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PART THRE:E PRESIDING CHAIRNIA~- Howard T. Fisher Howard T. Fisher ~ Associates, Inc. Chicago, Ill. Research and New Technical Developments M R . C . E . S ~ ~ ~ ~ N G: Sometime during the confusion of ~ ~ a Harvard education that incluclec] being a teacher, ~ ~ acting as consultant to our Fecleral~ Government and the United Stations, 3 ~ research on land use. housing and integrated buil(ling design, 4 ~ practicing as an architect. 5) presiding over a music school board of trustees, and 6) associating with a variety of professional societies harboring consultants, architects, planners ant! others, your next session chairman found tinge to erect a personal cor- porate facade to cover his manifold activities. ~ ant sure you are all aware of his solid professional accomplishments as an architect and a planner. Ladies and gentTen~en, Mr. Howard T. Fisher, Howard T. Fisher & Asso- ciates, Tnc., Chicago. 51

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Thermal Performance of Clay Masonry Walls R . F ~ s H E R: Mr. Walker this morning made one statement that interested me espe- cially and which T wrote down at the time. He said substantialZy as follows: "The joining of material is more important than the mate- riaZ itself." This is a statement of the very greatest importance in the construction indus- try, and not perhaps generaZZy recognized by all of the manufacturers o f materials and the _1 'r _ r _ ' 1 architects, engineers who are concerned with design. Our first speaker this afternoon is Clarence 17\1onk, manager of the Structural Clay Prod- ucts Research Foundation's Architectural and Engineering Research Division. He is IN recent years designers of air conditioning systems have come to realize that predictions of heat loads based on tile conventional cal- culations (using the "U" factor) gave higher C. B. Monk, Jr. Structural Clay Products Research Foundation. Geneva, III. particularZy concerned with this question of the joining of materials not only how these materials join, but how these materials join other materials-how walls meet roofs how f oors meet partitions, and so on. Mr. Monk was an architectural engineer with the Armour Research Foundation of the Illinois Institute of Technology, and has been an instructor in the civil engineering depart- n~ent of that school anal in the mechanical engineering department of the University of ZZinois. He is a member of the American So- ciety of Civil Engineers and the National Society of Professional Engineers. design requirements than the completed buiid- ings demanded. This experience plus both analytical and experimental findings have high- lighted the importance of the influence of 53

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density and specific heat of building materials on the thermal transmission into and within structures. The usual way of making heat gain (or heat loss ~ calculations is to think of some fixer! outside temperature, perhaps 95 to lL05 F. The inside temperature is usually chosen from some control level, 70 to 80 F. The fixed temperature difference between the outside and inside temperature is the n~eas- ure of the amount of air conditioning ~ or heating) needed as calculated from the k or U factor. The fallacy in these assumptions is thinking in terns of a constant outside ten~- perature. The inside temperature nary be con- stant; we like to have it so. But since the sun rises anc! sets every 74 hours, there is inevitably a rise and fall of outside air ancT building sur- face temperatures. This cycle in heat gains (or losses) is affected to a n~arkec! extent by the mass characteristics of the builcTing materials (specific heat and density) as well as their thermal transmission coefficients. Recent field experience has shown that consideration of the thennal transmission coefficients alone is not a sufficient basis of calculation; specific heat and density are equally important. Specific heat is the measure of the amount of heat requirec] to raise a certain quantity of substance, we'll say; a pound, one degree of temperature. Certainly it takes snore heat to raise the temperature of one pound of water one degree than of one pound of alun~inun~. Archaeologists tell us that primitive Nan soon learned that the continued warmth sus- tained in the stone he heated to cook his food was ren~arkably effective in keeping hint warns over a perioc! of tinge after the fire cried out. In the modern age, the hot water bottle is familiar to all of us. This is a means of con- veying heat by means of specific heat an density. In climatology the influence of n~aritin~e bodies over continental lane] areas on te~- ~4 perature is well known. Cities near the Great Lakes area enjoy higEcr temperatures cluring the winter than cities in the central plains area at the same latitude. The reason is that the relatively higher specific heat of the water means that the water temperature never sinks to the same Tow level as the lancI masses. NVall constructions having high heat storage capacity; (i.e. high specific heat and density characteristics) will dampen the effect of the ~naxin~um rate of heat gain (or Toss). As soon as the ~naxin~un~ outside surface wall tem- perature is reached. the surface begins to cool. As tile outside wall continues to cool, the heat flow that 1las started on its way through the wall at the time the maximum surface tem- perature was reached will be split into a quan- tit~; that will flow out as well as in. This cia~npens the amount of heat finally reaching tile inside surface. The greater the heat stor- age capacity the sneakier will be the instantane- ous rate of heat flow to the interior. Obviously this reduces the capacity size require(1 of the cooling equipment. What floes this mean to Duncan comfort? The (la~npening effect of wall mass wit] reduce the fluctuations of inside wall temperatures. People living in frame houses frequently ex- perience the necessity of setting the thern~o- stat higher to compensate for a rapidly noosing coIc! front which suddenly engulfs the house. This sense of chilling is due to a sudden fluctuation in insicle wall temperatures. In~- ~nediatel~, radiant heat is lost front the Duncan boils; to the wall. Another matter that is of importance is that mass contributes to a lag in time of the heat progressing through the wall. For example, this Slav amount to six or eight hours for a relatively heavy masonry wall, before the heat which has accumulated during the day begins to reach the interior later in the evening. But in the n~eantin~e the external temperatures hex e cTroppecT deciclecITy ancT you can then avail

