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Walking surface ends and guard begins

tbz

tbz

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Joined
Sep 10, 2010
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PA/NJ - Borderlands
Good morning to all on this snowy Monday morning.

This question comes to me at least 3 times a week and I seem to be getting more and more and well would like others opinions on this.

As an inspector weather IBC or IRC, how do you define the end of the walking surface to where a guard begins as compliant?

More and more architects are designing guards to hang off the side of the walking surface. This brings up the following questions

1. Is the floor space allowed to stop before the protection of a guard begins?

2. If so how do you measure for this, 4" sphere between bottom of guard and floor, thus allowing 3.875" of open floor when the bottom of the guard is level with the floor surface?

3. How would you handle second floor roof deck, 3" gutter then guard begins?

4. Do you figure this different for level walking surfaces like decks than for stairways?

I am trying to establish a common agreement for in the field, this seems to greatly vary from town to town and state to state, all input is welcomed and so to additional questions if you don't follow my badly worded question.

Thanks - Tom
 
ok, 58 views 1 reply lets try a sketch or two.

The 3 sketches below comply (yes/no) if no why not?

deckedge.jpg


Rick, lets follow your note why only accessible and if not required accessible how big an opening allowed in floor or at edge?
 
a required is a required guard whether its the open side of a stair or deck. Whatever it's hanging off of needs to be able to support it (the outside of a gutter?). It doesn't matter what dimension you use - it needs to prevent passage of a 4" solid sphere.
 
So peach the open space in the floor between the edge of the floor and the guard is allowed, as long as, it does not allow passage of a 4" sphere to fall through and down?

It also does not matter if it is on a stair, ramp or walking surface?
 
The purpose of guardrail is to prevent walking into an area where vertical fall can occur. I believe that code is that the guardrail gap (the vertical plane) must be less than 4", and the tread / walking surface must be not exceed 1/2" gap.

Therefore, going counterclockwise in the sketches:

Lower left: no, because the 1" gap in the walking surface is greater than 1/2". High heel could theoretically get caught here. (Could've been fixed just by bringing out the drip flashing another 1/2".)

Lower right: no, because the 3 3/4" gap in the walking surface is greater than 1/2". A narrow foot could fall through.

Upper right: no, because even though an adult may be kept within the walking surface area, a little kid reaching up to grab onto the rail may step underneath the overhanging handrail above, and thus is exposed to the 3 1/2" gap in the walking surface (which is greater than 1/2").

I realize this is different than my opinion of a week ago in a different thread.

IMO it does not matter if it is a stair, ramp or walking surface.
 
Yikes nailed it. 'NUFF SAID.

The architects that come up with this goofy stuff need fixin'. Nowhere in any Code does it give permission to provide openings in a horizontal walking surface that exceeds 1/2" and that would ONLY be in industrial or storage type occupancies on stairs and grated landings and catwalks where no children would typically be present.
 
Sorry to (maybe) beat a dead horse but isn't the 1/2" maximum opening in floor surfaces an element of accessibility and promulgated by the ADA (codified by the acceptance of ANSI A-117 in the IBC) - implied by Rick? If so, then any area not required to be accessible (such as a balcony on a story which is less than 3000 sf) would not be governed by this and, therefore, the 4" sphere guard requirement would apply (as Peach indicates). What the question really gets to is the idea of edge protection - which is only dealt with in the ADA in respect to ramps (and recreational facilities). If the example were an accessible fishing pier, the answer would be simple (ADA-AG 1005.3). To play Devil's advocate, in the absence of threat of a wheelchair wheel or crutch slipping off the side of this balcony/deck/whatever (i.e. a space not required to be accessible), I don't think anyone could argue that a series of vertical balusters complying with the 4" sphere limitation, attached to the fascia of the deck (without a lower horizontal rail), and extending up to create a guard would be contrary to the code. This would then create an equally dangerous series of openings that childrens' feet could easily slip through. That said... It seems that the spirit of Yikes' and RLM's posts are correct - the danger of slipping vertically is certainly there.

I agree that the design generates a very significant liability concern for the design professional, but I'm not sure that any of the diagrams above are expressly prohibited by the code (assuming no requirement for accessibility to the location).

Hope that made some sense...and please correct me if I'm looking at this all wrong.

