Flexible Steel Cable Balusters

[Nick Ostrowski]

I saw a new construction home yesterday that had these steel cables as balusters on handrails and railings. As you can see in one of the pics, they are easily manipulated with pressure and their openings will exceed 4 3/8". The builder said the cables will be tightened but I have a hard believing the turnbuckles used on this railing system will be able to get these cables so tight that they will not move. Is there any code verbiage that applies to the rigidity of spindles/balusters/guardrails?

There was also an exterior stairwell in the basement that only had 5'6" of head clearance from the step directly beneath the stone lintel. I whacked my head good on that sucker.

[John Arnold]

...The builder said the cables will be tightened but I have a hard believing the turnbuckles used on this railing system will be able to get these cables so tight that they will not move...

I agree.
Plus, even though it might not be in the code, I would note that the cables, being "horizontal", can be climbed.
Here's a nice scenario: Tot #1 puts his weight on a cable doing his jungle gym routine, deflecting the cable enough that Tot #2 puts his head through, then Tot #1 gets off. Ouch.

[Nick Ostrowski]

The buyer said he and his wife are planning on having kids and I mentioned all those types of things to him (ladder effect, heads stuck in between cables). He said the railing system with all the areas it is being installed in the house is running $6,000.00 Yow!

[Ted Williams]

Let's hope the kids don't become pro-wrestling fans.

[Jerry Peck]

Those are not prohibited, nor are they allowed ... sort of not allowed. :)

The guard in-fill panel needs to be able to withstand a 50 pound per square foot load, and those will not.

The catch is that the test for guard in-fill panels was designed before any idiot thought wires would be neat to have. :(

The test for the guard in-fill panel is performed with the guard laying down horizontally, a specified weight, shaped as specified, is dropped onto the in-fill panel, the weight is removed, the guard is checked to see if it still rejects the 4" sphere. A rigid guard will deform under the test weight, and stay deformed for the measurement.

Wire in-fill guards will deform and allow the weight to drip right on through, and, of course, also allow the weight to be pulled back out, upon which the wires return to their original position.

In testing guard wire in-fill panels, I use a 4" sphere (actually a 4" circle so as to not "cheat" and allow the spherical shape spread the wires apart) and push on that 4" circle - the wires will deform and the 4" circle will go through long before you reach 50 pounds of force. (I used to use the sphere and push it, but some people said I was "cheating" as the shape of the sphere would easily separate the wires - yeah, I responded, just like the spherical head would do which the guard in trying to reject).

You can't fix stupid, so using a flat circle eliminates that argument.

The 50 pounds comes from here:
- TABLE R301.5
- Guardrails in–fill component sf - 50i

- f. Guard in-fill components (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds on an area equal to 1 square foot. This load need not be assumed to act concurrently with any other live load requirement.
- i. Glazing used in handrail assemblies and guards shall be designed with a safety factor of 4. The safety factor shall be applied to each of the concentrated loads applied to the top of the rail, and to the load on the in-fill components. These loads shall be determined independent of one another, and loads are assumed not to occur with any other live load.

If someone want to push the "50 pounds sf" versus the 4" circle size, I will argue that we can go back to using the sphere which represents real-life conditions - they will lose the practical and emotional argument every time when a client or buyer is there, even though they will win the technical "per sf" load argument. The client or buyer will understand that a falling head is like a sphere and will spread the wires out.

[John Kogel]

They could screw plexiglass panel over the openings and keep the designer look.
To any kid, it will look like a jungle gym built just for them. Looks stupid to me. :confused:

[Garry Sorrells]

Jerry,
The sphere vs circle argument boils down to contact surface area. The tangent of the sphere and the circle are the same (ok not exactly depending on the thickness of the circle).

These cable systems are designer (appearance) great but safety speaking bad.
When installed the contractor need to have the customer sign off on all future responsibility for their installation (speaking form experience). If the customer wants them they need to take on the problems, despite that coded allows them.

Informing a client of potential hazards is one of the reasons that the inspection is done.

You can not realistically tension the cables to the level that would prevent potential entrapment.
Forget about the climbing issue.

[Garry Sorrells]

They could screw plexiglass panel over the openings and keep the designer look.
To any kid, it will look like a jungle gym built just for them. Looks stupid to me. :confused:

If they were going to go that rout then just install the plexi panels and not the cables. Neither are inexpensive. But that is not the look that they wanted.

[Rick Vernon]

Michigan allows this type:

Michigan Codes-Online Builder Video Training Series (http://www.michigancodes.com/m11_rele.html)

[Nick Ostrowski]

They could screw plexiglass panel over the openings and keep the designer look.
To any kid, it will look like a jungle gym built just for them. Looks stupid to me. :confused:

I mentioned that as an option John. I know the buyer doesn't like the railings and he said his wife really doesn't like them. It doesn't sound like the builder really gave them any other options.

[Jerry Peck]

The sphere vs circle argument boils down to contact surface area.

Not just the surface area, but the shape of the surface too.


When installed the contractor need to have the customer sign off on all future responsibility for their installation (speaking form experience). If the customer wants them they need to take on the problems, despite that coded allows them.

