Could it be considered hazardous or could it be dangerous, to have a mirror reflecting sunshine coming in from the window, in your child s bedroom? Particularly if the there are cuddly toys around?

Dangerous meaning, would it be able to ignite and cause a cuddly toy to burn or catch fire, even if the cuddly toys are good quality.

Additional note;

This question was asked with the intention to raise safety awareness when there are mirrors/sunlight/ and cuddly toys in children s bedrooms. It has been asked in the way that I have asked myself and is by no means intended to "annoy users who have spent time researching an answer" so I can answer my own question in an obnoxious manner. I have gone on to answer it with a personal incident which I hope will give greater insight to other parents as will the "final section" of Adam Davies answer

asked 09 Mar '10, 07:47

Emi's gravatar image

accept rate: 19%

edited 10 Mar '10, 14:22

Melting, Charing and Ignition

The cuddly toys are likely composed of a blend of natural and plastic fibers - polyester, acrylic, cotton, wool, etc, which actually have an ignition temperature well above that of boiling water:

Material  Melt/char Ignite
Acrylic   105C      150C
Paper     150C      230C
Cotton    ---       250C
Polyester 250C      450C

However, the melting point of those plush toys (extra soft ones are often made out of acrylic fibers) is especially low at 91°-125° C - just around the boiling point of water.

In a very warm room with direct sun on a dark plush toy, and with a flat mirror also pointing the sun at the toy (ie, the toy is getting about 2x the power of the sun) I can see reaching the melting point of some of those plastics.

However, I don't expect to see them ignite without more solar power - a parabolic mirror, prism, or some other focusing mechanism that puts 50-500 times more power into a smaller spot on the toy.

That doesn't mean it won't/can't happen, but that the risks are low because you have to heat a given area up to 150C or higher (1.5 times the boiling point of water - that is to say that if water were in a dark container at the same spot it would be boiling rapidly) just to ignite pure acrylic. Most of those toys are blends of different fibers, and many have fire retardants in them, so the actual ignition temperature is likely to be significantly higher.

Toy Regulations

If you check out the toy's safety markings, and it is CE or UL marked and purchased from a reputable source, then it meets certain regulations in regards to children's toys, one of which includes (in the CE toy directive) the following:

  1. Flammability

    (a) Toys must not constitute a dangerous flammable element in the child's environment. They must therefore be composed of materials which:

    1. do not burn if directly exposed to a flame or spark or other potential seat of fire; or
    2. are not readily flammable (the flame goes out as soon as the fire cause disappears); or
    3. if they do ignite, burn slowly and present a low rate of spread of the flame; or
    4. irrespective of the toy's chemical composition, are treated so as to delay the combustion process.

    Such combustible materials must not constitute a risk of ignition for other materials used in the toy.

(source: EU New Directive 88/378/EEC Annex II, section 2, part 2.a)

So the toy can have one of the following properties regarding flammability:

  • Never ignite, even when continuously exposed to a flame or source of ignition
  • Only burn while flame is present, but will not continue to burn if flame is removed
  • Burn very slowly if it does catch fire
  • Takes a long time with direct exposed flame before it'll continue burning on its own.

A focused point of light counts as an ignition source. A flat mirror probably would not, though it could apply 2x the sun's power to a surface.

So yes, the toy can burn, but it's not a high risk - even if it does burn it will burn slowly and likely put itself out once the source of ignition is removed. Given that the sun is moving, no toy is going to be in the focal point forever, so only those toys that fall under 2.a.3 (ignite immediately, but burn slowly) should pose any minor risk.

Turn the Problem Around

Keep in mind that while the toy is CE marked as safe for use by children, the mirror is most definitely NOT. In fact I'd expect parabolic mirrors (magnifying makeup mirrors, for example) to be marked as "not suitable for children", and "not to be used, placed, or stored in direct sunlight".

So it's not the bear's fault, and in fact the bear may have saved you. If it had been paper or thin stationary in the way (which doesn't have the same non-flammability requirements) then you could well have had a real fire, instead of the melting or slow burning that the bear suffered.

