sythetic gypboard?

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Author Message Bill Morley Senior Member Username: billm Post Number: 9 Registered: 08-2005 Posted on Monday, March 05, 2007 - 07:18 pm:    I am interested in LEED points and sustainable use of materials. I have no experience with synthetic gypsum wallboard. Do you know if it has physical or performance weaknesses or drawbacks in comparison to ordinary (ASTM C36) gypsum wallboard? Is synthetic gyp as fire-resistant as regular Type X wallboard? Is there any reason to hesitate in specifying synthetic gypsum wallboard? What about an "either/or" spec - either mineral gypsum based, or the sythetic stuff? George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 264 Registered: 11-2004 Posted on Monday, March 05, 2007 - 07:37 pm:    By “Synthetic gypsum”, do you mean the byproduct of powerplant flue gas scrubbing? As I understand it, this byproduct is identical chemically to natural gypsum and gypsum board manufacturers use it in abundance. I don’t think the lay person is able to look at a sheet of drywall and tell if it is synthetic, natural, or a mixture of both. I understand that for the past decade or so, manufacturers have been "co-locating" with power plants; that is building their new gyp plants in proximity to the source of synthetic gypsum. You probably need to go to the manufacturers themselves to get information on how much of their product is synthetic, and which of their plants produce it. With LEED as popular as it is these days, and use of synthetic gypsum a "no brainer" for being green, I am sure that information is readily available. Also try the GA, at www.gypsum.org Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 467 Registered: 07-2002 Posted on Monday, March 05, 2007 - 08:04 pm:    US Gypsum has a synthetic gypsum plant located in Chicago and the LEED consultant on a project back there recommended it and said that its performance was equal to or better than the "real" stuff. that project is under construction so I have no real-experience knowledge of the product. However, I'm sure that USG could give you all the technical information and performance data you might need. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 665 Registered: 03-2002 Posted on Tuesday, March 06, 2007 - 10:05 am:    Synthetic gypsum products meet all the same standards as "natural" gypsum. However, it is not available in every local market since, as pointed out, it is made from coal-fired power plant scrubber waste. (Sulfur dioxide in the exhaust stack, a by-product of burning high-sulfur coal, combines with the calcium in the limestone or lime used in the scrubber to create calcium sulfate--or gypsum.) Each wallboard manufacturer can advise you on the local availability and how much synthetic gyp is in the product. Richard Howard, AIA CSI CCS Senior Member Username: rick_howard Post Number: 118 Registered: 07-2003 Posted on Tuesday, March 06, 2007 - 10:51 am:    Here in the Great Lakes Region, where most of our electricity is produced by burning high-sulphur coal, synthetic gypsum is very common. Folks who live in the east, where my friend John is, convinced us back in the 70s to stop sending them our sulfur in the form of acid rain, so now we capture it and make gypsum instead. According to the USGS, more than 1/4 of the total tonnage of gypsum consumed in the US is synthetic. Most ends up in gypsum board and plaster products, but it is also used in hydraulic cement production and agricultural soil treatment. Modern gypsum plants using sythetic gypsum utilize nearly 100 percent recycled materials and recycle their own waste back into the manufacturing process. About the only "virgin" materials they use are the organic starches and sugars that are added to control the set of the gypsum and help adhere the paper facing. I highly recommend arranging a tour of one these plants if you can. Marc C Chavez Senior Member Username: mchavez Post Number: 185 Registered: 07-2002 Posted on Tuesday, March 06, 2007 - 11:17 am:    PS Where do you think fly ash comes from? Lynn Javoroski CSI CCS LEED AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 505 Registered: 07-2002 Posted on Tuesday, March 06, 2007 - 11:20 am:    The burning of all those little fly bodies in the bug zappers? Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 200 Registered: 10-2003 Posted on Tuesday, March 06, 2007 - 11:45 am:    While we are on the subject of fly ash - I came across a requirement in the CHPS Program for minimum of 20% fly ash in the concrete mix in order to achieve a point credit. Two of my structural engineers said they normally would not use more than 15%, but the engineer of record for the project finally agreed to 20-25%. Any one have any thoughts on how much fly ash is reasonable? I also discovered that since CA does not have any coal-burning power plants, there are only 2 sources for fly ash for So Cal and both are in Arizona As for my personal opinion of fly ash - I like Lynn's definition. Oh yeah, CHPS stands for "The Collaborative for High Performance Schools" and not the CA Highway Patrol, although you can get "points" from CHP too! - a little CA humor. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 651 Registered: 10-2002 Posted on Tuesday, March 06, 2007 - 11:59 am:    One of the things that has to be remembered is that for some locations, using a requirement for synthetic gypsum to go after 1 point might have put that product out of the 'local' range radius, so it does not help get the local production point. Or, it may be that it limits manufacturers so that there is only 1 or 2 that can provide the product so you don't get as good a price. Or, that though it aids in going after a LEED point with the material, that other sources of natural gypsum may be closer to the project site and inadvertantly you end up doing more harm to the environment through use of fuels and exhaust emissions by bringing in the synthetic product from much further than the natural product. And then, if you are inclinded to use any of the "Dens" family of products for sheathing or tile backing or moisture resistance in general, they do not use synthetic gypsum in their products, at least not the last time I asked them. The big one for me is the potential of doing more harm to the environment by going after a particular LEED related requirement. It can happen with a number of different situations if you are not careful - often related to transportation and even you are still in the 'local' radius. William Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 201 Registered: 10-2003 Posted on Tuesday, March 06, 2007 - 12:18 pm:    I have to agree with William. When doing LEED or CHPS projects, you have to remeber to look at the BIG picture and not get bogged down with getting that 1 point that you miss some larger potential elsewhere. Richard A. Rosen, CSI, CCS, AIA Senior Member Username: rarosen Post Number: 6 Registered: 08-2006 Posted on Tuesday, March 06, 2007 - 02:02 pm:    Note to all: regardless of what MasterSpec says about specifying both standards to "aviod confusion" ASTM lists C36 as being superceeded by C1396. