Even if a small experiment is being run inside a fume hood, the best practice is to use a dedicated vent line for hydrogen which vents hydrogen to a safe location outside.  This is especially recommended for planned venting.   This practice avoids situations where flammable mixtures could develop. Each system is unique and should be evaluated and approved for  use independently. For example, the relative flow rates could be considered to understand the concentration within the vent duct. Also, it is not recommended that safety relief devices be vented into a hood due to the high flow.