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yourself of nocturnal cooling by an attic fan. Allis leas been a great benefit in Australia. Their people have e~nployecl this n~etho<1 to the fullest extent, almost eliminating tl~e need for air conditioning systems in low-cost blousing in that particular part of the globe. In sugary, theory and experimental facts to ciate show evidence that high heat storage influences tI~ennal flow in the following ways. T. Reduces the instantaneous rate of lariat gain or loss. The initial size of the air condition- ing or heating equipment may be reduced by; as much as 25-50%. 7. Dampens variation of inside surface ten~- peratures, thus contributing to greater co~n- fort to the incliviclual clue to racliant ex- cI~ange between Lois and his environment. 3. Delays the peak lint Toad reaching the in- terior (time lag) which allows the use of nocturnal cooling by attic fan for uncondi- tionecT space or of favorable electrical rates on air conditioners for conditionecT space. T~_ HEORETICAL L)ISCUSSION Tl~e factors that contribute to the ~nagni- tude ancT variation of surface wall temperatures are complex. Direct solar radiation plus rac:lia- tion frown the atmosphere anc! terrestrial ob- jects are tl~e initial sources of heat. The amount of this latest that goes into the outside wall surface is a function of the reflective characteristics of the surface. Wl~ite or buff surfaces may reflect 40-60~7o of energy received, Wylie dark colors may absorb as much as 90~ and reflect only ~0~. (The building surfaces the~seIves are sending out radiant energy to their total environment to further con~plicate the excl~ange.: As a builcTing is surrounded by air, tem- perature variation in the passing air masses plus the speed of air movement affect the con- vective transfer of heat into a building wail surface. Surface texture characteristics influ- er~ce this phenomenon. The contained effects of solar radiation, air temperature, and air velocity is frequently rep- resented by the "Sol-Air Temperature" which is the equivalent temperature at the weather surface of the wall to give the saline heat flow that actually takes place on to the surface due to the above causes. It is similar to (but by ~nathe~natical definition not exactly) the ten~- peratures of the outside wall surface. Outside air temperatures may hare daily variations ranging front ~ 7 to ~ ~ clegrees on the east coast to 33 to 47 degrees in the Rocky Moun- tain area. It is important to note that the air temperature selclo~n exceecis a n~axin~u~n of 100 to TI0F. whereas the Sol-Air ten~pera- ture may have peaks ranging front ~ 30 to ~ 60 F clepending on the wall surface. Tl~e daily variation in Sol-Air temperature may be 70F on a north wall to /0F for a west wall. The flow of such a periodic heat cycle as cTescribecl above through a builcTing wall is ciepenclent on the physical parameter: Thermal cliflusivitv (`x) a k , PA Adhere k coefficient of thermal transmis slon p density C specific heat It is this physical property that is of signifi- cance in discussing periodic heat flow as op- posecl to k or U for steacly heat transfer. Un- fortunately ~nathe~natical expressions relating this property to heat flow are not in a form suitable for office computation. However the 1950 edition of tile ASHAE Guicle approxi- n~atec] the exact solution as follows: q U ~ t,~-ti ~ + ~ U ~ te-tm ~ Revere q snag. rate of instantaneous heat gain where to= average Sol-Air temperature te= Sol-Air temperature at a tinge earlier by an amount equal to the time lag 55

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ti average inside air temperature g- a factor that ciepencis on the wall thick- ness and orientation. The tinge lag is the delay in the heat gain clue to mass in passing through the wall. For 8" of brick this is theoretically 5.5 hours; for 2" of wood T.3 hours. The two wails have about the sense U factor, yet the theoretical n~axin~um rate of heat gain is 60: greater through the wood for a west wall. The n~axi- ~nun~ heat gain would occur around 6:00 P.M. for the wooc! and 10:00 P.M. for the brick. Exact theoretical solutions taking into ac- count mass effects have been achieved analyti- cally by thermal circuit analysis or experi- ~nentally by electrical or hydraulic analogies. These methods depend on the ~nathen~atical parallel between electrical or fluid flow and heat flow. These exact solutions substantiate the above approximation and emphasize the influence of the heat storage of interior walls in re(lucing peak loacis. ExPER~ExT~ DEs~oN To determine with precision the influence of heat storage on tile thennal performance of cIav ~nasonrv the Structural CIav Products Research Foundation undertook tile experi- ~nental stucly of eight wall constructions: 6 clay n~asonrv;, ~ wood frame, and ~ natal pane! (See Figure ~ for details). The technique of the experiment employed cubical huts (10' :; 10' in plan). Taxis pern~itted erecting 8' 2: 8' HEAT FLOW THROUGH MASONRY 1 500 1 400 10" CAVITY WALL /__ 8" TILE WALL \ \ 6" TILE WALL \ 8" B R IC K WALL '\ 'A- 1 300 , ~ f RAME WALL _ BRICK VENEER _ TRAILER _ METAL PANEL f 6" BRICK WALL FIGURE 1 Plot plan of test site showing ar- ran~,ements of thermal huts. 56 panels in each wall of the but. oriented to the four points of tile compass. Tile purpose of adopting an experimental study on such a relatively large phonological scale was to obtain representati~eness hotly as to flee panel construction and ~orI;n~ansl~ip ancT as to tl~e statistical influences of weather patterns. Smaller specimens were held not to yield this effect. Prior to e~nbarI;ing on flee program it was obvious that much fine theo- retical work had been cone in the field of periodic latest flow. However. for clay masonry, the projection of this theoretical work into practical results depen(led entirely on i(lealizecl mathematical assumptions and on existing laboratory cleter~nination of physical prop- crties. It was felt that the combine(1 influence of all variables subject to periodic weather patterns could best be studiecl by full scale huts. However elaborate the theory, it is no better than tl~e experin~ental ~ ork on which it is based. The use of thermal huts for experimental treat flow studies has been employed by several Con~nonwealth Experin~ental Stations. Scan- dinavian researchers have built then. In this country vapor transmission studies at Penn State and thermal circuit investigations at UCLA are letdown to have used thermal huts. The n~etho(ls of constructing the huts are shown in Figure 7. Each hut rests on a rein- forcecl concrete slalom. The walls are separated front each other at the corners by plywoo(1 colun~ns filled with insulation. The walls were erected on a 12" bed of rigid insulation (k- .34~. The floors are covered with rigid insula- tion board (K=.25) to a depth of 9". The ceilings are insulated with 10" of loose fill in- sulation covered by reflective insulation. The attic space is vented and the roof surfaces are painted alun~inun~. The construction is de- signed to force the heat floss primarily through the wall panels. Figure 3 show-e how access' after the soZid waZZ panels are in place, is pro

