The time limit for. shipping a POV is the same as for travel and HHG transportation limits (JTR Para 5366, POV. Transportation Time Limitation), 1 year from the date of retirement/separation with severance. pay or 180 days from the date of separation.
The envelope is the large bag that holds the helium gas. The envelope is generally cigar-shaped, for aerodynamic purposes, and made of a durable, airtight, lightweight fabric (polyester composites) that is much like the fabric of a space suit.
Helium is a chemically inert element that is odorless, tasteless and noncombustible. Because of its low density it is easily moved through the air passages and therefore requires little effort in breathing on the part of the patient who is in respiratory distress.elium is a chemically inert element that is odorless, tasteless and noncombustible. Because of its low density it is easily moved through the air passages and therefore requires little effort in breathing on the part of the patient who is in respiratory distress.