I think you mean sub-floor. There are a few standards. 3/4 plywood or osb. 1 1/8 Plywood. 2 x 6 tounge and groove pine. Each has its advantages. I would consider the 1 1/8 T&G plywood to be the minimum standard.
Do not confuse stairs with steps or treads! All depends on floor to floor height. Floor to ceiling 8 ft. + floor thickness (8 to 12 in.) would give you approx. 10 or 11 steps. but my answer would have to be 1 (one), there is one stair in a standard spiral staircase
The recommended plywood thickness for floor installation is typically 3/4 inch.
The thickness of a standard 39mm casino chip averages about 3.38mm.
The thickness of a standard European door is about 33 inches (919mm).plissescreen.com
The standard drywall thickness for ceilings is typically 1/2 inch.
The standard thickness for ceiling sheetrock is typically 1/2 inch.
The standard thickness of picture frame glass is typically 2mm to 3mm.
It will depend greatly on the thickness & install method, however a standard unit of measure would be .020 for 1/4" thick tiles which is almost the same value as Concrete at .100 for 1" thickness
Generally speaking, the thickness of the plywood layed directly over floor joist.
The standard pcb thickness is 1.57mm, 0.063", or 63 mil.
20,000,000mm
A Pencil has a thickness of about 7 milimeters (mm).