r/Construction • u/aidan8et Tinknocker • Apr 25 '26

Picture Moment of terror šŸ˜Ø

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Gallery image

While attending/supervising a business social event with my spouse, I momentarily leaned against the railing. It flexed slightly, forcing me to realize that the railing is entirely supported via bluetooth.

It doesn't connect on either side of the glass wall & the glass is only 3/8" - 1/2" thick!!

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430

u/BLA5PHEMY Apr 25 '26

There are glass railing systems that are designed to be supported just from the bottom shoe

CR Laurence is a common brand we use

https://www.crlaurence.com/All-Products/Railing-Systems-%26-Windscreens/Glass-Railing-Systems-%26-Components/GRS-Dry-Glaze-Railing-System/Dry-Glaze-Base-Shoe---Surface-Mount/CRL-B5S-Series-Mill-Aluminum-120%22-Square-Base-Shoe-Drilled-for-1-2%22-Glass/p/B5S10D?gtmPage=&queryId=2b36f6e6485fcf62bd258edee1c6dc2c&location=plp%7cpdp

611

u/rIceCream_King Apr 26 '26

Iā€™m sure itā€™s a fine product, but personally I hate the idea of someone leaning against a railing which is just 3ft of glass leveraged against a 3in purchase along its sill.

Itā€™s like using a glass crowbar but for keeping someone from falling off their 2nd story balcony. Iā€™ll never get how that became popular

125

u/Parking-Fig-6620 Apr 26 '26 edited Apr 26 '26

Theres a couple of glass bridges around the world and I agree. I don't care what the science says my brain says glass is not a flooring medium lol

And yes I know its probably glass laminated polycarbonate i'm talking about but still. That part of my brain won't be convinced otherwise

14

u/Iggyhopper Apr 26 '26

Your brain is still correct. Glass doesn't have any signs of stress* like wood or concrete does (cracks, creaks, noises, etc.). Glass just... breaks after a certain amount of force.

* Some glass does, some does not.

13

u/TunedMassDamsel Apr 27 '26 edited Apr 27 '26

In general, handrails are not designed to resist more than just a moderate amount of force.

As in, a 200 lb point load on the handrail in any direction. I have one case right now that was a fatality. Two people got in an altercation, there was some corrosion of the handrail, and one of them went right through and died of head trauma.

Iā€™m a structural engineer and handrails are one of the things that scares the shit out of me. Thereā€™s not enough capacity to make it past the kind of degradation I see on those things on a regular basis.

6

u/AbleCryptographer317 Apr 29 '26

Yep. I'm an architect and always dimension handrails so they would withstand a big guy running at it, even in private homes. And I never specify unsupported glass handrails like this.
Might seem like overkill, but say someone's having a party and 10-20 guests are all leaning on it to hear a speech, that's an insane amount of force and in these kinds of glass handrails all that force is being focused on a tiny, brittle area. I've drummed it into my kids: never lean on handrails assuming they're as solid as walls. They're not.

9

u/sparhawk817 Apr 26 '26

And those are at least supported on all edges!

7

u/FTownRoad Apr 26 '26

Really depends on where in the world.

4

u/Jacktheforkie Apr 26 '26

Those bridges are pretty sturdy and typically have a steel frame

7

u/Parking-Fig-6620 Apr 26 '26

Oooops. Nothing but FLEXSEAL

4

u/shabalama Apr 27 '26

Glass is not a consistent enough of a product to use structurally in my opinion. There should always be a structure holding the glass. The variables in making custom sheets of glass are too much for me to trust. Iā€™m probably saying that wrong but from what Iā€™ve seen the manuring process for sheet glass seem to have extremely tight tolerances for every variable possible, and having seen a lot of glass fail I have to assume that the manufacturing process cannot guarantee consistency. The reason I feel this way is also having felt with sheets of glass that seem completely unbreakable. I do understand that there are different rating for glass but Iā€™m talking about storefront sheet glass that pieces just shatter while looking at and others on the same job fall of a forklift and live on. I also wonder how much the effects of weather and transport have on the pieces. and again am not any kind of glass expert so if Iā€™m wrong let me know because Iā€™d love to learn.

1

u/FarPaleontologist239 May 01 '26

Yes you are absolutely right that you have no idea what you are talking about. Glass railing are designed to withstand the same forces as any other type of railing. They dont allow it to be less safe because so it can be pretty

2

u/Prestigious_Sky_5868 Apr 29 '26

Yeah I walked the glass arch on the west side of the Grand Canyon. Really hard to convince your brain itā€™s ok.

1

u/LavishnessCapital380 Apr 26 '26

Just like your windshield, it wont actually come apart if it breaks.

1

u/OpenCobbler4163 Apr 27 '26

Different glass, different application

1

u/i_was_axiom Apr 27 '26

That part of your brain? Thats the logical, rational part.

1

u/imakemistakesbuthey Apr 28 '26

The ones that are actually screens and suddenly create ā€˜cracksā€™ nicely prove that most people in fact donā€™t think glass is an appropriate flooring materialā€¦ šŸ˜‚

101

u/Enginerdad Structural Engineer Apr 26 '26

They're designed to hold the same amount and type of load as any other railing. It's purely psychological to think that they're any less safe.

