2009 IBC Openings in guard with horizontal aircraft wire. Can a 4inch sphere pass

[joetheinspector]

On a new commercial project there are guard rails that have the posts 4ft apart with aircraft wire strung horizontally. The wire has an opening that is 3 and ¾ of an inch at the post. In the middle of the posts the opening is less than 4inches, however, the wire can be stretched to allow a 4inch sphere to pass through. My question is do you know how to test this to see if it complies with code or not? Are there other code sections in regard to this other then the one below

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.

 

[cda]

http://www.thebuildingcodeforum.com/forum/commercial-building-codes/4109-guards-2006-sec-1013-cable-infill.html

http://www.thebuildingcodeforum.com/forum/commercial-building-codes/4355-cable-rail-codes-inspector-problems.html

 

[steveray]

Without going to the old threads, if you take the 50 psf and divide by the sphere area you could argue that way if needed....If it passes that, no way to fail it....

 

[Francis Vineyard]

Be nice to get an opinion from tbz.

Searches revealed several AHJ reference IBC section for loading and deflection with the same following results; what do think?

Cable rail loading requirements

Guardrail components 25 psf over entire area

IBC 1607.7.1.2 Components

50 lbs Conc. load over 1 sf

Application to cables

-Uniform load = 25 psf x

​

•3” / 12” = 6.25 plf

Concentrated load 1 sf

3 cables minimum

50/3 = 16.7 lbs on 4” sphere

Produces 8.63 lb upward and downward on adjacent cables.

Deflection – since cables are 3” O.C. and maximum opening width = 4”



​

 

[tbz]

Just my 2 cents...

On a new commercial project there are guard rails that have the posts 4ft apart with aircraft wire strung horizontally. The wire has an opening that is 3 and ¾ of an inch at the post. In the middle of the posts the opening is less than 4inches, however, the wire can be stretched to allow a 4inch sphere to pass through. My question is do you know how to test this to see if it complies with code or not? Are there other code sections in regard to this other then the one below1607.7.1.2 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.

Sorry for being late to the party;

Joe, I will first say if you have read the other 2 previous threads you will have a good idea were the myth and truth start and stop.

However I will add the following brief notations, as if I could ever be brief with additional notes:

1. First off ask for information on the cable fasteners and or system manufactures specifications fittings. In other words the cable fitting manufacture, if they are any good they publish base specifications. Feeney & Ultra-Tec both publish guidelines for distance between cables, distance between verticals supports & tension on the cables. Others do also, but they are the 2 main manufactures in the USA.
   
2. If they purchased and installed a complete product, meaning a mass produced guard frame with cable infill, Feeney Architetural is one manufacture, then that cut sheet should be good IMO as it will give you all that information also.
   
3. Then look to see if they have a tensioning plan, I always tell inspectors, ask the installers in a curious way, Hum whats the process you used for tensioning the cables. If they can spell it out and don't look dumb founded by the question, its a good sign. My main installer has it down in his sleep all by feel. I had a town we did 3 installations, the inspector wanted us to show tension with a gauge, over 70 spot checks at 3 different locations we didn't miss a one, needless to say he got off our back.
   

So with that said, before you go in to having a test done, have them produce the fitting manufactures documentation for centerline spacing between holes, max distance between verticals and also max distance on a single run, length of cable. If the produce falls in to those specifications, then question them on how they tensioned the cables, per fitting manufactures specs.

If all that falls in to place and they produced sealed drawings and the installation matches the drawings, I am not sure more is needed.

Now with that said, Pretty much every commercial cable installation our firm has done is based on using 3/16" diameter cable, set at a maximum of 3-3/8" on center with a maximum of 46" between vertical stablizers. We also tension are cables for commercial to about 400lbs, why because when we do the ASTM E935 cone test for spreading of infill (Not in the code), these specifications passed during physical testing. Both Feeney & Ultra-Tec have specifcations based on meeting 125lbs pulling on a 1sqft panel and then checking for 4" sphere. So those specs also work well to their published tensions and spacing. Ultra-Tec also publishes an engineers paper which uses the 50lbs on a 1 sqft area and figures the percentage of a 4" flat circle and comes up with about 12.75 lbs of force, however I am not a big fan of this because 4" flat circle is not the same as the edge of a sphere.

However, check those specs by the fitting manufactures, because 1/8" diameter cable and 3/16" diameter cable both have different parameters and most publish the 1/8" spec for all cables, and yes the stronger cables can go a little bigger.

Also note when reading the specifications which braid of cable they are installing. A 1x19 braid is much stiffer than 7x7 braid and hence you need to look at that also.

Also if they can't produce a fitting manufactures spec, I would ask for how they came up with the spacing and tension they are doing and who engineered it?

Here are a few links for additional

http://www.artisticrail.com/CableRailings.htm Here are a few examples we did, if you then navigate to the glass railings and scroll down to picture GR-12 you will see a job we did at a Staples were my men are running cables on the stairs.

http://thecableconnection.com/metal-framed-railings.html Here is Ultra-tecs page on their installation parameters

http://www.feeneyinc.com/Technical-Documents#CableRail Here is the link to Feeney's documentation.

Now with all that said, you are able with the proper framework and tension to go a little larger and wider, but if not per manufacture spec, then get an engineers complete drawing set, not only base design but every piece listed on drawings and have them list tension on cables also.

I hope this helps - but in short, there is no force applied to the sphere in the IBC, the sphere is only for size without force.

Tom

 

[fatboy]

Awesome reply Tom, thanks...........

