minute must be delivered to the head enclosure 12 thus a first conduit 42 conducts air from the manifold to the head enclosure 12 in the required range of volume per unit time to provide a positive pressure or respiration air within the head enclosure 12 this insures that the wearer will have a constant supply of fresh air to breathe and also prevents the entry of contaminated air into the head enclosure 12 by the flow therefrom fig2 more clearly illustrates the manifold 22 according to the preferred embodiment of this invention the manifold 22 comprises a chamber 27 having a cross sectional area at least approaching the cross sectional area of the hose 40 the chamber 27 is provided with an inlet 26 which is preferably a quick disconnect fitting for coupling the hose 40 the chamber 27 is also provided with a first outlet 30 which is preferably a quick disconnect fitting for coupling to the hose 42 finally the manifold is provided with a plurality of second air outlets 32 34 36 and 38 the second air outlets 32 38 include fittings each connectable to one end of a different one of a plurality of flexible second conduits 48 50 52 and 54 as best shown in fig1 according to this embodiment of the invention the first air outlet 30 is dimensioned with respect to the inlet 26 and second air outlets 32 38 such that when the air pressure at the source not shown is 25 pounds per square inch gauge.