▁the ▁name ▁implies ▁the ▁spl ash ▁protection ▁su its ▁are ▁designed ▁to ▁prevent ▁the ▁wear er ▁from ▁coming ▁into ▁contact ▁with ▁a ▁liquid . ▁These ▁su its ▁do ▁not ▁protect ▁against ▁g ases ▁or ▁dust . ▁Gast ight ▁su its ▁addition ally ▁protect ▁against ▁g ases ▁and ▁dust . ▁ ▁Gas / v apor ▁protection ▁ ▁Such ▁su its ▁( level ▁A ▁in ▁the ▁US ) ▁are ▁gas ▁or ▁v apor - t ight , ▁providing ▁total ▁enc aps ulation ▁and ▁the ▁highest ▁level ▁of ▁protection ▁against ▁direct ▁and ▁air bor ne ▁chemical ▁contact . ▁They ▁are ▁typically ▁worn ▁with ▁a ▁self - cont ained ▁breath ing ▁appar atus ▁( SC BA ) ▁en closed ▁within ▁the ▁suit . ▁ ▁These ▁su its ▁are ▁typically ▁constructed ▁of ▁several ▁layers ▁and , ▁being ▁a irt ight , ▁include ▁a ▁release ▁val ve ▁so ▁the ▁suit ▁does ▁not ▁over inflate ▁from ▁air ▁ex h aled ▁by ▁the ▁SC BA . ▁The ▁release ▁val ve ▁does ▁retain ▁some ▁air ▁to ▁keep ▁some ▁positive ▁pressure ▁(" over press ure ") ▁inside ▁the ▁suit . ▁As ▁noted , ▁such ▁su its ▁are ▁usually ▁limited ▁to ▁just ▁ 1 5 – 2 0 ▁minutes ▁of ▁use ▁by ▁their ▁mobile ▁air ▁supply . ▁ ▁With ▁each ▁suit ▁described ▁here , ▁there ▁is ▁a ▁manufact ured ▁device ▁designed ▁to ▁protect ▁the ▁resp ir atory ▁system ▁of ▁the ▁wear er ▁( called ▁a ▁resp ir ator ) ▁while ▁the ▁suit / ensemble ▁is ▁used ▁to ▁protect ▁skin ▁exposed ▁to ▁potential ▁ha z