radiant heat

RADIANT HEAT

Radiant heat loss is for all intents not a factor of any consequence. Radiant heat which the human body produces just like the sun is always absorbed by the first solid object that it hits, just like the objects that the sun’s rays hit. If you are active and the temperature is 8o degrees F your core temperature is 98.6 degrees. As your core temperature increases due to your activity your internal body temperature increases and automatically sends the excess heat to your skin surface. Along with the heat coming off of your skin surface—which is radiant heat— there is moist vapor coming out of your pores, which is also warm. This vapor will condense, coating the surface of your skin, which absorbs the heat on the skin’s surface and cools your body; this is because the moisture is absorbing that heat. The heat coming off of your skin’s surface is radiant heat, which is being released into the air. Now if you are dressed and the air temperature is 40º F your body is still giving off radiant heat, only now it is being absorbed by the fabric i.e. the object covering your body. It does not travel any further away from you. If you are dressed for temperatures as low as -40º F again you are giving off radiant heat but the loss getting outside the layers of clothing is again non-existent, therefore radiant heat loss is not to be considered.

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I recently read a promotional article on SBG on line magazine I get daily about a new product that is being sold by a Swedish company HeiQ. They are a chemical company, and they create chemicals that are applied to fabrics that will keep your fabrics from becoming odorous to name one. They have many more that also do ridiculous things. Now they have come up with a chemical that applies to helping to keep people warm. They apparently are putting a coating of a reflective nature on material that will reflect your radiant heat back to you.

In the 60’s when we were developing the space program a company in Dover, Delaware called Dover LLC. or some name close to that who was to make the first space suits used reflective mylar for the same purpose, reflect body heat back to the wearer of the space suit. Of course, this drew my attention as I was interested in learning what was being done to keep the astronauts warm. As I learned the suit consisted of twenty-nine layers of material which has 9 layers of mylar reflective material with one interspersed between the other layers.

The purpose was to reflect their radiant heat back to them. The way it worked was as follows, the first layer reflected back 5% of the 100% of radiant heat that hit it and each subsequent layer reflected back 5% of what hit it and so on as whatever reached each layer it would reflect back 5%.

Now in the space suit it is closed so nothing gets out such as your sweat.

These Low I.Q. as I think of them do not have this knowledge as well as the knowledge that the reflective coating, they are putting on the fabric will most assuredly keep the moisture of the user of the sleeping bag that utilizes this fabric which will be the case of anyone buying a NF Dark Star model bags. I do not know how many models they are using the fabric for. They will also work the same. It should also be noted I am sure the coating side will not face your body. The end result will be a “vapor barrier” which means all of your moisture will not get out of the bag and as it cools you will cool.

I am constantly reading about as Gerry Cunningham stated in his booklet ‘HOW TO KEEP WARM” that I have reproduced a new “Jim Dandy Insulation” will never replace thickness to keep you warm. I can add to that nobody will ever replace the efficiency of Lamilite/Climashield to allow moisture out of a Wiggy bag.

I have written and pointed out the bogus information that they publish about the chemicals ability to do whatever it is they claim. They do successfully sell these chemicals to the current crop of employees at companies like NF who have no particular knowledge of the history of the industry and what existed before they were born and what works and what has failed.

As an example I have been using single ply nylon taffeta for all of my existence as a sleeping bag manufacture [two companies] and I have yet to see a fabric that is capable of replacing it. This material goes back to the mid 1930’s when Dupont first developed nylon. Almost 100 years in the market place. This is knowledge they do not have. So, they are taken in by the salespeople at Low I.Q. with their bogus story, but the NF people eat it up or maybe they will get advertising dollars.

The lure of advertising dollars is why the consumer is often shown textile garments that always fail to perform once you buy the product and use it.

Now a days more than ever before buyer beware and if you see a Low I Q or HeiQ hang tag on a textile product stand clear of it.