Author Topic: Induction Hobs - Are They Safe?  (Read 20973 times)

Paul Singleton

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Induction Hobs - Are They Safe?
« on: November 16, 2008, 10:41:10 PM »
Has anyone got any information about the safety of induction hobs? Considering the issues related to people living too close to electrical sub stations due to the EMF, surely the same applies to an induction hob? I would imagine there is a substantial magnectic field surrounding the saucepan which you will be putting your hands through. What about the children whose heads are at the same level as the saucepan?

Has there been any research done on the effects of EMF in these applications?

Dave Howorth

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Re: Induction Hobs - Are They Safe?
« Reply #1 on: November 17, 2008, 10:13:13 PM »
I saw your other post about mains circuits, so I see you have general worries. I expect your difficulty is that most electricians don't support your concerns. You need to decide who you are willing to trust on the subject, because there's no way to reconcile orthodoxy with some of the more extreme views. I think you need to educate yourself some more so that you can judge the statements that people make. For example, you need to distinguish between electrical fields (which can be stopped by metal screens) and magnetic fields (which usually can't).

With regard to induction hobs, they work by magnetic induction. Putting a magnetically-susceptible pan on the hob "short-circuits" the magnetic field, just like putting an iron keeper on a horseshoe magnet does. That short-circuit is what generates the heat. So whilst the pan is in place, there's very little external field. When you remove the pan, the hob detects that and shuts off the power. So again there's little external field. (n.b. this paragraph is over-simplified! See para 1 for why)

Do you think there is more chance of a child getting ill from a stray magnetic field or from putting their hand in a gas flame? Or on a hot electric resistance hob? In short, stop worrying.

fostertom

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Re: Induction Hobs - Are They Safe?
« Reply #2 on: November 26, 2008, 06:38:12 PM »
No, keep asking - and publish the progress of your investigations! (please)

Alan Clarke

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Re: Induction Hobs - Are They Safe?
« Reply #3 on: July 12, 2009, 10:18:05 AM »
I have been proposing induction hobs as the best choice for both safety and energy consumption, so would be interested to hear of any real health concerns.

As far as safety goes, my view is based on personal experience - my Gran had her hand and wrist badly burned  by her gas cooker when I was young - needing long hospital stays, skin grafts etc.

Also there is ample evidence that gas cooking is harmful because of the products of combustion, some of which are defintitely toxic, and the unburned gas itself. Whilst we now require a gas boiler to be sealed from the room, with both flue and air intake directly connected to the outside air, we seem OK with 10kW or so of completely unflued gas combustion in our living space. In a work place situation this is not allowed and the gas stays off until an extraction hood is running.
I do like cooking on gas, but the more I look into it, the more keen I am to ditch our gas hob!

Alan

Geoff Stow

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Re: Induction Hobs - Are They Safe?
« Reply #4 on: July 14, 2009, 01:40:41 PM »
Given that Induction Hobs are broadly similar to gas in terms of carbon produced would they be the best way to heat a saucepan for rural areas with only say electricity, calor gas or oil.

Andy Simmonds

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Re: Induction Hobs - Are They Safe?
« Reply #5 on: October 26, 2009, 10:00:57 PM »
"Also there is ample evidence that gas cooking is harmful because of the products of combustion, some of which are defintitely toxic, and the unburned gas itself."
Alan, re your quote above - is this dealt with in buildings with MVHR to the point of it becoming a non-issue?

Alan Clarke

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Re: Induction Hobs - Are They Safe?
« Reply #6 on: November 14, 2009, 09:51:55 AM »
Andy I'm not sure that MVHR extract rates are high enough to deal with poor gas consumption - the extract rate of a good cooker hood is often higher than the whole -house rate for an MVHR systyem.  And if you have MVHR you probably have a very airtight house, with lower ventilation rates than traditional housing.
Alan


Andy Simmonds

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Re: Induction Hobs - Are They Safe?
« Reply #7 on: November 15, 2009, 08:05:27 PM »
"And if you have MVHR you probably have a very airtight house, with lower ventilation rates than traditional housing."

'traditional housing' is....?

Just concerned that 'lower ventilation rates' does not imply (to those skimming posts) lower air quality!
But thanks for the quantitative answer Alan.
Anyway - aware this thread about induction hobs.

David OLIVIER

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Re: Induction Hobs - Are They Safe?
« Reply #8 on: November 19, 2009, 03:37:27 PM »
It could be helpful for people to stop rubbishing gas cooking as part of the discussion of induction cooking.

