EBF and pumping at work

Hi ladies. My LO is EBF and I have a question about pumping and supply. I am going to be working one day a week a full 10 hour day, and would only be able to pump on my lunch break. If I'm doing this just one day a week, will it harm my supply? Has anyone had experience with this? EDIT: The BF law doesn't apply to employers with under 50 employees.