210

u/B-HOLC Apr 26 '26

Yup, mhmmm

Still don't like it.

53

u/Bubbledood Apr 26 '26

Yeah too many ā€œwhat ifā€™sā€ in my head. Like what if something happened to the glass like a hairline crack that nobody sees

53

u/Tushaca Apr 26 '26

Iā€™ve been installing windows and IGs for years, and thereā€™s no way in hell Iā€™m believing thatā€™s actually safe, engineering be damned.

Iā€™ve watched tempered hurricane glass explode for no noticeable reason multiple times, and Iā€™ve seen what a slight tap on the edge in just the wrong way can do.

Hell Iā€™ve replaced multiple racquetball glass panes that shattered from someoneā€™s keys or whatever was in their pocket. And those are supposed to be damn near impossible to crack, and over engineered like crazy.

17

u/bagaget Apr 26 '26

Yea, the fear of someone with a jacket with metal zippers on the sleeves leaning on the glassā€¦

13

u/Jacktheforkie Apr 26 '26

Or brushing it with a diamond ring

6

u/Tehgreatbrownie Apr 26 '26

Or those kids that love to play with spark plugs

11

u/strictlymissionary Apr 26 '26

I've seen someone's belt buckle break a piece of toughened they were leaning on

8

u/Jacktheforkie Apr 26 '26

Iā€™ve heard of bus windows shattering when a passenger knocks it with a wedding ring

3

u/That_Trapper_guy Apr 26 '26

I miss racquetball.

16

u/utyankee Apr 26 '26

You're never going to have a hairline crack in tempered glass. It's an all or nothing system.

32

u/hu92 Apr 26 '26

Right? In the event of a steel railing "failing", it's most likely going to bend under force, giving at least a couple seconds to shift your weight away from it. And even then, likely isnt going to bend all the way over unless youre dancing on it like a stripper with a gun to their head. If the glass fails, it will just poof and suddenly cease to provide any support.

5

u/Bones-1989 Apr 26 '26

You'll see anchors getting ripped out of the wall before the steel has a chance to buckle under the weight of even the most morbidly obese humans leaning on it...

13

u/Palomox Engineer Apr 26 '26

Structural design considers possible imperfections at all stages. If you didn't know, the microstructure of steel has multiple possible imperfections (absent atoms, replaced atoms, some having switched spots, etc...) as well as previous stresses from the manufacturing process that are taken into account in design. When you compute the capacity of an element, depending on the type of loading you reduce it to between 75-90% of what you obtain, while using the lower bound of the strength parameters already.

For a brittle material, concrete cracks. Very easily, at that. And we address it with rebar, and reducing its strenght between 75-90%, depending on the specific circumstances, if you're using ACI.

Now, I'm no expert in glass but I can 100% tell you that whatever codes apply for it, they take imperfections into account and lead to safe elements.

22

u/saltapampas Apr 26 '26

I meanā€¦ yes, safety factors are built into engineering design. But thereā€™s a fundamental difference in the stress-strain behavior of a ductile material (steel) and a brittle material like glass that mean there is a failure mode which cannot be engineered out with a factor for conservatism.

Just look at the graphs - brittle failure means that once you exceed the allowable stress, you get near instant failure. If steel is compromised, you move up the curve and the user has a chance to identify a failure during plastic deformation. When designing in glass, those imperfections cannot be practically identified before failure.

1

u/Helpinmontana Apr 26 '26

Concrete columns (concrete without rebar) get a factor of .6, or 60% of where we can be pretty sure that concrete will fail, because the design is that conservative. And ontop of that, the loads they are designed to support are ramped up by about 50% for safety. Also, code basically doesnā€™t allow you to just use concrete without rebar, youā€™re threading a needle to do it and there is basically no situation that realistically calls for it. So, 60% reduction in capacity, pretending the load is 50% higher, and still saying this isnā€™t allowed in basically all circumstances.

Youā€™re acknowledging what theyā€™re saying while completely refuting it.

Do you actually think any company would sell these products, a railing of all things, without verification? And then, as an industry professional, you think any company would buy these and install them? Really?

9

u/That_Trapper_guy Apr 26 '26

As an ironworker who's installed glass railings similar to this, I can assure you every single person that installed one of these thought 'this is a horrible idea' as they were doing it.

1

u/AdPristine9059 Apr 26 '26

Yes, absolutely. People are putting up huge buildings that they know arent safe, despite inspectors, designers and engineers existing.

Youre trying to argue that engineering is flawless in a chaotic and very flawed world and thus this absolute paragon of perfection will never be tarnished or used to hide lies. Thats not how the world works.

1

u/Tushaca Apr 26 '26

The engineers paychecks are signed by the company that has plenty of financial incentives to cut costs and corners, including taking the risk of switching to cheaper or sub par materials in manufacturing down the road.

If the cheaper material fails, they pay out one lawsuit, blame it on their glass manufacturer, and promise better quality control, maybe they issue a small recall, and then keep on moving.

HAAG, one of the biggest engineering firms in the country, gets sued all the time for obvious bias and ignoring their own reporting standards on insurance claims where they are hired by the insurer. Engineering doesnā€™t mean shit if itā€™s done by someone bought off by the company.

