[ Page 6 of 8 ]

By Alex Wilson

Searching for greener solutions

To date, there’s been little attention paid to health and environmental concerns related to wiring, but one group that has studied the issue in some depth is the Massachusetts Toxics Use Reduction Institute (TURI). According to TURI deputy director Liz Harriman, there are significant international efforts to reduce lead use in insulation and jacketing. The European Union’s directive on Waste Electrical and Electronic Equipment (WEEE) and the Restriction of Hazardous Substances Directive (RoHS) will ban lead from electrical equipment and electronics by 2006, and some manufacturers are removing lead from their products before this deadline. “TURI is working with the wire and cable industry and their suppliers in Massachusetts to keep them competitive in the global marketplace,” Harriman says.

In terms of fire safety, U.S. codes rely exclusively on test standards for flammability and flame spread, ignoring the risks of toxic and corrosive gases released before and after ignition. This approach differs from some European codes, which assume that incapacitation from irritating gases can affect occupants’ ability to escape from a building fire.

ADVERTISEMENT

There is clearly interest in some circles in specifying halogen-free wiring. Clear alternatives to halogenated wire and cable are polyolefin products; to use these for insulation and jacketing, compounds are typically added for flame resistance, as described earlier. Borealis Compounds, the U.S. division of the Danish company Borealis A/S, offers such products in the U.S., but sales are limited. They’re used primarily in subway systems and other locations where acid emissions from halogenated compounds are unacceptable. The manufacturing costs of flame-resistant polyolefin wiring are significantly higher than those of PVC, according to a Borealis engineer, and regulatory changes would probably be required to bring about a significant shift toward polyolefins from PVC.

Some manufacturers, including Mohawk/CDT, offer PVC-insulated wiring without lead or other heavy metals. Demanding lead-free or heavy-metal-free cable can hasten the transition away from these toxins.

Yet another approach is to specify polyolefin cable with lower flame resistance and place it in a fire-protected environment (e.g., metal conduit or cellular cores of concrete floor panels). Such a method will add to a project costs, however, and the trends are generally in the other direction: specifying plenum-rated, FEP-insulated cable that can be installed in plenums without additional protection.

For data and voice signals, fiber-optic cables and wireless technologies are increasingly viable options. One fiber-optic cable can replace many copper cables in high-capacity applications, and wireless data networks are quickly supplanting hardwired connections in settings such as classrooms and meeting rooms.