I would also recommend an enclosed 3D printer if you don't want to build your own enclosure. But yeah in a school where safety is important its nice if its enclosed because the printers do have hot working parts which could be a safety issue. For schools you also don't really have to spend so much on one 3D printer, I would say just buy a couple of cheaper FDM printers so more people can use them and you'll get more out of your money.

For schools i would say get a couple of Qidi tech dual extruder 3D printer.Its enclosed,one of the top sold 3d printers and is a dual extruder 3d printer which lets you print with 2 different color materials at the same time making it a bit more colorful. If you have any problems the company has excellent costumer service which is very helpful.

Here is a review of the printer if your interested http://3duality.com/top-color-3d-printers-under-1000/