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Author Topic: Apr 2 Nitrate booth fire at the Stanford, Palo Alto Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 04-15-2009 02:52 AM                     Sam, A platter with a magazine cover would be pretty funny actually. I would have thought your first two points would be obvious enough that they would have been a bit of a "well duh", but in hindsight you never know who is reading this stuff and how they are interpreting it.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 04-15-2009 06:49 AM                     Again...loose the "platter" visual. Now replace that with a pair of magazines driven by torque motors...okay...now we are talking about the SAME apparatus that looks familiar...the only difference is that we are separating them from the projector so that one has time to cut the film (manually or automatically) before the rest goes up. They need NOT be in another room anymore than the print needs to be in another room (not according to federal code...you local codes WILL vary). There is no particular danger in having strips of film exposed for that 20-feet because it is a very limited fuel source and could not catch anything else on fire unless the path was right below a flamable object. Heck, you could use a common wire trough as a film path to the magazines. It is something worth considering. It would reduce damage to theatres, people and even the film itself. Steve  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 04-15-2009 07:11 AM                     Brad said to me, "You know how slow the film burns." Actually, embarassingly, I don't really know how fast nitrate burns. I've only ever burned 1-perf wide cuts of nitrate, never a 35mm width of appreciable length. How fast does a strip of nitrate running across the room burn? Naively I would guess something like 10 meters/second, but are you saying it's a lot slower? --jhawk  |  IP: Logged Bill Enos Film God Posts: 2081 From: Richmond, Virginia, USA Registered: Apr 2000 posted 04-15-2009 09:44 AM                     I've had nitrate that burned a 6 ft 35 mm strip in a couple of seconds and I now have a small roll of unexposed 70mm unperforated that burns only slightly faster than paper. Big difference, but what makes them different? The 70mm is dated 1945, the super fast 35mm was from a few years later.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 04-15-2009 09:59 AM                     quote: John Hawkinson How fast does a strip of nitrate running across the room burn? Naively I would guess something like 10 meters/second, but are you saying it's a lot slower? It burns pretty fast, but not that fast; I was going to say about half to one metre per second, so that seems pretty close to Bill's 'fast' sample. I don't know why the 70mm sample should be slower; if it's that date then it's too new for Fox Grandeur, and too old for Todd-AO, so I'm guessing it was for some sort of still photography, and the fact that it's unperforated also tends to point that way, possibly some sort of small wartime aircraft camera or something. This wouldn't need to be as tough as cinematograph film, so maybe it wasn't normal nitrate, but a mixture, as I believe the Pathe 28mm film was, to reduce the hazard. I've only ever burned short sections to test the fire traps on projectors before running nitrate film. (Not in a public cinema).  |  IP: Logged Philip Krikau Film Handler Posts: 4 From: San Francisco, CA. USA Registered: Jan 2008 posted 04-15-2009 11:10 AM                     Take it from me it burns fast. Too fast for some chopper to catch.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 04-15-2009 11:31 AM                     It only seems to burn fast when just a foot or two is what is you have to work with. That is, with just a typical set up...in less than 2 seconds, it is in the magazine...pretty fast. With 20 or more feet you have closer to 20-seconds to react...the chopper would certainly work. Especially if the design was layered to have both manual and automatic means of chopping the film. Steve  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 04-15-2009 01:26 PM                     ..and why it burns fast since the film path is vertical and fire loves to climb upwards since the fuel to supply it is greater. But, you run that film horizontal and the flame has to actually "hunt" for fuel to keep ignited, thus the flame travels slower. You light up a wood match and hold it head down and see how fast that stick goes up in flames compared to holding the stock at a horizontal level. You would then construct a 'roller tray' system to keep the film horizontal, so if the film does torch up, the rollers won't allow the film to drop to a vertical position to allow it to torch faster...and in this tray assembly is where the 'chopper' mechanisms can be placed. And this assembly can be completely covered with a opening side panel for threading. -Monte  |  IP: Logged Jack Theakston Master Film Handler Posts: 411 From: New York, USA Registered: Sep 2007 posted 04-15-2009 03:14 PM                     Monte is correct. The orientation of the film means everything. Horizontally, nitrate burns no faster than a strip of paper (and will actually go out under most circumstances). Burning UPWARD, it's just like matchstick. The actual rate of burning for nitrate horizontally is quite slow-- about 2 to 3 seconds/foot, ample time for the operator to simply rip the film with his bare hands, or even snuff the flame out with his fingers.  |  IP: Logged Rick Raskin Phenomenal Film Handler Posts: 1100 From: Manassas Virginia Registered: Jan 2003 posted 04-15-2009 03:36 PM                     I got news for you, by the time you realize what has happened it'll be inside the magazine. There is a reason magazines had doors.