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FIGURE 2-View of huts prior to installation of wall panels. viclecT to the inside through~a trap door in the roof. Instrumentation includes thermocouples in each wall (16 in eacl, face plus several ac~cii- or navies TF ~ record of the inside ambient air temperature is continuously, obtained. The instrument sI~eiter contains watt hour meters that measure total power consumption by each lout and flow meters that measure the total flow of water through the air conditioner. Thennopiles measure the temperature gra- ~lient in the air conditioning water. It is ap- parent frown this instrumentation that the total heat flow into the huts may be checlce against the heat re~nove(l. This has been done and found to balance within 3 to 66,7G. NVeather data obtained inclu(le outside ambient air temperature, wind speed, wind direction, amount of precipitation, and solar radiation. Provision exists to measure air con- ditioning condensate (latent heat ~ and hu- ~nidit~; inside each hut. An over-all view of the test installation is shown in Figure 5. i. ~ ~..~..~.~ ~ ~ . .... . ~ FIGURE 4 Instrument shelter housing 144 point longer. FIGURE 3 Typical hut with access trap door open. tional ones of interest within the wall). Three heat flow meters are placed on the inside of each wall (ancT eventually on the outside). Data front these instruments are recorclect (see Figure 4 ~ in an instrument shelter which houses a I14 point logger. The tc~nperature within the huts is ~nain- tained constant with the aid of 3 kw electric heating cements and a sneaks 3~4 ton air con- ditioner. A spiral type ther~noregulator ~nain- tains temperature in the huts to within plus ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ .~ ~ ~ ~ ~ . ~ ~ ~ i. ~ ~ ~ ~.~.~ ~ ~ ~ ~ . ~ it. it. FIGURE 5-Complete test installation. 57

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TES T RESULTS Since tile test project started in Sentencer of 1955, only ciata for the winter season are now available. The influence of heat capacity during the winter season has not been studiecl bv theoretical analysts for it has been assurnecl J J that the range of ciaily temperature variation was greater in the sundrier than in the winter. the incident solar racliation is greater in sun~- ~ner than in winter, and the difference be- tween insicle and outside mean temperatures is n~uch greater in the winter than the sum- mer tending to mask the influence of tee ciaiTy tenaperature range. Due to these consiclera Building Ail Brick Veneer (a Building #2 10" Cavity (c ) Building #3 S" Solid (b) Building #4 "SCRbrick'(b) :3rlilding #> 8" Tile (c) Building #6 6" Tile (c) Building #7 Steel Panel (a) Building #8 Wood Frame ~ a Ma';. Teacup. F Min. Teacup. F Average Wind Nic1. % Possible Sun Precipitation Trace tions the conv~ntior~al steady flow Sterna properties were felt adequate for heating sea- son calculations. Data presented below sug- gest a re-exan~ination of this viewpoint. Table ~ su~nn~arizes the experimentally ob- tainec] Us factors cletern~ined uncler periodic tl~er~nal flow clue to varying weather patterns. This factor represents tile average heat Toss through the walls of the thermal hut for the period of stucly per clegree F temperature dif- ference between average inside ancT outside ambient air (see Table If. Four three-day periods have been chosen as typical results for n~icT-winter ancT earls; spring. TABLE I UV VALUES OBTAINED FROM THERMAL HUT PROGRAM Jan. 10-13 Feb. 3-6 Us i\/Iar. 9-17 A,br. 77-30 .10! .320 .936 9 .47, .507 .767 .092 .297 .421 .452 .339 .394 .189 .1'T 38 78, 15 MPH 6 MPH 0-0-100 100-99-76 NOne .117 .397 .491 .678 .186 .146 .408 .375 .42) .1,0 ( a ) NNiall constmction includes interior Lisle and insulation # ] (b) Interior finish and insulation added between Feb. / and Liar. S. #a. =4 (c) Exposed masonry on interior, - I. ~5. -'6 58 .094 .096 .347 .183 .117 .397 .704 .167 .17) .40& .431 .439 .750 .12) ~9 14 MPH 14 RIPE 100-70-68 7 5-0-0 7.38~, Rain .93/ 775 .150 .179 .110 78 36 .47 3