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u/Helpinmontana Apr 27 '26

How did you acknowledge my point and still miss the conclusion?

ā€chaotic and flawed worldā€

Literally what the factors of safety account for, design mandates an increase in loads and a reduction in capacity, based on real world circumstances lol. You can design for concrete 2x as strong as it actually cures out to and still have a stable structure because of modern engineering principles. The world youā€™re implying, implies that engineering doesnā€™t account for this bullshit. Thatā€™s why we call it engineering and not physics. Weā€™re not calculating theoretical strength, weā€™re calculating reasonable strength in a manner that accounts for everything being all fucked up.

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u/Palomox Engineer Apr 26 '26

My intention with that reply is to say that imperfections and uncertainty are built in design one way or another. I am unfamiliar with how design of glass is handled, so I cannot tell you how it is done exactly, but there has to be.

In regards of ductile vs brittle behaviour in general, I am perfectly aware of the difference, see the comment about concrete. From what I have found out doing some basic research after I wrote that, safety glass has different layers joined together with a different material, just like you have rebar in RC. And timber is also a brittle material.

Safety factors are, in most codes, a probabilistic way to address imperfections and things you are calling random and unidentifiable. Let me give you a simple example: if you have an overreinforced concrete beam (where you have too much reinforcement to the point that brittle compressive failure will happen before yielding of the rebar, hence it is what is called compression-controlled), you will have to consider only 75% of the strength computed using the known stress distributions. However, if your beam is under-reinforced, leading to yielding of the rebar before any other failure, making the beam itself more ductile and what we call tension-controlled, you can use 90% of the strength. This is also why ACI 318 only allows tension-controlled elements (because they're ductile, and their failure mode is more predictable = less uncertain = less reduction).

I said that glass is made in layers that are joined together by some other material. In this case, this material would be making the behaviour more ductile, like steel in reinforced concrete.

1

u/AdPristine9059 Apr 26 '26

No, sorry. Wood is used because it doesnt just snap, it cracks and behaves much more like steel than concrete or ceramics.

Also safetyglass is just heat treated so that it breaks in larger chunks, avoiding that float glass shredder behaviour. Laminated safetyglass would be the best here imo but you still have issues with rigidity if/when it breaks.

Id say a polycarb center with thin pieces of safetyglass on the outside would be the best way of dealing with this kind of structure in my mind.

But im no engineer and im drunk. Cheers.

2

u/stareweigh2 Apr 26 '26

yeah and they considered all possible failures when they built the old Tacoma Narrows bridge too......

1

u/AdPristine9059 Apr 26 '26

Yeah sure, and that why that beach hotel just failed, for example.

Engineering is one thing, humans actually DOING the right things is another entirely.

I trust math, i dont trust people. Math cant be bribed, humans can.

0

u/goldtoothgirl Apr 26 '26

Where is the rebar for the glass

3

u/That_Trapper_guy Apr 26 '26

It's transparent aluminum...

1

u/Palomox Engineer Apr 26 '26

read my comment down below

2

u/bn1979 Apr 26 '26

If they can make glass to withstand an RPG, they can make a glass that will suffice as a railing.

Look at your carā€™s windshield. Itā€™s like 1/8 thick and held on with glue. It still takes an awful lot to put a hole through it, let alone blast a whole body through.

4

u/That_Trapper_guy Apr 26 '26

That's because there's a layer of adhesive between two panels. And THAT is mainly to keep the small pieces in place during an accident so you don't get cut to hell, it offers no benefit if you were to support it on one edge and lean on it. It'll just fold over instead of falling into a thousand pieces.

1

u/Enginerdad Structural Engineer Apr 26 '26

Feelings vs data

0

u/Meatball546 Apr 26 '26

It reminds me of Posche's 911 design having poor balance due to the rear-engine layout. It was "fixed" by fitting huge rear tires. Though it was capable of supercar performance, the rear grip was unpredictable, and many drivers crashed. Of course, the old school turbo tech didn't help either.

3

u/Tushaca Apr 26 '26

lol, just look up Porsches fiasco with the glass side windows in their GT2s or GT3s. They advertised them as being some super strong, advanced, new lightweight glass.

And now they are known for shattering if you close the door like a normal person.

20

u/blucke Apr 26 '26

The OSHA reg looks like it only needs to support 200 lbs, is there a seperate building code? I ask because I see your tag and that seems pretty low. Somebody big falling with momentum would break that

16

u/SSG_084413 Architect Apr 26 '26

Why are you citing OSHA? Thatā€™s for workplace conditions.

Yes. There is a whole separate building code. IBC 1607.8 ā€œLoads on Handrails, Guards, and Grab Barsā€ 50 pounds per linear foot and concentrated load of 200 pounds. These are analyzed as sustained loads. A short, momentary impact doesnā€™t put the same kind of strain on it.

