MicroCare recommends nonflammable solvents to minimize costs and maximize worker safety. In general, the MicroCare, Tergo, Vertrel and Opteon products all are nonflammable monosolvents, such as Vertrel™ XF, or azeotropic blends of fluids such as MicroCare HDS which have been engineered to be 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 solvents. 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 several 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.