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Guards (2006) Sec: 1013 (Cable Infill)

tbz

tbz

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Sep 10, 2010
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Good afternoon everyone,

Please comment on the following situation, I am not sure of all the facts, but enough to be able to layout the question for comments.

1. Fabricator built a guard for a commercial client to sit on top of a solid wall 24" High (example pic below is not the site but only for reference)

CableRailWharfClup.jpg
CableRailWharfClup.jpg

2. Posts set with 38" between verticals

3. Cables set with maximum of 3" between cables

4. (I am not sure about how much tension is on the cables) But I am told that it takes a strong shove with 2 hands and some weight behind him for the inspector to push/force a 4" sphere through between 2 cables mid span (center would be 19").

I personally have done many guards with cable infill like this over the past 27 years and never had an inspector fail for forcefully pushing the 4" sphere through.

Again I point out, not my project.

The fabricator is telling me that the inspector is not correct because the inspector will not give the fabricator a section other than 1013's 4 sphere rule and the fabricator says that 1013 tells you to look to 1607.7 for loads and the force on infill is 50 lbs/per sq/ft.

I am told that a 50 lb force on the 4" sphere will not pass between the cables, Have not seen this with my own eyes, just told.

Here in lies my question to all?

When inspecting for infill spread, if you do, I would venture that you all treat all types of infill the same (IE: wood balusters, metal balusters, plastic, cable, concrete, Fypon and so on, at what point to you treat pass and fail for the 4" sphere?

I have always been told treat the guard like one of those games with the little steel balls and the maze with the holes in it, if you are rolling the sphere over the guard and it falls through it fails, no load.

I have had many conversations with inspectors on 4" sphere force or no force, but still an open opinion.

Please comment
 
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Good question.

I have always thought the intention of the 4" sphere rule is to prevent an infant/toddler from working himself through the railing.

I am not aware of a sphere-force rule, but it seems reasonable that a sphere that can be passed with less than 40-50 lbs of force would allow an infant to pass through.

I don't have a code section to back that up, but would interpret it that way in the field.

mj
 
Everyone seems to recall the 50 pound rabbit

1607.7.1 Handrails and guards.

Handrails and guards shall be designed to resist a load of 50 pounds per linear foot (plf) (0.73 kN/m) applied in any direction at the top and to transfer this load through the supports to the structure. Glass

handrail assemblies and guards shall also comply with Section 2407.

Lest we forget the 200 pound rabbit

1607.7.1.1 Concentrated load.

Handrails and guards shall be able to resist a single concentrated load of 200 pounds (0.89 kN), applied in any direction at any point

CONCENTRATE!!
 
If I pushed a 4" sphere hard enough, I could get it through the guards at stairs and balconies in my McMansion.

And they aren't cable.

Architect 1281: you left out an important detail for the 200lb rabbit; "in any direction at any point along the top". I may be wrong, but I don't think the average individual wood guard is required to resist a 200lb load applied perpendicular in mid-span. I think the rail is required to resist that concentrated load and the guards are to transfer the load to the structure.
 
The cables are a ballustrade and not the guardrail. Different load requirements for guardrails and ballustrades. There is no requirement for a 50 pound 4 inch sphere. Apply the 50 pounds over a square foot area. This will include at least 2 cables. The cables cannot distort to allow the 4 inch sphere to the next cable.
 
IMHO, the cables function as "Guards". However, please note section, "1607.7.1.2 Components."

1607.7.1 Handrails and guards. Handrails and guards shall be designed to resist a load of 50 pounds per linear foot (plf) (0.73 kN/m) applied in any direction at the top and to transfer this load through the supports to the structure. Glass handrail assemblies and guards shall also comply with Section 2407.

Exceptions:

1. For one- and two-family dwellings, only the single concentrated load required by Section 1607.7.1.1 shall be applied.

2. In Group I-3, F, H and S occupancies, for areas that are not accessible to the general public and that have an occupant load less than 50, the minimum load shall be 20 pounds per foot (0.29 kN/m).

1607.7.1.1 Concentrated load.

Handrails and guards shall be able to resist a single concentrated load of 200 pounds (0.89 kN), applied in any direction at any point along the top, and to transfer this load through the supports to the structure. This load need not be assumed to act concurrently with the loads specified in Section 1607.7.1.

1607.7.1.2 Components.

Intermediate rails (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds (0.22 kN) on an area equal to 1 square foot (0.093 m2), including openings and space between rails. Reactions due to this loading are not required to be superimposed with those of Section 1607.7.1 or 1607.7.1.1.
Click to expand...
 
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Architect1281 said:
yeah I also was snoozing when the reference was for 2006 cause my clip is 2009so does that mean that in 2009 at any point includes the guard

I think it is so
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'09 also says along top for the 200lb rabbit.
 
