Questions about the thermal radiation effects of nukes.

[Clangeddin]

Greetings everyone, this is my first post here.
I have noticed that when people talk about nuclear war and the effects of nuclear weapons, they usually mention the blast, the fallout (this seems to be everyone's favourite for some reason) and, in some cases, the nuclear winter.
However, I notice a lack of discussion about the thermal radiation, for some reason it doesn't seem to be taken into consideration as the other effects.
I always wondered why this was the case, therefore I decided to ask a bunch of questions to help me understand better this problem, I know that some of the questions might sound dumb, but please bear with me:

1) I've heard that light colored clothes offer some sort of protection against the burns. Is this correct? In case it's correct, does a light colored light cloth protect more than a dark colored thick cloth? For example a cotton white shirt vs a black suit made of fireproof materials. How important is the color of the cloth vs its material (well, I'm gonna exclude of course materials that catch fire easily such as acetate) or its thickness to protect you against the burns?

2) I've read that higher megaton yield devices have more of an "incendiary" effects compared to the lower yield ones, that is: the thermal radiation range escalates with yield more than proportionally compared to the blast radius. This seems to find partial confirmation on the Nukemap website.
If this was the case, wouldn't this give higher yield megaton bombs a better strategic value instead of many smaller ones? I know that more smaller devices summed together have a larger blast zone than a single large warheads, but what about the thermal effect radius? Isnt that capable of triggering secondary fires over several square kilometers?

3) Most importantly, how do buildings fare against thermal radiation where third degree burns are expected? Not wooden buildings of course. If we exclude the secondary fires from an explosion of the gas forniture are the walls of a building capable of shielding a person from third degree burns?

4) Is it true that cloudy or foggy weather can partially reduce the effects of the thermal radiation? If so, by how much? Are there any estimates on this?

Thanks to whomever will have the knowledge to answer this questions. If I have more I will eventually post them, other people can add questions about this if they wish too as well, of course.

 

[Clangeddin]

5) Would a FFP2 white mask offer any kind of protection against the heatwave? Is there any realistic change it could prevent burns on your face?
6) Glasses. Same as above, would sunglasses (or even normal glasses) help in any way, no matter how minimal?

 

[TCharley300]

Here are some answers for you. White colored clothing does help, but remember--if you're close enough to feel the heat, you're already in immediate danger. 2. Compare wounds--you can easily die of several small stab wounds just as easily as one big stab wound. 3. A concrete structure does fare better than wooden against the heat wave 4. I don't know. 5. It would a little, say changing a 3rd degree burn into a 2nd degree burn. 6. Sunglasses??? useless. It takes a very dark shielding like a welders helmet to protect the retinas of the eyes. Regular glasses would intensify the effect. Think of it like a magnifying glass held to the sun to start a fire on paper.

To sum it up, you're really not going to be able to protect yourself unless you are underground. You're concerned about the burns, but remember, any living plant, trees, grass, etc is all combustion and will burn, so your changes of escaping a burning area is pretty slim. Think beyond the heatwave. Look under emergency preparations and you will find several articles that I put in the discussion area.

 

[DEFCON Warning System]

1) I've heard that light colored clothes offer some sort of protection against the burns. Is this correct?

Yes. From the flash burn. It won't help when the main fireball gets there if you're close enough.

2) I've read that higher megaton yield devices have more of an "incendiary" effects compared to the lower yield ones, that is: the thermal radiation range escalates with yield more than proportionally compared to the blast radius. This seems to find partial confirmation on the Nukemap website.
If this was the case, wouldn't this give higher yield megaton bombs a better strategic value instead of many smaller ones? I know that more smaller devices summed together have a larger blast zone than a single large warheads, but what about the thermal effect radius? Isnt that capable of triggering secondary fires over several square kilometers?

Blast effects are geometrical, not exponential, for the size of the weapon. That's why you get more coverage from two smaller weapons than one large one.

