MicroCare recommends nonflammable solvents, or cleaning fluids, to minimize costs and maximize worker safety. In general, most of the the MicroCare, Tergo and Chemours Vertrel and Opteon products all are nonflammable. The full line of precision cleaning choices can be reviewed on this web site.
In terms of the hardware, most vapor degreasing systems are engineered for the use of nonflammable cleaning fluids. There are a few machines which can handle flammable fluids (for example, degreasing with alcohol) but these machines are very specialized and very expensive.
MicroCare does have some products which are flammable, such as the Swellex™ fluid, and some of the MicroCare benchtop PCB aersosol cleaners. These products, however, are not designed to be used as stand-alone products in vapor degreasers.