Document mDx0DzkaL01dBmwOQoB5xazZ

I- ^ 0. Dobay M. M. O'Hara . wLm.r .m- Sponge Products - Shelton nun east ea uaea oaf min' * mom. m Avon Lake Technical Center Combustion Products From RigiceLL J if " OafS *1 1 1 August 3, 1973 LLii An analysis of the primary combustion products from Rigicell (PVC- urethane foam from GPC) was carried out. Three different foams were exposed to radiant heat in the NBS smoke chamber (one foam exposed to flaming con ditions) and the concentrations of CO, CO2, HCL and HCN were monitored - function of time. Concentration data were subjected to a toxicity factor calculation (1) and toxicity factors (T) were determined for each of the foams. In general, significant contributions to T were made from HCL, HCN and CO. The yields of HCN from Rigicell are within the yield limits already published in the literature. There is an approximate 2-10% conversion of nitrogen in the samples to hydrogen cyanide. Under NBS flaming condltions^^mly low level of HCN was found. Introduction ' You submitted three samples dHglceH, the G.P.C. urethane - P?C roam, which exhibits an excellent ,*T1asm spread rating, for a combustion product analysis. The main confetti was the evolution of HC1, HC1 and the oxides of carbon. Aa of thla vrfting, we are continuing our Investigation with respect to the Identification of combust lon/de gradation products other than these primary products. A subsequent note will be published on this aspect of the analysis. Analytical terlals 1-650 (5/73), 1-650 (1/71) and R-300 ware exposed to pf radiant beat in the NBS smoke chamber. One of these (R-300) yElamiag conditions. The combustion gases were analyzed by the "'"Mi BC1 - ion specific electrode 00, CO2 - gas chromatography BCI benzidine-hydrochloride method a. (a) gas analysis ^ The carbon oxIda analysis was preformed by sampling a stream of combustion products from the NBS chamber. This was accomplished with the aid of a gas settling loop (Ice volume) connected to a vacuum pump. Sample is withdrawn at m rata of 0.8 llters/mlaute and the batch analysis is initiated after a 15 sacoad purge time. Dual column chromatography (Porapak Q, Molecular Slave SA) la used to sparata the primary combustion pgg^eta. 't+tr&M BFG09143 T006AOTZ D. Dobay Page 2 August 3, 1973 The HC1, HCN analyses were obtained with a 50cc ground glass syringe. Previous work with an HCN gas standard indicated this was an acceptable procedure. (b) C, H, N Analysis of Foams The three rigid foams were submitted for a carbon, hydrogen, nitrogen analysis. The data are summarized in Table 1. Table 1 C. H. N Analysis of Rjgicell Foams R-650 (5/73) R-650 (1/71) R-300 C 45.6.3 47.4.2 48.6*.3 H 4.&.0 5.14.03 5.0*.1 N 6.5.l 6.8.l 6.Tt.l Analysis R-650 (5/73) Table 2 contains a stannary of the combustion gas analysis for R-650 (5/73). Saaple weight: 6.48g (in.) 2.5 4.0 5.0 8.0 10.5 12.0 15.0 16.0 20.0 24.0 25.0 SCI (PP-) "fc 159 439 m - m Table 2 Analysis of R-650 (5/73) HCM (PP) 0 m 28 77 87 62 as ja2(pp) - 1006 4044 5369 CO (PP> 0 - - 971 m 1959 20C4OT: BFG09144 D. Dobay Page 3 August 3, 1973 Since we are still developing the chloride specific electrode it should be pointed out that the weakest link is this analysis. Theoretically this particular sample should release 2600 ppm of HC1 (53.4X PVC; sample weight, 6.48g; volume of chamber, 514 liters). The fact that the actual value is lest than 2SX of this theoretical value is, however, not surprizing due to the absorptivity of this gas. Although there la no accepted method for assessing the toxicity of combustion products, Suni'*' has suggested the use of a toxicity factor. In this application the overall toxicity of the combustion products is: T Z Ce/Cf where Ce is the concentration of the gas when one gram of material is burned and the products are diffused in a volume of one cubic meter and Cf is the concentration that is fatal (or dangerous) to man in a 30 minute exposure. With respect to Rigicell, Chi equation becomes: Ce (CO?) _ Ce_ (CO) , Ce (HC1) f Ce (HCHl T " Cf (CO2) + Cf (CO) Cf (HC1) Cf (HCH) The following values for Cf apply: sa f Reference bcs GO KL 135 4000 70,000-100,000 1000 2 3 2 4 I have calculated Ca values based on the combustion of 1 gram of material diffused in a volume of one cubic mater. These values for R-650 (5/73) are besed an --concentrations of each gas with no reference to time. Data are sumanrlsed in the next table. IlfelO el^ Factor Calculation Tor R-650 (5/731 Hi HCi CO CO2 BOX T ocl 100O + Concentration 439 1959 5369 87 CO 154.7 4000 + HO AJ* 135 + _*_ 34.7 154.7 424.2 6.86 CO* AZiaL. 