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importance of IRR material?

#2
Looking forward to an answer to this one. Surely Infra-Red Absorbing material would be better as, with no reflection, the infra-red wouldn't be returned to be viewed by the IR transmitter/receiver (either night-vision goggles or range-finder).

New thought: Or does the IRR prevent the wearer's heat signature from passing through the fabric, thereby reducing the effectiveness of passive night-vision equipment e.g. thermal image intensifiers?

Another new thought: Do we then need IRR liners to our clothing, the outer shell of which should be IRA?
 
#3
Best practice is to equip and prepare for dealing with a competent/capable enemy.

Then you can't go wrong!

Okay - most of the guys we shoe-in ponce around in toyota pickups with rusty 30 year old FNs, but I don't think we should start getting issued adidas trackie bottoms and combat flip flops cos thats what the enemy have got.

Are you by chance wanting to save some cash and buy some Webtex kit? :wink:
 
#4
cunning_plan said:
Best practice is to equip and prepare for dealing with a competent/capable enemy.

Then you can't go wrong!

Okay - most of the guys we shoe-in ponce around in toyota pickups with rusty 30 year old FNs, but I don't think we should start getting issued adidas trackie bottoms and combat flip flops cos thats what the enemy have got.

Are you by chance wanting to save some cash and buy some Webtex kit? :wink:
Nah, I want free (issue) stuff, just wondering why IRR is so important and what it actually does.
 
R

really?_fascinating

Guest
#6
Infra red reflective important to give you a similar appearance to natural foliage etc. If completey absorbaent, you would provide a huge contrast against a background - and therefore stand out.

I knew mil tech would one day prove useful
 
#7
I'm just following the party line on that one mate...

There must be plenty of spotters who can go into the detail of it.

All I know is my old windproof smock is about as 'IRR' as a bloody lighthouse. CWS can ping a typical squaddies kit well easy as it's been ironed/washed to buggery and lost all that expensive coating!
 

Gook

Old-Salt
#8
How do you reapply said IRR-ness then?

Does Thermal imaging come into this at all or is it just Image intensifiers? If IRR keeps you hidden from II, then how do you hide yourself from TI? Uniforms aint that thick to keep all the heat from showing and engines, weapons, tyres etc would all show up too.

How about active IR sources? Anyway to hide from them or do you just call in a fire mission on the source?
Maybe not all our enemies are as advanced as we might be but there are some possible enemies who are VERY advanced (you cant tell who we'll be fighting its rather unpredicatable!) and even rusty old Soviet Dragunovs have night vision!

And if the issue kit isnt IRR in reality as its washed and ironed etc, then why worry about non IRR non-issue kit...
 
#9
Right...I'm no expert but here goes:

Gook said:
How do you reapply said IRR-ness then?
I reckon its permanently knackered...esp when a new pair of 95 pants only cost about £5.


Gook said:
Does Thermal imaging come into this at all or is it just Image intensifiers? If IRR keeps you hidden from II, then how do you hide yourself from TI? Uniforms aint that thick to keep all the heat from showing and engines, weapons, tyres etc would all show up too.
I've seen a civvie TI camera in action and I can't imagine being able to defeat it at all without covering every square of your body in 'stuff'. You can see stuff like squirrels no dramas so a bloody globe head like mine would be like a bloody floodflight.

Gook said:
How about active IR sources? Anyway to hide from them or do you just call in a fire mission on the source?
Maybe not all our enemies are as advanced as we might be but there are some possible enemies who are VERY advanced (you cant tell who we'll be fighting its rather unpredicatable!) and even rusty old Soviet Dragunovs have night vision!

And if the issue kit isnt IRR in reality as its washed and ironed etc, then why worry about non IRR non-issue kit...
If you've seen some rich kid using an ebay-nightvison-special through a CWS then you'll know there's nothing to worry about. It's like someone using a 100,000,000 candlepower torch on a moonless night.

"Watch my tracer!"

Anybody more learned than myself please feel free to give me a verbal kicking...
 
#10
really?_fascinating said:
Infra red reflective important to give you a similar appearance to natural foliage etc. If completey absorbaent, you would provide a huge contrast against a background - and therefore stand out.

I knew mil tech would one day prove useful
Sorry, not satisfied with this answer. I use a Thermal Imaging (TI) camera at work, essentially a souped up version of the TIs used in tanks and helicopters (and made by the same company). The sensitivity can be adjusted so that you can identify 0.2degreeC differences in temperature at 100m+. Even with thickly insulated clothing, the warm areas (armpits, groin etc) still show through, to say nothing of face and hands. I can identify footprints 30 seconds or more after the person (wearing thick-soled boots) has walked away.

Foliage generates very little temperature but absorbs ambient temperature gradually. For clothing to simulate foliage, it would have to have remarkable insulative properties to prevent transfer of body heat and be faced with a highly thermally conductive material to remain at ambient temperature. It would also have to be frictionless to prevent heat generation through rubbing.

Furthermore, if you were to stand in front of a different background, e.g. a wall, lake or sky, these properties wouldn't help.


