-3004 associated with common floor cable hole fire-stopping systems
requires the intumescent sheet and cover plate arrangement on the top of the floor penetration
only to maintain the two-hour Fire (F) rating. As a result, the intumescent sheet and cover plate
is no longer required on the bottom portion of a floor-oriented cable hole. Refer to Figure
2.




                                                                                       Bottom steel cover
                                                                                       and CS195+
                                                                                              Bot
                                                                                       intumscent sheet
                                           Figure 2                                    removed per 3M
                                                                                       judgment.

Once the bottom cover plate and the 3M Composite CS195+ intumescent sheet, have been
removed, it is recommended that the Service Supplier inspect both items for the possibility of
reuse. These items may be useful for reuse in an upcoming cable mining job and could delay the
procurement of new covers and sheets.

All cable holes through fire-rated walls will still require CS195+ sheets on each side of the wall
penetration.

                              Additional Notes and Clarifications

Note 1: The term “cable hole” refers to an individual cable hole penetration. A “cable slot,” a
long narrow floor penetration that may, or may not, be portioned, will still require covers on both
the top and bottom of the penetration at this time.
                        Additional Notes and Clarifications (Continued)

Note 2: When the Service Supplier runs new cable through a firestopped penetration without
completely removing the CS195+ intumescent sheet or breaking the sealed firestopping label
(this is accomplished by removing a portion of the putty bead around the cable bundle, and
nibbling enough of the composite CS195+ sheet back to gain entry, and then resealing just that
section after cable entry), that penetration is still considered properly sealed. This practice is
considered to be the same as “opening and closing” a cable hole.

However, by doing so, the Service Supplier should be aware of the possible presence of mineral
wool bags still remaining in cable holes (Refer to Note 3).

Note 3: All cable holes and slots that utilize mineral wool bags shall be retrofitted per TP 77350
Iss. N Par. 4.1.8:
“All penetrations shall be fire/smoke stopped using the approved intumescent
method. Occupied cable holes utilizing wool bag type firestop materials shall be
upgraded to preferred materials when opened for a cabling addition or as soon as
practical.” (The phrase “as soon as practical” in this sense is indicative to meaning
getting the cable hole retrofitted during the current job that discovered the presence of
the mineral wool bags.)

Acknowledgements to Rick Stockton and Cheyenne Cook (Qwest) and Ron Engfer and Tom
Thorson of 3M for their contributions to the content of this Bulletin.

Qwest Installation Quality Assurance
Jeff Bostow
612-798-2460
mailto: jbostow@qwest.com

								
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