As per NBC 2005,for institutional buildings like hospitals, what will be the minimum width of the stair case, minimum width of the tread and maximum heightofriser?

Minimum width of staircase — 1500 mm, minimum width of tread — 250 mm and maximum height of riser — 190 mm.

Minimum width of staircase — 2000 mm, minimum width of tread — 300 mm and maximum height of riser — 150 mm.

Minimum width of staircase — 2000 mm, minimum width of tread — 250 mm and maximum heightof riser — 170 mm.

Minimum width of staircase — 2500 mm, minimum width of tread — 300 mm and maximum height of riser —- 150 mm.