Document 4Jbog6nmG3J23X3zgVwQjYZYe

FILE NAME: WR Grace (WRG) DATE: Unknown DOC#: WRG302 DOCUMENT DESCRIPTION: 0000 Unpublished Internal Report Vermiculite Fireproofing Past and Present 4 * , " VERMICULITE FIREPROOFING Pa st an.d Present The old prospector poked s le e p i ly a t the remains of the previous evening's f i r e . He had-banked i t c a r e f u l l y and here and there tongues of flame f lic k e r e d in the hot bed of c o a ls . As the f i r s t rayfe of suntight shot down from the ridge to the east h?s eye caught the g l i n t o f gold in the bankings he had used. His disappointment was considerable when he discovered that what a t f i r s t appeared to be pea siz e d nuggets of the precious metal were o nly granules of an almost w eig htless laminated . t . golden m ineral. ' Whether t h is or other e q u ally p la u s ib le s t o r ie s o f the ? discovery-are the real truth is r e la tiv e ly unimportant but th is one serves w ell to point up the p r in c ip a l p hysical p roperties * l of the mineral v e rm ic u lite and the industry which developed from its discovery. |* x * t ' The time would have been s h o r t ly a f t e r the end of World War I . The p lacet the Rocky Mountain area in Montana near the Canadian border. Present day maps show the s i t e as Libby* Montana, where the townspeople w i l l t e l l you w ith unabashed p rid e that they have the la rg e s t v e rm icu lite deposit and mining operation in the world and that the ne arly seven m illio n d o lla rs Zonolite is p re s e n tly spending on new f a c i l i t i e s w i l l t r i p l e the ca p a c ity . 't . . o f the operation by l?7 k . . A . ** . -2 When the old prospector banked his lonely f i r e that night some f i f t y odd years ago the presence of the small brown mica lik e fla k e s in the earth he used probably went unnoticed. C e r t a in ly he would have had no way of knowing that these flakes were composed of m icro sco p ica lly thin laminates, between which were entrapped water c e l l s . As the flak es grew hot from contact with the coals the water c e l l s turned to steam forcing the laminates to separate. At the same time o x id iza tio n was occurring . and the co lo r changed from dark brown to a high ly r e f le c t iv e gold. The r e s u lt was a granular m aterial roughly ten times the o rig in a l s f 2 e. impervious to f i r e , and an e x c e lle n t in su la to r. E a r ly marketing of the new discovery concentrated on the home in su la tio n f i e l d High re s is ta n c e to f i r e , permanence, lightweight and ease of in s t a lla t i o n found ready acceptance in the market p lace. The remarkable a b i l i t y to ship ore in concentrated form and expand i t a t s t r a t e g i c a l l y located p lants made the new product an economic success from the s t a r t . i i t was World War II however, that gave i . entree to the Construction Industry and the i today. | " the fledgling business uses which are so common The f i r s t major job was the M ercantile National Bank Building in O a lla s , Texas. As was common p ra c tic e the ste e l was to have \ i I been encased in Concrete for f i r e protection. At the la s t minute K\ ' ' 1 however the government cut the ste e l tonnage a llo c a tio n and i t was 3 mandatory t.hat another f i r e protection method be devised to elim in a te the dead load fa cto r of the concrete. A f i r e te s t of v e rm ic u lite -p o rtla n d cement was run at the National Bureau of Standards and passed. The s te e l was redesigned and the p ro ject was b u i l t with the same usable space, but with only 2/3 of the steel required in the o rig in al design. The high f i r e r e s is ta n c e of the ve rm icu lite -p o rtlan d cement combination came to the atte n tio n of the m ilit a r y and with the impending th reat of bombing attacks on our m ilit a r y in s t a lla t io n s thousands of cu b ic yards were poured on roofs of defense f a c i l i t i e s . The Pentagon B u ild in g alone required 275 carloads of expanded verm iculite to complete the in s ta lla tio n . The use of v e rm ic u lite concrete has continued to grow and today a national group of over 100 C e r t if ie d Roof Deck A pplicators pour an estimated m illion square feet of insulating concrete an n u ally. A wide range of systems is a v a ila b le for in s t a lla t io n over s tru c tu ra l concrete or steel decks providing high in s u la tio n v a lu e s, permanence, proper drainage and maximum fire resistance. i . The end of World War II was marked by an immediate revival of the p riv a te sector of the Construction Industry. A ll m aterials were in sho rt supply and ste e l was one of the most c r i t i c a l . If the n e e d s o f the country were to be met A rchitects*and Engineers- were going to have to u t i l i z e every tori to the ijiaximum. Again v mk~ v e rm ic u llte played a major r o le . Research and te s tin g had continued and a number of assemblies had s u c c e s s f u lly passed F*ire Tests at Underwriters' Lab o rato rie s. Gypsum had replaced portland cement as the binder with resu ltin g reduction in thickness requirements and a p p lic a tio n time. The West Coast led the way in acceptance of the new concept. Two major p ro je c ts in Los Angeles, the