 

[joetheinspector]

Thanks to everyone who replied. The old threads were very helpful. I now know "a thing or two about a thing or two."

tbz a lot of good info (a lot more then 2 cents worth).

They are unable to provide manufacturers installation instructions. Very limited info.

 

[tbz]

Thanks to everyone who replied. The old threads were very helpful. I now know "a thing or two about a thing or two."tbz a lot of good info (a lot more then 2 cents worth).

They are unable to provide manufacturers installation instructions. Very limited info.

If the manufacture can't supply these basic items, then my fist question is, how were they designed and speced by the architect and more important engineer of record?

So your options are this, IMO, if you have nothing to verify if correctly built and unsure, did they provide a complete set of drawings that are signed by a Lic. Engineer? If they did then you can compare size of materials, mountings, connectors and wire sizes? I would then ask them to produce from the engineer a tension parameter to meet the 50lb infill requirement and proof that it meets this requirement.

You have a simple reason and I would note not unreasonable. The major cable fitting manufactures publish the information that I am asking for that you can't produce, therefore since your currently installed product does not meet readily published industry standards and you can't produce your manufactures specifications, therefore I need this information spelled out on sealed drawings and I need proof that the infill complies load wise with what the code requires, therefore drawings and documentation of a cable tension level and that the cables are tensioned to those requirements.

If the guard is properly designed and manufactured to meet the code, these are not hard things to provide, nor unreasonable for you to request.

You are not asking them to replace anything (possible yet), you are just requiring proper confirmation that the product in place conforms to the requirements and this additional information because the product is not fabricated and installed per readily published industry standards.

I don't see the issue they should have unless the Architect just drew what they wanted and then a fabricator just built it without confirming compliance with an engineer's review.

Tom

 

[mark handler]

Cable Rail, one of the cable manufacturers recommends 3" maximum, Due to deflection. So the 3 3/4 would not even meet the manufacturers recommendations

Without the brain damage of calcs

 

[tbz]

Cable Rail, one of the cable manufacturers recommends 3" maximum, Due to deflection. So the 3 3/4 would not even meet the manufacturers recommendationsWithout the brain damage of calcs

Mark,

The 3" spacing has many parameters that affect it that the OP did not provide, thus a blanket statement of the 3" is not correct IMO, but valid, if they are using 1/4" or 3/8" cables then the 3-3/4" has stance based on the tension. However these sizes and the weave pattern are not mentioned.

Also if the distance between vertical stabilizers is closer you would be fine however, the OP posted multiple parameters over the most common base limits, but failing it just for being over 3" is incorrect IMO, failing it based on providing documentation proving it complies with the code because of documented industry design standards are exceeded in more than one portion of the design.

Because of this, we need documented proof the design does comply and it does here is the paperwork.

 

[mark handler]

Mark,The 3" spacing has many parameters that affect it that the OP did not provide, thus a blanket statement of the 3" is not correct IMO, but valid, if they are using 1/4" or 3/8" cables then the 3-3/4" has stance based on the tension. However these sizes and the weave pattern are not mentioned.

Also if the distance between vertical stabilizers is closer you would be fine however, the OP posted multiple parameters over the most common base limits, but failing it just for being over 3" is incorrect IMO, failing it based on providing documentation proving it complies with the code because of documented industry design standards are exceeded in more than one portion of the design.

Because of this, we need documented proof the design does comply and it does here is the paperwork.

Incorrect?

The Cable Rail website, one of the cable manufacturers, recommends 3" maximum, That is a Manufacture's recommendation.

Where is your "here is the paperwork."

Can the cables be spaced farther apart than 3 inches?

No, we strongly advise against exceeding a 3-inch spacing. The International Building Code states that a 4" sphere cannot pass through any opening in your railing, and since cable is non-rigid, the flex of the cable must be taken into account. Therefore, we recommend spacing the cables no more than 3 inches apart and the posts or vertical members (intermediate pickets) no more than 3 feet apart in order allow for possible cable deflection and meet the intent of the code.

http://www.feeneyinc.com/FAQ

Cable Railing Spacing

Our standard cable spacing is 3" on-center running the length of each post.

http://www.atlantisrail.com/cable-railing-how-to

Cable spacing should be targeted at 3” to meet the 4” sphere rule

http://www.cablerailings.com/technical-cable-information.html

 

[tbz]

Mark,

You are only reading what you want and not looking at the post.

The OP was looking for how to verify if the designed met code, not looking for a reason to fail it.

Anyone can pull one point and toss up a red sticker.

My note to your 3" spacing is that there are many cable manufactures that note within their paperwork for certain cable sizes that 3-3/8" and even 3-3/4" is allowed. They are however for larger cable sizes and shorter vertical spacing. And since the OP did not post cable size or weave I was covering all.

My point with saying you are wrong, is that you are saying fail it because of this! That is wrong because it is not his question, they already figured out that.

I am saying, that is not a good response nor do I recommend it, it's simple there are more than just 1 industry standard that the installation does not meet.

Thus as an inspector taking in the whole view and putting it down on paper saying, I see a lot of items here that don't follow common industry standards, for this reason I am not passing the installation until you can produce the documentation showing compliance in its currently installed design.

The fact that the hardware manufacture does not have documentation will put a lot of strain on the engineer because the infill needs to meet loads, so the engineer now needs to produce a tension requirement and verify the hardware will hold it in place.

It's not about failing it, its about explaining to the OP what to look for besides just 3".

So I will say it again, the 3" spacing note by you was not correct for the OP question.