One alternative I can think of is non-flammable methylene chloride (aka METH, CAS RN 75-09-2). It must be checked in the lab. However, if found satisfactory as a solvent, don't forget it is toxic to humans and negatively affects the environment. MEK and MiBK, higher ketones, are a bit less flammable (lower VP) than acetone, and may also be tried out. Anyway, inert gas atmospheres are recommended when handling flammable solvents.