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A variety; of weather patterl-;~s is represented. The period front Jan. 10-13 represents as near a steacly state as was obtained during the period of record: even here a 10F range was experiencecI. Feb. 3-6 was a period of high temperature range, Tow wincT speecTs, ancT large percent possible sunshine; therefore, cyclic in- fluences shouicT be most pronounced cluring this period. Tile period April 27-30 inclucTecT mostly overcast skies witty consiclerable rain. The Us factors are those calculatecT front tee ASHAE Guide for steady state condition. The one exception is the natal pane} which value was obtained front the manufacturer who reporter! the results of laboratory tests on wall sections inclucTing through-the-war:! metal ties. The construction will not be clescribecl in detail leers, but suffice it to say blat tile clay masonry walls were all composed of red clay units, lightly texturecT. The wall finishes used consisted of conventional furring, blanket in- sulation, ancT ciry wall techniques. The woos] France but was coverer] with white ship-lap sicling. The metal panel was a typical in- Justrial type containing ~ ilk" of Fiberglas insulation with a metal sheet interior finish. Tl~e metal surface being galvanized was left unpainted; this surface has darkened with age. Generally speaking, there is a marked clif- ference between the Us ant] Uv values. The France and metal huts have Uv values above Us; the clay masonry buts have values below. While differences in color do have an effect, it should be noted that the frame was white and the metal was darkened galvanizecT, each representing racliation extremes on both sides of the reel brick color; yet both of these con- structions having sn~all mass showed heat Tosses greater uncler periodic heat flow than predicted front steady state knowledge (10- 20G/G for France and 30-6070 for metal). The clay n~asonr,v (lisplayed Us values that were 0-705 below tee Us values with a trend to smaller differences occurring with the hollow units and larger ctifl:erences with the solid units. A comparison between the brick veneer and France is of interest since these two construc- tions hac] nearly identical Us factors. Yet the veneer experienced heat Tosses roughIv lL0~7O less than caTculatecl, Whereas the France showed 15':0 snore. Maltese two constructions were near- ly iclentical except the outside covering being 4" of red brick in the one anc] I" of white wooc! siding in the other. The table below shows for tile Feb. 3-6 period the daily Us values for the north anc] south walls of the two huts. Us UN North NVall _/ ~ 2/4 2/5 . . . . . . . . . . . . . . . U>. Softly NVall 2/3 2/4 / ~. Brick Wood Veneer Fit ame .112 .110 .118 .135 .119 .148 .12S .131 .069 .096 .067 .11 3 .063 .089 Tllese data, typical of other perio(ls. show that even on tile north wall (where color dif- ferences are n~inin~ized) the veneer values are much less than the frame values. The low Us values of the soutl1 wall are due to the solar radiation received during the day. The data; also point out tile difficulty of choosing an arbitrary U factor to be representative of Motif orientation and periodic effects. Tllose designs based on U factors carried to tile third decimal place suggest an accuracy not warranted. A comparison between the "SCR brick" (a 6" througll-the-wall clay unit) and the metal louts is worth noting. Tl~e insulated values of these walls are roughly the same (.175 and . 150, respectively) . The Uv for the "SCR brick" is on the average 157 under tile Us value whereas flee Uv for the metal is about 507 above. On this basis. if the two waZZs had 59

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identical U factors, 55C:o more heat would be lost through the metal pane, than the "SCR brick." Presumably these differences are due to mass. The experimental determination of Us for the metal panel is reported to have taken into account through-the-wall ties. The darkened thetas surface should have had the advantage in receiving solar radiation to re- cluce treat loss. Thought not studied in as n~ucl~ detail as the U factors above, the maxin~un~ rates of heat loss shown for the brick veneer and frame during the Feb. 3-6 period are: Brick Veneer Wood Frame btu/ fir. btu/ hr. North Wall 2/3 2/4 2/5 South Wall 2/3 . . . 274 . ... ... 2/5 60 500 450 400 400 350 300 600 500 350 600 500 350 Thus tile demands on the capacity of tile heating source were 20WG less in the case of the brick veneer. SUMMARY The results obtained thus far in talc Floral hut program were primarily for the winter season. Contrary to orthodox assumption, periodic heat flow was shown to have a signifi- cant influence on heat losses. Under the periodic heat flow of actual winter weather patterns wall constructions having low mass, such as France and metal panels, were shown to have total heat Tosses significantly greater than front steady state calculations (ranging front 10-20~7o for the France and front 30-40% for the metal). For walls having high mass. such as clay masonry, the total heat losses were less than front a steady state calculation (rang- ing front 0-20~7O ~ . The precise extent to which mass (both density ant] specific heat) affect this result may await future detailed stucly of all the physical parameters concerned.

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Ceramic Veneer Panelizing M R . F ~ s HE R: One of the fine things about these BuiZ6ing Research Institute Con- ferences of this kind is that a wide variety of viewpoints is re,~resented. In contrast to the viewpoint of Err. Monk for the engineers, we have an industriaZ viewpoint expressed by Mr. Barnes who wiZZ speak on ceramic Veneer pane7lizing. EVERY alert November of the buiTcling industry has, ~ awn sure, noted with great interest the trend in recent months toward the extensive use of curtain wall construction. It has become so well known and so widely used that no definition at this time is requirecl. Mender manufacturers of the Architectural Terra Cotta Institute have noted this trend and recognize the obvious merits of curtain wall construction. Albert E. Barnes Cladding, McBean & Company San Francisco, Calif. In ad`lition to his 29-year connection with GZadding, McBean ~ Company as manager of architectural products promotion, Albert E. Barnes is also Secretary of the Architectural Terra Cotta Institute, a past president of the Southern California Chapter of the Producers Council, and a member of the Construction Specifications Institute. As has so often been pointed out, curtain wall design elin~inates the need of a back-up wall, thereby reducing the required wall thick- ness and reducing the weight of the exterior wall. As a matter of fact, there has been a trencT toward thinner mason curtain walls for a number of years and some of the largest and finest recent buildings on the Pacific Coast have had exterior masonry non-Toad bearing walls of S" thickness rather than the 61