70,000 (cent.) e m o L o ifi BFG09145 D. Dobay Page 4 August 3) 1973 T .035 + .039 + .051 + .0061 T - .131 This analysis indicates significant toxicological contributions from HC1, HCN and (CO+C02). Analysis of R-650 (1/21/71) This material is similar to R-650 (5/73) except for the date of preparation. The question with respect to this sample was what effect does aging have on the subsequent release of hydrogen cyanide uoder combustion conditions. The C, H, N analysis of this material indicated that it was identical to R-650 (5/73). The combustion gas data and toxicity calculation are sumaarized in the following tables. Table 4 Analysis of R-650 (1/21/71) Sample weight: 4.84g Time (min.) 3.0 5.0 8.0 12.0 13.0 15.0 16.0 17.0 25.0 HC1 (PP) 558 -- mm mm 634 -v., HCN (PP) -- 11 25 mm mm 20 mm mm (pp) 1326 -- -- mm 4169 mm -4441 (ppm) -- 138 mm --834 -- -894 1079004 BFG09146 D. Dobay Page 5 August 3, 1973 Table S Toxicity Factor Calculation For R-650 (1/21/71) Maximum Concentration gas in NBS Chamber Ce HC1 CO co2 HCN HC1 684 894 4441 25 CO HCM 72.4 94.6 469.8 3.65 CO* T = J1A + 94.6 + 2.65 1000 4000 135 469.8 70,000 T - .072 + .024 + .020 + .007 T - .127 The combustion analysis shows that aging does afect the subsequent release of hydrogen cyanide from R-650 when the material is burned. Although the nitrogen contents of the two materials are the same, the concentration of the molecular nitrogen structure which is responsible for the release of HCM is not. In this case, the mein contribution to the toxicity factor is due to the release of hydrogen chloride. One of the interesting outcomes of this analysis and the previous one is the different Ce values obtained for carbon monoxide. I have previously demonstrated(5) that charring has a significant effect on the rate of carbon monoxide generation. He observed more charring under smoldering conditions with R-650 (5/73) than with R-650 (1/21/71). Thus this trend in carbon monoxide generation l.e., higher Ce value for R-650 (5/7)), wee expected. of carbon monoxide and carbon dioxide was constant for If a comparison of Ce) + ^*(C0) w*14*** *t*ie following R-650 (5/73) R-650 (1/71) R-300 (pg. 7, TabU 7) 1 ^(CCM + C(CO) 578.9 564.4 574.3 21079005 BFG09147 D. Dobay Page 6 August 3, 1973 It should be noted once again the Ce is the concentration of combustion product resulting from the combustion of l.Og of product in a volume of 1000 liters. The fact that the total carbon oxide concentration for each of the three foams is constant is somewhat fortuitous. The C, K, N analvsis indicates that this should not be so. The presence of other organic decomposition products would have to be accounted for to obtain a true material balance. Ia a previous communication^) ft was shown that there is a slow gas phase oxidation of organic degradation products which occurs under KBS smoldering conditions. Analvsis of R-300 (5/73) The combustion gas data and toxicity calculations for R-300 (5/73) are fumarlzed in the following table. Table 6 Analvsis of R-300 (5/73) Sample weight: 3.28g Time (min.) 4.0 5.0 7.0 8.0 10.0 12.0 13.0 15.0 16.0 17.0 20.0 25.0 HC1 (PP) 90 -- 120 730 120 -- JfSUJarggf_c JB5jyV HCN <PP) ea --- 17 -- 32 -- mw 82 as as 73 * CO? (PP0 2047 -- -- -- -- 2793 -- -- -- 2905 CO (ppm) 413 -- -- -- -- -- 591 -- --- 774 The toxieityfiketor calculation from these data are sunarized in Table 7 1079006 BFG09148 0. Dcbey Page 7 August 3, 1973 naa HC1 CO COj HCH Table 7 Toxicity Factor Calculation For -R--3.00 C?/73) Maxlaua Concentration in NBS Chamber Ce 730 774 2905 82 114.0 120.8 453.5 12.8 HC1 00 HCM CO2 T 114.0 . 120.8 + Alii + 1000 4000 135 453.5 70,000 T- .114 + .030 + .094 + .006 T- .244 This analysis shows that again the main contribution to the toxicity factor is hydrogen chloride. The contribution from HCN is also significant. Discussion The validity of the toxicity factor as proposed by Suai (and as presented in this paper)1 is open to dlsucssion. Personally Z feel that it is too simple. It does not take into account the rate of gas build-up nor, more importantly, the time at which the maximan concentration of gee occur*. With respect to this study, the e4rly evolution of HC1 is of concern. This study has gone beyond Suai's study'' on PVC however, in tta&np Ce values for HC1 take Into account the decay of HC1; Sun! presenCewlj|||Nitical K1 concentrations. Even ay approach leaves sone thing to .iHBjilxntf. The decay of HC1 in a large scale fire is going to be nore dbBSgXjtjLc than In tha OS sacks chaaber. Until we have more large scale fl|pita on JVC and have an understanding of the factors which cause the decayof Hd, this problem cannot be resolved. However, if we assuaa that all of tbs HC1 will be lost during the early stages of a fire, tha toxicity factors change significantly. 