A number of scientists and environmental groups warn that a critical mass of cable sitting unused in buildings multiplies the risk of fires and associated health problems to office employees. Once the cable deteriorates, it can release a witch's brew of nasty toxins.
July 1, 2004
One of the chief health and safety concerns today is what we ought to do with the millions of miles of abandoned cable that has been stuffed in the plenum spaces of office buildings in Canada and the United States.
The removal of abandoned cable has become a front-line issue, now that the requirements of the 2002 editions of the National Electric Code (NEC) and the National Fire Protection Association (NFPA) are beginning to trickle down to the local level as the law of the land, to varying degrees in Canada and the US.
“We might have made an error in judgement in allowing all this cable in plenum spaces,” says Frank Bisbee, a data cable consultant and editor of Wireville.com in Jacksonville, Fla. “Now we are facing a problem of clean-up.”
Bisbee compares the problem to one companies faced with asbestos in the 1980s.
To be sure, the problem developed over the last 30 years, notably during the telecommunication boom of the 1990s. At its height, companies re-cabled on the average every three years, essentially installing new cable on top of old.
In the U.S. alone, for example, there is an estimated 45 billion feet of cable housed in the ceilings, walls and raised floors of the estimated 500,000 office buildings .
A significant portion has been abandoned.
Although the safety codes state that abandoned cable must be removed, it is taking place slowly, as some building owners find ways to circumvent the law, or at least delay its implementation as a way to reduce costs.
Even so, the slow pace of removal is raising alarm bells, because for many experts and safety bodies, including at the NFPA, cable in plenum spaces poses a fire risk, if not a public-health risk.
For one, as reported in last year’s issue (May 2003), cable in plenum spaces acts as a fuel load equivalent in energy to gasoline. Each day, there are a reported 15 office fires in the U.S. and although most are minor and quickly put out, it gives one reason to pause.
A number of scientists and environ-mental groups say that a critical mass of cable sitting unused in buildings multiplies the risk of fires and associated health problems to office employees, once the cable deteriorates, thus releasing a witch’s brew of nasty toxins.
PVC cables, for example, emit both hydrogen chloride and dioxin.
Dioxin, say environmental group Greenpeace, “is the most toxic synthetic chemical known to science,” and long-term exposure has been linked to health problems such as cancer, reproductive disorders and birth defects.
The real message
Even in buildings that contain only plenum-rated cables, occupants are still at risk to health hazards ranging from mild skin burns, to eye injury, to severe lung injury and even death.
The key fire-retardant components of plenum-rated cable may in themselves pose a health risk in a high-temperature fire of over 400C, such as that seen in the aftermath of the terrorist attacks on the World Trade Centre on 9/11.
As the saying goes: In a fire, it’s not only what you can see, like smoke, but also what you can’t see – the invisible airborne gases that you inhale – that kill you.
Although NEC and NFPA 90A addresses the problem of abandoned cable, its intended message is not clearly followed.
“I still see and read a lot about tagging cable for future use, in order to avoid taking it out, which goes against the intent of the code,” says John Michlovic, national marketing and technical manager with H.H. Robertson Floor Systems of Pittsburgh, Pa, makers of in-floor raceway systems for cable. “The NFPA clearly wanted people to take it [the cable] out, and not tag it for future use.” (There was a comic strip making the rounds in the industry of a worker using duct tape to wrap a mass of cable and tagging it, “For future use.”)
Part of the problem stems from differing views of the two national standards-setting bodies in the U.S. — NEC and NFPA.
“There are battles between these standards-writing committees,” Michlovic notes. “The NEC are in the electronics business and their interest lies in getting power to workstations. They are not experts on fire, smoke and flame. Therefore, they are ready to let you off the hook if you want to red-tag it for two, five or 10 years.
“The NFPA on the other hand cares about what happens inside the plenum space. They consider any material not in use as storage. And storage material must be removed. No exceptions, ” he adds.
Given its more flexible requirements, the telecom industry generally likes to cite the NEC as its safety source, and not NFPA 90A.
Even so, these safety issues are being scrutinized in Canada and the U.S. Gary Lougheed, a project manager with National Research Council of Canada in Ottawa, has been working on a study, Initial Investigations on Plenum Cable Fires, since 2000. The report has been handed to its lead sponsor, the American Society of Heating, Refrigeration and Air-Conditioning Engineers, or ASHRAE, which is based in Atlanta, Ga.
Lougheed, the report’s lead author who expects it to be released this summer, refused to comment on it before its official publication. (To view it, go to the NRC Web-site at http://irc.nrc-cnrc.gc.ca/frm/ cable.html.).
Although the report is preliminary, it confirms that at above 350C, there are measurable effects on the cable jacket. Even so, the report seems to downplay the risks of fire.
As the initial report puts it: “Higher thermal exposures or direct flame impingement was required for the insulator materials to be affected.” In other words, the insulator material breaks down when heated to a high temperature.
The Teflon file
In the U.S., however, the level of concern is heightened. For example, even the installation of plenum-rated (CMP) data cable does not guarantee workers are safe from health problems. (In some jurisdictions in Canada, such cable is labelled as FT4.)
