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History and meaning of the 4 inch rule for guards fences etc...

H

Hesterd

Member
Joined
Mar 17, 2014
Messages
5
Location
United States
Hello all for one.

I have a curious question. The rule/intent of 4 inch for balusters, guards and like. I always thought was based on head entrapment. I know the rules started off as preventing through fall when spacing was larger. Curious if someone has the good history on this.
 
Hesterd said:
Hello all for one. I have a curious question. The rule/intent of 4 inch for balusters, guards and like. I always thought was based on head entrapment. I know the rules started off as preventing through fall when spacing was larger. Curious if someone has the good history on this.
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You are correct. The intent was to prevent children from going through.
 
A child's head will fit through any gap that is greater than the size of it's head. At one point it is the size of a walnut. Later it's an orange and finally a melon like what Brent hauls around. The four inch dimension is only effective for a segment of a child's growth cycle if it is to prevent entrapment of a head. Why not 3" for a different segment. So I don't think it has anything to do with baby heads.
 
"At one point it is the size of a walnut. Later it's an orange..."

ICE, those would be in the womb...

D'OH!:banghd
 
ICE said:
A child's head will fit through any gap that is greater than the size of it's head. At one point it is the size of a walnut. Later it's an orange and finally a melon like what Brent hauls around. The four inch dimension is only effective for a segment of a child's growth cycle if it is to prevent entrapment of a head. Why not 3" for a different segment. So I don't think it has anything to do with baby heads.
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I get stuck in street manholes. Too much brains.

Brent
 
A 1-1\2- 2 year old can walk through 6 inch spaced pickets. Just before the hearing we were at my brothers on his new neck and I was sitting on the top of the steps to keep my toddler son from falling down the steps. He turned sideways and stepped right between the 5-1/2 inch spaced pickets and was standing on a 6 inch ledge 5 ft off the ground when I grabbed him. I questioned my brother if his builder had spaced the pickets correctly and they measured right at 5-1/2 inches spaced by the 2x6 with a handle method. I related this story at the BOCA code change hearing supporting this change. There were arguments for the 2-3/8 inch crib rail spacing to prevent head entrapment but it was argued that the 4 inch spacing was adequate to keep in toddlers that could walk. The testamony at the BOCA hearings also mentioned a couple cases where kids had run off from parents in malls and taken a quick trip to the floor below. The two story mall here, on the "advice" of their insurer, put up temporary plywood on the inside of their rails untill the new glass railing system could be installed. This was before the 4 inch standard was formally enforced here.
 
MASSDRIVER said:
I get stuck in street manholes. Too much brains. Brent
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That happens to fatboy ..... but it's not brains.
 
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I remember in the late 70's the spacing was 9 inches. Then somewhere along the line it became 6 inches, Until we arrived at less than 4 inches. My only guess is that baby's heads are getting smaller.
 
It's Darwin at its finest. In three years they will squeeze through keyholes like mice.

We aren't helping them here. They just adapt.

Brent.
 
"That happens to fatboy ..... but it's not brains."

Well...........we won't go there.

I thought the spacing went from 8" to 6" to 4", (then to 4 3/8" on stair runs), will do some research tomorrow.
 
If memory serves me correctly... NFPA 101 used to allow either less than 6" (to avoid head fitting through) or greater than 9" (to allow head to come back out easily). The issue was clarified when children fell through the wider spacings on elevated decks/balconies. At that point is became < 4", eventually the stair folks got the 4 3/8" on stair runs due to stair geometry and aesthetics.

But I could be mistaken...
 
Rick18071 said:
Is it 4 3/8" on stairs because only biger kids get to use the stairs?
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Commentary; "Exception 6 is to allow a stairway within a residence that chooses to use the 7-inch rise/11-inch run (178 mm rise/279 mm run) stair configuration to have two spindles per stair tread instead of three spindles. Where the 73/4-inch rise/10-inch run (197 mm rise/254 mm run) configuration (see :Next('./icod_ibc_2009f2cc_10_par096.htm')'>Section 1009.4.2, Exception 5) is utilized, the two spindles would meet the 4-inch (102 mm) maximum provision."
 
If they are smart enough to use the stairs they won't get stuck...Makes me look like a wicked jerk when I call a guy on his 4-1/16" balluster spacing on his deck...
 
Initially the code change proposal submitted by Elliott Stephenson to reduce the opening between 34 and 42 inches to 4.375 inches from 8 inches was disapproved for climbability; but made it (approved) into code without explanation.

The new height exception for R-3 and within R-2 not more than 3 stories uses injury statistics for potential risk with different heights for example reducing the gap at the bottom to 2 inches where 6 ft. or more above the surface below to prevent objects from "rolling" underneath and hitting a person below.

ICC Code Technology Committee Climbable Guards
 
I was at the hearings when the 4 3/8" on the stairs was approved. Part was cosmetic, but it was also argued successfully that toddlers were not spending that much time on stairs vs. flat walking surfaces.
 
Francis Vineyard said:
Initially the code change proposal submitted by Elliott Stephenson to reduce the opening between 34 and 42 inches to 4.375 inches from 8 inches was disapproved for climbability; but made it (approved) into code without explanation. The new height exception for R-3 and within R-2 not more than 3 stories uses injury statistics for potential risk with different heights for example reducing the gap at the bottom to 2 inches where 6 ft. or more above the surface below to prevent objects from "rolling" underneath and hitting a person below.

ICC Code Technology Committee Climbable Guards
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Funny how that happens.
 
Not a sawhorse, so can't edit... 'balluSter spacing' is not regulated by the Code.

"If they are smart enough to use the stairs they won't get stuck...Makes me look like a wicked jerk when I call a guy on his 4-1/16" balluster spacing on his deck..."

Mine was a spelling error, yours was a poor choice of words or an attempt to regulate something the Code does not address... :eek:ops

"
 
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