How long do scrap and armor packs persist?

Solution 1:

From my experience, scrap seems to last forever until I pick up a certain number of them. I am not certain what this number is since scrap still exists around the map even when I have reached the full 200 scrap limit. The game does indicate where the scrap is located with two downward arrows being shown throughout the map (can even see them through walls), but I have noticed these indicators disappearing after a certain number of picked up scrap (or possibly time, but I am going with number of scrap items - each giving you 25 scrap). As for armor packs, like Powerlord said they last forever as long as your teammates are not hit. Obviously this armor deteriorates first with enemy damage.

The Overwatch wiki pages don't really mention how long scrap lasts on the map without being picked up. Source: http://overwatch.gamepedia.com/Scrap