R ic h f ie ld O il 8uilding and the Prudential Insurance Building amazed old timers in the . co n stru ctio n f i e l d with major reductions in ste e l tonnage and completion schedule. Metal lath and v e rm ic u llte gypsum p la s t e r for columns and v e rm ic u lite p la s t e r suspended c e ilin g s had permanently replaced the old slow cumbersome and expensive procedure of e re ctin g wood forms around every member of the ste e l frame and then ted io usly f i l l i n g each form with concrete. Metal la th and p la s t e r f i r e protection continued as the standarc through the r e s t of the i0's and into the mid f i f t i e s . Other forces were a t work however which were destined to replace the new concept by the end of that decade. In England laboratory work was being done with d ir e c t ly ap p liec asbestos f ib e r encasement of s tru c tu r a l s t e e l . Reports reaching the United S tates indicated that the method had considerable promis-: Not to be outdone by t h e ir European counterparts work was starte d on d ir e c t ap p lica tio n of v e rm ic u lite . v 5- Introduction and widespread use of the p la s t e r pump accelerated in te re s t in the idea and in 1958 the f i r s t formulations were ready for testing. Old timers in the p la s te r in g business w i ll r e c a ll that one ' of the major breakthroughs in membrane fire p ro o fin g was a v e rm ic u lite a co u stica l p la s t e r c e i l i n g . The system had passed the f i r e te st with a 4 hour rating and gave the p la s te r in g industry its f i r s t fir e rated acoustical ce ilin g . The b a s ic formula for that a c o u s tic a l p la s t e r was modified and became the f i r s t v e rm ic u lite based m aterial to pass the f i r e te s t for d ir e c t a p p lic a tio n on s t e e l . The new system was r e a d ily accepted by the design p ro fessio n . Heating, a i r conditioning and lig h tin g of major stru ctu re s had become exceedingly complex and the n e c e s s ity to maintain the ' in t e g r ity of membrane f i r e r e s is t a n t c e ili n g s made proper design even more d i f f i c u l t . The new fire p ro o fin g system,because it was d i r e c t l y on the s te e l and out of the way, provided complete f l e x i b i l i t y and a much wider choice in fin ish e d c e ili n g s . i t was obvious too, that the new approach was fa ste r and more economical than metal lath and p la s t e r . Elim inatio n of the time and expense of lathing accounted for most of the savings. A number of West Coast build ing s were f i r e protected with the new system during the next few years. Among the f i r s t were the Zellerb ach Building in San F ra n c is c o , a C a lif o r n ia State O ffic e Buil'ding in Oakland and another in Los Angeles. * * 6" The new m aterial was d i f f i c u l t to handle in the f i e l d , improvement in a p p lic a tio n and reduction in thickness was needed. M0N0*K0TE^ fire p ro o fin g was the r e s u lt , and i t became the Vermiculite Industry standard. . in I 9 6 S rumblings were heard of a p o ssib le health hazard In the use of d ir e c t ly applied fireproofing m a te ria ls, which contained asb esto s. The percentage of asbestos in the M0N0-K0TE fire p ro o fin g formulation was low and i t was not believed that its use co n stitu te d a health hazard. To confirm th is b e lie f a job s i t e a i r sampling was done on p ro je cts in a l l parts of the country. The stu d ies showed that because M0N0-K0TE was low in asbestos content and was premixed with water and applied in a wet s ta te the asbestos p a r t ic u la t e matter at job s i t e s was well below government e sta b lish e d Threshold Limut Values. The co n siste n t clamor of the Environm entalists continued and i t was decided that an asbestos free product was ad visab le. M0N0-K0TE Type IV Asbestos Free Firep roo fin g was f i r e tested in 1971 and is now a v a ilja b le for use when required. While the asbestos controversy was raging a more subdued i change but one with f a r greater e f f e c t s on the industry was slowly working it s way through the E5 Conmittee of the American Society for Testing M a te ria ls . This Committee is responsible for w ritin g the te s t procedure to determine the F i r e Resistance provided by b u ild ing m a te ria ls and construction assem blies. The te s f procedure in use u n til January 1, 1972, had been adopted o r ig in a lly in 1908. I t is designated as ASTM Test Method E-119. v -7 Serious doubts had a rise n in recent years about the adequacy of this particular test. Assemblies were not performing in F ir e Tests in the manner ind icated by the known performance c h a r a c t e r i s t i c s of the m a te r ia ls . I t is known that the t e n s ile strength of s te e l f a l l s o ff sharply a t temperatures *between 1000o F. and 1200o F. Contrary to t h i s , s te e l beams were passing the f i r e te s ts with temperatures which sometimes reached 1800 F. to 2000 F. F i r e te s ts are conducted in a massive reinforced concrete c e ll which r e s is t s the expansion of the specimen as the temperatures r i s e . The forces developed puts the assembly in compression with a resultant increase in its load carrying cap acity. F a ilu re only occurs then at