My first post, ever!
 
Ok,

RLM not enough said need to go a little deeper.

JEH, welcome to the board and your input is welcomed and a reason for my question in the first place.

Yikes,

I agree with all your statements, the floor needs to be protected from someone walking off the edge when over 30" above the landing area below.

However, as you can see many would allow the opening only restricted by the 4" sphere.

This also comes up a lot with me on IRC, exterior small balconies with large openings over 1/2", the code requires there be a landing, yet the inspectors don't require the landing to meet the 1/2" sphere, thus I ask why not?

With, all the views and I know this crowd has some opinions, please chime in on your view, I am not looking to hold anyone to a certain point, just trying to get more input and discussion on this IMPORTANT field issue.

Please comment....
 
JEH, welcome!

1. I believe the 4" sphere comment is for guards, which are designed to resist a horizontal motion, not a vertical fall. That's why in IBC 1607.7.1.2 the 50 lb. load is applied horizontally, not vertically. Anyone weighing over 100 pounds would put more than 50 lbs of vertical force on a walking surface, thus invalidating the guard engineering.

2. The example you gave about the story under 3000 Sf does not exempt the balcony from all accessibility features. It only exempts it from requiring a (wheelchair-acessible) path of travel from the public right of way (ramp, elevator, lift, teleporter, etc.). A person who uses a cane or other mobility device may still use the stair. In fact, they me more likely to walk very close to the handrail.

3. In last week's thread titled "Walking surface", fatboy quoted IBC 1009.6.1 for stairways. I realize this does not apply to balconies, but there you have a code rationale that is based on life safety, not accessibility.

Most people would agree that a 3 7/8" spacing of bars on a balcony walking surface would not be acceptable. At some point as the surface plane in question is rotated / becomes more vertical, it becomes more reasonable, until finally all would agree it meets code as a vertical guardrail.

I agree that it is unlikely that a person would fall through the example in the lower left corner of tbz's sketch, but all I'm saying is that it goes beyond the prescriptive requirements of the code. Why take the chance? You could easily retrofit a fix to that scenario.

P.S. Enjoy the following photo link.

http://cache2.asset-cache.net/xc/79572137.jpg?v=1&c=IWSAsset&k=2&d=D4DA32DF5F8999C330F60B823F3BA1B67CEE58882EDCF475C632E1CB0AEE4941E30A760B0D811297
 
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Yes, Section 1009.6.1 is for stairways and should be limited to stairways because that's what the code says. I'm not sure how you could make that apply to the most outer edge of a deck. That's like applying the stairway handrail requirement to the deck guardrail.

I would not agree that the edge of the deck would be a vertical guardrail, it's simply the edge of the deck.

I am not disagreeing that Tom's examples are the ideal way of constructing a guardrail, but I do think someone needs to clearly identify a code section that regulates the specific scenario.
 
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.

This section does not allow an opening in the floor surface it allows the opening in the guard.

Agree with Yikes non of the examples are code compliant
 
Yikes said:
JEH, welcome!1. I believe the 4" sphere comment is for guards, which are designed to resist a horizontal motion, not a vertical fall. That's why in IBC 1607.7.1.2 the 50 lb. load is applied horizontally, not vertically. Anyone weighing over 100 pounds would put more than 50 lbs of vertical force on a walking surface, thus invalidating the guard engineering.

2. The example you gave about the story under 3000 Sf does not exempt the balcony from all accessibility features. It only exempts it from requiring a (wheelchair-acessible) path of travel from the public right of way (ramp, elevator, lift, teleporter, etc.). A person who uses a cane or other mobility device may still use the stair. In fact, they me more likely to walk very close to the handrail.

3. In last week's thread titled "Walking surface", fatboy quoted IBC 1009.6.1 for stairways. I realize this does not apply to balconies, but there you have a code rationale that is based on life safety, not accessibility.

Most people would agree that a 3 7/8" spacing of bars on a balcony walking surface would not be acceptable. At some point as the surface plane in question is rotated / becomes more vertical, it becomes more reasonable, until finally all would agree it meets code as a vertical guardrail.

I agree that it is unlikely that a person would fall through the example in the lower left corner of tbz's sketch, but all I'm saying is that it goes beyond the prescriptive requirements of the code. Why take the chance? You could easily retrofit a fix to that scenario.