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to existing wood or fiber sheathing with spe- cial metal clips to hold it in place. The joints are filled with a real mortar applied through a special pressure gun which we have devel- opecT. Special L-shaped corner units are en~- ployec} so that a genuine brick appearance is achieved. Economic studies inclicate that it can be applied in place and be directly cornpet- itive with many types of residing materials on the market. It also has a very definite place for interior redecoration of existing buildings since it will not require the strengthening of walls or floors to carry its weight. It is currently being test n~arketec! in the Colun~bus, Ohio, area to learn marketing techniques and facts prior to its national introduction to the builcting indus- try. If this new product reaches 10% of its po- tential market it will provide a 58 nonillion clol- lar annual market for our Industry in a ren~od- eling field in which it has never hac] a major foothold. At the present time in another of our major markets it has been established, and ~ ant sure it will be confirmed! tomorrow, that masonry curtain walls are one of the n~ost economic forms of construction available on the market today despite all cIain~s to the contrary by the pane] wall people. Even in the matter of speed of building enclosure, the proper size mason crew for a job can still keep up with the other trades that must complete their work in the over-all construction schecluTe. The one dubi- ous advantage that panel walls today might have lies in their reducer! thickness. In order to protect our future economic position in this field we have been carrying on considerable long-range work in precast panelized wall sec- tions for exterior curtain wall applications. NVe have developed an extremely fast setting cement grout which wit] enable us to produce such panels without large nooks investments. In its exterior applications, such panels are two and one-half inches thick, and reinforce(l to carry tile required wine} anti other structural 84 loads. Only two sizes would be needed in any specific building. It appears that these panels can be produced at a plant price of $~.00 per square foot an(l installed with lath ant! plaster interior for another $~.00 per square foot. We have also produced a structural ceramic glazed clay tile unit four inches thick that has a sound absorption of 60N, and a sound trans- emission loss of 47 db. unplastered and 54 db. plastere(1 on the back sicle. Production equip- ~nent for this tile is currently being (developed. A process for the production of economic lightweight clay units has also been developecI, and is currently being refiners on a pilot plant scale. It wit! permit a reduction of weight for structural brick an(1 tile units of 40GNo in addi- tion to that weight saved through coring. In other words, a current five pound brick wouic! weigh three pounces and the eight pound "SCR brick" would weigh less than five pounds. This lightweight process provides sealed cells, and the water absorption of such units is not appre- ciably higher than current clay bodies. Our process, which we believe to be unique, will permit the production of such units by nearly every one of our November manufacturers de- spite the great variation in clay properties that exists in our industry. It will permit a greater control of unit size, and will make grinding to exact size an economic possibility. Best of all, it can be pro(luced with the existing facilities of our industry without requiring that they be obsoleted or discarclec] before this development can be offered to the construction industry. Another important current phase of activity of the Foundation involves physical research to learn new facts about the behavior of clay masonry walls front a thern~al transmission basis. ~ believe we have the most elaborate buil(ling thorns research program uncler way in the country. We have built six test buildings with six different types of masonry wall con- struction, ant} one identical builcling with metal pane} walls and another iclentical build

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ing with wood France walls. Each building is heater! anc] eoolecT as desired by a special air conditioner and electrical heating device. Hun- drecis of thermocouples and dozens of heat flow meters are employecT plus a very elaborate control ancT instrumentation builcling. These tests are already showing that the thermal ea- paeity of masonry walls can be a deeicled factor in reclueing the initial size ancT cost of heating and cooling plants. They are definitely show- ing that the U-faetor of a wall is not necessarily the only factor that will cletern~ine the thorns perforn~anee in a building of a given wall eon- struetion. The first public progress report on the results of this research has been given to this conference earlier tociay by Mr. C. B. :Monk. Fundan~ental research into mortars has be- gun to show real progress. Certain cement eon~binations currently under study are devel- oping ultimate bond strengths in excess of 700 psi, instead of the name usual 50 psi. It is still a mortar that can be handIec! with the trowel. Funcia~nental research into efflores- eenee and greenstaining is cleveloping knowI- edge that is aIreacly being en~ployed in some of our plants to recluee this problem in wall ap- pearanee. Tmprovec] methods of cleaning n~or- tar stains from masonry have also been cle- veloped. In connection with effloreseenee, ~ would like to eall the following facts to your atten- tion. Sonnetizes on a given building, arehi- teets, contractors ant! owners fins! effloreseenee on eIay units which in the past have never giv- en then any trouble. It must be remembered that effloreseenee means that there was water within the wall to carry soluble salts to the sur- faee. Without such water, regardless of where it originates, effloreseenee cannot oeeur. We have also established that even if the brick is absolutely effloreseenee free, serious amounts of effloreseenee can result if there are soluble salts in either the mortar or the back-up ma sonry materials. It has also been established that even if the bricklaying workmanship is perfect so that water cannot enter the exterior face of the wall, effloreseenee can still occur if proper flashings have not been installed at crit- ical points in the building or if moisture vapor is not prevented by suitable vapor barriers front entering the wall from the interior side. A large amount of our work in the past and present involves architectural research studies. For example, facing tile shapes are being an- alyzed with a view to a sin~plification of shapes to reduce plant production and inventory prob- len~s as well as the design of such walls by the architect. It is believed that this study will per- ~nit more rapid deliveries of facing tile to the public ant! will make estimating of facing tile a much simpler procedure. Architecturally and structurally we have also stucliecT school construction requirements and costs. There has been a substantial amount of publicity given to purported] savings in school construction costs by means of prefabrication of buildings constructed of either metal or wood. Widespread claims have been made that such schools can be erectec] for the school boars! at classroom costs of 15 to 20 thousand dollars. This has been coupled with the claim that this cost is one-third or less of the usual typical masonry school which has been stated to be as high as 50 thousand dollars a cIass- roon~. Our school cost studies have shown the "per classroom cost figure" to be completely misleading. On a recent public platform with Nile one of the prefabricated school suppliers stated that they had just completed a six cIass- room school for $120,000, or $30,000 per cIass- room. The square foot cost of his buildings however, turned out to be more than AS per square foot of space. There are many, many masonry schools being built today in all parts of the country for costs of 10 to 12 clolIars per square foot. Further, they provide the school board with yearly savings in the form of low 85

