According to NLRB, you only need the signatures of 30% of your department to trigger a union election in that department. After you send those signatures to the NLRB (put “Petition” and the name of your proposed union on the top of each page), the NLRB will hold an election in your department. If 50% of those who vote end up voting in favor of unionizing, then it’s over & you get a union. It’s very simple.