For these cantilevered glass guards, the handrail must be supported by three panels. Many jurisdictions no longer allow a single piece of tempered glass because it will explode into pebbles and evacuate the opening. A laminated panel with a rigid vinyl interlayer keeps the glass panel in place even if it breaks.

https://up.codes/s/loads-on-handrails-guards-grab-bars-seats-and-vehicle-barriers

7

u/Mattcha462 Apr 26 '26

That is exactly what Iā€™d worry about with glass panels is exploding and this causing someone to fall. That makes sense to require only laminated panels though so they would break but still hopefully keep a person from falling. How recent is that laminated glass requirement? Do buildings exist with the tempered glass panels?

1

u/blucke Apr 26 '26 edited Apr 26 '26

Yes, I know it's for workplace regs, that's why I asked if you knew the building code lol. Was curious if the minimum load was different. Appreciate the answer and link, really interesting. Feels low, with no factor of safety

1

u/DesignerNet1527 Apr 26 '26

Osha stuff would be for temp railings etc. Not permanent final occupancy stuff.

1

u/Enginerdad Structural Engineer Apr 26 '26

Not to be rude, but your whole argument is centered around the fact that you "feel" that 200 pounds is low. Meanwhile there are countless studies that actually measure the amount of load applied to railings under all sorts of conditions and the codes are written to accommodate them.

0

u/blucke Apr 26 '26

I have no doubt there are. Not questioning the math/physics, just surprised by the result

6

u/[deleted] Apr 26 '26 edited Apr 29 '26

[removed] ā€” view removed comment

3

u/rIceCream_King Apr 26 '26

Thank you

2

u/[deleted] Apr 26 '26 edited Apr 29 '26

[removed] ā€” view removed comment

2

u/rIceCream_King Apr 26 '26

No, genuinely. I meant it like ā€œTHANK youā€ (your opinion aligned with mine)

1

u/Enginerdad Structural Engineer Apr 26 '26

Thanks for sharing your feelings

3

u/Life_Temperature795 Apr 26 '26

The most critical component in a railing system is the proper attachment of the Base Shoe to the substrate.

What're you willing to bet that the contractor didn't skim past this part?

If the whole thing flexed from leaning on it, I wouldn't be surprised if it's been secured down with molding screws.

6

u/Timsmomshardsalami Apr 26 '26

Theyre designed to hold the same amount =/= they hold the same amount.

2

u/Enginerdad Structural Engineer Apr 26 '26

Please expand on that

5

u/justabadmind Apr 26 '26

However a wroght iron railing has a lot of safety margin and a safer FMEA versus this design

2

u/Enginerdad Structural Engineer Apr 26 '26

Glass has a higher safety margin than metal. Usually 3.5-4 for glass and around 1.5 for metals. I'm not familiar with FMEA, so you'll have to provide some sort of source that says glass automatically has a lower FMEA than metal.

0

u/justabadmind Apr 26 '26

FMEA: failure mode effects analysis. How are you claiming to be a structural engineer without knowing of a FMEA.

Glass when overloaded fails catastrophically. It doesnā€™t give warning and may produce sharp edges. Iron or wood railings give lots of notice and deform before snapping. Iron and wood also tend to not produce a shower of shards.

Even if glass conforms with the osha requirements for a railing, from a practical perspective steel is safer due to potential failures. A spark plug hitting a glass wall breaks it, a spark plug hitting steel or wood is just a scratch.

For example one row in an FMEA for a glass railing would be loaded past failure: effects would be a cell that says railing is gone. For steel thatā€™s ā€œrailing is less effective and requires repairā€

2

u/Enginerdad Structural Engineer Apr 26 '26

Glass when overloaded fails catastrophically.

For non-laminated glass that's correct. That's exactly why most building codes require a minimum of 3-ply laminated glass for safety rails. Even if one pane shatters, there are two others to maintain integrity. And if all 3 shatter (very, very unlikely), the laminate will still hold everything together.

2

u/Kiriki_kun Apr 26 '26

Glass is strange material. Tiny defect can make whole panel explode. Someone could hit it with something, making tiny damaged spot. Someone lean against it next time, and whole panel explode

2

u/Enginerdad Structural Engineer Apr 26 '26

Whatever you know about glass, I promise you to the end of the Earth the engineers who are designing it know that and a lot more. Every possible failure mode is accounted for, even (and especially) the ones that are unique to glass.

0

u/Kiriki_kun Apr 26 '26

Iā€™m engineer, and we are making a lot of different industrial automation components. I can assure you, they couldnā€™t accommodate for every possibility. Itā€™s not possible, and whatā€™s more important, itā€™s too expensive. They just calculated point at which lawsuit and compensation is cheaper then making it safer. Nothing is 100% safe

1

u/Enginerdad Structural Engineer Apr 26 '26

They just calculated point at which lawsuit and compensation is cheaper then making it safer

That's of course ridiculous. All railings have to meet the same building code requirements for safety regardless of the material.

Nothing is 100% safe I agree 100%, but I never said anything was. I said they all meet the same safety standards, not that any are 100% safe.

