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Author Message Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1571 Registered: 05-2003 Posted on Monday, February 22, 2016 - 12:24 am:    Perhaps one of my peers can explain what it means to heat soak glass and how to specify it? A Consultant is asking us to specify that all tempered glass be heat soaked, I must admit to not being familiar with this term nor how to specify the glass. Is there a standard for this? Margaret G. Chewning FCSI CCS Senior Member Username: presbspec Post Number: 275 Registered: 01-2003 Posted on Monday, February 22, 2016 - 09:35 am:    Does he mean Heat Treated? Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1574 Registered: 05-2003 Posted on Monday, February 22, 2016 - 09:41 am:    NO Margaret, I THOUGHT THE SAME, Heat Soaked it is, Viracon's website has a lengthy explanation, not sure why this is the first I've heard of it, perhaps Ron the Man Geren has an answer. I've reached out to a couple of GG Consultants, waiting for an answer. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 943 Registered: 10-2002 Posted on Monday, February 22, 2016 - 09:44 am:    Jerome, Margaret, Its a fairly common term in the glass industry. Tempered glass can spontaneously break due to inclusions of crystals in the glass. Actually its fairly rare, but I have seen it happen on a project (1984 and another in about 1990 or so). I have never bothered to include the requirement in my spec - unless I am doing structural glass glazing. Then its something that should always be required. There was a fairly good discussion on the topic here back in 2006, this is the link to it, or if it does not work for you just search for "heat soaked" http://discus.4specs.com/discus/messages/4403/2566.html William C. Pegues, FCSI, CCS, SCIP Affiliate WDG Architecture, Washington, DC | Dallas, TX Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1575 Registered: 05-2003 Posted on Monday, February 22, 2016 - 09:49 am:    The job in question is a simple apartment building, no structural glass, stick frame. The GG Consultant is new and I guess he's trying to make a name for himself, his report is filled with recommendations that barely apply to the specific project and has given me my first mega migraine of 2016. Thanks William, it seems for now you are the Man. Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Monday, February 22, 2016 - 09:52 am:    EN 14179-1 A condensed explanation: reheat fully tempered glass, hold at temperature....if it survives the "test", it is used for the project. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1576 Registered: 05-2003 Posted on Monday, February 22, 2016 - 09:57 am:    William, the last poster on that thread is Max Perilstein from Arch Aluminum. Arch Aluminum has come and gone, I wonder if Max still reads 4specs? Max knew his stuff, I need Max? Cool thread, good info all around. Hey even Ron posted, Ron where are you? Well I'll have to read your post later, right now I am headed to a dark room, for migraine meditation and some mag citrate, I hate starting a new week in pain. Ronald L. Geren, FCSI, AIA, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 1382 Registered: 03-2003 Posted on Monday, February 22, 2016 - 10:00 am:    See this: http://www.viracon.com/pdf/TTHeatSoak.pdf It has to do with preventing spontaneous breakage due to nickel sulphide (NiS) inclusions in the glass. NiS inclusions, which have a different thermal coefficient of expansion, may cause glass to spontaneously break if a NiS inclusion fractures the tensile body of tempered glass. All heat soaking does is catch the panels of tempered glass that may have NiS inclusions before they are fabricated into insulated units or installed as monolithic panels in other applications. By heating up the glass, the intent is to cause the NiS inclusions to expand and break the glass. If the glass does not break, it is considered safe to use. Heat soaking is not inexpensive, so you may want to get the owner's acceptance of such a practice. In all my career I've had only one incident of spontaneous breakage, which was in a glass railing. There are reasons for spontaneous breakage other than NiS inclusions (chipped edges, differential stresses within frames, etc.), so heat soaking will not prevent them all. After that one spontaneous breakage incident I experienced, I have only required heat soaking where falling glass could be a potential hazard for occupants below. However, in most cases, I only specify laminated glass, which will prevent falling glass and does not require tempered glass that must be heat-soak tested. Ron Geren, FCSI, AIA, CCS, CCCA, SCIP www.specsandcodes.com Colin Gilboy Senior Member Username: colin Post Number: 423 Registered: 09-2005 Posted on Monday, February 22, 2016 - 10:01 am:    I tracked Max down through LinkedIn and asked him to comment. Colin Gilboy Publisher, 4specs.com 435.200.5775 - Utah 800.369.8008 Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1577 Registered: 05-2003 Posted on Monday, February 22, 2016 - 10:09 am:    Thanks Colin. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1578 Registered: 05-2003 Posted on Monday, February 22, 2016 - 10:09 am:    oops, you too Ron, now I need a dark room and serenity. Dave Metzger Senior Member Username: davemetzger Post Number: 625 Registered: 07-2001 Posted on Monday, February 22, 2016 - 11:46 am:    My experience has been similar to that of William and Ron. We have specified heat-soaking for glass to be used in structural glass walls; but IMHO it's overkill for "normal" uses such as glass in glazing frames and in frameless glass doors. Chris Grimm, CSI, CCS, SCIP, LEED AP BD+C Senior Member Username: chris_grimm_ccs_scip Post Number: 348 Registered: 02-2014 Posted on Monday, February 22, 2016 - 12:16 pm:    We have it in a current project that is a high-end office building that had extensive glass, at the request of Viracon and the facade designer, with the Owner's and Design/Builder's OK. That is the only one I have had other than structural glass such as in elaborate shopping malls. Usually heat soaking is not required due to the cost and the lack of agreement among manufacturer/fabricators as to how it should be done. But a European standard has been developed and I think that is the basis loosely for the fabricators who offer it here, and Viracon seems to be the main proponent. I think it would be from the fabricator if they are doing the tempering. Most fabricators can offer it. I have heard from some manufacturers that nickel sulfide inclusion is a thing of the past due to current quality controls. I do know of one project that had spontaneous glass breakage in 2006, but it was thought to be lack of provision for thermal movement. Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Monday, February 22, 2016 - 12:35 pm:    I feel it is more common than believed. In my experience, most incidents go unrecognized even though it is a very classic and obvious pattern. One project believed bird strikes were causing approx. 4 breaks per month (surprisingly no bird bodies were ever found). It looks like impact damage if you have the luxury of reviewing the broken ply still in the opening. Most of the time its a pile of fragments (to my point on being under reported). Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1579 Registered: 05-2003 Posted on Monday, February 22, 2016 - 04:52 pm:    I spoke with the VP of a respected National Building Envelope Consultant, in SFL, heat soaked glass adds significant cost to the building and is not considered worthy of inclusion in the specifications. In fact, and just to be sure, he spoke to the VP of Construction for a current 52 story condo we are working on, this is a very experienced and respected Developer, again the answer was no thank you. C'est la vie Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1580 Registered: 05-2003 Posted on Monday, February 22, 2016 - 04:54 pm:    Trying to get Building Envelope Consultants in SFL to agree on anything is difficult, near impossible, and frustrating. Do my peers in other parts of the US have this same problem? Steve Gantner, RA, CSI, CCS, CCCA Senior Member Username: sgantner Post Number: 49 Registered: 08-2007 Posted on Monday, February 22, 2016 - 05:15 pm:    Last I heard, Viracon was the only one heat-soaking glass, and by specifying it, you were closing the spec. Does anyone know if that is still correct? Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 119 Registered: 10-2003 Posted on Monday, February 22, 2016 - 05:27 pm:    Jerome, We have to be careful when basing a specification decision on the recommendation of a VP of Construction. I am sure the VP has invaluable hands-on experience, but he always has the defense that the requirement was not in the spec. Michael Chusid, RA FCSI CCS www.chusid.com www.buildingproduct.guru ken hercenberg Senior Member Username: khercenberg Post Number: 985 Registered: 12-2006 Posted on Monday, February 22, 2016 - 05:31 pm:    That's pretty normal, sort of like asking a question at shul (synagogue). Three people, 5 opinions. I find it funny that some glass rail manufacturers put on their shop drawings that tempered glass edges should be captured. Their marketing literature is silent. Sheldon Wolfe Senior Member Username: sheldon_wolfe Post Number: 900 Registered: 01-2003 Posted on Monday, February 22, 2016 - 07:11 pm:    A couple of years ago I dug up several articles and comments on the web. Most of the articles were neutral, merely discussing breakage. A couple leaned in that direction but didn't say "do it" , and a couple didn't think it was worth the expense (none indicated how much it cost). Then I talked with my glass and curtain wall reps. One of the glass reps said, "We have never seen a lite of heat soaked glass break because of NiS." He also said that "breakage like this is rare (.5% or so), when it does happen it tends to come in batches. So a project that has an issue might see 4 or 5%." In other words, most of the time the warranty is a waste of money, but if you get that rare bad batch of glass you'll probably have a lot of broken glass. One rep said heat soaking reduces the occurrence of NiS breakage from 8 per thousand to 5 per thousand, but breakage still could occur. If you're going to use heat soaking, check the warranty. One I found guaranteed no breakage beyond 5 per thousand. So even with the warranty, you can still get breakage that won't be covered. The cost was about a buck per square foot, or two bucks for an insulating glass unit. The warranty period was five years, and it did not cover anything else, so if the glass breaks because of, say, improper insulation, it's not covered. We have only one client who requires heat soaking for all projects. As always, it’s easier to explain something like broken glass if the client knew of the issue and what the potential risks were. Last year, both Viracon and PPG said they also heat soak glass. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1581 Registered: 05-2003 Posted on Monday, February 22, 2016 - 07:35 pm:    Michael, I disagree with your comment, I have been fortunate to work with several VP's of Construction for several large SFL Developers, perhaps my experience is unique, but I've learned more from them than from any fellow spec writer, they rarely point fingers, and are some of the best sources of information for a spec writer, at least in SFL, these fellows actually read the specs, where many of my fellow architects do not. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1582 Registered: 05-2003 Posted on Monday, February 22, 2016 - 07:45 pm:    Max Perilstein has a blog: http://fromthefabricator.blogspot.com/ Max's family has been in the Glass Business in SFL since 1898, certainly a source worth considering. Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Monday, February 22, 2016 - 06:13 pm:    Steve - no. Others can heat soak. For whats its worth, I hear around $2/sqft. Ask a few fabricators how much glass breaks during heat soak testing (generically because it will vary based on the substrate, float line and the individual batch ingredients). The responses I received were not reassuring. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 120 Registered: 10-2003 Posted on Monday, February 22, 2016 - 08:42 pm:    Is the decision to heat soak just an economic tradeoff? Or is there a life-safety issue, too? Since tempered glass breaks into small pieces, how much risk does it pose to people or things it might strike on the way down? If so, then we need to look at where the glass is installed with regard to pedestrians or other items below. I welcome your thoughts. Michael Chusid, RA FCSI CCS www.chusid.com www.buildingproduct.guru J. Peter Jordan Senior Member Username: jpjordan Post Number: 889 Registered: 05-2004 Posted on Tuesday, February 23, 2016 - 06:27 am:    "Significant" cost is somewhat relative. Curtain wall is running between $35 and $45 per sf. This would be more where wind debris resistance I requires a laminated lite. $2/sf for heat soaking would add about 2% to the cost of the curtain wall. So the cost for the curtain wall system would have to be 1/4 of the total construction cost for the heat soaking to add even 1/2 of 1% to the construction cost. Condo construction, however, probably includes balconies which may have residential glass rather than commercial glazing units. Heat soaking for these products may be a higher percentage of the glazing cost, but I still don't think it is significant. While many projects struggle to control all costs, I am always at the effort to save pennies without looking at the larger cost items. Max Perilstein (Unregistered Guest) Unregistered guest Posted on Tuesday, February 23, 2016 - 03:07 pm:    Sorry for my delay folks- I was out west at the Building Envelope Contractors Conference. Jerome- thank you for remembering me! Hope you have been well. There's quite a bit of excellent feedback on this thread already. So I'll try to not to step on anything. Sheldon's post was right on with regards to it- when you heat soak you are only reducing the percentage of potential breakage from 8 to 5 per thousand. For some that is an extra safety blanket- and you will see Heat Soaking used for the following- Rare glass make ups or long lead-time products, sophisticated projects and finally ones that will have very difficult installation setups. Cost is as Brett noted- though it does vary on sizes of glass- the bigger the sizes, the longer the Heat Soak process may take and so more expensive. There's a few folks that do heat soak aside from PPG/Viracon listed. JE Berkowitz does, as does Dlubak Specialty Glass and Rochester Insulated Glass (RIG). Hope this helps- please advise if you want or need more info- always glad to help. Chris Grimm, CSI, CCS, SCIP, LEED AP BD+C Senior Member Username: chris_grimm_ccs_scip Post Number: 349 Registered: 02-2014 Posted on Tuesday, February 23, 2016 - 03:42 pm:    Not surprised if it is a possible anti-competitive tactic. The leading fabricator who does it whispers in the designer's ear enough about the things that they and very few others do, for little benefit to the project, and they misconstrue it as though anyone COULD offer it - but if they otherwise qualified fabricators don't and if it adds needless cost, these are things to watch out for on behalf of the project Owners. I heard another one from the same company that they can put a low-e and ceramic frit on the same surface. I am skeptical about this but supposedly there was an aesthetic advantage. If no one else offers it period, it should not be used on a project with tight funding or taxpayer funding. That did not thwart them or this designer though, so I expect similar tactics might be used when it comes to heat soaking too. "Oh, you really want to heat soak all that glass" (when what they mean is, we really want a virtually closed spec). Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1584 Registered: 05-2003 Posted on Tuesday, February 23, 2016 - 05:47 pm:    Thanks Max, good to hear you are alive and kicking, Scott sent me your blog link, so I will be listening as well, don't shy away from 4specs, your expertise would be an asset. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1406 Registered: 07-2002 Posted on Wednesday, February 24, 2016 - 07:08 pm:    Heat soaking is a minor upcharge to the glass -- if the fabricator has the facilities to heat soak. If they do not, it always becomes a big deal. I've worked with curtainwall consultants, and worked on projects where interior glass spontaneously broke (a museum case) so for critical installations, I always require heat soaking. I have also received letters from glass fabricators in Texas that basically compare heat soaking the glass to doing a deal with the devil. (there are no heat soaking facilities in Texas). I specify heat soaking for: glass handrails (interior or exterior) unless they are fabricated from laminated glass; any extra large glass; any glass that, when breaks, can fall on someone's head (unless it is laminated). We don't have a problem getting heat soaking on the west coast, and the upcharge is in the single digits. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1590 Registered: 05-2003 Posted on Thursday, February 25, 2016 - 12:53 am:    Anne, most exterior glass in SFL is laminated, due to the hurricane code. In fact since Hurricane Andrew 20 years ago I've always specified laminated glass for exterior, perhaps that is why I have never specified heat soaked glass. I've reached out to several SFL Glass experts, none are recommending heat soaked glass. Randall A Chapple, CSI, CCS, AIA, SE, LEED AP Senior Member Username: rachapple Post Number: 93 Registered: 12-2005 Posted on Friday, April 15, 2016 - 05:14 pm:    Heat soaking is only required for tempered glass. It provides a bit of insurance for large installation of tempered glass. By the way I have had 2 lights of interior glass break in my office do to nickel sulfates. Chris Grimm, CSI, CCS, SCIP Senior Member Username: chris_grimm_ccs_scip Post Number: 501 Registered: 02-2014 Posted on Wednesday, September 04, 2019 - 07:18 pm:    Washington Post has an article about new glass breakage in DC area. I'm revisiting this thread from a couple years ago. I learned from a conference last year speaking with a national director from Guardian that they (or their fabricators) do heat soak testing as well, so to update what I wrote here previously, it is not a proprietary thing. The cost is around 50 cents a SF for over projects having over 50,000 SF of glass, otherwise $2 to $3 per SF. As noted here, it definitely makes sense for structural glass, handrails, other critical glass installations or extra large glass, unless they are for sure going to be laminated glass instead of tempered. In other cases it could just be seen as a lot of money. So that tells me it may be wise to make it an owner decision, if the architects are willing/able to ask them. Then the owner almost always says no, and the architect has it on file that they said no. I previously added this as a checklist item which I review with the architect, flagged as one they may need to also review with the owner. (Until several except a precious few clients think my checklist is too long and wordy. I think I’ll have to make most of my notes easily expandable/collapsible - though I wish I could get them all to read for their benefit. I think the new notes will all be expanded unless they want to collapse them and not read, at their own peril. I already pre-edit it to delete things I think don't apply to the project and let them see the deletions. Well that's a whole different topic, one that I hope Beth Stroshane's Bluebeam Studios presentation at SCIP, and Dave Stutzman's Uniformat session in tomorrow's Specifying Practice Community, might help me address - sorry to mix topics here!) Phil Babinec Senior Member Username: pbabinec Post Number: 25 Registered: 09-2004 Posted on Friday, September 06, 2019 - 05:09 pm:    We have had breakage on several projects - interior and exterior, both structural and framed. PA had a sample explode in his hands recently. We have specified heat soaking but also provide a waiver if contractor warrants glass for 5 years. Nickel Sulfide and Spontaneous Breakage http://glassed.vitroglazings.com/topics/nickel-sulfide-and-spontaneous-breakage ken hercenberg Senior Member Username: khercenberg Post Number: 1246 Registered: 12-2006 Posted on Sunday, October 20, 2019 - 05:16 pm:    Good article here - https://www.constructionspecifier.com/spontaneous-glass-breakage-why-it-happens-and-what-to-do-about-it/ Based on this and other articles and studies I've read, it sounds like heat-soaking can weaken the tempered glass to the point of turning it into heat-strengthened (big oops if you thought you were getting safety glass). Going from 8% breakage to 5% breakage doesn't really seems worth it to me. I've never had glass breakage due to nickel sulfide inclusions that I know of. I keep in contact with former co-workers so I would hope that I'd have heard something if it ever happened. I've seen way too many instances due to improper framing (glass to metal contact or not enough clearance during expansion and contraction), edge damage, and similar issues. Had a tempered glass guardrail explode because of a man's ring hitting the exposed edge of the glass; now I only use ionoplast interlayers in laminated glass for guardrails. I'll use Type LT (laminated tempered) if the ICC ES report requires it, otherwise laminated heat-strengthened seems to work just fine. Chris Grimm, CSI, CCS, SCIP Senior Member Username: chris_grimm_ccs_scip Post Number: 519 Registered: 02-2014 Posted on Monday, January 13, 2020 - 10:14 am:    From 0.8% to 0.5%