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maintenance and operating costs, real fire pro- tection for the students and the wealth of color ancT architectural form that architects can so well fit to the local site ancT surroundings. In a (lesire to provide a simplified design for even lower cost masonry schools we have also developecl a concept of load bearing interior wall construction that, in the Chicago area, can pennit econon~ical masonry school construc- tion at an estin~atecT $8.35 per square foot in- clucTing the mechanical services. ~ sin~ilar cost study in Texas employing this concept yielcled an estimated cost of $7.14 per square foot. However, contracts for three schools of this type leave since been let in Texas at square foot costs of $6.7l, $6.86 and $7.25, respectively. This is dramatic proof that real utilization of the structural properties of masonry combined with the attendant savings in the roof and framing structure can result in a balanced de . , . sign or maxllnum economy. A recent phase of our work that has been extremely interesting is a series of high explo- sive shock loading tests of various masonry walls. In the final test, ~ walls were simulta- neously tested in an octagon test-fixture ap- proximately 30 feet in dian~eter. Four of the walls were n~ounted as vertical beans, 9 x 10 feet in size. These were: ~ a ~ standard S" brick and block construction; (b) S" rein- forced lightweight concrete block; (c) 9" re- inforcec] grouted brick wall with the same amount of steed as in "b"; (cT) 9" reinforced grouter] brick wall with twice the steel of "b" and "c". The other four walls were testecI as horizontal beans with end restraint against pilaster-type piers to develop "arching" action. These walls were 10 x 9 feet in size. They were: ~ e ~ S" brick wall ~ unreinforced ); ~ f ~ 12" brick wall (unreinforcecl); (g) 9" rein- forced grouted brick wall with the same steel as "b" and "c"; (h ) 6" "SCR brick" wall with ~ pencil rods in every other horizontal mortar joint. 86 Forty-five pounds of high explosive were detonated within the octagon, developing a peak surface pressure of 140 psi for 3 miTTi- seconds. This is in excess of the energy im- puIse sustained at 4700 feet front ground zero during Operation Cue's atomic building test in 1955. At that time, wall "a" in a two-story home failed, and wall "b" in a one-story structure withstood the blast. In our test, these two walls were employed as control speci- n~ens to provide direct comparison with Opera- tion Cue performance. In our test, wall "a" was co~npleteliy de- n~olished as at Operation Cue and wall "b", which survived Operation Cue, was completely destroyed. All six of the other walls stayed in- tact and were all structuraZZy sound after the tests. This dramatically illustrates the fact that economical brick walls can be designed to withstand the tremendous lateral pressures generated in atomic blasts, earthquakes, hurri- canes and tornadoes. The engineering design criteria developed in this program are being assembled into a "hand-book for blast resistant design" to be released to the architectural and engineering profession this fall. We began our research effort in 1950 be J employing the technical and industrial re- search facilities and staff of Armour Research Foundation of Illinois Institute of Technology. This was supplemented by contractual arrange- ~nents for our architectural research witl1 tile architectural firm of Howard T. Fisher Nz Asso- ciates of Chicago. In ~ 95 ~ we leases] labora- tory space of our own to supplement the con- cract work, and began to acquire our own staff and equipment as our objectives and programs began to develop and nature. In 1954, our n~anagen~ent demonstrated its faith in its research effort by authorizing the establishment and construction of a new na- tional Research Center for our industry. It was built on a 15-acre site 40 unites west of

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Chicago in Geneva, Illinois, and occupied last fall. \Vithin the engineering section of this buiTcling full size two-story tonnes, or two-story prototypes of a n~ulti-stor,v builcling, can be erected to stucly engineering ancT construction techniques anc] to develop short cuts that will result in lower construction costs. Space Las also been provided for the establishn~ent of pilot plant production lines such as for the automatic packaging machine and for tee pilot production of pre-cast wall sections. Facilities have been provided for engineering stucly ancl testing of full size wall sections for water penneabilit~i ancT for compressive, transverse and racking strength. Complete ceramic re- search facilities of both a funcian~ental and production nature Lave been installecI. En- gineering ancT architectural laboratories have been provicled. Sufficient :lanc] is available at the site to permit tile outdoor erection of full size prototype structures to test builcling tecL niques and materials clevelopecl in the labora- tor~;. For speciaTizec] personnel or equipment, or for certain projects of short duration, we still intend to employ tile services of establisllec! research organizations. The Foundation with its adequate reserves, new facilities anc] trainee] stab, is cleclicated to the in~prove~nent of masonry structures and to the development of more economical ways in WIliCI1 to buiT(1 tiled. Research leas given our industry a new Took into its future a new confidence in that future a future of better present products, and with new products for new markets. It has en- couragecl the Industry to increase its capacity by snore titan 20: in 1955 an(l 1956. Truly, research is enlarging tile frontiers for brick and tile and we are confident that our inclustrv will continue to maintain its pre-en~inent position in the construction industry, Motif today and to~norro~7. 87

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Discussion M R . F ~ s H E R: Our first question is di- rected to Mr. Howe: With expansion and contraction in New England temperature ranges, what is the maximum size sheet recom- ~nended for n~arble veneer if maintenance of joints is desired? M R . H o sv E: T think we said this ~orn ing that the n~axin~un~ size is what the quarry would produce, but it would vary some on the quarry itself as to size. But I'cI think the naximun~ panels would be somewhere in the neighborhood of six to seven feet long and three to four feet high. Although the other clay we had one ~ 5-foot square. M R . F ~ s H E R: Mr. Taylor, what provi- sion was Inane in your blast tests to com- pensate for the pressure relief afforded] by the failure of walls in determining the resistance to the blast? M R . T A Y ~ O R: Tile velocity of the mass propagation and the short duration of tile total blast of only three milliseconds. Our pressure measurements incTicated that there was no cti~ninution of an;; specific wall, because two walls went out. M R . F ~ s H E R: Here is another question to Mr. Howe: Is any serious work being clone toward structural applications of natural stones, such as prestressed stone assemblages, utilizing new cutting methods and high strength, low creep characteristics of stone? M R . H o w E: ~ don't believe so. MR . FISHER: In these panels Mr. Taylor just spoke of, they are using the brick structurally there. ~ think they first asked that question, wondering if any similar work was being (lone in the marble field. MR. HOWE: I'm not on the research committee of our institute, but ~ have not heard that they are starting that as yet. M R. F ~ s H E R: Here is a question for Mr. Monk. If you had used a porcelain enameled pane] instead of a galvanized one, would your results have been any different? MR . M ONK: The only difference wouIcl have been in the color. And you will note that 89

