Unpaid employment irrespective of the major

[abigan]

Hello guys,
I am at present in my OPT status and I am looking forward to work in as a volunteer in some humanitarian organization that is not related in anyway to my field of study. I just want to know is it going to be an eligible employment ?? Because under the revised SEVP policy guidance it has been mentioned to work for an unpaid employer, one has to work for a minimum of 20hrs/week for a student on post completion OPT where this practice does not violate any labor laws..

Please help me out....looking forward for your suggestions..
Thank you