3) Most importantly, how do buildings fare against thermal radiation where third degree burns are expected? Not wooden buildings of course. If we exclude the secondary fires from an explosion of the gas forniture are the walls of a building capable of shielding a person from third degree burns?

Depends on what the building is made of, how thick the material is. Nuclear weapons are just heat, wind, and radiation. Just like any material can protect you from heat, so any material can protect you from nuclear weapon heat. You just need more of it.

4) Is it true that cloudy or foggy weather can partially reduce the effects of the thermal radiation? If so, by how much? Are there any estimates on this?

It is true. I don't know if there are charts or anything. But any material will give some protection against nuclear weapons. Even clouds. Even air. A nuclear weapon blast is more dangerous on a clear day than an overcast day.

 

[RiffRaff]

1) I've heard that light colored clothes offer some sort of protection against the burns. Is this correct? In case it's correct, does a light colored light cloth protect more than a dark colored thick cloth? For example a cotton white shirt vs a black suit made of fireproof materials. How important is the color of the cloth vs its material (well, I'm gonna exclude of course materials that catch fire easily such as acetate) or its thickness to protect you against the burn

This is true, and was proven in both Hiroshima and Nagasaki. However, this only works at greater distances from the detonation. Thermal pulse sufficient to cause third degree burns is also sufficient to just ignite the clothing, regardless of its color.

2) I've read that higher megaton yield devices have more of an "incendiary" effects compared to the lower yield ones, that is: the thermal radiation range escalates with yield more than proportionally compared to the blast radius. This seems to find partial confirmation on the Nukemap website.
If this was the case, wouldn't this give higher yield megaton bombs a better strategic value instead of many smaller ones? I know that more smaller devices summed together have a larger blast zone than a single large warheads, but what about the thermal effect radius? Isnt that capable of triggering secondary fires over several square kilometers?

You get a larger field of destruction using 4 100 kiloton weapons than you do using a single 400 kiloton weapon. So while you are technically correct, current nuclear strategy relies more on smaller yield weapons than the old multi-megaton weapons. Largest yield weapon currently in active US inventory is 1.2 MT.

3) Most importantly, how do buildings fare against thermal radiation where third degree burns are expected? Not wooden buildings of course. If we exclude the secondary fires from an explosion of the gas forniture are the walls of a building capable of shielding a person from third degree burns?

Concrete reinforced buildings might not ignite from the thermal pulse, but depending on the exact situation, they could quickly absorb the heat from the thermal pulse and radiate that heat inside the building, essentially turning it into a giant brick oven, cooking every living thing inside alive.

4) Is it true that cloudy or foggy weather can partially reduce the effects of the thermal radiation? If so, by how much? Are there any estimates on this?

Yes, this is 100% true. There are some very precise calculations on this effect, but they are extremely complex and I don't pretend to understand that part of the science. But rain, fog, snow... all can reduce the effects of the thermal pulse.

 

[RiffRaff]

5) Would a FFP2 white mask offer any kind of protection against the heatwave? Is there any realistic change it could prevent burns on your face?

Same answer as with the clothing. It would help protect you at greater distances, but if you are too close, it will just ignite on your face. Bigger question is if you are wearing this kind of clothing because you are expecting a nuclear detonation, why would be outside in the first place?

6) Glasses. Same as above, would sunglasses (or even normal glasses) help in any way, no matter how minimal?

No, sunglasses will not protect you from being flash blinded if you are looking at the detonation. Normal prescription glasses will not help you either. My wife and I have taken a page from the B-52 pilot's book and we have glasses used to observe solar eclipses with one lens removed, so that if we are inadvertently looking in the direction of a detonation at the time it occurs, only one eye is blinded. This is because if we get attacked while we are at work, it will take us a minimum of one hour to drive home, assuming we can drive at all. Wearing those glasses will prevent total blindness during that time. But, if we are to the point that we are worried about that, we probably won't go into to work in the first place or be outside.