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~ e~phasizecT, but ~ clicIn't have a chance to explain it, that the France Lut was white. The metal hut happened to change to a ciark color, so we hacT two extremes of color so far as mass was concerned. The enamel, of course, wouIc] be somewhere between these two extremes. The difference probabiv wouicT be onIv in J J color, and therefore it wouicT be someplace between ~ ~ per cent ancT 50 per cent heat Toss in excess of what you can expect with Horns U factors. ~ R. F ~ s ~ E R: There is a general question to all of the technical speakers this afternoon. If the jointing material for masonry is more important than the masonry n~ateriaT itself, whv taken has this important factor of n~asonrv J J work not receiver] more discussion by techni- cal speakers of this conference? Before passing that question on, ~ wouIcl like to sac- it is no own ingression that a J J considerable portion has clealt with the rela- tionship to the jointing between panels. Who wouIc] care to comment? Mr. Taylor? \{ R. T A Y ~ O R: Front nay point of view, I'c! say it takes approximately 75 per cent of our total research, both in the prefabricated panels and research having to do with stanciard type units. AncT we have work, as ~ mentioned, where we have achieved 200 psi bond strength compared to '0 psi. We also have evaTuatecT mortars. It's a very important thing, because the strength of a clay wall is no better than that of its weakest component, which in this case happens to be mortar. And it is essential, to get the best results, that the design of our inclustr,nT's products follow the kinds of speci- fication we know will really give good per for~nance. M R. F ~ s H E R: WOUI] anv~oUv else like , , to comment on that last question? Mr. Mc- Knight? 90 M a. M e K N ~ G H T : T think, Mr. Fisher, along with joining mortar tilers has been quite a revolution in the mastic industry in tee last year with some new discoveries in mastics, which we Lave usec! in broadening our scope in joining these panels. M R. F ~ s H E R: How permanent are tee penetrating stains to outdoor exposure? Mr. McKnigllt. M R. M e K N ~ G T-T T: NVe have run some of the most elaborate barometer tests possible with the latest equipment. NVe know (lefinite- Ty that we can penetrate with special spraying cquip~nent the stain to a clepth of a quarter of an inch. Tllat is consiclrecT an average because we clo have some variance of natural n~aterial. Groin all indications frown the technicians and engineers, we can say, for all reasonable appli- cations, it is good for 15 years. M R. F ~ s ~ E R: Mr. Barnes, can satisfactory lateral (reflection of one story with respect to the next be per~nittecl, say /-inch per story;, with safety to the panels? ~ assume the ques- tioner has in noting! the wind stresses on the building possibly cracking the terra cotta. M R. B A R N ~ S: We were faced with that on a recent project in Oakland, where it was ex- pressed in IS of an inch drift per story. what depends entirely on the connection and it is quite practical, and the material itself is very adaptable to the proper connection for that. M R. F ~ s H E R: What is the effect of stack bond versus running bond in RBM? Mr. Dickey isn't on our pane] at the moment. Would he care to convenient on that front the floor? Someone said this morning they thought it would not have too much effect on the strength. M R. D ~ c ~ E Y: Yes. Normally the engi- neers just don't like to fool; at tile stack boncI. It (loesn't look as strong, lent the tests show

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that we shouldn't Took clown at stack bond, that we should be snore optimistic. Tests showed that reinforced stack bone! wouIcI be just as good as your design valuation but that your unreinforced running bond would be eight tinges as good, which wouIcT indicate an extremely 1ligl1 factor of safety in masonry. M R. F ~ s ~ E R: What is the relative cost of cut stone and clay brick-say a cost per cubic foot? What is the ~nini~nu~ thickness of stone paneling? Mr. McKnigllt? M R. ~ C K N ~ G H I: Well, Mr. Fishier, there are several things teat are contingent here. For one thing, freight rates, location of the job. But for the roost part, you have the source of brick near every metropolitan area in the country;. Whereas limestone is very limited as to its location in areas. With regard to that last question on tl~ick- ness of our panels, today we are working on two incises. They have been adapted ancT are being applier! now to the two-inch thickness. We flack it clown to one inch, but at the present tinge our specifications call for the two-inch thickness. MR. Fisher: Mr. Taylor and Mr. Monk, Las any research been done on tile prospect of reducing tee thickness of joints on S.G.F.T. I'n~ not sure just what this means without grinding on the job, especially clouble-faced partitions? Can you continent on the general problem, Mr. Taylor, of joint thickness ant] flow you look upon it in the future research? MR. TAYL OR: It is a very important problem, and the control of clay to an exact size is often difficult in solve of our clay procT- ucts. But in terms of some cloul~le-faced parti- tions, they are available in some places in this country in two colors. The surfaces are glazecT. Sucks units are available in certain tripes of manufacture units tociay. We do fee] that when we leave a lightweight aggregate that we . . wit] cone even closer to having that sense control size available in all of our clay; products. M R. F ~ s H E R: How creep floes the color stain penetrate limestone, and can it be ap- plie(1 on tile job? Mr. McKnight? M R. :~! C K N ~ G H T: ~ think, Mr. Fisher, that ~ answered that question a minute ago when ~ said as an average the stain can now penetrate to a point of 3/16 of an inch to a quarter of an inch, according to the density of a product. You have to understand tllat, witty tile process of taxis special spraying equip- n~ent, you can put the stain into the stone with an absorption point where it will last for ~ 5 or 20 years. But you also have to take into consideration that stone is a natural product anc! will vary maybe son~etin~es within four or five feet running length. But ~ ant speaking now of tile average, and we wit] say it is 3/16 of an inch as the average and is good without any noticeable fading for 15 years. M R. ~ ~ s H E R: What are the limitations in the use of I~ighly-colorecl and figured ~nar- bles for very thin stabs? Mr. Ilowe? M R. H 0 w E: Well, of course up to this tilde we have used generally what we call the sound Garlic. But stuclics are going on, ancT T awn sure in the clays to come we wit] finch ways to perfect nature's shortcomings to use the colorcc! marble very successfully. M R. F ~ s H E R: Tllis is in connection with granite ancT marble research. How are the marble panels attached to tile buiTcling frame to prevent moisture pcnctration, to per- ~nit structural cleflection, but to be safe in earthquakes? Mr. Howe? Ma. HOWE: ~ clon't believe that ~ will attempt to answer that, sir. Of course on the west coast the present requirement is that tile n~arble panel, as an orclinar-y veneer, is joined 91