1 have recalculated these factors aaaueing a saro contribution froa BC1. They are: CO + CO2 HCM t-650 (5/73): E-4SO (1/71): t-300 (5/73): (average for 3 fwa) T T T - .043 .031 .034 .037 + .031 + .020 + .094 + .053 1079007 BFG09149 0. Dobay Page 8 August 3, 1973 This approach indicates that the toxicity of the combustion products from these foams is due in part to carbon oxides (407.) and in part to hydrogen cyanide (60%). Sumi^ has reported that the toxicity of the combustion products from an unmodified urethane foam was due in part to carbon monoxide (50%) and in part to hydrogen cyanide (50%). A comparison between the absolute toxic icy factors of Sumi's urethane foam (T = .10) and Rigicell* (T = .092) shows no significant difference. It is of interest to compare the yields of HCN from the Rigicell foams with yields reported in the literature. In this analysis, the yields aie compared on a "g of HCN/g sample consumed" basis. Data as sunmaried in the next table. Table 8 HCN Yields From Rigicell and Other Urethane Foama (Literature Values) HCN Yield (g/g sample) Rigicell 650 (5/73) Rigicell 650 (1/21/71) Rigicell 300 (5/73) Rigid urethane foam7 Flexible urethane foams' BFC's Estaoe 5707Fl<b} BFG's Estaoe 5740X210(b) 0.0076 0.0029 0.014 0.008 0.007-0.046'c' 0.034 0.015 It can be seen from this calculation that the HCN yields from Rigicell are within the limits already determined by others .for a variety of urethane materials. Out other calculation which i* of interest is the per cent conversion of nitrogen in the polymer to hydrogen cyanide. Based on the C, H, analyses of Rigicell, the following yields of HCN would result all of the sample was converted to HCN: N HCN Yield (g/g sample) R-650 (5/73) R-650 (1/71) R-300 (5/73) 0.125 0.131 0.129 ^ignoring the contribution from HC1. see reference 1 ^ see reference 9 (c) rmtm of cyanide found for four flexible foana under varying combustion conditions BFG09150 21079009 D. Dobay Page 9 August 3( 1973 Comparing these values with the actual experimental values (Table 7) indicates that ther Is a 2.2 - 10.9% conversion of nitrogen to HCN. The introging question at this point is what chemical structure or physically induced combustion conditon is responsible for this range of yields. Aa stated in the introduction, we carried out one experiment in which R-300 (5/73) was burned in the flaming mode. The purpose of this experiment was to determine the fate of HCN under flaming conditions. Under these conditions, the maximum amount of HCN found was less than lOppm. Most of the HCN formed thus undergoes combustion in the NBS burner. Ih- .^xicity factor should be a function of both modes of burning. Obviously the contri bution from HCN would be diminished. It is obvious that more work needs to be done in this area. However the results should provide some guidelines with respect to the toxicity of the combustion products. Unfortunately we cannot put a "number" on the toxicity. One of the problems with respect to this is our current inability to analyse every combustion product present. Current pyrolysis-gas chromatographic-mass spectrometric studies are now underway to provide us with some guidelines along this line. Nevertheless, this study is in good agreement with other published studies and provides some information with respect to possible toxicological hazards from the burning of Rigicell. ch Distribution: ALTC A. L. Schultz L. B. Crider R. R. Bloor E. G. Kolycheck E. M. Haber Brecksvllle A. Talalay E. D. Dickens A. U. McRowe D. E. Ley C. S. Schollenberger M. M. O'Hara Cleveland D. L. Kent R. Markley C. V. Elliott R. Naranch R. J. Fawce`t D. Ditmer G. E. Thompson 6()(46Z.OTZ BFG09151 D. Dobsy Page 10 August 3, 1973 REFERENCES 1. K. Suml, Y. Tsuchiye, J. Fire and Flam., 4, January 1973, p. 15. 2. see reference 1 3. see reference 1 4. Y. Henderson, H. W. Haggard, "Noxious Gases and the Principles of Respiration Influencing Their Action", The Chemical Catalog Co. Inc., New York (1927). 5. M. M. O'Hara, "Analysis of the Combustion Products From Wood and Synthetic Polymers", presented in part at the 1973 NFPA Meeting (St. Louis). 6. Y. Tsuchiye, K. Suni, J. Fire and Flam., January 1972, p. 46. 7. 0. Gross, "Smoke and Toxic Gases Produced by Burning Aircraft Interior Materials", AD675513, June 1968. 8. National Bureau of Standards Report #10870: "Field Measurement of HC1 Concentration From PVC Electrical Conduit Involved In Fire", February 4, 1972. 9. E. A. Boettner, "Combustion Products from the Incineration of Plastics", Final Report to 0. S. Eoviromental Protection Agency, February 1973 (copy available from M. M. O'Hara). 36 833 % BFG09152 21079010