A quick Google search leads me to believe that IRR is used to reduce the absorption of ambient heat (it can't do anything about transmission of body heat through clothing as that's heat transfer and has nothing to do with infra-red). Is the reason for IRR really just to cool us down in the midday sun (or has MoD been conned again)?
 
#11
putteesinmyhands said:
really?_fascinating said:
Infra red reflective important to give you a similar appearance to natural foliage etc. If completey absorbaent, you would provide a huge contrast against a background - and therefore stand out.

I knew mil tech would one day prove useful
Sorry, not satisfied with this answer. I use a Thermal Imaging (TI) camera at work, essentially a souped up version of the TIs used in tanks and helicopters (and made by the same company). The sensitivity can be adjusted so that you can identify 0.2degreeC differences in temperature at 100m+. Even with thickly insulated clothing, the warm areas (armpits, groin etc) still show through, to say nothing of face and hands. I can identify footprints 30 seconds or more after the person (wearing thick-soled boots) has walked away.

Foliage generates very little temperature but absorbs ambient temperature gradually. For clothing to simulate foliage, it would have to have remarkable insulative properties to prevent transfer of body heat and be faced with a highly thermally conductive material to remain at ambient temperature. It would also have to be frictionless to prevent heat generation through rubbing.

Furthermore, if you were to stand in front of a different background, e.g. a wall, lake or sky, these properties wouldn't help.


A quick Google search leads me to believe that IRR is used to reduce the absorption of ambient heat (it can't do anything about transmission of body heat through clothing as that's heat transfer and has nothing to do with infra-red). Is the reason for IRR really just to cool us down in the midday sun (or has MoD been conned again)?
Thermal imaging and infra-red are quite different when it comes to hiding from them.

As previosuly stated, natural vegetation reflects Infra-red light (I think because of the chlorophyll in leaves) - both IR devices and image intensifiers are sensitive to IR light, and therefore any contrast (from a non-IRR object) would stick out like a turd on a snooker table.

Unfortunately, the properties required to make clothing 'thermally invisible' are quite opposite to those needed to make them IRR! I suppose the the theory is that an enemy are more likely to have IR night-viewing devices than TI?
 
#12
Every object emits Infra Red Radiation, Thermal cameras detect this and slight differences in the amount of energy emitted make up the picture on a TI display screen. IRR material and paint is designed for defence in the Near Infra Red (Image intensifiers etc) This is used primarily in woodland areas as plant life reflects almost all IR light and thus appears white.

Thermal imagers operate in the Far infrared and detect heat radiation so IRR is useless for them. Thats why we have thermal sheeting.

PHEW!!
 
#13
We may be getting there, but being a naturally doubtful person...

"As previosuly stated, natural vegetation reflects Infra-red light (I think because of the chlorophyll in leaves) - both IR devices and image intensifiers are sensitive to IR light, and therefore any contrast (from a non-IRR object) would stick out like a turd on a snooker table."

Not disputing this but this infers that the IR reflectance is down to the colour, rather than any "magic" additive. So IRR is a colour code with Ministry of Defence
Defence Standard 00-23 www.dstan.mod.uk/data/00/023/00000300.pdf essentially specifying the shade? If chlorophyl is the magic ingredient, then IRR properties can be repaired by rubbing CS95 with a handful of grass?

"Unfortunately, the properties required to make clothing 'thermally invisible' are quite opposite to those needed to make them IRR! I suppose the the theory is that an enemy are more likely to have IR night-viewing devices than TI?"

But isn't the tendency for man portable equipment to be II, while vehicle borne equipment is TI? II intensifies the available light, rather than amplifies IR, so is not an issue. TI isn't going to be fooled by IRR. IR equipment generally requires IR illumination (as I understand), therefore the IR lamps become a glaring target to the en wearing IR goggles. Does this infer that IRR is an outdated concept?


"Every object emits Infra Red Radiation, Thermal cameras detect this and slight differences in the amount of energy emitted make up the picture on a TI display screen. IRR material and paint is designed for defence in the Near Infra Red (Image intensifiers etc) This is used primarily in woodland areas as plant life reflects almost all IR light and thus appears white."

I'm not sure that every object emits IR - it would need an internal heat source (or storage) with a greater output than the surroundings, surely. If plant life reflects IR to appear white and the human body emits IR, thus appearing white, why bother with clothing?


Very good topic, this. I'm sure most of us have wondered and just accepted the wisdom of it.
 
#14
norfolk_boy said:
Every object emits Infra Red Radiation, Thermal cameras detect this and slight differences in the amount of energy emitted make up the picture on a TI display screen. IRR material and paint is designed for defence in the Near Infra Red (Image intensifiers etc) This is used primarily in woodland areas as plant life reflects almost all IR light and thus appears white.

Thermal imagers operate in the Far infrared and detect heat radiation so IRR is useless for them. Thats why we have thermal sheeting.

PHEW!!
Spot on. IRR is intended to deal with a mid 20th century threat, the IR illuminator, by making our reflectivity similar to that of living foliage. There are a number of caveats:

1 IR reflectivity of an urban environment is total different from that of foliage, so you stand out like a doggie's genitals if IR illuminated.

