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Author Topic: RealD port glass problem Zlatko Jelacic Film Handler Posts: 2 From: Zagreb, Croatia, HR Registered: Mar 2011 posted 03-09-2011 06:25 PM                        Lectori salutem to all of you, Cinema Pros. Glad to be here. A problem worth registering ... It seems there's a little mess on the topic of port window glass. We have a situation where we have to use fire rated glass (up to 60 mins) in combination with RealD. The most available FR glass on the European market is Pyran S-AR by Schott, but is tempered. RealD does not like tempered glass, but laminated. Suggestion in RealD paper is Pilkington Pyrodur, but is not anti-reflective. And as I've been told by the very helpful and friendly guys from Pilkington, Pyrodur is not recommended for the 3D applications according to some test made by UK exhibitors. They recommended Pyroclear, another Pilkington product, but with special AR coating made by another UK company. But then, this AR coating is restricted in sizes. Seems I'm missing something. Could it be that there's no fire-rated, anti-reflective glass out of the factory, which is not tempered and therefore is convenient for RealD? How did you others, the proud owners of RealD in fire protection booths, solved this problem? Thank you in advance for your valuable comments.  |  IP: Logged John Wilson Film God Posts: 5438 From: Sydney, Australia. Registered: Dec 1999 posted 03-09-2011 07:23 PM                     quote: Zlatko Jelacic How did you others, the proud owners of RealD in fire protection booths, solved this problem? Yes. We ditched the RealD and went to Master Image.  |  IP: Logged David Stone Film Handler Posts: 75 From: Hornsby, Sydney, Australia Registered: Jun 2008 posted 03-12-2011 02:43 AM                     Hi Zlatho, IN Australia the glass does not need to be fire rated, the shutter assembly needs to be. In the event of a fire the port shutter drops manually or automatically depending on the needs and seals the projection box from the auditorium. Cheers, David.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 03-12-2011 04:29 AM                        Given the difficulty you are having obtaining a compatible FR glass, you might want to check with the inspectors and whoever it is that enforces those regulations and see if traditional fire shutters would be an acceptable substitute for the FR glass -- they perform the exact same function as fire glass, i.e., stop fire from migrating out of the booth into the auditorium. I think if those regulators are ruled by logic, they would have to admit that the fire shutters which were used for decades during the era of nitrate film, would certainly fully protect the hall from a booth fire. Nitrate fires were a much bigger threat than anything that could happen in a booth today. And fortunately, a fire shutter mechanism is very inexpensive (MUCH cheaper I expect than the special fire rated glass that is mandated) and can be easily obtained from any used cinema supply house. Hell, if you were closer, I'd send you our old ones. OR you can fabricate them yourself VERY easily with slab of steel -- the trick is the small fusable link -- a small hook made of two pieces of metal that are held together with solder which hold the steel shutter above the projection port. In the event of a fire, the solder melts and lets the slab of steel fall in front of the booth port, sealing it. The sliding steel shutter is kept in place with runners. Seems that is a very easy solution, very cheap and easy to build if need be. BTW, what's with RealD that they can't use particular types of glass? What does it do to the image? Next question -- how often do inspectors come and check to see what kind of glass is in the booth ports? And how can you even tell if it is that specific type of glass?  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-12-2011 08:20 PM                     Master Image has exactly the same glass requirement as Real-D. Tempered glass interferes with the polarization and either you have poor or no 3D. You can tell easily if glass is tempered by looking at it through Real-D glasses or polarized sunglasses. Good glass looks like, well, glass both looking through and at reflected light. Tempered glass will have faint stripes especially with reflections.  |  IP: Logged John Wilson Film God Posts: 5438 From: Sydney, Australia. Registered: Dec 1999 posted 03-13-2011 05:41 PM                     quote: David Stone IN Australia the glass does not need to be fire rated, the shutter assembly needs to be. In the event of a fire the port shutter drops manually or automatically depending on the needs and seals the projection box from the auditorium. That varies state to state. In Queensland for instance the port does not need to be able to drop.  |  IP: Logged Fabian Schreyer Film Handler Posts: 63 From: Aachen, Germany Registered: Feb 2009 posted 03-13-2011 08:11 PM                     I am wondering, why the glass still has to be that fireproof in most parts of the world. While I don't know the exact laws regarding fireproof separation of projection and screening rooms here in Germany, I know a lot of small cinemas, which just use cheap acrylic glass. You can imagine how the picture looks on screen...  |  IP: Logged Chris Slycord Film God Posts: 2986 From: 퍼항시, 경상푹도, South Korea Registered: Mar 2007 posted 03-13-2011 08:46 PM                     It's because the pertinent laws were written during times when everyone ran nitrate.  |  IP: Logged Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 03-14-2011 10:02 AM                     The fireproof glass may be required to reduce the spread of fire between screens through the booth area. It may be that if the projection booths only serve one screen then fireproofing is not required.  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 03-14-2011 12:36 PM                     I'm going to be little OT, but thing did remind me to this, why all they made soo big port windows today, if there is some fire-proff aprovement, why port windows can be just fitted smaller so that it fits projectors and one for projectionist? Next, I see Zlatko is from Croatia like I, there is verry little things about cinema in it concidering law, mostly things are same for theatres, cinemas and all kind of auditoriums. As it could be good to cut out big port glass and just fit in smaller which permits RealD to be good, but then, on other hand you need to check with some inspector if that can get aprovement!  |  IP: Logged Zlatko Jelacic Film Handler Posts: 2 From: Zagreb, Croatia, HR Registered: Mar 2011 posted 03-14-2011 06:24 PM                        Thank you all for the feedback. This fire resistance regulations really are insane - you have to install 60 mins FR glass in the bulging which has to be evacuated in max 5-8 minutes. And with sprinklers placed all around the projection booth, especially above the projectors and server rack. Sometimes it seems the real threat in the case of fire is water, not the heat. Fire inspector just couldn't care less about some 3D technology and 60 min fire resistance should it be. Therefore shutter really is the best solution. It's just it has to go through pretty rigid procedure of certification and costs far more than the glass only, in our case. Frank, I would take your old shutters :-). Having in mind that FR glasses are mostly not anti-reflective coated and it has to be added separately on certain expense, how important do you consider is for FR glass to have AR coating?  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-14-2011 06:51 PM                     You can skip the AR coating. make sure the glass is tilted inward about 10 degrees (top closer to the projector) or you will have nasty "ghost" images off the Real-D adapter.  |  IP: Logged

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