Even then, the potential is there for the owner at that time to become a seller in the future and their buyer will not have 'signed off on' that safety hazard, and the contractor's responsibilities does not end with the owner who hired them, the contractor's responsibilities continue for as long as that work exists, even though state law may deem a shorter time exists (i.e., a jury knows no bounds when a contractor does something which leads to the death of a child).

[Bob Boepple]

Add a fence charger.....That will keep the kids off!! ;)

[gene schafer]

I don't like them but they are allowed as long as spacing is correct. I have seen building inspectors pass them if they meet code. Remember building departments only look for code violations, not cosmetics.

[Garry Sorrells]

Gene,
There in lies the problem. If the cable system is installed to manufactures spec. they meet code.

The problem is with the code.

Jerry,
Having the owner sign off on the potential safety issues that are adherent in the cable system, just helps the installer in the liability arena. If the owner is made aware that there are potential safety issues the owner can not come back later and claim ignorance because the installer did not provide warnings.

Just like having the warning label on a lawn mower not to put your fingers under it when it is running.

[erika krieger]

Most cable railing manufacturers recommend no more than 3" vertical spacing to insure compliance with the 4" sphere test. In addition, post spacing, cable diameter, cable tension, and top rail strength all affect cable flexibility.

[Door Guy]

Aren't horizontal railings allowed per IRC? If the cables are tight enough to resist the 4" sphere than it meets code also. The suggestion of 3" spacing makes sense on the flex of the cables being limited to code compliance. I'm not saying horizontal or cables are the way to go... but if it's what meets code what else can we do?

[Jerry Peck]

Aren't horizontal railings allowed per IRC?

Yes, they are allowed because they are not disallowed.


If the cables are tight enough to resist the 4" sphere than it meets code also.

... but if it's what meets code what else can we do?

However, one must be careful how they define and use "meets code".

If the horizontal wires are 4" apart on center, then they meet the 4" spacing ... except that it does not state '4" spacing' it states that it must not allow the passage of a 4" sphere, and it also states that the in-fill must resist a load of 50 pounds psf, therefore the horizontal wires must resist a the 4" sphere at 50 psf to "meet code".

The horizontal wires would need to be extremely taut to resist movement at even half the required load, but, yes, if the horizontal wires were strung as taut as piano strings, then, yeah, they might meet code ... but I would not want to be near one when it lets go and breaks or comes loose - that would create its own safety hazard to be considered.

[Door Guy]

Yes, they are allowed because they are not disallowed.



However, one must be careful how they define and use "meets code".

If the horizontal wires are 4" apart on center, then they meet the 4" spacing ... except that it does not state '4" spacing' it states that it must not allow the passage of a 4" sphere, and it also states that the in-fill must resist a load of 50 pounds psf, therefore the horizontal wires must resist a the 4" sphere at 50 psf to "meet code".

The horizontal wires would need to be extremely taut to resist movement at even half the required load, but, yes, if the horizontal wires were strung as taut as piano strings, then, yeah, they might meet code ... but I would not want to be near one when it lets go and breaks or comes loose - that would create its own safety hazard to be considered.

Agreed completely and fully!

[erika krieger]

Aren't horizontal railings allowed per IRC? If the cables are tight enough to resist the 4" sphere than it meets code also. The suggestion of 3" spacing makes sense on the flex of the cables being limited to code compliance. I'm not saying horizontal or cables are the way to go... but if it's what meets code what else can we do?

Yes, the code allows the horizontals; the "ladder effect" prohibition was in the 2000 IRC, but deleted in either the '01 or '02 supplement. So we code officials are back to just making sure that the 4" sphere can't pass through the guard, and the top rail can't be pulled lower than 34". It takes a combination of cable spacing, cable gauge, tension, post spacing, top rail strength, etc. to achieve this.

[Rick Hurst]

Add a fence charger.....That will keep the kids off!! ;)

Now there is the best idea....:D

[Michael Thomas]

See my response here: climbable element on railing - Home Inspection & Home Inspector Services For Inspections and Inspectors (http://www.inspectionnews.com/ubb/Forum6/HTML/000554.html)

[gary carroll]

Assuming the cables are stainless, 1/8 inch, and 12 feet long, you would not be able to tension them enough to prevent spreading based on tension alone. It only takes a few ounces of pressure to deflect a wire with 1,000 pounds of tension on it, and the breaking strength of such a cable (depending on alloy and many other factors) is probably less than 2500 pounds total. I see eight or nine cables. If they were all tensioned to 1000 pounds imagine the load on the end post.:eek:
Now consider this: the tension on the cable rises much faster than the lateral load on the tensioned cable. The lateral move at the center translates to a smaller movement at the end, and this is the mechanical advantage. You would tension the cables to break before being able to prevent deflection by hand, except the end posts would be ripped up long before that happened.

The way to eliminate the deflection is not via more tension, but by shortening the section of the cable that can deflect by intermediate posts.
You can do this most effectively by clamping the cable as it passes through each vertical post, making the effective length of the cable section the distance between posts rather than the distance from one end of the cable to the other end.

It’s still a questionable design from a practicality standpoint – I know I would climb on it if I was a kid, it is expensive, and needs to be really, really stout to work at all.

[Mike Pagozalski]

Well one way to pass an inspection for a CO is to zip tie chicken wire it:D because it is pretty much impossible to tighten the cables to the point where it won't move even an 1/2 inch without tearing out the fasteners or bending the posts...........looks cool but not the best idea