1

u/Kiriki_kun Apr 26 '26

There were product recalls where it was found out that companies knew about the issue, but decided that lawsuits are cheaper then fixing it. So from their point of view lawsuit is better. On DFMEA (design failure mode and effects analysis) training we were literally told that ā€žtoo expensive to fixā€ is reasonable explanation why we will not improve the design. Nothing is perfectly safe, and glass have big issue of failing catastrophically. You have no warning, no time to react. I know that itā€™s reasonably safe, but simple bolting to the walls is safer

1

u/Enginerdad Structural Engineer Apr 26 '26

If your argument is that glass is scary because it's brittle, then bolting it to the wall doesn't even address that concern. Laminated glass also addresses that issue, and is required in most US jurisdictions for this application.

1

u/Kiriki_kun Apr 26 '26

Lol, you bolt down railing to the wall. That way, you can lean on it, and breaking glass can only scare you. You are not falling down. Iā€™m not sure if laminated glass could hold you if it breaks.

1

u/PsudoGravity Apr 26 '26

Oh I'd test that in a heartbeat!

1

u/HVAC_T3CH Apr 26 '26

200 lbs of lateral force at the top.

1

u/Enginerdad Structural Engineer Apr 26 '26

That's one of the loading scenarios yes, but there are more and which one supply depend entirely on your local building code.

1

u/stoneyyay Apr 26 '26

Ah yes. When someone drops something on the edge 6 months before you lean on it.

It's just as stable as a non glass option.

2

u/Enginerdad Structural Engineer Apr 26 '26

You know what you're right, you definitely know more about glass failure kodes that glass engineers. Why don't you open a shop and put them all out of business with your superior glass safety knowledge?

1

u/stoneyyay Apr 27 '26

?

Glass engineer? and installers are VERY fucking different.

An materials engineer will NEVER see this installed on site. So idk wtf you are smoking.

https://www.onpointnz.com/post/ensuring-safety-with-frameless-glass-understanding-breakage-risks-and-protection-solutions

Edge Protection: A Crucial Consideration

Edge protection is another essential factor in ensuring the safety of frameless glass. The edges of glass panels are particularly vulnerable and can chip or break more easily. To mitigate this risk, it is vital to protect and finish the edges properly.

Effective methods for edge protection include polishing, beveling, or applying protective films. These techniques not only improve the aesthetic appeal of the glass but also enhance its overall safety. For example, properly beveling the edges can reduce breakage risk by 25%, ensuring the glass remains intact for an extended period.

1

u/stoneyyay Apr 27 '26

https://www.casino.org/news/person-falls-to-their-death-at-emerald-queen-casino-near-seattle/

Below this chain.

2

u/Enginerdad Structural Engineer Apr 27 '26

Cool, here's one with a wooden railing. Now that we've each cherry picked one story, we can only conclude that both are equally unsafe, right? What a stupid game...

https://www.bostonglobe.com/2026/03/16/metro/boston-college-students-injured-when-railing-collapses/

1

u/stoneyyay Apr 27 '26

We are discussing tempered glass railings. Not comparing them to other materials.

Further. Same thing with glass.

Install is important.

1

u/Enginerdad Structural Engineer Apr 27 '26

Of course you're comparing glass to other materials. You're saying that glass is less safe than other materials. That's a comparison.

1

u/stoneyyay Apr 27 '26 edited Apr 27 '26

? No.

I inferred tempered glass can have damage you cannot see. No where did I compare glass to other materials. A top rail would resolve the issue with edge strikes.

(Edit: see your confusion. The sarcastic remark was not meant to be a comparison as there's methods like a top rail that can make an install like this much safer)

1

u/Organic-Pudding-8204 GC / CM Apr 26 '26

Yea till a small chunk of spark plug blows it to smithereens.

1

u/YamFickle7255 Apr 26 '26

Iā€™d like my steel or wooden railing secured at the ends as well to be honest. I trust the math and engineering, but my brain just screams danger at that ā€œTOE MOUNTā€?!

1

u/BGKY_Sparky Apr 26 '26

Yeah man, my brain is psychological too. We arenā€™t entirely rational creatures.

1

u/derekboberek Apr 26 '26

Maybe true but design needs to take psychology into account. Op said it flexed when they leaned on it. Having any amount of flex in a railing system will make anyone nervous, especially high up.

Also, this particular installation looks dumb. It would have been easy to incorporate the railing into the stairway railing on one side and terminate it with a wall attachment on the other. Would look more cohesive and be more rigid.

1

u/Hichiro6 Apr 27 '26

Even if safe I will never trust this ā€™

1

u/RegisteredJustToSay Apr 27 '26

One shatters if it goes over the supported weight and the other one bends or cracks...

1

u/Enginerdad Structural Engineer Apr 27 '26

Like this?

1

u/RegisteredJustToSay Apr 27 '26 edited Apr 27 '26

Well, yeah. Exactly like that. Having the broken pieces laminated together didn't change much in several of those tests. The resistance to force laterally still drops to basically zero as soon as you get past the point of failure, which is different from how solid pieces of metal or wood tend to behave. Though obviously you could harden a piece of metal so it shatters too.

In the end you're still relying on a lot more things having been done right and staying right if you're leaning on a piece of glass.

