Q: Is the National Electrical Code (NEC) changing its position on the removal of old cabling when installing new cabling? I seem to remember hearing that the NEC was going to make removal of old cabling mandatory whenever it is replaced with new technology. Could you point me in the right direction so that I can find this information? Or am I out in left field on this one?
Randy Hayes
NC Office of Information
Technology Services
Raleigh, NC
A: NEC 1999 800-52 (b) states "Spread of Fire or Products of Combustion. Installations in hollow spaces, vertical shafts, and ventilation or air-handling ducts shall be made so that the possible spread of fire or products of combustion will not be substantially increased. Openings around penetrations through fire resistance-rated walls, partitions, floors, or ceilings shall be firestopped using approved methods."
In my September 1999 column in this magazine (see page 14), I wrote about the National Fire Protection Association Technical Committee on Air Conditioning action on the Standard for the Installation of Air Conditioning and Ventilation Systems, NFPA 90A, to "Add a new subpart (g) to 2-3.10.1: Electrical wire and cable removed from service that is not listed as noncombustible or limited-combustible and does not have a maximum smoke developed index of 50 shall be removed."
While the NFPA National Electrical Code Committee is primarily responsible for preparing documents on minimizing the risk of electricity as a source of electric shock and ignition source of fires and explosions, they are also responsible for developing requirements to minimize the propagation of fire and explosions due to electrical installations. Telecommunications cabling falls under their domain. So it is their responsibility to address the concerns of the NFPA Technical Committee on Air Conditioning regarding abandoned telecommunications cable in plenum spaces.
Telecommunications cable installed in plenum spaces are, more often than not, abandoned in place rather than removed when no longer in use. In fact, as telecommunications systems are modernized-which often requires installation of new cabling-layer upon layer of abandoned cable accumulates in the plenum space above suspended ceilings. Abandoned cables in older buildings frequently include unlisted cable along with the listed plenum cable.
Everyone had an opinion, and there were many proposals for changing NEC 1999 800-52.
Some cables currently manufactured can meet NFPA 262, Standard Method of Test for Fire and Smoke Characteristics of Wires and Cables. They are the costly fluorinated ethylene propylene (FEP) versions.
Seeing this as an opportunity to market a new "super plenum" (CMP-50) cable that could be substituted for any CM-rated cable and left in place forever, cabling and plastics manufacturers wasted no time in proposing their products/solutions as the only exception to the new "take-it-out" rule.
They even had a marketing jingle-permanent plenum.
But alas, common sense prevailed. Even totally noncombustible cables should not be allowed to accumulate in the numbers that we have observed in the last 10 years. The panel rejected the exception because leaving this debris in the infrastructure is fundamentally bad workmanship. It uses up already limited space, adds weight to the support structure, and causes confusion when dead cables are combined with active ones. And even if it has an excellent fire rating, it still adds to the fuel load.
Designer/installer approach
BICSI's (Tampa, FL) proposal read, "Abandoned cables in ducts, plenums, and other space used for environmental air should not be allowed to accumulate. Excessive accumulations of abandoned cables in ducts, plenums, and other space used for environmental air shall be removed where practicable."
This proposal is all based on NFPA 75, standard for Protection of Electronic Computer/Data Processing Equipment, Section 4-2.4, that states, "Abandoned cables shall not be allowed to accumulate. Cables not identified for future use shall be removed."
The idea was to have removal of the old cabling included within the scope of the new cabling-system installation.
It works for me, because it addresses the issue of excess combustibles in plenum spaces without requiring the removal of all abandoned cable-only accumulations of abandoned cable and only when the cables can be removed without disruption of active services.
Current status
The Letter Ballot on Panel Actions on Proposals for the 2002 NEC, dated January 21, 2000, indicates that Panel 16 revised NEC 2002 800-52(b) to read, "Spread of Fire or Products of Combustion. Installations in hollow spaces, vertical shafts, and ventilation or air-handling ducts shall be made so that the possible spread of fire or products of combustion will not be substantially increased. Openings around penetrations through fire resistance-rated walls, partitions, floors, or ceilings shall be firestopped using approved methods. Abandoned cables not intended for future use shall not be permitted to remain."
So far Panel 16 has defined "abandoned cable" as cable that is neither terminated at both ends, at a connector or other equipment, nor identified for future use with a tag. Just picture some contractor tossing piles of 25-pair cable-with connectors or even "cans" still attached to the ceiling-with NEC in hand, telling the inspector, "It is not abandoned. It still has connectors." I predict this definition will be further revised before we see it in NFPA 70-2002.
According to the June 2000 NFPA News, the National Electrical Code Report on Proposals, which contains the amendments for the 2002 NEC, will have been available on the NFPA's Website since July 14. This report records the actions of the code-making panels and the correlating committee on each proposal to revise the existing 1999 Code.
For more information on how we can participate in the NFPA process, visit www.nfpa.org.
Donna Ballast is a communications analyst at the University of Texas at Austin and a bicsi reg-istered communications distribution designer (rcdd). Questions can be sent to her at Cabling Installation & Maintenance or at PO Drawer 7580, the University of Texas, Austin, TX 78713; tel: (512) 471-0112, fax: (512) 471-8883, e-mail: [email protected].
Remember telecom cabling before CMP?
The National Electrical Code (NEC) requirements for plenum cable were first pro mulgated in NFPA 70-1975. Underwriters Laboratories initially listed plenum cables by comparing the smoke production of plenum cables with that of conventional cables of the same physical design (but not plenum-grade materials) in conduit. Plenum cables not in conduit were tested and compared with an equal number of conventional cables in conduit. It was assumed that the plenum cables were a replacement for conventional cables and that in case of a fire, the amount of smoke would be reduced because of plenum cables' lower smoke production. No consideration was given to the prospect that plenum cables would be abandoned. Since conventional cables in conduit were deemed to be acceptable, the smoke from these cables is the benchmark for comparison, and a fire involving an excessive amount of abandoned cables could emit an excessive amount of smoke.