Two common scenario loss ratios are used when calculating Probable Maximum Losses from earthquakes: Scenario Expected Loss (SEL) and Scenario Upper Loss (SUL). Analyses of seismic loss ratios prepared by fi ve seismic consulting fi rms, four loan pools securitized in the capital markets, two very large loans with many properties, two large hospitality portfolios and a general account portfolio indicate that use of SUL rather than SEL would yield signifi cantly larger numbers of loans with loss ratios in excess of 20%. When using SEL, the percentage of loans in the four large pools exceeding a 20% loss ratio was 3.8%. When SUL was used on this same data set, 47.8% of these properties had SUL values above 20%. Common industry practice has been to use SEL. Some of the implications of tightening seismic underwriting standards to apply a 20% threshold to the SUL, rather than SEL, may include: lower loan production, properties may lose value, properties may be costlier and more diffi cult to fi nance, existing loan portfolios may appear more seismically risky, and demand for insurance and seismic retrofi t could go up. Equally undesirable effects could be that seismic consultants and lenders who do more rigorous analysis will be less competitive than those who do not.Prudent evaluators look to ASTM E2026-07, a revision of ASTM E2026-99, and E2557-07 standards for guidance in how to measure seismic risk for equity investments as well as lending for individual buildings and for portfolios. ASTM E2557-07 recommends the use of SEL DBE as the appropriate measure for loans. SEL DBE is the abbreviation of Scenario Expected Loss, and is defi ned by ASTM E2026-07 as the average loss in the Design Basis Earthquake (DBE) ground motion. The DBE is defi ned as the ground motion with a 10% probability of exceedance in 50 years, equivalent to a 475-year return period for exceedance. The task group developing these standards included a wide range of mortgage banking, life insurance, fi nancial institutions, and technical specialists, including registered architects and professional engineers. Consequently, this standard represents the best that the profession collectively knows and it can be relied upon. E2557-07 references ASTM E2026 that provides a number of technical tools and defi nitions used by E2557-07.ASTM E2026-07 also defi nes Scenario Upper Loss, SUL DBE , as the loss that has a 10% probability of being exceeded in the DBE ground motion. It is one of several measures of damageability defi ned and used in seismic risk assessment. In light of changing economic and market conditions, some institutions are questioning whether SUL DBE is the more appropriate and conservative measure compared to SEL DBE .When scenario losses are used as the measure of seismic vulnerability of a property, then there are two issues posed in its use: fi rst, what scenario to use, and second, should damageability be measured by SEL or SUL?What scenario should be used? There are two common options: the DBE or the MCE earthquake ground motions. The MCE...
The effects of percent fluorine, filler, and cure systems on the thermal and acid resistance of fluoroelastomers were evaluated over temperature ranges that would be typical of actual flue duct installations and accelerated conditions such as 275°C for thermal resistance and 149°C for concentrated sulfuric acid resistance. FKM 2176, which contains 65% fluorine by weight, became hard and brittle after two weeks of accelerated air aging at 275°C. The balance of physical properties of FKM 2176 were good when aged at 200°C. FKM 4894, which contains 67% fluorine by weight, retained useful properties after six weeks of accelerated air aging at 275°C. This indicates this material has improved properties for flue duct applications compared to FKM 2176. FKM 4894 filled with MT carbon black had improved retention of tensile strength after aging at 232°C relative to the FKM 4894 filled with SRF/HAF black, Austin Black and litharge. FKM 2176 was totally degraded after aging three days at 149°C in concentrated sulfuric acid. Aging of FKM 4894 in concentrated sulfuric acid at 149°C resulted in a loss of approximately 75 percent of the original tensile and an increase in the elongation, and the appearance of the exposed surface did not indicate chemical attack. Although FKM 4894 was superior to FKM 2176 when aged in sulfuric acid at 149°C, there was little difference between FKM 4894 and FKM 2176 when aged at 121 °C for up to four weeks or after eight weeks at 100°C in concentrated sulfuric acid. Austin Black showed the best retention of tensile of the four filler systems evaluated after aging at 100°C in concentrated sulfuric acid. FKM 4826, which contains 69% fluorine and is vulcanized using organic peroxide and triallyl isocyanurate, has indicated a compatibility with fiberglass that is superior to all fluorocarbon elastomer gums that were tested.
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