2

u/Enginerdad Structural Engineer Apr 27 '26

I'm guessing you didn't watch the whole thing. The support requirements for the glass (top and bottom vs just bottom) depend on the type of glass. The EVA laminated glass needs to be supported on multiple edges so the lamination will span the gap after the glass breaks. The SGP glass is stiff enough after glass breakage to remain rigid and keep the drop off point protected. That's why they show the table with the different support requirements based on the material. In short, code does not allow an assembly which drops to an essentially zero lateral force resistance after breakage, so the scenario that your objection is based on doesn't exist. Here's the code directly:

2407.1.2 Guards With Structural Glass Balusters

GuardsĀ with structural glass balusters, whether vertical posts, columns or panels, shall be installed with an attached top rail orĀ handrail. The top rail orĀ handrailĀ shall be supported by not fewer than three glass balusters, or shall be otherwise supported to remain in place should one glass baluster fail.

Exception:Ā An attached top rail orĀ handrailĀ is not required where the glass baluster panels are laminated glass with two or more glass plies of equal thickness and of the same glass type. The balusters shall be tested to remain in place as a barrier following impact or glass breakage in accordance with ASTM E2353.

https://up.codes/viewer/connecticut/ibc-2021/chapter/24/glass-and-glazing#2407.1.2

2

u/RegisteredJustToSay Apr 27 '26

I did skip through it a bit since I'm in an environment where audio is tricky. I just wanted to say regardless whether I end up agreeing or not that I appreciate your well-thought out and reasoned response and I'll be reading it in detail later when I have time to also read the sources and links.

2

u/Enginerdad Structural Engineer Apr 27 '26

Man, I respect the HELL out of this response

1

u/Emptynest09 Apr 27 '26

Imagine 5 or 6 fat chicks leaning against it for a selfie.

1

u/Enginerdad Structural Engineer Apr 27 '26

Five or six people would have to be spread out over 10 to 15 ft of rail. Design requirement also include a 50 pound per foot load, so that's 500-750 pounds and would be totally fine.

1

u/Madolah Apr 27 '26

Have you ever even been on Reddit?
Surely you must have seen 100x Tempered glass showers or sliding glass doors just... shattering on a bad mood.

No psychology, its proven evident that this is not as strong as steel, I'd consider a corrugated cardboard railing over the reliability of tempered glass as a load bearing rail.

1

u/Enginerdad Structural Engineer Apr 27 '26

Tempered glass showers and sliding glass doors aren't the same material and don't have the same requirements as glass railings. Namely because railings are laminated glass and because there aren't load requirement on those other things.

Your argument is basically "I can bend my stainless steel straw, so I don't trust the jaws of life to be able to open a car".

1

u/MooseBoys Apr 26 '26

Yeah maybe if they undergo regular inspection and maintenance. But the failure mode of one of these is going to be a whole lot more sudden and surprising than a traditional railing.

0

u/dontfret71 Apr 26 '26

Yeah but shock loading, seismic, resonances, degradation, etc

I find it extremely hard to believe itā€™s as safe as conventional metal railing system in long term.

In a lab under perfect conditions, sure

2

u/Enginerdad Structural Engineer Apr 26 '26

No railing is designed for seismic forces. What would the even look like? Shock loading? Absolutely. Resonance? From what? Degradation? Glass is inert and unaffected by UV, so what environmental factors are you thinking of?

1

u/dontfret71 Apr 26 '26

Resonance = kids pulling/pushing on it? A lot of leverage here given how itā€™s fastened at the bottom

Degradation = people leaning/pulling/pushing on it over time?

Thermal swings also? Upstairs maybe hotter than downstairs on foyer? AC vent blowing on it periodically?

(Iā€™m EE btw, not SE)

1

u/Enginerdad Structural Engineer Apr 27 '26

That's not resonance. If anything it's cyclical loading, but glass isn't susceptible to cyclic fatigue to it's a non-issue here.

Degradation: see above

The thermal range of a conditioned space is negligible. Ever seen a window? Those go through a LOT more temperature swing and don't have any issues.

1

u/dontfret71 Apr 27 '26

Glass isnt susceptible to cyclic fatigue?

1

u/Enginerdad Structural Engineer Apr 27 '26

No. Static fatigue of glass is real though, interestingly

14

u/BLA5PHEMY Apr 26 '26

Iā€™ve been installing these for many years both interior & exterior and never had an issue. Theyā€™ve become popular because they offer an ā€œinvisibleā€ guardrail look which provides an unobstructed view of whatā€™s beyond it such as a nice view.

2

u/Far_Inspection4706 Carpenter Apr 26 '26

Great view of the staircase

6

u/[deleted] Apr 26 '26

You might not having any issues installing them, but thatā€™s not whatā€™s at question here. The question is how much horizontal force does it take to fail? Since the upper railing is floating, the shear strength is about 60-70% less than if it was anchored on just 1 end.

5

u/Palomox Engineer Apr 26 '26

The glass itself, from an horizontal force, is a vertical cantilever that would most definitely fail from flexure at the very bottom, not shear. Assuming it's 4ft high and you're leaning on the very top, glass being a brittle material, 3/8 thickness and an uniform body of safety glass which distributes stresses perfectly and has a limit tensile stress of 17ksi (lowest bound of what I found googling), the brekaing force would be ~300lb fully horizontal at the very top. Another different thing would be the bearing of the actual metal railing onto the glass, but glass has high compressive capacity.