If the exhaust is harmful, well, a prototype balanced-flue gas cooker was developed in Canada 1991-92 in association with the Advanced House project for use in I think eight of the homes and it only needs an organisation prepared to provide the ££ to commercialise it.

If on the other hand the exhaust is adequately dealt with by MVHR or MEV systems; e.g. the first Passivhaus project had gas cooking, and I suspect this is the case, then within reason we can stop worrying.

FWIW, electric cooking appears to be responsible for the extreme peak in electricity demand which occurs in the UK at 6 pm on winter evenings, this is clearly visible on National Grid Co.'s records. For this extra demand, £billions extra must be spent on power stations as unlike gas electricity can't be stored. Some years ago it was found in the UK that an average dwelling with electric cooking imposed a coincident peak demand of 1 kW on the national grid. Quite an expensive investment.

D.

Dave Howorth

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Re: Induction Hobs - Are They Safe?
« Reply #9 on: November 19, 2009, 09:42:21 PM »
David,

As I understood the thread, it's discussing hobs rather than ovens. In that context, I'm having difficulty understanding the possibility of a balanced flue. If you have any more details, I'd love to peruse them since it might preempt marital discord.

My understanding of the potential issue with gas cooking is that the concern largely postdates the first Passivhaus and it concerns particulates and nitrogen compounds emitted from the hobs. I'd love to know any definitive sources.

I suppose that in the rosy electric-blue coloured vision of our future, the need for electric cooking will immediately follow the plugging in of the newly-returned electric vehicle with its battery or other electrical resource able to meet said demand.

At some point, perhaps I'll feel confident I understand things well enough to form an opinion on this topic!

David OLIVIER

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Re: Induction Hobs - Are They Safe?
« Reply #10 on: November 21, 2009, 11:25:25 PM »
They looked just like an electric halogen hob but the radiant heat was created by a gas flame below the glass, not electricity. I didn't discover at the time or soon after why exactly they weren't then commercialised, but I could ask contacts in Canada. Myself I'd like an LPG version.

I'm sure you agree that on most tables which set out the emissions from old or new woodstoves, pellet boilers or oil  boilers, the particle emissions from gas appliances tend to be relegated to a footnote and described as negligible - though it may depend on one's measurement device and the adjustment of the burner.

To raise a possibly heretical question, if particles from a piped gas or LPG flame are unsafe in the building, what about the woodstove in the cottage 100 m away? That could in theory be dliuted, by many orders of magnitude and still provide as great an exposure as the emissions from the methane or propane-fired device. 

David.

Nick Grant

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Re: Induction Hobs - Are They Safe?
« Reply #11 on: November 22, 2009, 09:12:25 AM »
Not my area of expertise but I wouldn't be too surprised if the emissions from smoking oil and sizzling bacon didn't rather swamp the gas emissions. Time for breakfast, sadly muesli.


Dave Howorth

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Re: Induction Hobs - Are They Safe?
« Reply #12 on: November 22, 2009, 03:21:07 PM »
Those hobs sound interesting; unfortunate that they're not available.

I don't think your question about woodsmoke is heretical. I think it's banned in built-up areas just like smoke from coal, isn't it? AFAIK, gasifiers are the best way to deal with wood. It seems to me that burning anything is likely to lead to products that aren't good to breathe.

Not my area of expertise either, though.

fostertom

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Re: Induction Hobs - Are They Safe?
« Reply #13 on: January 20, 2010, 05:48:47 PM »
Oi! what about the safety of emanations from induction hobs? Has all human knowledge on the subject been covered in just the first two posts above, leaving the field free to talk about something else?

Paul Singleton

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Re: Induction Hobs - Are They Safe?
« Reply #14 on: March 20, 2010, 07:14:07 PM »
I've just noticed the return of this subject on the forum and feel slightly guilty for starting it and then disappearing to let other people to carry it on. I did do some research after my first post and found some recommendations for using induction hobs. It's been a while now but from what I remember......

1. The manufacturers do not recommend induction hobs to be used by people fitted with pacemakers
2. Do not stir with metal spoons as this can allow leakage current to flow through your body
3. Do not touch the pan for the same reasons as above
3. Always ensure the pan completely covers the hob as any exposed areas of hob will release stray magnetic fields
4. Keep a safe distance from the hob to reduce exposure to magnetic fields (I think it was something like 12")

There doesn't appear to be any evidence to suggest exposure to magnetic fields is harmful but the experts admit they don't really know, hence the recommendations above to be on the safe side. Maybe we will find whether they are safe or not after there have been enough guinea pigs using them for long enough.