In the non-schengen area there are showers in the spa. They are a pay-service except for AY plats who have free entrance. There might have been a recent change in policy to include free entrance for OW sapphires too, check this thread:
http://www.flyertalk.com/forum/finna...ing-schen.html
In that thread there is also info on showers in the schengen area lounge, which you will have free entrance to.