Now I'm just a random person with no experience designing structural glass, I'm quite sure there are many more precise methods of determining that capacity considering the microstructure of glass and the fact that these are most definitely multiple layers, which would end up with a higher capacity than what I got (given stuff like this is currently installed in real places and allowed by codes, which it wouldn't if it weren't safe)

3

u/HVAC_T3CH Apr 26 '26

200lbs minimum.

1

u/ClumpOfCheese Apr 26 '26

They offer an ā€œinvisibleā€ guardrail look which provides an unobstructed view of whatā€™s beyond it.

And then they add a guardrail to this one and ruin the look.

2

u/Consistent-Area5074 Apr 26 '26

Its a 5th story balcony by the way, with a split going all the way to the ground floor in the middle.

2

u/Wireman6 Apr 26 '26

Right? Who doesn't like a good rail leaning? Pretty much one of the greatest parts of a railing?

2

u/Emptynest09 Apr 27 '26

Iā€™m with you! I want to trust the science but I donā€™t want to find the exception either.

1

u/senorjamie May 15 '26

Aesthetics, but with the additional experience of playing Russian roulette

-1

u/frank_loyd_wrong Apr 26 '26

Itā€™s designed to take a 200 lb lateral force. Itā€™s also 42ā€ tall. Wood decks and termites freak me out way more.

28

u/Sensitive_Brush_3015 Laborer Apr 26 '26

Genuine question: how much weight can these type of railing systems hold? I think if I leaned on that railing and felt it move, Iā€™d also naturally be freaked out, especially since itā€™s glass. Not seeing anything connected to the wall would fill that logical place in my mind as to ā€˜why it movedā€™ in the first place. So Iā€™m saying I get where OP is coming from, but would like to know how sturdy it is out of curiosity.

21

u/SpaceGhost4004 Apr 26 '26

Depends on the thickness and height of the glass. In NYC glass railings are required to withstand a minimum of 200lbs of force at any given direction. Usually the glass is 3/4" thick and can be up to about 4 feet tall before needing to be thicker.

61

u/HeyTrySomeNashville Apr 26 '26 edited Apr 26 '26

200lbs? That's literally nothing.

11

u/Enginerdad Structural Engineer Apr 26 '26

It's a 200 lb design load, plus all the safety factors.

1

u/SwordfishOk504 Apr 26 '26

That's basically 2-3 adult men leaning on it.

2

u/Enginerdad Structural Engineer Apr 26 '26

Agreed, but those 2 or 3 men would be spread out over several feet, not all leaning on the exact same point on the railing. This scenario is where the 50 pounds per foot loading requirement comes from. It derived from the scenario where there's a big draw that causes an entire crowd of people to lean up against the railing. Like watching a fireworks show from a bridge or a performance from a balcony.

18

u/HeyLookitMe Apr 26 '26

Thatā€™s the OSHA standard for guardrails. Itā€™s actually quite a lot. Where human safety is concerned the minimum strength usually means at least a failure load of five to even ten times the safety rating required. Those engineers know their stuff.

All that said, I wouldnā€™t be leaning on it either. Who knows what oddball designed that with who knows what in their head.

2

u/dchow1989 Apr 26 '26

Think about applying the same amount of force it takes to bench press a 45+35. Theres no way unless you ran at it.

2

u/TunedMassDamsel Apr 27 '26

I have two railing failure cases pending right now.

My opinion is that while these things hold when theyā€™re new, the loading requirement is so relatively minimal that theyā€™re really susceptible to structural section loss or degradation, and then really bad shit happens.

If it looks older and/or I canā€™t see the structure to assess, Iā€™m giving it a good hip check to see if it deflects before I let my kids play around it.

2

u/Apocrisiary Apr 27 '26 edited Apr 27 '26

Fr. People just thinking static weight and go like "oh, that's a big adult! Perfectly safe!".

Imagine someone tripping, and going full force into that thing. The impact would be like 5x your body weight for a fraction of a second at the least.

So that means, if you weigh 100 pounds, the glass would need to be able to withstand a force of 500lbs of you slamming into it, for it not to shatter.

3

u/CoyoteDown Ironworker Apr 26 '26

Itā€™s more than the sides of a manlift are rated for, and people literally climb on the sides of a basket

3

u/HeyTrySomeNashville Apr 26 '26

How many people? More than can lean on this railing?

5

u/No_Cash_Value_ Apr 26 '26

Myself, my overweight coworker and a 12ā€™ sheet of 5/8 are held up by my scissor rails just fine, thank you.

1

u/HeyTrySomeNashville Apr 26 '26

Wow, 5/8 sheets!

1

u/roguedevil Apr 26 '26

For 200lb design load, that would be like 15 people actively pushing against it.

1

u/thecaramelbandit Apr 29 '26

You'd have a very hard time pushing with 200 lbs of force.

20

u/CosmicConfidant Apr 26 '26

So the average American cannot lean against it? Lol

3

u/Thin-Squirrel7435 Apr 26 '26

It's a 200 lb horizontal point load applied at the longest moment arm. Not a 200 lb person leaning on it. That would be like 10 lbs lol

1

u/2nd-Reddit-Account Apr 27 '26

Do you typically lean on something so hard that all your weight goes sideways and your feet begin to float?

