Vision/Hearing precautions when detonating?

[Tyler_Durden]

((this seems like the best category for this topic...?))

What precautions should one take when detonating explosives?

How far away should you stay if there is no shrapnel? Of course it would vary between the size of charge, etc, but, in general, how far?

What should you do to protect your hearing? Is earmuffs enough for everything? Are those even necessary?

Vision: when are sunglasses needed, and are there any situations where you should not watch at all? (maybe thermite?)

Any advice regarding hearing/vision protection?

I don't think this has been formally discussed any, or maybe I just couldnt find it when searching...

[ALENGOSVIG1]

I'd say if you dont have any cover such as lower land, big rocks, or walls then you should be around 100m away from 1/4 - 1 lb charges.

If you have cover you can be closer ofcourse.

For smaller stuff like 40 grams for example i'd wanna be about 25 meters away.

As for ear protection, i dont wear any. the thing i like most about explosives is the sound.

I dont think eye protection is necessary when detonating explosives. If theres going to be shrapnel, then take cover. As for thermite, just dont look at it. Mabe you could wear some welding goggles. You'd probally have to wear like # 10's or something though.

<small>[ July 14, 2002, 11:16 PM: Message edited by: ALENGOSVIG1 ]</small>

[Tyler_Durden]

Do you think sunglasses, in the day time, would be sufficient for thermite?

Is looking directly at thermite w/o protection a real risk?

As a result of past injury, it's important that I be especially careful in regards to light sensitivity, which is why I want to know what I am getting in to before I play w/ thermite.

<small>[ July 15, 2002, 01:05 AM: Message edited by: Tyler_Durden ]</small>

[Charlie Workman]

Hearing protection should ALWAYS be worn when detonating explosives. I lost over 40% of my hearing from this (well, actually it was a combination of gunfire, high explosives, and rock n roll)and let me tell you, being partly deaf sucks. I miss a lot of what's going on around me and have to say "What?" alot. I can't always tell where a sound comes from, or even vaguely what it is. This is no joke. If your ears ring, you've damaged them, at least a little. I always thought earplugs were for pussies. I was wrong.
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"To paraphrase Aristotle, life is a gas"
-Gidget

[mongo blongo]

You should always have ear protection when making sensitive explosives like primaries. If it unexpectedly goes off when your near it you could easily get deafened.
A while ago I was testing Lead Azide for the first time. I made a shitty fuse out of powdered match heads in a line down the grove of some folded paper with the LA at the end (I couldn't be arsed to make a proper fuse at the time). When I lit it the wind blew in the direction of the LA and my 10 second fuse turned into a 2 second fuse! I had enough time to stand up and turn around and BANG. I lost the hearing in my right ear for about a day.
I should have used ear protection. :(
And a Proper fuse!

[Anthony]

I personally don't use hearing protection, like others I like to listen to the blast as a way of assesing the performance on the charge and also because it's more fun. I never get ringing ears though, so the level of damage must be negligable. It's not like I am exposed to it every day of the year. I also like to be fully aware of my surroundings, right up to the second the charge goes off. No good crouching there, hands over ear defenders and some dickhead dog walker comes up from behind, taps you on the shoulder and says "wot you doing then?".

Eye protection could apply to small pieces of shrapnel getting blown into your face, but if that happens then you're too close anyway. I guess if using aluminised explosives at night could damage your retinas if you looked right at the blast, since your irisis would be wide open from the dark.

I tend to take the "if you can see it, then it can hit you" approach so will take cover behind something solid about 30yards away from up to 100gm charges.

The trouble with open ground is that a smallish stone could potentially travel a mile even when propelled by a small charge. It's unlikely that being 100 or 200 yards away is going to make sure no shrapnel can reach you. You're really just reducing the odds of being hit because the further away you are, the lower the concentration of shrapnel.

Putting a foot of wood between you and the charge lets you be nice and close so you get to feel the shockwave and the only way you could get hit would be by a richochet.

[Arkangel]

Likewise, I want to hear the blast.

Yorkshire saying regarding use of Condoms: "I don't wear me wellies when am 'avin a bath lad".

Applies equally to our hobby. I think that lengthy, extended loud noise is more damaging than peak events. I spent a number of years riding around in helicopters and tracked armoured vehicles and made sure I had earplugs in. Buddies who didn't now can't hear properly, and the same is true of people in modern dance clubs.

To defend yourself against shrapnel and flash, the best thing is to dig a pit for your tests. Put something a couple of feet below ground, even in an open pit and you'll be safe even a few yards away - that's precisely why they developed the projecting fuses on daisycutter mortar rounds/bombs. The ordnance explodes at surface level instead of below it.

<small>[ July 15, 2002, 07:18 PM: Message edited by: Arkangel ]</small>

[Tyler_Durden]

Also, you could safely watch blasts that throw shrapnel if you used a mirror. Get a nice big cheap one, get behind a barracade of some kind (big tree, sand bags, whatever), and set the mirror in such a way that you can see the blast. The chances of getting hurt by something then would be less than the chance of injury when preparing the device, so if you think of it that way, its not a big deal.

With this mirror method, one could get pretty close (maybe under 10-20 yards) without much risk. Then, you might wanna wear ear protection, depending on what you are setting off.

I was thinking of how to best set up a testing range...

