Rail Spacing

[jakeg]

Dear Codeman,

I am trying to determine when rail spacing of 4 3/8" (inches) applies. The 2006 IRC 312.2 says "required guards on open sides of stairways, (then other things), shall have intermediate rails which do not allow the passage of a sphere 4" or more in diameter.

As you know, it also goes onto 2 exceptions. The second exception being, "openings for required guards on the sides of stair treads shall not allow a sphere of 4 3/8" to pass through.

I realize that guards can be handrails, as long as certain requirements are met from 311 (grip, height, etc.).

Thanks in advance for your help.

Jake

[Jerry Peck - Codeman]

Hi Jake,

The 2006 IRC states that section slightly differently, and that difference makes all the difference when reading it.

From the 2006 IRC. (underlining and bold are mine)
- R312.2 Guard opening limitations. Required guards on open sides of stairways, raised floor areas, balconies and porches shall have intermediate rails or ornamental closures which do not allow passage of a sphere 4 inches (102 mm) or more in diameter.
- - Exceptions:
- - - 1. The triangular openings formed by the riser, tread and bottom rail of a guard at the open side of a stairway are permitted to be of such a size that a sphere 6 inches (152 mm) cannot pass through.
- - - 2. Openings for required guards on the sides of stair treads shall not allow a sphere 4 3/8 inches (107 mm) to pass through.

The maximum allowable size for a sphere is 4 inches, except ...
- except at that triangular area = 6 inches
- except at the side of the stair treads = 4-3/8 inches

If you code states it differently, would you please post the exact wording and the code it is from? Thank you.

[jakeg]

Hi Codeman,

Mine says what yours says, I just abbreviated it because my confusion is coming from 'guards on open sides of stairways' versus 'guards on the sides of stair treads'.

I think this is what I'm not understanding. In my mind both of these describe guards for for guardrails, where the guardrail is also the handrail (so long as it meets 311).

It seems this is where the key is, but I'm not 'seeing' the difference between the two. Does this have to do with the rails that connect to the guard/handrail at the top, but do not attach directly to a stair, but rather a rail parallel to the top of the guard/ handrail?

Thanks,
Jake

[Jerry Peck - Codeman]