The CE directives can be found and read here:


answered 09 Mar '10, 13:54

Adam%20Davis's gravatar image

Adam Davis
accept rate: 31%

edited 09 Mar '10, 14:42


+1 Nice information Adam thanks. Now I am just wondering whether the fact that the magnified side of the mirror was reflecting the sunshine, and the fact that we have sea view, and the fact that traditional Winnie wears a cropped red t-shirt are all contributing factors to the incident we had? I will post the photos this evening!

(09 Mar '10, 14:00) Emi

@Emi - I'm definitely interested in seeing the photos - toy carnage ahoy!

(09 Mar '10, 14:24) Adam Davis

@Adam Davis I have just added the photos Adam. Thank you for your edited answer "Turn the Problem Around" section. I think that its very valuable information.

(10 Mar '10, 08:59) Emi

If the mirror is flat, there is no risk. Light reflected off the mirror will be slightly weaker than direct sunlight (a lot weaker if you dust as often as I do...). To have any fire risk, sunlight needs to be focused to raise the temperature at the focal point above the ignition point of the fabric. This should be several hundred degrees. If it is not you've got some really unsafe toys.

You need a prism or lens can concentrate light at a point to have a fire risk, so if the mirror has cut edges or has a parabolic (domed) shape, it is possible then that enough sunlight may be concentrated to raise the temperature past the ignition point. On a very sunny day in particular, concentrated sunlight can scorch surfaces.

It should be emphasised that the risks are very minor. You need to have a lot of unlikely things combine to get a fire. Though if you're concerned just use a flat mirror.

  • the mirror to be just the right (wrong) shape.
  • Have the room set up so the flammable object is in the focal path of reflection as the sun tracks through the sky.
  • Have a very sunny day (rules it out for me in England)

You're more likely (but still very unlikely) to start a fire by leaving your glasses in sunlight, they're designed to focus light in a small region, and can easily be left on a pile of papers or other kindling-like material.

Having said how unlikely it is, one of my colleagues once got some paperwork scorched because a cut glass prism caught the sun just right. The moral of the story for me was don't buy ugly paperweights.


answered 09 Mar '10, 10:56

Rich%20Seller's gravatar image

Rich Seller
accept rate: 19%


The odds of a mirror or prism causing a fire seem astronomically small. You definitely don't have to worry about that.

(09 Mar '10, 12:12) brandstaetter

Small maybe but not impossible, we witnessed a freak incidence on Sunday which I will share.

(09 Mar '10, 12:22) Emi

+1 nice answer but am afraid I have to tell my version as well.

(09 Mar '10, 13:56) Emi

+1 for pointing out the basics of optic fysics.

(15 Mar '10, 11:09) Fisherman

Well the answer is yes, it can be dangerous. On Sunday afternoon, my daughter called me in to her room and pointed to her Winnie the Pooh bear, that was seated on one of her chairs facing inwards towards the room, the back of the toy was facing the window.

She pointed to a section of the bear, and upon close inspection, and to my dismay the bear looked like it had caught fire. Dumbstruck I quickly picked up the bear and examined it further. Yes it had burnt. I asked calmly if it had happened by accident, but my daughter said no, I told her that I would not be upset, angry or cross, but that she should tell me how it happened, and again she insisted that she just found it like that.

We called daddy, and showed him the toy. I placed the toy back on the chair and we thought about what could have possibly happened.

Then we saw what had happened. My daughter had placed her flat double sided mirror on her table that is in front of the bay window, playfully at an angle, and around the table were all her chairs and on the chair facing the mirror was Winnie. I think it may be important to add that it was the magnified mirror side that was facing the window.

What is also important is that Sunday was a relatively cold day although there was some sunshine during the middle of the afternoon. Her curtains were not drawn, and we do have a view of the sea if that makes any difference.

The angle of the sun hitting the mirror which then reflected on to the corner of the singed/burnt part was enough to ignite the stuffed toy. The "Winnie" was a good one purchased from Hamleys Toy Store, several years ago, so I am guessing that it was pretty good quality otherwise the burning would have been quicker and have caused a much more serious incident.

