I think it is law that an employer must provide a clean private environment where practable and allow time for lactation breaks. You really would need to negotiate this with your employer as to whether or not you'll get extra breaks on top of your normal ones and/or if they will be paid or unpaid breaks.
I'm fortunate to have an employer who is very flexible in this regard and has several areas available. I just express once a day as my DD now has formula about 95% of the time and I am able to go when it suits me.