An expert in electromagnetic fields at Hydro-Québec advises against the use of certain radiant electric floors which could increase the risk of infant leukemia. <<As children are often laying and sitting on the floor, it is to be avoided, not recommended due to the doubts we have on this>>, declared Jan Erik Deadman, labour hygiene counsellor at the company. <<It would surprise me if Hydro-Québec recommended (these systems) in daycares.>>
This labour health doctor was reacting to the fact that certain of these heating systems, composed of an electric wire typically installed under a ceramic floor, emit a magnetic field measuring up to 100 milli gauss (mG0) at ground level. According to nine epidemiological studies, a chronic exposure to an average field of more than 4 mG doubles the risk of child leukemia. In 2002, this is what incited the International Center for Cancer Research, along with the World Health Organization, to class magnetic fields of 50-60 Hertz in Group 2B as ‘potentially cancer-causing’. The Canadian Mortgage and Housing Corporation in its Mechanical Equipment Guide for a Clean Interior Environment, that radiant electric floors <<can emit significant electrical and magnetic fields.>>
Four Cancers Targeted
The most solid proofs of noxious effects of electromagnetic fields come from epidemiological studies, explains Health Canada: <<The studies have led to suppositions of the existence of a weak positive association between being exposed to fields of 50-60Hz and leukemia, brain cancer, breast cancer and lung cancer.>> But we cannot exclude that other statistical, environmental or socio-economic factors may be responsible.
Also a researcher at the McGill Faculty of Medicine, Jan Erik Deadman is co-author of a historical study published last July. It concluded that female workers, whose average weekly exposure was at least 4mG during or within two years preceding their pregnancy, doubled their risk of having a child who will develop this type of blood cancer. Other studies concluded that chronic exposure to a field of 2mG doubled the risk in children.
Should owners of electrically heated floors disable their system or turn it off before entering a room? <<The risk is considered too weak and too uncertain to change heated floors in houses and daycares, analyzes Denis Gauvin, biologist at the Institut nationale de santé publique du Québec (INSPQ) Must the population be informed? Yes. If people have the possibility of choosing a floor which exposes them less, all the better.>> Electromagnetic fields are composed of electrical fields produced by voltage (live wires) and magnetic fields from amperage (power consumed) They are measured with a multi meter which frequently acts as a voltmeter, gauss meter and radio frequency and microwave reader. The intensity of the field and the degree of human exposure diminish rapidly when moving away from the source, easy if the radiant system is in a ceiling but impossible in the case of a floor.
At one foot from a floor emitting 100mG at ground level, the field can measure 16mG, a level at which very brief daily exposures are, according to a recent California study (Li, 2002), associated with an increased risk of false labour. These fields are weaker in a house where electrical consumption is lower and if the wires are close together and laid out in parallel, their fields have a tendency to mutually cancel themselves out.
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Deciding on which contractor will build your home is a critical step in making your dream a reality. There are many things to consider when making your choice.
ROLE OF THE CONTRATOR
The contractor’s role is to control the construction process and manage all aspects of the job from start to finish. They will work from your floor plans, obtain the necessary permits for construction in your local area, and arrange for materials to be delivered to your site from your local lumber yard when needed. The contractor will also manage other necessary trades people (excavation, carpenters, electricians, plumbers, drywall installers, etc.) that will work on your home so that they arrive when needed and complete their jobs efficiently and quickly. All this will be done in a time frame that you agree on and at a quoted cost.
Contractors should be members of the provincial or local home builders’ association which requires them to conform to a code of ethics as well as attend courses on the latest techniques, building code requirements and technologies to remain in good standing. They should also be licensed to work in your area and you should be able to see these licences upon request.
Contractors should also carry insurance in case of an accident during construction or in the event of a dispute. You should be familiar with the rules required by your local government, your home owner’s insurance policy and your bank to ensure that you understand the liabilities involved with building a home and how to protect yourself.
LOCATING A CONTRACTOR
It takes more than just looking in the phone book to find a contractor. A good place to start is often with friends, family or neighbours. Ask them if the contractor they used lived up to expectations and delivered what was agreed to. Ask if they had any problems with the contractor and, if so, how they were resolved. Most importantly, ask if they would hire the same contractor again. You want to know they have a good reputation and a history of satisfied customers.
Your local home show can be a perfect place to look for local contractors who do the type of work that you are planning. You will be able to talk with several contractors and see photographs of their projects while learning about construction materials and getting advice from professionals.
You can also approach the Canadian Home Builder’s Association (visit www.chba.ca). They will be able to put you in contact with contractors from your local area that are members in good standing.
DO YOUR HOMEWORK
Before you begin hiring, take the time to do research. Go online to familiarize yourself with the materials and local requirements for your job. You can’t expect to learn as much as the professionals, but by educating yourself you will more likely be able to identify a contractor that may not be fully competent (or even dishonest). Educating yourself now will also save you time and increase your confidence later when it comes to making decisions like picking fixtures and making choices on items such as flooring materials that will have to be done when construction is under way.