Keep in mind, it was forced altruism that Rand objected too.
If it was in your own rational self-interest to be altruistic (it made you fell better, or it made your community a better place etc.) then go for it.
It was the 'looters' who took from you to give to others and call it altruism that she thought was evil.
In this country we all owe a great deal to many who have sacrificed themselves for the good of their fellow citizens... soldiers killed or maimed in battle come to mind. I am not familiar with her advocating someone giving their life or fortune for their country... especially since this is a concept always encouraged in totalitarian regimes.
Yet I know of many instances where someone did voluntarily give up their life or their fortune for the good of others and it was a good thing despite having no apparent benefit to the person who made the sacrifice. I think that she would say that unless the person felt that this action would somehow directly benefit at least their loved ones that this would be an irrational behavior.