Stairs

Stairs take up space and are unsafe the more they are used.  ideally, stairs should

• Have a secondary use besides moving up and down
• Take up the least area as possible
• Be safe
• Be flexible and change as needed.

I like this example of the Chand Baori (or Baodi) Well in India, about 800 CE.

Pilgrims were to wash themselves prior to entering the temple.  However, Rajasthan has a varying water level due to extremes of drought; pilgrims would have to search for water prior to entering the shrine.

The solution was to dig a 'step well' within the temple.  Lining the well with stone to the lowest drought level made a resistant surface that could be flooded by rising waters.  Making the walls stairs meant efficient use of space.  Therefore:

• Stairs were part of the wall--secondary purpose
• It is not clear what the tread width is, yet the well is big enough to accommodate the stair/wall.
• Note the use of landings at each descending junction as well as the well corners.  This well had a large influx of pilgrims, yet even old and infirm could reach the water.  Even though there are no railings it appears that one could only fall about six steps before landing on a platform. -- Safety.
• About the only thing wrong with the design is that it makes more access available as the water level rises, and therefore the well would be less needed.  Everything else is very well advanced.

Safety

Great paper with statistics and design information on stair accidents is here.  Stairs with the best ascending and descending speed with high quality foot contact have the following dimensions (p. 13ff):

• Best ascent speeds with safety (RxT dimensions in inches): 8.7 x 12.3  (35.2 degree)
• Best descent speed: 7.2 x 10.7  (33.9 degrees)
• The best compromise for overall safety is a 35 degree stair with treads no less than 11 inches (95th percentile of foot length in US) (p.18)

It suggests a 'minor stair accident' is possible every 63,000 steps (p.41/45).  Considering a 10 foot rise between stories and a 9-inch riser gives 27 steps per round trip between floors.  Some calculations of return trips between floors per day:

• 5-round trips per day per floor - 466 days between accidents
• 10-round trips per day per floor - 233 days between accidents

It suggests:

• Build floors around lifestyle themes to keep activity within the floor.  Like a department store, items are organized around themes to keep the shopper on one floor.

Ideas

• Have a wet bar in the office area to avoid having to change floors to go to a kitchen
• Kitchen--family area--open dining--even office on one level.
• Garage to basement with close access to avoid going through multiple areas of the house (less steps)
• more?

Images I like 

• uses space for books, which are important to us. 
• May be distracting when going up stairs.

•  A possibility to go from ground floor to second floor using a loft plan.
• Could be suspended to allow windows.
• Could be in the NE corner of the building
• Sky space is clear.  Forces upwards views from the ground floor.