6th Order Posted April 2, 2008 Share Posted April 2, 2008 So, we currently use a sports hall as a church venue. We have a Logic CA10 system, ground stacked, which we are tweaking to get the best results from. To ground stack the system you use the fly frame inverted on the subs. Ideally I'd like to get the Mid/Highs in the air but none of the system is installed and therefore they would need to be flown each time the venue was used. Setting aside the issues of competent persons to oversee the flying for a moment, my question is, does anyone have any experience, or suggestions, of how to permanently install a hoist/fly system in the venue to allow these to be flown, whilst at the same time letting the sports hall remain safe to use as a sports hall? The roof is simple, as per the picture. There is a cross beam just in front of the stage which may be useful. The pic is taken from the stage, during construction, but it gives the idea. Link to picture There would be two drops of approx 70-80 Kgs each. I'm looking for ideas and possible solutions. Any installation would be carried out by a suitable contractor bearing in mind it's a school sports hall (and for the record I am not a pupil!) Ideas, questions....Go! Link to comment Share on other sites More sharing options...
mumbles Posted April 2, 2008 Share Posted April 2, 2008 Talk to a structural engineer. They'll calculate whether the structure can safely take the laod, it is what they train for years to do. It may be quite expensive, if they have to model the building from scratch, expect a good 1-2k upwards depending on the complexity of the building. If it is a recent build, then the firm that undertook the original analysis may have the model still, and so it may be cheaper. HTH M Link to comment Share on other sites More sharing options...
Simon Lewis Posted April 2, 2008 Share Posted April 2, 2008 Not an easy one... a) You need the structural sign offb) you need a pair of winches mounted up on one of the girders (presuming that's in the right place?)c) you need ground level control of the winch, and a means to stop a single pickup spinning the speakers round (or some other pickup method)d) you need to be able to access the system at (6 and) 12 monthly intervals for LOLER tests etc.e) you need the permission of whoever owns the sports hall.... If you fly the tops alone, might a heavy duty wind up stand be suitable? (maybe something like this - although I cannot guarantee it's suitable for purpose). Simon Link to comment Share on other sites More sharing options...
Seano Posted April 3, 2008 Share Posted April 3, 2008 None of the above is insurmountable, the load you're talking about is pretty trivial really. Your "suitable contractor" should be able to deal with that for you. Do you have a contractor in mind, or are you looking for suggestions? A location in your profile might be helpful. b) you need a pair of winches mounted up on one of the girders (presuming that's in the right place?)A pair of chain hoists mounted on the beam might be an option. A couple of CM Prostars on beam-clamps perhaps. In that case the hoist installation itself would be fairly trivial and have no permanent effect on the fabric of the building, the major part of the work would be the electrical installation. Single phase hoists are available if necessary. (Even these baby hoists run more smoothly on 3 phase though.) The downside to mounting something on the beam in a sports hall is that its likely to get battered with tennis balls, basketballs, etc. A prostar is a pretty robust little beastie, but its conceivable that a basketball could spill the chain out of its bucket, and it wouldn't run so well with a shuttlecock wedged in its chainguide. (Wire rope) winches on the other hand, probably wouldn't be mounted on the beam. It'd be neater to wall-mount them and divert the rope over a pulley or 2. Electrically operated winches could be mounted at the end of the beam, or on the wall just below it. Since you're talking about a relatively light load, and a relatively low trim height, a pair of wall-mounted hand winches might be a good budget option. (Something along these lines for example.) No electrical installation required, and you get the bonus of a nice little Sunday morning upper body workout for your assistant. :( (You also get the bonus of being able to mark a precise 'dead' with nothing more elaborate than a bit of lx-tape.) a means to stop a single pickup spinning the speakers roundThis could be as simple as a piece of string. For a super de-luxe solution, perhaps the install could include a couple of cable picks, consisting of a bit of black sash a few pulleys and a cleat or two - that way you get to stabilise the speakers' aim and tidy up the cable management in one hit. e) you need the permission of whoever owns the sports hall....The op seems pretty together to me, I think its probably safe to assume he's thought of that. ;) Seanx Link to comment Share on other sites More sharing options...
6th Order Posted April 3, 2008 Author Share Posted April 3, 2008 Extra info: Location is Norwich, UK. The hall has only recently been finished, so structural info would be accessible if required. Seano has the flavour of the issues of the dual usage. With kids running round underneath anything that gets installed, it would have to be tough and very safety. The hand winches are not something I had come across, but I'm not sure I could get away with the exposed cable covering the wall. The walls/doors are particularly free from anything not sport related (display boards, projecting door handles etc.) From what little I know, conventional hoists with a chain bag seem like a bad idea. The possibility of the chain coming out of the bag is not acceptable. Does anyone have any links/experience to the electrical wire rope winches as mentioned? Obviously the right calculations need to made to ensure any install is safe, but having seen how the building was made, I know that the only part of the structure that is likely to be able to hold any significant load are the roof crossbeams. The walls are blockwork up to a point and then a metal/insulation/plasterboard sandwich, so winches on wall is not going to happen. It is of note that they have a basketball hoop/backboard which is lowered by a cable winch. The weight is transfered through a metal frame and the winch lowers it in to place. As for stands, I did look at this possibilty, and I was looking at systems around the time that Peavey showed a small line array with a very nice windup stand at Plasa. I like the idea, but the hall has an unusual flooring. It's a semi-ridgid plastic, but has a certain amount of give. For example, a standard four legged chair will leave indentations in the floor. I appreciate the footprint of most suitable windup stands is quite large, but all the same, I'm not keen to use the flooring unless it's solid. Link to comment Share on other sites More sharing options...
