From: Jeffrey Epstein <[email protected]> Sent: Wednesday, March 7, 2012 12:02 AM To: TOM MELNICK; <http://en.wikipedia.org/wiki/Ergonomics> and for safety <http://en.wikipedia.org/wiki/Safety> reasons, stairs must have certain measurements =o that people can comfortably use them. Building codes chttp://en.wikipedia.org=wiki/Building_code> typically specify certain measurements so that the stairs are not too steep or narrow. American building codes specify the following parameters:[5] <http://en.=ikipedia.org/wiki/Stairway#cite_note-4> <=sup>[6] <http://en.wikipe=ia.org/wiki/Stairway#cite_note-5> <=up id="cite_ref-6" class="reference">[7]<http://en.wikipedia.orqwiki/Stairway#cite_note-6> • Minimum tread length, typically 9 inches (229 mm) excluding th= nosing for private residences. Some building codes also specify a minimum riser height, often 5 inches (127 mm).[8] chttp://en.wikipedia.org/wiki/Stairway#cite_no=e-7> • Riser-Tread formula: =ometimes the stair parameters will be something like riser + tread equals =7-18 inches (432-457 mm);191 <http://en.wikipedia.org/wiki/Stairwayncite_note-8> another formula is 2 times riser + tre=d equals 24.6 inches (625 mm), the length of a stride.[31<http://en.wikipedia.org/wi=i/Stairway#cite_note-Neufert-2> Thus a 7 inches (178 mm) rise and a 10.6 inches (269 mm) tread e=actly meets this code. If only a 2 inches (51 mm) rise is used then a 20.6=20 inches (523 mm) tread is required. This is based on the principle that=a low rise is more like walking up a gentle incline and so the natural swing of the leg will be longer. This makes low rise stairs very expensive in terms of the space consumed. Such low rise stairs were built into the Winchester Mystery House chttp://en.wikipedia.org/wiki/Winchester_Mystery_H=use> to ac=ommodate the infirmities of the owner, Sarah Winchester <http://en.wikipedia.org/=iki/Sarah_Winchester> , bef=re the invention of the elevator <http://en.wikipedia.org/wiki/Elevator>