Can the hydrogen and nitrogen separate? If so is there a possibility of accumulating dangerous levels in my building?
Hydrogen and nitrogen are totally soluble in each other. Once mixed they will not naturally separate. Even heavy gases properly mixed will stay mixed. Carbon dioxide, for example, is a heavy gas and will stay at floor level, however when properly mixed with the air, it will not exhibit this feature. Even liquids, if totally soluble in each other, stay mixed. For example, no matter how long you left a bottle of liquor standing up, the alcohol, which is lighter than water, will not float to the top.