paulears Posted April 3, 2008 Share Posted April 3, 2008 If it's Norwich, then the very people are right under your noses. TV & Theatre Services. A small firm but they work country wide. They will design and install - and being local, they won't be mega pricey. They also are willing to take on projects when funds are tight. They look after all the serious work carried out at my venue in Gt Yarmouth - and are really good at unusual jobs. They will use off-the-shelf products, but will fabricate anything that isn't available. We've got some refurbed 2 tonne power winches, that they've adapted and derated for us to be able to use to fly two of our heaviest LX bars. Their work is first class, and they'll look after certification and testing. PM me for more info on them if you like. Link to comment Share on other sites More sharing options...
DSA Posted April 3, 2008 Share Posted April 3, 2008 It's not really your problem to decide how it should be done - leave that to the engineer. Just give them all the info about what you intend to do with the installation so that they understand your underlying requirements! There will be columns "hidden" in the walls between the masonry infill panels, else how are the roof loads transferred to the ground?! Given the likely age of the structure you are almost certainly going to be best off going to the same consultant who designed the hall in the first place, as they will have all the existing calcs to hand and immediately understand the structure. They will most probably also had the discussions about what is or is not acceptable to be protruding from the walls. The job does appear trivial, but careful implementation may require a little thought. Obviously the engineer will need to consider that whatever winch system is used, it could still be loaded to capacity in the future. Electric winches of some sort would be my choice, where the load can be easily controlled and electronically locked off if needed. Did you know that you would be using this building before its construction? If so it would have been much easier to install a system then! Link to comment Share on other sites More sharing options...
6th Order Posted April 3, 2008 Author Share Posted April 3, 2008 paulears, I know of them and it's good to have a good recommendation of them. DSA, the budget was never in place for a seemingly simple extra such as this. The extra over cost would have been rediculous, and the contractor couldn't even build the stage to the right height! so apart from slightly neater wiring, I don't think we've missed out too much. Given that this was built by a local authority.... As for the support struts, They are indeed hidden as you put it in the walls, but the side walls, and therefore no use to us. As the end wall had a stage 'tacked' on, I suspect the end wall steels are in the wrong place to mount any winches. Slightly OT, it may not be my problem to solve, but I am interested in how it could be done, especially as all I need is for the boxes to be higher. I'm not goin to ask someone to install winches if I know of a better way. That's why I'm tapping the collective brain power of the BR (dangerous I know). Link to comment Share on other sites More sharing options...
Jivemaster Posted April 3, 2008 Share Posted April 3, 2008 Would all your members be capable of flying the system if it were to need hanging every time! I think not! Would a flown system be beyond the others if you were to move to a different county. Link to comment Share on other sites More sharing options...
6th Order Posted April 3, 2008 Author Share Posted April 3, 2008 Setting aside the issues of competent persons to oversee the flying for a moment, Not something I would ignore. Thanks. Link to comment Share on other sites More sharing options...
nateflips Posted April 4, 2008 Share Posted April 4, 2008 All those footballs hitting the PA is also a point... :( ;) B-) Any Rock N Roll Rigger should be able to help you with this topic.. Link to comment Share on other sites More sharing options...
cfmonk Posted April 17, 2008 Share Posted April 17, 2008 Setting aside the issues of competent persons to oversee the flying for a moment, Not something I would ignore. Thanks. I really don't think the OP was. Just making the point that he didn't want this to turn into a discussion on competence of people or otherwise but rather be a technical excercise in possible solutions. Quite sensible in my opinion. Link to comment Share on other sites More sharing options...
AndrewR Posted April 19, 2008 Share Posted April 19, 2008 From what little I know, conventional hoists with a chain bag seem like a bad idea. The possibility of the chain coming out of the bag is not acceptable. If that is your only issue with chain motors... would a properly designed motor/chain bag combo work? (not a 50 year old combo like a certain popular hoist... that I've seen come very close to killing someone...)Look at Liftket motors, they have a chainbag design that renders it almost imposible for the chain to come out of the bag. (UK dealer is Unusual Rigging). Link to comment Share on other sites More sharing options...
mikienorth Posted April 20, 2008 Share Posted April 20, 2008 Or a Gis Hoist? Designed to allow for lifting loads over people without additional safeties to BS 7906? Very nice, quiet units with (on the ones supplied to us, a two position chain bag allowing for motor up or down positions bringing the bag closer to the chain port where needed, and a good snug fit. Lift Turn Move are the people for hoist supply, well, this type and the Loadstar at least, and loads of other wire winch systems... Link to comment Share on other sites More sharing options...
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