I would probably dig a 5 foot diameter area out about a foot deep, and lower towards the center, down to about 3 feet. I would probably have a ring around the edge of about a foot wide of sand, a couple inches deep, this way there is almost zero risk of a fire spreading, should there be trouble with a pyrotechnic devices (this is probably unnecessary, but maybe for testing incendiaries?).

The next thing I would want at my test site would be a convex mirror (similar to those used in stores that allow them to watch people while shopping) so that i could safely see shrapnel devices.

Then again, maybe its not worth the trouble.

[nbk2000]

You, behind bolder or LARGE tree or in deep ditch/hole.

Device, in hole or ditch.

&lt;yoda&gt;
If watch you must, use plastic mirror on stick you should.
&lt;/yoda&gt;

Definitaly have safety googles on. All kinds of dust and bits flys around.

As for distance, it's all dependant on the size. A couple of pounds or less, you can be 30 yards away (behind cover). A few ounces, a couple of yards.

Now, if you're testing a claymore or frag device, the distances are radically altered, but for bare charges...

Ear plugs are always a good idea just before setting off a charge, least till you know how close you can get without going deaf.

[piro]

Tyler, with that method you could get quite close, but make sure you dont get blast lungs from overpressure!

[ENGINEERKILLER]

I never use earplugs and I blow stuff up all the time , the chances of you seeing a piece of frag coming at you are pretty slim but you can usualy hear it.Put your fingers in your ears wait for the boom, take your fingers out and keep quite for a few seconds and get ready to kiss the ground.
Other than that I wear a nomex cvc(combat vehicle crewmember )suit Oakley wraparound sunglasses Kevlar helmet Pointblank interceptor vest with trauma plates throat and groin protector all leather combat boots kneepads and heavy leather gloves.

I've never had a problem with thermite hurting my eyes but photo flash will mess up your eyes. I got a safety book that says your supposed to wear #6 safety goggles when you burn it .

[Helos]

I posted a new topic but it was closed and I get a warning :mad: , I searched before but couldnt find this one... shit the same!
well its an ok dicussion here, but if anyone can get more scientific information on how dangerous blasting are (for the hearing) and why it had been really grat! :)

For example I know that it is mainly the high frequenzies that are dangerous when blasting. High frequenzies is dying out faster than lower, this can be a problem if you have earprotection but are really close (as mentioned above) Then the sound maybee dangerous even if you have earprotection, but Iam not shure about this.

It is obvious(no negative effects) that you should have protection when working with primaries, but what I really want to know is the effects when detonating maybee apound of explosive above ground, then you want to hear the sound directly, but if it is damaging the hearing you probably shouldnt, anyone who know more about this effects, take for example the ANNM charge that i detonated, 45 m away, 400g.

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Here are my post from the now closed topic that I created... (if you want to read it)
When are my ears possible damaged? For example once if I set of 400g of ANNM and was 45 m away without ear protection, was it dangerous (Ifelt no pain afterwards or even directly when the shockwave hit, what I can rembember ) An otehor time I hit a small ammount of AP with an hammer BANG, a high frequenzy ringing in my ears for some minutes, I hadn´t expected it to be that loud, here it is of course good to wear protections, but how dangerous was it) Three times when I detonated a wery powerfull mix of Ap/mg/kcl04 (filmcanisters) from 15-25m away I really felt it in my ears, but it didn´t thurt afterwards, just when the soundwaves hit. How damaging was this, for example compared with the ANNM explosion I metioned.

I also want to know if you use to wear earprotections, and when you find it necessary. Is the common earplugs ok, or do I need something more sometimes( that sorts higher frequenzies out)?
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<small>[ September 11, 2002, 02:43 PM: Message edited by: Helos ]</small>

[Anthony]

You could try some of those electronic ear defenders used for shooting. They apparently only block out the harmful frequencies that come with the blast, so you can hear normally before and after. I.e. they don't impair your hearing like normal defenders do.

[Helos]

Yes, ofcourse that is the best soulution, but a guass is that they are not cheap at all, but it could be worth it, as many other valuble things.

The question still is how dangerous it really are to detonate a medium quantity of high explosives and stand a bit away, you get hit by a shockwave but get no aftereffects that you can feel( 400g ANNM, not burried, 45m away,), but can it still be dangerous..?

[Anthony]

You are really asking two seperate questions - the damaging effect of a shockwave on the body generally, and hearing damage from the blast noise.

Simply, if a blast makes your ears ring for more than a few minutes, chances are that you've done some degree of permanent damage to your hearing.

You really have to be a lot closer to suffer ill effects of a shockwave or over pressure. Generally at 5psi you can look forward to things like burst ear drums. At about 10-15psi you're going to get lung haemoraging and bleeding from one or all of your bodily orifices. At 55psi you stand a 50% chance of death and at 65% a near 100% chance of death.

Of course, those kind of pressures will destroy most above ground buildings and your death will probably come from being slammed into an obstruction at considerable speed. You'd have to be damn close to a damn big charge to experience such over pressures though.

[sinstar]

Personally, I have never been seriously injured due to being to close up, I don't wear ear protection, what I usually do is have my right hand connecting wires to terminals and my right ear pressed agaisnt my right shoulder, and one of my left fingers in my left ear. Its not really seeing the blast that I like, but hearing the explosion and seeing soil blown 20ft up in the air.

[Helos]

By dangerous I meant, dangerous for the hearing, at that distance the shockwave will not be dangerous, at maybee 15-20m, it can harm you a little (for example you can start bleed from your nose!) And after that it is really dangerous