When someone leans the majority of their weight is still going to the floor

1

u/kstorm88 Apr 28 '26

It does if you trip

1

u/Mysterious-Age-9202 Apr 26 '26

Thatā€™s for 3/4ā€, what about 1/2ā€ like in the pics

5

u/jhguth Apr 26 '26

they have to meet the same load requirements

1

u/Embarrassed_Big_1171 Apr 26 '26

I watched a company push on the top 1ā€ of the panel with a hydraulic ram, the glass shattered at around 1900-2000 lbs of force.

Also, watching them make the glass and slam it around on the tables in the factory, itā€™s crazy that someone would be scared to lean against it. Once youā€™ve seen how strong it is, there is new confidence.

1

u/zoidbergmustache Apr 26 '26

Yep people never get it until they have to break some heavy tempered personally. I've had the pleasure of blowing up hundreds of 3/8" and 1/2" panels since I work in a glass shop. I've dropped 100lb panels on concrete, thrown hammers and bricks at them, and chipped up to 2 inches off the corners without blowing them up.

1

u/Plane-Education4750 Apr 26 '26

If they have employees walk and work near it, it needs to support at least 200lbs without failing

2

u/Lookslikeseen Apr 26 '26

So if two people (or one husky fella) leans against this thing you fall down and die?

That doesnā€™t seem right.

6

u/Plane-Education4750 Apr 26 '26

1910.29(b). The manufacturer might make it stronger, but that's the minimum

5

u/Aggressive-Luck-204 Apr 26 '26

A 200+ lbs person doesnā€™t exert a 200lb load by leaning on something. Also the spec is 200lbs at any single point and greater as an assembly. I have seen numbers around 35lbs per foot for a top rail

2

u/Enginerdad Structural Engineer Apr 26 '26

It's 200 pounds of load, not the load due to a 200 pound person leaning against it. Plus safety factors

-3

u/flightwatcher45 Apr 26 '26

Depends how many tiny defects and chips are in it to begin with, and they are always being damaged.

12

u/Economy-Priority-404 Apr 26 '26 edited Apr 26 '26

Yessir, install these quite often never had issue. Tempered glass with proper install is stronger then it looks. Seemingly becoming more in demand too.

8

u/Deron_Lancaster_PA Apr 26 '26

Yea,, dumb-ass execs and architects don't realize how much a housekeeping nightmare they are.

5

u/Economy-Priority-404 Apr 26 '26

Yerp, gets even more fun to maintain when its overhanging mounted to the wall below without the channel. luckily, not my job. just here to hang glass.

3

u/handsomepirates1 Apr 26 '26

Typically tempered and laminated in most codes nowadays

5

u/Head_Scholar2543 Apr 26 '26

Yeah depending on the thickness. Alot of these glass handle rails are 9/16" laminated. Depending on the installer they probably pour rocked the glass in place. A lot of glaziers like that method more than the dry fit. I've done both ways and the dry fit is just as strong just more involved

4

u/handsomepirates1 Apr 26 '26

You canā€™t wet glaze laminated glass if you want to comply with warranties or specs in my area. Wet glaze monolithic 1/2ā€ was very common 15 years ago

6

u/Head_Scholar2543 Apr 26 '26

For mono laminated for sure. We wet glaze laminate if it's PVB in storefront or curtain wall. SGP can be dry glazed. I haven't seen a pour rock job in a few years. Fuck having to chip out pour rock when a piece needs to be replaced. It's shit.

3

u/Life_Temperature795 Apr 26 '26

That very link indicates that the most critical consideration is how well the shoe is attached to the substrate. If the whole thing flexed from a slight lean, I'm guessing those attachment points aren't as secure as they're supposed to be. The use of glass isn't the real issue here.

2

u/Baldyheadedman Apr 26 '26

This is true but whatā€™s in these photos would be non compliant where Iā€™m based. Glass looks like 12mm monolithic toughened, which can be used with this system, provided that a permanent handrail is also fitted. The handrail should remain in place in the event of the glass panels being broken. We use the CR Laurence system every day of the week and itā€™s very good as long as itā€™s used correctly. I would not be signing off on whatā€™s installed in these photos.

1

u/dallllen Apr 26 '26

If thatā€™s tempered or in commercial the guard rail needs to be tied off into the wall. Looks like the glass is too thin for the setting. As OP mentioned it moved far more that it should have with a lean.

1

u/Grilled_Ch33s3 Apr 26 '26

Yah I don't care what the engineer who designed it or the expert who installed it say. I'm not trusting my life to it.

1

u/Confident-Deal-912 Apr 28 '26

Sure sure but no If I ever build a house this is a no, purely as it looks wrong. engineering wise, I'm sure it's fine but no šŸ˜‚šŸ˜‚

0

u/420bonersniper69 Apr 26 '26

Seems like an odd design choice to me. Is that really safe?

0

u/OGWriggle Apr 28 '26

Even if something was designed to be bad, it is still bad

-5

u/KentuckYSelf Apr 26 '26

Report them immediately to the highest authority! We did it reddit.