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 468 Registered: 07-2002 Posted on Tuesday, March 06, 2007 - 02:58 pm:    Richard: I was involved in a City of Seattle study about fly ash, and oddly enough they actually had concrete fabricators involved in it also. They said that anything more than 25% fly ash made the concrete mix "unworkable". apparently its like putting teensy ball bearings in the concrete mix and if there is more fly ash "it gets all balled up in the tremie". (Marc -- no snide remarks, please). One of the green architects in the group said "well, we regularly specify at least 50% fly ash and I've heard no complaints" and one of the contractors said "if I were you, I wouldn't be on that job site alone after dark. ". Keep in mind that fly ash will extend the break time on the cores -- instead of 28 day break strengths, you will have more like 56 or 84 days, and since most building codes require specific strengths at specific times, you will be adding fly ash in addition to cement content, not instead of. (sort of defeats the whole green thing right there). Also, in some areas, there is not very much quantity available and fly as is getting more expensive and adds to the cost. the original point was 1) to not use as much cement and 2) save cost. neither of those seem to be working very well. George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 265 Registered: 11-2004 Posted on Tuesday, March 06, 2007 - 03:36 pm:    A lot more discussion than I thought would occur on synthetic gypsum. Since we have morphed to fly ash and concrete, some more random thoughts / questions: 1. Fly ash will turn the concrete grayer / blacker than you might want, and so therefore you probably don't use it where concrete will be exposed architecturally. 2. Fly ash and silica fume were jumbled up in my head. Silica fume makes the concrete denser (fills in the tiniest spaces) and more waterproof. Silica fume good, fly ash maybe not so good.... 3. So that lead me to the internet, and sure enough there is a flyash website www.flyash.info and this nice and highly technical document that talks about the optimum fly ash % and the need to perhaps add silica fume, depending on the chemical composition of the cement and the flyash used: flyash But the paper is a lot more engineery than architecty, leading me to believe that perhaps our structural engineers should be involved in how much fly ash goes in. And final question, all this stuff -- synthetic gypsum, fly ash, silica fume -- is essentially waste products of industrial flue gas scrubbing, right? George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 266 Registered: 11-2004 Posted on Tuesday, March 06, 2007 - 03:42 pm:    ...or the fly ash is what is left at the bottom after combustion and never goes up the flue, I guess. It is a waste product but not a flue gas? Helaine K. (Holly) Robinson CSI CCS CCCA Senior Member Username: hollyrob Post Number: 287 Registered: 07-2003 Posted on Tuesday, March 06, 2007 - 09:34 pm:    ASTM C1396/C1396M-06a Standard Specification for Gypsum Board http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/C1396C1396M.htm?L+mystore+ohfh5719 Mark Gilligan SE, CSI Senior Member Username: markgilligan Post Number: 138 Registered: 05-2005 Posted on Wednesday, March 07, 2007 - 01:10 am:    Our office regularly specifies 56 day strengths for concrete and if we are violating the letter of the code then nobody is saying anything. If a 28 day strenght is specified but does not come up to strength it is common to wait a little longer and test again, so what is the difference. There are a few instances where the full strenght is needed earlier than 56 days but in most cases this is not a problem. We have talked with local suppiers and they have not reported significant problems with high percentages of fly ash. One of the problems is that fly ash is becomming so popular that the price is going up and they are looking for new ways to make more of it. this seems to defeat the original intent. We should be looking at slag. In a discussion with a local supplier they put forward the idea of a mix with slag and fly ash with little if any cement. This is something worth considering. Bill Morley Senior Member Username: billm Post Number: 10 Registered: 08-2005 Posted on Wednesday, March 07, 2007 - 09:53 am:    Thanks for all that education. I contacted a local gypboard manufacturer and got the following reply: "There is no difference in the physical properties or performance between natural mined gypsum and synthetic gypsum. When you see a 95% recycled content for our wallboard, this is for our Type X products which have fiberglass in their core. Fiberglass is not considered a recycled product and therefore, those products only have a 95% recycled content. The products that have a 98% recycled content do not have fiberglass in their core (Ex: ½" regular core) so they are totally recycled. We don't say 100% recycled because we allow for different binding agents, trace elements, etc. For a project in Memphis, we will ship from our West Memphis plant, which is either 95% or 98% recycled content. It's certified by SCS as recycled because the raw material is synthetic gypsum." "Because synthetic gypsum performs the same as natural mined gypsum, there is no distinguishing the two products in UL fire-rated assemblies." I wish they'd think of a better term than "synthetic". I think it's the same chemical material. It just comes from a different source. How 'bout "man-made gypsum"? John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 669 Registered: 03-2002 Posted on Wednesday, March 07, 2007 - 11:27 am:    The power/coal industry seems to call it FGD gypsum, from Flue Gas Desulfurization. Ronald L. Geren, RA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 409 Registered: 03-2003 Posted on Wednesday, March 07, 2007 - 11:45 am:    Call it "gypsum." If there's no difference, why distiguish between the two? Steel is predominately recycled material, but manufacturers don't distiguish between mined materials and recycled materials. If the recycled content is needed for LEED credit or other sustainability documentation, then certifications from the manufacturers can be obtained.