P.S. Enjoy the following photo link.

http://cache2.asset-cache.net/xc/79572137.jpg?v=1&c=IWSAsset&k=2&d=D4DA32DF5F8999C330F60B823F3BA1B67CEE58882EDCF475C632E1CB0AEE4941E30A760B0D811297
Click to expand...
Yes, Section 1009.6.1 is for stairways and should be limited to stairways because that's what the code says. I'm not sure how you could make that apply to the most outer edge of a deck. That's like applying the stairway handrail requirement to the deck guardrail.

I would not agree that the edge of the deck would be a vertical guardrail, it's simply the edge of the deck.

I am not disagreeing with you and saying that Tom's examples are the ideal way of constructing a guardrail, but I do think someone needs to clearly identify a code section that regulates the specific scenario.
 
Thanks high desert. I did not mean to imply that the edge of the deck would actually be a vertical guardrail. Instead, I was playing a hypothetical mental game wherein a flat surfaced walking deck with gaps in it is bent upwards (like in the movie Inception) until we start thinking of it more like a guardrail instead.
 
IBC 1604.2 Strength. Buildings and other structures, and parts thereof, shall be designed and contructed to support safely the factored loads..........

If there is nothing there, then there is no support of the required loads for a floor.
 
The balcony has a floor and the floor is the walking surface until it is guarded. The rail is the guard and the toe space / edge protection is in the vertical plane not the horziontal plane. The 4" sphere rule is the vertical plane not the horizontal plane. The detail is in error by leaving a gap in the horizontal plane.
 
Examiner said:
The balcony has a floor and the floor is the walking surface until it is guarded. The rail is the guard and the toe space / edge protection is in the vertical plane not the horziontal plane. The 4" sphere rule is the vertical plane not the horizontal plane. The detail is in error by leaving a gap in the horizontal plane.
Click to expand...
Examiner the details are of projects drawn by architects all the time, my question is is the horizontal space compliant or not and if not explain why not and the same if you say it is compliant.

I believe that the floor opening is non compliant because floors are not allowed to have 3 in holes in them I think, but can't back it up with a code section.
 
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Yikes - i appreciate the morphing walking surface/guard - that's a great mental image...

Ignoring issues of accessible routes, the purpose of the guard, it seems to me based on the code commentary, is to prevent the building occupant from falling through the guard to the level below, avoiding serious injury. So the length of the fall is important, otherwise, all edges of walking surfaces would require a guard, not just where the grade or floor is > 30" below. In occupancies where kids are likely to be, the 4" sphere is what has been deemed appropriate to prevent them from falling completely through the balusters. Because there is no specific requirement for edge protection for a guard (only for ramps), it seems reasonable that as long as the guard prevents the occupant from falling completely through and to whatever hard surface is below, it has done its code (minimum) mandated job... Examiner, while I agree that it's a problematic detail at best, I can't see where the letter of the code defines the 4" sphere rule specifically / solely in the vertical plane. Tom, the edge of the balcony seems like it is the edge of the balcony, so there's not really a 3" hole in the floor... the guard, to me, is it's own separate thing but I don't have a code section to back that opinion up - see below, though.

The example Yikes posed is really interesting. The code does not mandate a guard to be 90 degrees from the adjacent walking surface. So if we imagine vertical balusters rising from the horizontal edge of the balcony angled at 60 degrees (or so) from horizontal and complying with the 4" sphere rule, an occupant could easily step through the gap between the rails. They would be prevented from completely falling through to the level below, though, due to the 4" space - but this is more or less the same thing that would happen with a purely vertical guard as well as in Tom's diagrams. In other words, it's bad and liability ridden design - but code compliant. (of course, that's also just my opinion)... Thoughts?
 
You know what's really great? I you try to Google "openings in walking surfaces" to find out what the rest of the world thinks on this subject, the first result takes you right back to this forum.
 
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9715

OSHA toe board or toe guard.

