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This topic comprises 2 pages: 1 2
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Topic: Nitrate handlers
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Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 11-30-2018 05:18 PM
There are only two ways.
1 - Reduce the ambient temperature to below the point at which nitrate can combust (flash point is 39F / 4.4C, so this is a tall order!).
2 - Exhaust the supply of fuel (i.e. let the fire burn itself out).
Remember the "fire triangle" you were taught in middle school science lessons: fuel, oxygen, and a source of ignition. Remove any one of those three, and no fire can start. Nitrate is especially dangerous, because the fuel actually contains the oxygen.
Because oxygen is created as a by-product of the combustion process (very chemistry-geeky explanation here), you cannot put it out by depriving it of oxygen. If you throw a fire blanket over it (for example), it will continue to burn. There are videos of nitrate burning inside a container of water kicking around on the net.
The most widespread way of extinguishing a fire - pouring water over it - does so by two simultaneous actions: lowering the temperature, and depriving the fire of oxygen. Neither action is effective in the case of nitrate, which is one of the two reasons why the emphasis on nitrate safety is on preventing the stuff from going up in the first place, and providing quick and safe exit routes if it does. The bottom line is that if it ignites, then basically, you're buggered (or at the very least, the film is). The second is that as well as oxygen, burning nitrate releases nitric acid fumes. A room full of those would make the San Quentin gas chamber seem positively pleasant. When nitrate was in mainstream use, the main causes of deaths and injuries resulting from nitrate fires were inhaling the VERY poisonous fumes, and stampeding for the exit. There were hardly any actual burn injuries.
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Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 12-01-2018 02:59 PM
quote: Phillip Grace
Some nitrate vaults are built with dump tanks above them to operate automatically in the event of a fire.
I guess that's feasible: if there is a known quantity of nitrate in a totally enclosed space, then it's possible to figure out how much water, and at what temperature that water would need to be, would be needed to reduce the temperature far enough below that flash point to extinguish the fire, if you dumped it all out into the vault space at once. Also, as the film elements in the vaults would be in individual cans, not all of it would ignite at once, and so if the water was dumped early enough, you'd likely save a lot of the film, too. Water-damaged film might be able to be saved, but burned film is guaranteed not to be.
quote: Richard May
There is a bunch of test film, trailers, reels of mag track, etc.. Most of it is indeed nitrate. Most are in cans. Some loose film. The smell is horrible. It's worse than any other old film smell I've ever dealt with. Also, the fumes were so bad that it actually hurt my eyes.
The mag track is unlikely to be nitrate. It started to be used on a significant scale at the same time that nitrate started to go away (late '40s / early '50s).
I've never experienced nitric acid fumes that were strong enough to make my eyes sting, but I sure have been hit with acetic acid (vinegar syndrome) fumes from early cellulose triacetate that were. Is this collection mixed late nitrate and early acetate? If so, that's the worst possible combo for decomposition.
Paradoxically, late nitrate is the fastest decomposing (all other factors being equal), because when the war broke out, film base manufacturing plants took to using cheap, nasty, and highly acidic wood pulp to make the cellulose pulp for the feedstock: the stuff that was NFG for making aircraft fuselages and all the other war stuff that needed wood. That continued right up until nitrate was phased out. So from an archivist's point of view, 1940s nitrate is generally the worst.
As others have pointed out, it's the content and its condition that will determine whether any archives are interested. A lot of trailers might not survive, or if they do, the elements held by archives may not be in as good a condition as yours is. It's a lot of work, but if you're interested in saving the stuff worth saving, a basic list of what each element is and what sort of physical condition it's in would enable an acquisitions officer to make a decision as to whether it would be worth footing the bill for shipping to take it off your hands.
Otherwise, it's looking increasingly like a bonfire in an empty parking lot in the middle of the night. If you only burn small quantities at a time (I would suggest no more than 1,500 to 2,000 feet), completely in the open air, and well away (as in, at least 100 feet) from anything else combustible, then IMHO, that's the cheapest and safest way to get rid of it. Unroll 20-30 feet from one of the rolls in the pile, so that you are well away from where the main fire will be when you put the match to it, wear a face mask, and ensure that you are upwind from the fire, and that no-one is immediately downwind. I should stress however, that doing this is entirely at your own risk, and I accept no responsibility for the consequences of anyone reading this and trying.
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