temperatures exceeding those which would cause f a il u r e in an actual b u ild in g f i r e where the restraining forces are not p resent. Several years ago San F ra n cisco , Los Angeles and Uniform B u ild in g Code o f f i c i a l s recognized th is d e fic ie n c y in the f i r e t e s t procedure and had e sta b lish e d t h e ir own c r i t e r i a for acceptance based s o l e l y on temperature. F a ilu r e point was e stab lish e d at 1000 F. average a t any quarter sectio n or 1200 F. at any s in g le point. i . ! The ASTM E-5 Committee worked for 10 years tryin g to develop a new t e s t but i t wasn't u n til 1970 that a compromise solution was f in a lly reached. The re v isio n s are complicated and confusing and there are thos who b e lie v e that the problem has been compounded rather than solved. % -8 In it s sim plest form the new f i r e te s t provides for two ratings RESTRAINED and UNRESTRAINED. Under its provisions portions of a b u ild in g can be considered restrain ed while other portions of the same b u ild in g could be unrestrained. Temperature lim it a tio n s have been e sta b lish e d for a l l beams and flo o r assemblies but a time fa cto r has been introduced which provides that in the te s tin g of beams in the restrained condition the temperature of the ste e l s h a ll not exceed 1100 F. average or 1300 F. maximum at any point for at le a s t one hour or for one h a lf of the c l a s s i f i c a t i o n period. A Restrained beam then could be rated a t k hours i f i t sustained it s design load for k hours and the lim it in g temperatures were not exceeded for 2 hours. In the case of Unrestrained beams the temperature lim ita tio n s cannot be exceeded during the e n t ir e c l a s s i f i c a t i o n period. A k hour Unrestrained beam then would have to be protected with s u f f ic i e n t m aterial to prevent a temperature r is e exceeding the 1100 F, average or 1300 F. maximum at any point for the f u ll 4 hours. Obviously the Unrestrained beam requirements are much more severe, and except fo r a 100 d iffe re n ce in temperature are s im ila r to the present San F ra n c is c o , Los Angeles and the Uniform Building Code requirements. Floor and Roof Assembly Tests have a lso been revised . They must be f u l l y loaded and c a r ry the load for the f u ll time period. Temperature transm ission through the flo o r or roof cannot exceed 250o F. average or more than 325o F. at any point. Cotton waste * -9- on the unexposed sid e cannot ig nite from passage of hot gas or . flame. This portion of the te s t procedure has not been changed but a new element has been added. The beam supporting the flo o r or roof assembly is now considered an integral part of the assembl-. The requirements for the beams in restrain e d or unrestrained floors or roofs is id e n tic a l to those outlined p re vio u sly for beams only. In unrestrained flo o rs or roofs one other provision has been added. The temperature of the s te e l from which the deck is f a b r ic ; cannot exceed 1100 F. during the e n tire c la s s if ic a t io n period. Column t e s t s have not been changed. F a ilu r e is based on temperature and occurs when temperatures exceed 1000 F. at any quarter se c tio n of the member or 1200 F. at any s in g le p o in t. Tb same te s t procedure and temperature lim ita tio n s are a p p lica b le to both s te e l and concrete co n stru ctio n .. The whole te s t procedure has been furth er complicated by f a i' of the E-5 Committee to define RESTRAINT in r e a l i s t i c terms. It reads as follows "Floor and Roof Assemblies arid individual beams in b uild ing s s h a ll be considered restrain e d when the surrounding or supporting structure is capable of resistin g substantial them' expansion throughout the range of an ticip a te d elevated temperatur Constructions not complying with th is d e f in it io n are assumed to b fre e to rotate and expand and s h a l l , th erefo re, be considered as unrestrained." k 10 This language is so broad and so vague that many feel that only the s tru c tu r a l engineer who designed the build ing can determine what is restrain e d or unrestrained. There are even those who i n s i s t that such a determination cannot be made r e a l i s t i c a l l y ^ that f i r e loading changes in stru ctu re s and who can say what is "su b stan tial thermal expansion" or "anticipated elevated temperatures". It is t h is group who have fo r p ra c tic a l purposes rejected the "RESTRAINED" c r i t e r i a and wi l l use the more p r a c t ic a l "UNRESTRAINED" co nd ition. The next few years w i l l be d i f f i c u l t and r is k y fo r everyone concerned but it wi l l be p a r t i c u l a r l y so fo r those who are bidding and are doing the f i e l d a p p lic a tio n . There is reason to be l i eve that there wi l l not be agreement among Code A u th o ritie s on the subject^- Some wi l l adopt the new c r i t e r i a others w i l l r e je c t i t . There w i l l be varying time schedules for adoption or r e je c t io n even by communities operating under the same b a s ic code. Extreme caution plus r e lia n c e on q u a l i f i e d m aterial manufacturers rep resentatives w i l l be necessary unt i l some of the unresolved issues are settled. .