The edge protection is to prohibit items from rolling under the guard's bottom rail which might injure someone below. The Code has the 4" sphere rule that would be between the horizontal bar of the guardrail's bottom bar vertically above the floor surface. ADA and the building Code both address the floor openings such as grate openings being limited to 1/2". If the gap between the guardrail and edge is more than a 1/2" in the horizontal plane then a walking cane or high heel would go through. All graphics in the ADA and Code show the guardrail is directly above the walk surface and not beyond the edge of the walk surface. In my opinion OSHA would cite the edge detail as a violation. Professionals are also to keep in mind requirements of OSHA in their designs.
 
Thanks, Examiner - really good info on OSHA and one that I didn't even consider. I completely agree that design professionals need to be cognizant of all of the various requirements that are out there and especially with the concern for disabled employees... Maybe edge protection should be more widely incorporated in the ADA and IBC beyond ramps. The graphical representations of guards in the IBC and ADA are generalizations and can't be assumed to be the only permissible solution. The (IBC) Code never states that the guard must be in any relationship to the edge of the floor, only that a 4" sphere can't pass through it. That said, the arguement I would make for having to allow the detail is three-fold:

I would argue that the detail does not show a 3-1/2" opening in a floor surface, but rather that it is a gap between an edge of a floor surface and a guard (the IBC allows unguarded vertical changes in elevations, and specifically denotes them "open sided walking surfaces" of up to 30") - in other words, the guard is not part of the floor.

Applying this to an occupancy where Labor regulations are applicable, based on OSHA 1910, I'd call the edge of the balcony an "open sided floor" rather than a "floor hole", and governed by (1019.23©). Let's assume a balcony off of a lawyer's office - not a typical industrial plant, but certainly a place with employees and, one could easily argue, regulated by OSHA as well as the IBC. Take Tom's 1st sketch. There is a 3-1/2" opening between the end of the open sided floor and the beginning of the guard (as OSHA defines, railing, or as the IBC defines, guard). Clearly this does not allow persons to fall through, lawyers don't possess any moving machinery, and there is no equipment nearby - therefore, no toeboard required (per 1910.23©1:i,ii, & iii). But even if the lawyers had some moving machinery close by, the only additional element to make Tom's first sketch compliant with OSHA would be a 4" toeboard at the edge of the balcony. There could still be a vertical gap between the toeboard and intermediate rail of about 17" (21" from floor to the intermediate rail minus 4" of toeboard) - which is a pretty big hole for someone to fall through - much larger than the 3-1/2" horizontal gap in Tom's sketch. However, if we're using OSHA, there is no 4" sphere rule (correct?) but this would violate the IBC - so if we're being especially stringent the maximum distance between the toeboard and the guard would be <4" - just like the sketch. An aside, the OSHA regulation does not include any language as to elucidate the location of the rail as related to the edge of the open sided floor - it is much less clear than the IBC. But its job is the same as defined: "...to prevent falls of persons".

If the condition were proposed in a single family residence, edge protection (and OSHA) wouldn't apply. It's back to whether the Code allows, where a guard is otherwise required, any gap such that a 4" diameter sphere can pass through any opening... The detail does not allow the passage of the sphere, and therefore complies.

I really hate to argue (at length) for something that I think is especially poor design, but I just can't agree that the Code forbids this detail. I'll just have to respectfully disagree with those who respectfully disagree with me, and leave it at that!!
 
I agree with jeharrarch. To call it a hole in the floor that exceeds 1/2" is a streach.

I've seen this before. As a matter of fact, it was at a local vocational school that I finaled. My daughter started attending there, and she told me about how the chair leg that was at some tables near this guard at a second floor seating area would go off the edge and get caught in the guard. I made a site visit and concluded that, yes, it may be a bad design, but there is no specific code section that can be used to prohibit it.

If this was a floor area (using the max 1/2" opening arguement), and you installed a 4" "curb" then one could argue that you cannot have a 4" curb in a floor area (I supppose it would need to be max 1/2" high with 2/1 slope like a threshold. Obviously not). The whole floor area arguement is flawed, IMHO.
 
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tbz said:
Examiner the details are of projects drawn by architects all the time, my question is is the horizontal space compliant or not and if not explain why not and the same if you say it is compliant.I believe that the floor opening is non compliant because floors are not allowed to have 3 in holes in them I think, but can't back it up with a code section.
Click to expand...
That's just the point. There is no code section to cite for noncompliance. It's not a hole in the floor, but a compliant gap at the bottom of the guardrail.
 
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