(57) The invention relates to a combined safety helmet and breathing apparatus and recognises
the inherent problem with all such prior art combinations, that the wearer is totally
dependent on the breathing apparatus for breathable air for the whole of the time
the helmet is in use.
The present invention proposes overcoming this problem by providing an air passage
(29, or 48) which, when open, connects the breathable volume in the helmet with the
surrounding atmosphere and which air passage (29, or 48)is closeable by a valve member
(30, or 49) to prevent contamination of the breathable volume by the surrounding atmosphere
via the said air passage (29, or 48) when the breathing apparatus is in use.
The air passage (29, or 48) and its associated valve member (30, or 49) may be independent
of, or incorporated into, the exhalation valve (41 to 47) for venting spent air to
the surrounding atmosphere when the breathing apparatus is in use.
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