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to the structural wall. I'm not experienced with this earthquake question. M R. F ~ s H E R: Mr. Barnes, what type of material is used for the intermediate or false joints in your panel? How was a satisfactory bond effected? MR. BARNES: The jointing mortar, ~ presume, is what is referred to, between the various elements of ceramic veneer in the one panel; ant] that is a rather dense jointing mortar application, approximately one to three, with one quarter part lime and a small amount of ammonium stearate added. What was the other part of that question? MR. F~sHER: Well, it's justthe same question, how is the satisfactory bond effected? assume the material achieves that. M R. B A R N E s: Yes, it will. if tile bone] material is well dampened, there is no problem on the bond. M R. F ~ s H E R: Mr. McKnight, are these penetrating stains inorganic colors? M R. M c K N ~ G H T : Yes, they are. These stains have been cleveloped not through our own laboratory anc] engineering abilities or facilities, but we have gone to some of the major chemical companies throughout the United States, told them what we were after, told them what the potential was, and they in turn worked with us in this coordinated effort in developing the stain. As a matter of fact, soda`; has been the first tinge a member of the Institute has released then; and the specifications preparer! for them will be distributed to the construction indus- try in the near future. M R . F ~ s I! E R: Mr. Taylor, your insti- tute has in the past frowned on silicones as a surface water-repellent treatment for brick, 92 etc., presumably because of suppression of efflorescence and hence promotion of spelling. T.s the Institute still committe.`l In that nosi M R. TA Y ~ O R: ~ have had experience with silicones and a knowlecige of them for a very long tinge. In fact one of my best per- sonal friends, probably, is the inventor and original developer of silicones; and ]: ant the first to admit that they wit} stop penetration of water through certain size pores and with a breathing action remaining. But they will not span, necessarily, cracks of more than a certain size, nor will they close up joint mortar cracked by erosion or other types of defects, unless the wall is first tuckpointed. I spoke about some of the danger of efflorescence due to interior water entering the wall from other sources. We leave firm proof and we have a building to point to in which silicone was put on it to cure the leaking condition that existed, without first putting the building into good masonry repair. And more than half the brick in that building have spelled. There are slabs a half-incl~ thick around the base of the build- ing. And silicone applied properly; wiT1 do a good job with masonry where special condi- tions make it necessary to use it. But T would hate to be the guy that put silicones on a building, made the decision to do it, and have to pick up the tab for rebuilding the building. And that is why we take that position. At one tinge our industry even considered supplying and furnishing contractors with silicone that we'd mix in our own plants. But we had to abandon that. It happens that, when soluble salts in the brick or mortar are dissolved, that solution of salt moves to the surface like normal water, only it is carrying efflorescence salts. When it reaches the silicone, it can moire no further, so evaporation of the liquid takes place at this point, because the surface is porous and crystal pressure develops which

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can be as much as 4,000 or 5,000 psi locally or cause splitting of the brick itself. M R . F ~ s H E R: Mr. McKnight, do your through-wall pane} tests indicate that the use of Tectun~ insulation board, as the back-up for your exterior stone panels, afforcIs sufficient water resistance to repel driving water surface penetration front rain storms? MR. MeK~cHT: We have run tests on this natural stone facing utilizing a number of welI-known insulating n~aterials. The use of Tectun~ for a complete through-wall panel is, however, still in the testing stage. We have not as vet officialIv released such a wall for J J recommended use, but anticipate cloing so in the very near future. My picture of a through-wall stone faced composite was not Tectun~ but fount glass nanufacturecT by Pittsburgh Corning Corpora- tion. The many tests we have run for thin natural stone wall panels in combination with insula- tion n~eclia have successfully passed our labora- tory requirements. The U factor has been highly satisfactory. It should be noted that the insulation part of the unit assumes no structural function. It is, rather, a ~nediun~ to which natural stone facing or possibly a natural aggregate composite can be bonded. The other type of pane] which we have re leased will probably mostly be used in the cona- mercial field. On this panel we apply several thin stone pieces to a single sheet of Tectun~. In this manner we can construct a thin, stone-faced panel of aIn~ost any reasonable size. We are negating use of this development on a large shopping center at Indianapolis. The panels we use there are lL0' high and 30" wide ant} consist of 2" of limestone n~echani- cally fastened to 7" of Tectun~. The masons working with this new material for the first tinge anywhere achieve a setting rate of ap- proximately 1,700 square feet per day. This is not a complete through-wall. But the con~- bination of natural stone and insulation re- duces the wall weight in addition to providing a high insulation value, low cost, and sheerly erection. The panels are anchored into the back-up of structural steel with strap anchors and clowels. This type of construction is highly practical ant] may be adapted to many (resigns. M R. S I L L I N G: ~ think one of the most interesting things about these sessions that I have always found tremendously impressive, and that has impressed people front other countries who visit technical sessions in Ameri- ca, is to find the wheels within wheels. And while they may respectively rub abrasively against each other, T invite you to remember that they also do interlock; and T think that is a very interesting commentary on industry and private enterprise in America. 93

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