2 TI works on the IR you generate yourself, not the ambient stuff you reflect, so ditto in a TI.

3 Who uses IR illuminators these days, anyway?

So having IRR kit is a bit like having ammunition boxes you can open with your boot - a legacy from olden days. The liklihood of its being operationally important is about the same as the liklihood that we will be faced with spear-wielding Zulus in a future conflict. But that's no reason to go back to ammunition boxes fastened with screws or non-IRR kit.
 
#16
So IRR is NO defence against image intensifiers, or the passive NVGs an enemy will most-likely have? It is only useful against outdated IR illuminators that nobody uses anymore and you could just call for fire on anyway?

And the ONLY thing to stop TI is thermal sheeting? I have never been issued or even seen this stuff! Maybe they should incorporate it as an extra layer in the bashas or something.

So basically don't worry about all your kit being IRR then? I can see your logic but other threads I've seen have basically said "wear only issued IRR kit or YOU DIE!!". Anyone done the counter surveillance courses?
 
#18
putteesinmyhands said:
We may be getting there, but being a naturally doubtful person...

"As previosuly stated, natural vegetation reflects Infra-red light (I think because of the chlorophyll in leaves) - both IR devices and image intensifiers are sensitive to IR light, and therefore any contrast (from a non-IRR object) would stick out like a turd on a snooker table."

Not disputing this but this infers that the IR reflectance is down to the colour, rather than any "magic" additive. So IRR is a colour code with Ministry of Defence
Defence Standard 00-23 www.dstan.mod.uk/data/00/023/00000300.pdf essentially specifying the shade? If chlorophyl is the magic ingredient, then IRR properties can be repaired by rubbing CS95 with a handful of grass?

"Unfortunately, the properties required to make clothing 'thermally invisible' are quite opposite to those needed to make them IRR! I suppose the the theory is that an enemy are more likely to have IR night-viewing devices than TI?"

But isn't the tendency for man portable equipment to be II, while vehicle borne equipment is TI? II intensifies the available light, rather than amplifies IR, so is not an issue. TI isn't going to be fooled by IRR. IR equipment generally requires IR illumination (as I understand), therefore the IR lamps become a glaring target to the en wearing IR goggles. Does this infer that IRR is an outdated concept?


"Every object emits Infra Red Radiation, Thermal cameras detect this and slight differences in the amount of energy emitted make up the picture on a TI display screen. IRR material and paint is designed for defence in the Near Infra Red (Image intensifiers etc) This is used primarily in woodland areas as plant life reflects almost all IR light and thus appears white."

I'm not sure that every object emits IR - it would need an internal heat source (or storage) with a greater output than the surroundings, surely. If plant life reflects IR to appear white and the human body emits IR, thus appearing white, why bother with clothing?


Very good topic, this. I'm sure most of us have wondered and just accepted the wisdom of it.
There are exceptions; blackholes for example, have a gravitational field so intense that EM radiation (part of which is IR) cannot escape.

In the 'real' universe however, everything above -273 degrees C (0 Kelvin or Absolute Zero) radiates in the IR field. Nothing can actually get as cold as absolute zero because you'd need something even colder to cool the first thing down , and so on , and so on... at 0 degrees K, all sub-atomic movement would cease - the object would literally have no energy and so could not emit any. So, effectively, all 'real' things emit. [It is arguable that something so close to absolute zero that it couldn't muster up the energy to emit a single photon (an EM particle) would not be an IR emitter - but either way, you're not likely to be engaging one in the 'contemporary battlespace'.]

Even where something is dimmer/cooler and there is energy flow to it, it will still radiate on the basis of imperfection in the flow resulting from entropy. Unless it falls into one of the categories above.

I knew S-Level Physics would come in handy - shame it's taken 15 years... 8O
 
#19
Very impressive. But the statement was in response to TI cameras detecting a difference in IR radiation. As TI cameras detect differences in heat, rather than IR radiation, differing IR radiance of dissimilar materials at the same temperature would not be identified. TI cameras would only detect the difference in IR radiation if that radiation caused the surface temperature of one of the materials to be warmer than the other. Leaves, being thin, tend toward ambient.

Could also have responded that, depending on the angle of view, the (generally) shiny surface of a leaf could reflect the sky (0 K) or the sun (>>>0 K), resulting in TI images of any colour (on rainbow settings) from black to white.

With emphasis on TI as this is the current technology.
 
#20
Why does everyone think that the enemy we're fighting today won't have night vis? It's not as if it's hard to get hold of is it. I'm pretty sure that the more switched on insurgent groups in iraq could get hold of night vision fairly easily and having seen night vision video recordings they obviously have it. I've found in everything, whatever technology comes out to do something, sooner or later someone invents a technology to counter it. So Mr. Iraqi is using his IR torch to illuminate something, brit observing through CWS is pretty much given a bullseye to aim for, vice versa, if brit is using IR light on his LLM mr. iraqi can spot them just as easily. But like has been said, just because modern technology may have advanced past this now with rifle mounted TI sights coming into the picture, there's no reason to scrap IRR then have someone come along using the tech it was designed to counter.
 

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