Glade to see input,

But seems to have gone off topic, then on, then off.

So as to be on the same page I was going to post a poll, but can't seem to figure out how to turn on the poll.

So how many believe or inspect the 4" sphere

(A) just for size no force pressure applied?

(B) Require the infill to meet 1607.7.1.2 50lb on 1sq/ft and then check 4" sphere ?

© Apply force to the 4" sphere to a limit they feel is good?

For the record Arch, the 200lb point load is only at the top, not anywhere on the guard.
 
B, and I don't really see where anything went off-topic. You brought up the subject of someone applying force to the 4" sphere, and so there was some discussion about it.
 
B

To attempt to force a 4" sphere between guard elements or ballestrauds is not a test required by the code.
 
tbz said:
For the record Arch, the 200lb point load is only at the top, not anywhere on the guard.
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Then what is the min requirement for pushing laterally against the top rail?
 
Yankee,

I agree that the code is some what directive, however, the reason for the wording is to set the standard to be in all directions at the top.

What the code is doing is being clear to not apply the 200 lb point load on the infill or balusters directly, but the main top of guard.

This also floats the point load for those times were the guard is higher than required and thus the point load follows the height.

As for your question, everything under the top is considered infill or as 1607.7.1.2 puts it components and thus covered by the 50lb on a sq/ft.

Note of point, this is why I always take point with the wood deck post testing that shows a 500lb point load on only the post. Everyone always forgets that the code does not require guards to have posts.

The code requires the load at the top, and transfer that load to the structure with the top of guard staying in place. It works as a system of components with a top as a whole, not each piece as a single part.
 
1013.3 Opening limitations. Required guards shall not have openings which allow passage of a sphere 4 inches (102 mm) in diameter from the walking surface to the required guard height.

If the sphere is 'forced' through, the guard opening did not allow the passage. If you ask to enter my home and I stand in the doorway saying no, but you push past me, did I allow you in?

I like the old language... 'such that a 4" sphere will not readily pass through.' But I suppose someone took exception to the word 'readily'...
 
If they do not prevent passage, then one could state they allow passage.

In this particular situation, I believe the guard was well designed and constructed.. 38" between verticals and 3" spacing, imho, is more than compliant (provided the cables are tensioned). FOrcing a sphere through there is unreasonable.

This 4" number is based on a child's head getting stuck in there, right?
 
Good morning all,

Texasbo, you are correct in that the subject stayed on topic, I was reading 2 posts at once, and mixed one in

For those wondering, I have 4 screens on the desk allowing many topics to be viewed at one time, besides other programs running.

Thank you to those that have voted and commented, however to those of you lurking please chime in with a choice.

Tom
 
If the 4" rule is to prevent a child from getting their head stuck why is the 4" rule only for guard that are for above 30" drops? 1013.3 says only required guards have the 4" rule. Why couldn't a kid get their head stuck in a space larger than 4" when the guard is at a place where a guard is not required.
 
Rick18071 said:
If the 4" rule is to prevent a child from getting their head stuck why is the 4" rule only for guard that are for above 30" drops? 1013.3 says only required guards have the 4" rule. Why couldn't a kid get their head stuck in a space larger than 4" when the guard is at a place where a guard is not required.
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That is why I believe the rule exists.. I think I heard it on the old forum. If anyone can confirm or knows anything to the contrary, their input is appreciated.

As for the spacing on non-required guards.. :beatdhrs

If I put a 2x4 rail at 42" where no guard is required, is it required to have any load resistance? What about a velvet rope on portable stanchions next to a 24" drop? We can (and have) what-if it to death. On a required guard the spacing shall not allow passage of a 4" sphere. JMHO.
 
I vote for B and have seen many copper pipe intermediate rails that would allow a 4" sphere to pass if you pushed hard enough
 
Tim,

The 4" sphere rule is not to prevent children from getting stuck in guards, it is prevent them from accidentally going though a guard and descending down from the high elevation.

See the link

http://www.injurypreventioncenter.org/pdf/Istre%20IP%20child%20falls.pdf''>http://www.injurypreventioncenter.org/pdf/Istre%20IP%20child%20falls.pdf' rel="external nofollow">

http://www.injurypreventioncenter.org/pdf/Istre%20IP%20child%20falls.pdf

As for guards being required to meet the loads of 1607.7 if the guard is not required this is still in debate and the rope stanchion example is a good one, but when the CTC re-worked 1013 & R312 these last 2 code cycles, the word required was specifically added to height & openings and not the load requirements.

The thought was that to leave the gray area there for the inspector on making sure if the product was installed at the edge, and looked like a guard that would hold weight, that they could require that product to meet the loads, however one could easily see if a product was short or no infill, but just by looking at it one can't tell if it is strong enough for them to lean on.

Tom
 
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