We were absolutely shocked that such an incident could occur...

Photos: Below are the images of the the bear and I have placed the bear and the mirror in the same place, as when the burning/charring/singeing took place. The second and third image shows the extent of the charring/burning.

alt text alt text alt text

Here are closer images of the mirror. I can say (after closer inspection) that the mirror has two different mirrors, and these are no more that 5 mm thick. One side is a normal mirror and the other side gives a more magnified image. It is set in a plastic frame and swivels around.

alt text alt text


answered 09 Mar '10, 13:53

Emi's gravatar image

accept rate: 19%

edited 10 Mar '10, 08:56


Chances are good that what appeared 'burnt' was actually melted. Still, the parabolic mirror with the bear in the right spot would certainly reach the melting point of some artificial fibers, and could possibly reach the ignition temperature.

(09 Mar '10, 13:56) Adam Davis

Yeah, well, a non-flat mirror is a slightly different thing. I find it a bit odd that you pose this question without giving out all data, and not mentioning that experience. What did you want to achieve?

(09 Mar '10, 14:25) brandstaetter

@brandstaetter - Puzzles are fun!

(09 Mar '10, 14:29) Adam Davis

@brandstaetter Excuse me? Without giving out all the data? I honestly wanted to know whether it was considered a risk because it had never ever crossed my mind. My question was asked in the way I had wondered it, the incident itself is something else.

(09 Mar '10, 14:44) Emi

@Emi - Don't worry about it - you're following the FAQ quite well: "It's also ok to answer your own question, even if you had an answer in mind before posting it, but just remember to phrase it in the form of a question." - You phrased it in the form of a question, and you answered it with a personal experience.

(09 Mar '10, 16:22) Adam Davis

I'm sorry if that came out wrong, I just found it a bit confusing that you posted a (unclear) question in such a way that the only logical answer would be: "not dangerous", then coming back and telling those who tried to research and answer you, that you asked because you experienced a dangerous situation with a non-flat mirror, which you did not mention either. I don't mean to imply any malicious intent, I just would have preferred a mentioning of these facts in the question

(09 Mar '10, 20:01) brandstaetter

"Magnifying" mirrors are not flat!!!

(09 Mar '10, 21:00) lgritz

@lgritz - Some people may perceive them as flat mirrors, even though they know they magnify. To most people, if the thickness is under 1/2 inch (1.3 cm) then the object as a whole is considered 'flat', even though it has a concave side.

(09 Mar '10, 22:11) Adam Davis

I found this answer quite intriguing. Thanks Emi!

(10 Mar '10, 01:13) Scott ♦♦

I am amazed at the interesting comments received from all you dads, both my question and my answer seems to have been evoked a strange mix of comments whereas I merely wanted to pass on and share an experience with you all. I hope you will find the pictures just as interesting.

(10 Mar '10, 08:43) Emi

Thanks for the pictures! I'm sorry if my comments came off as offending in any way, it was just that this is one of the first questions posed like that - I read a discussion on meta.stackoverflow which dealt with a similar thing: -- one concern is that if you have an answer yourself (any kind of, really), you should include that in the question from the beginning, to prevent annoying people who invest their time to research and type an answer, only to get corrected by you. That's just my position, I'm willing to accept another one if it's decided...

(10 Mar '10, 09:29) brandstaetter

Also, wow, that is just so unbelievably coincidental. You should get you daughter to pick some lottery tickets for you ;) -- The slightly magnifying mirror is such a tiny detail to overlook... I'm glad nothing serious happened.

(10 Mar '10, 09:33) brandstaetter
showing 5 of 12 show 7 more comments

Fascinating and also shocking. My friend's house burnt down last year through a similar experience. The fire service investigation showed that her magnifying mirror reflected sun onto soft furnishings whilst they were out at work during the day. I am just installing mirrored doors in my daughter's bedroom and was worried about whether there was any fire risk because of knowing what happened to her.


answered 15 Nov '10, 12:08

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Kate 1
accept rate: 0%

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Asked: 09 Mar '10, 07:47

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Last updated: 15 Nov '10, 12:08