The majority of CMP cable contains wire insulated with FEP, the only option allowed by NEC 2002. DuPont Corp., the world’s largest manufacturer of FEP, sells it under the brand name Teflon. About 500 million pounds of Teflon FEP resides in commercial buildings, or about 11 pounds per thousand feet of plenum cable.
There’s reason for worry. For one, Teflon contains fluorine-containing polymers like fluorinated ethylene propylene, or FEP, which environmental scientists say pose serious health concerns to humans.
Although FEP is highly fire-resistant, able to withstand temperatures up to 427C before it breaks down in a fire, FEP fumes give off a number of toxic chemicals, including hydrogen flouoride and other nasty toxins that are highly carcinogenic.
At 475C, Teflon breaks down to a nasty toxin known as perfluoroisbbutene, or PFIB, which is extremely toxic and its inhalation can lead to fluid build-up in the lungs, or edema, which can lead to death.
It is noteworthy that the Chemical Weapons Convention lists PFIB as a Schedule 2 compound, ten times more toxic than phosgene, itself a highly toxic corrosive gas listed as a chemical weapon.
Yet, perhaps the most alarming aspect of Teflon is that it contains perflourooctanoic acid (PFOA), or C-8, which has been linked to cancer, organ damage and other health effects in tests on laboratory animals. According to the US Environmental Protection Agency, some of the highest C-8 levels were found in children.
There is enough scientific evidence from independent sources to consider whether Teflon ought to be used at all. “In retrospect, this may seem like one of the biggest, if not the biggest, mistakes the chemical industry has ever made,” says Jane Houlihan, vice-president for research at the Environmental Working Group, a Washington-based research and advocacy group “And how could it not be in our blood.”
DuPont stands by its product. “We are confident when we say that the facts, the scientific facts, demonstrate that the material is perfectly safe to use”, Uma Chowdhry, DuPont’s vice-president of research and development, told 20/20, an American news show. Chowdhry claims that the su
bstance is completely safe, even though C-8 has been found in people’s blood.
“You get some fumes, yes, said Chowdhry, “and you get a flu-like symptom, which is reversible.”
The Environmental Protection Agency is moving quickly, however, to scrutinize the claims against Teflon. The EPA, which has been investigating the chemical giant for more than a year, says it is expecting to take “formal action against DuPont soon.” Houlihan of the Environmental Working Group says that what’s at the heart of the matter is safety. “That’s why they [EPA] are moving fast. The greatest concern about C-8 is that it may cause possible long-term harm to a generation that has grown up using Teflon products.”
Are these scare tactics? Granted, one can argue that life is full of risks. But the chief question is whether some risks can be avoided. Companies, and mega-corporations in particular, don’t typically voluntarily do something when environmental or social activists raise alarm bells. They have, as history shows us, to be forced into compliance, notably if they believe that business is at stake.
Although there is some recognition that, as a minimum, abandoned cable ought to be removed, the pace of removal is generally slow, and the status quo remains. That is, building owners and tenants are still using plenum spaces for re-cabling and new cable installations.
One long-term solution is to install in-floor systems, Michlovic says. Such a system uses galvanized steel raceways, which are buried in a concrete slab in which the underside has been fire-proofed. “You could have a good fire in a building before anyone is threatened with toxic smoke,” he says. The drawback is that steel or fibreglass conduits can increase the cost of a cabling system by between 40% and 300%.
Given the reality of the situation, it appears that it will take years, if not decades, for owners and tenants to remove the millions of miles of abandoned cable. Or at lease until better alternatives are manufactured. If that is, indeed, the case, there are some things that employers can do to reduce the risk to workers and other occupants. (See sidebar, Building Sensors.)
Another method is to use sensors to monitor air quality, in particular for toxic gases. Although in a fire, smoke inhalation is a leading killer, so is carbon monoxide, a colourless, odourless gas.
Sensors would give the building’s occupants an early warning that toxic gases are being emitted, and consequently give them a chance to escape. “I can buy a system that monitors carbon monoxide for home,” Bisbee says. “Why don’t we have a system like that in office buildings?”
For now, the problem continues to be above us, so to speak. “What do we do with all that cable up there?” Michlovic points out. “It’s a tremendous moral problem that we have to face up to.”
Millions of workers in Canada and the US spend their days in office buildings. “Today, for the most part, employees are working in buildings where they cannot open windows – steel-and-glass towers with miles and cable running through them. “If that’s the case,” Frank Bisbee points out, “then why don’t we at least install sensors to monitor toxic gases.”
Such sensors would be hooked up to the electronic systems that control the heating, ventilation and air-conditioning systems (HVAC). If the sensor picks up a toxic gas, it would stop the air flow immediately and outgas the poisonous air to outside the building.
In addition, if we take it a step further, employees might soon be wearing sensors to monitor a number of common toxic gases like carbon monoxide and hydrogen fluoride. The scenario, out of sci-fi, could become real if Frank Bisbee has his way.
Perry Greenbaum is a writer based in Montreal and a rural community near Concord, N.H.. He can be reached at email@example.com.