Building regulations regarding stair noses can vary by location. It is important to consult the specific building code for your area to ensure compliance with the required standards.
The building code specifies that stair railings must be at least 34 inches high, have balusters spaced no more than 4 inches apart, and be able to support a certain amount of weight.
There really is not a difference. A guard rail has a handrail on it so they are really the same thing. All staircases must be designed to fit any guard-rail type building code. No spaces greater than 4 inches and no less than 36 inches tall. Source: http://www.stairpartsblog.com
Standard minimum railing height is 36" from finished floor, according the the IRC 2003 building code.
Stair nosing is used to provide extra tread or grip for your feet while you walk up or down on the stairs. It also makes the stairs look cosmetically better. In most commercial buildings stairs are required to have nosing to comply with the building code.
The code for calculating the stair rise and run in a staircase design is typically based on building regulations and standards that specify the maximum and minimum dimensions for safe and comfortable stairs. These dimensions are usually determined by dividing the total height of the staircase by the number of risers and determining the ideal tread depth for each step.
code is no more then 7.5 inches
The specific requirements outlined in the residential stair railing code for the installation of stair railings in homes include the minimum height of the railing, the maximum space between balusters, the strength and durability of materials used, and the proper anchoring and support of the railing to ensure safety and stability.
what is the standard depth of stairs
See http://www.mass.gov/Eeops/docs/dps/780%20CMR/780061.pdf
Those types of regulations are usually controlled by the local municipalities. Talk to the local planning and zoning department. It may be a City or County agency.
In CA, stair railings must be 34" - 38" high.