Does expanded polystyrene (EPS) present a serious fire hazard?
The EPS in an Fox Blocks has a flame retar­dant that allows the forms to be flame resis­tant. The EPS will melt when exposed to sus­tained tem­per­a­tures over 300°F (149°C). The igni­tion point of the melt­ed styrene is 600°F (315°C) (wood is approx­i­mate­ly 500°F (260°C). Fox Blocks have been test­ed to meet the build­ing code require­ments for flame spread and smoke devel­op­ment, plus Fox Blocks may be used as fire resis­tant rat­ed wall assem­blies in schools and hos­pi­tals.
What is the typical Interior finish on an ICF?

All build­ing codes in the USA and Cana­da spec­i­fy that plas­tic insu­la­tion (EPS) must be cov­ered by a ther­mal bar­ri­er equiv­a­lent to 15 min­utes of fire pro­tec­tion in hab­it­able spaces. This is achieved with ½” gyp­sum board or an equiv­a­lent mate­r­i­al. Fox Blocks has spe­cif­ic fire test­ing that proves reg­u­lar ½” gyp­sum board with reg­u­lar dry­wall screws fas­tened into the plas­tic webs remains on the wall for the required 15-minute time peri­od.

Do I have to finish my basement walls with drywall?
All build­ing codes in the USA and Cana­da spec­i­fy that plas­tic insu­la­tion (EPS) must be cov­ered by a ther­mal bar­ri­er equiv­a­lent to 15 min­utes of fire pro­tec­tion in hab­it­able spaces. If the base­ment is clas­si­fied as hab­it­able space, then gyp­sum board must be applied but does have to taped and filled. Check with your local build­ing offi­cial.