I have 10″ treads with one baluster (spindle) per tread. does this pass code or do i need to put two balusters per tread ? Is there a staircase code in NYC ? any advice would be great. thanks.

We would like to drop a staircase down from our parlour floor to the garden apartment (currently no access). Can someone point me to the relevant code? This is a two-family brownstone, currently ...