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 04-15-2009 04:35 PM                     Guys, the SPEED of the burn is everything. Since in this concept the film would be fed and taken up from FULLY ENCLOSED FIREPROOF MAGAZINES in an adjacent FIREPROOF room, the film would be traveling horizontally and the speed of a burn horizontal is quite slow. There would be PLENTY of time for a projectionist to walk over and physically CUT/CHOP the film by the wall before it ever even tried to get through the fire rollers in the wall and then through the fire rollers in the enclosed magazines in that adjacent room. What I was proposing most specifically was to use the "chopper" (yes this is a product) that is designed to mount on a platter and cut the film in the event of a brain wrap, but to set it up in reverse so that once the tension was lost (meaning the film broke or caught on fire...which is also a "break") the chopper would come chomping down on the film at 10-15 feet away from the projector. No human could possibly react as fast as this device would enable the film to be cut...and to be cut from a safe distance. It would work VERY elegantly and be significantly safer. I understand that there are lots of people who just cannot make their brains reason and use logic toward new ideas, but try. Even if the "fireproof room" was only a steel fireproof box just big enough to hold a 2000' fireproof magazine inside of it and the box hung on the wall, the concept is still amazingly smarter than running with a reel of film mounted to the projector. The flames from a fire burn fastest upward. Take a piece of paper and light it from the bottom as you hold the paper vertically. How long were you able to hold that paper until you had to drop it? Now do the same but hold the paper horizontally and light it from one end. This isn't rocket science.  |  IP: Logged Tony L. Hernandez Expert Film Handler Posts: 158 From: Windsor, CO, USA Registered: Dec 2005 posted 04-16-2009 03:11 AM                     Ironic, I just ran a nitrate short a week ago last night. It was a special showing of a 10-minute short and the first time I have run nitrate or seen it on screen. There is a hands down difference between the way nitrate and safety film look...weather or not this indeed has something to do with the stock or the lab work of the time is something I do not know enough about to speculate on. The print was from 1939 and in almost perfect condition considering its age..even when gently bent it did not break or tear. I have projected countless prints over the course of my life and have yet to see one break or "jam" (I still do not know what is meant by the term "jam") in the gate. The only breaks I have had have been on very old, brittle prints and they usually break right above the take up. When I build prints, I always let the film run thru my fingers so that I can feel for any tears or damage and repair it before I run the show. I don't feel there is much to fear with nitrate so long as you take adequate precautions. In the case of a feature, I would have three people in the booth...one operator sitting right next to each machine and a "helper" rewinding, checking sound in the auditorium and bringing the operators the next reel of film after changeovers so that the operators never left the side of their machine. In the case of my little short, I just sat next to the projector the entire time with my hand on the dowser. Some have said "why run nitrate at all?" I would agree except for the fact that when you are dealing with classics, sometimes that's all you can get. In my case, that print was once of a kind. There was no safety 35mm print, 16mm print or DVD copy to be used. Weather or not Brad's platter idea is any good or not seems to be a moot point. Every year that passes, there will be less and less nitrate prints. That said, they are hardly ever run right now. So why bother constructing/inventing something that may get used once every couple of years? With all the diverse and specialized projection work I've done, that was my first nitrate print and I would imagine my last. [ 04-17-2009, 06:10 AM: Message edited by: Tony L. Hernandez ]  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 04-16-2009 03:23 AM                     So you just had your hand on the douser, eh? ...then again, maybe you are.  |  IP: Logged Tony L. Hernandez Expert Film Handler Posts: 158 From: Windsor, CO, USA Registered: Dec 2005 posted 04-16-2009 03:41 AM                     I take that as an insult. Don't know what else I should have had my hand on. I was not terribly concerned seeing as I had inspected the print previously and it was in perfect condition, as I stated above. A nitrate fire will start when the film breaks or stops in the gate, right in front of the light source. Hence, that is why I had my hand on the dowser. Should I have seen or heard anything go wrong (I had my eye on the projector at all times), I would have shut her down. I don't know about anyone else, but my reaction time is pretty damn fast. Every last one of us, weather we drive or take a bus, ride around with a huge tank of very flammable gasoline right underneath our behinds. Some of us commute long distances...I personally drive about 100 miles round trip almost every day of my life. Should we all either walk, bike or convert to horses so as to stay away from this flammable, dangerous substance that will burn and explode should anything go wrong?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 04-16-2009 03:55 AM                     Once the film ignites for any reason, you can close douser or even do a quick rain dance if you like, but the fire at that point has been initiated and that's the end of it. Were you running this in a proper facility, meaning nitrate-certified environment, or was this at a regular theater or at home? At least you didn't get hurt.  |  IP: Logged

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