Construction materials toxic laboratories

Those elements of conventional laboratory design that must be refined for facilities in which toxic chemicals will be handled are presented. Alarms, communications, construction materials, containment cabinets, filter systems, floor plans, security, compressed gases, and waste disposal are discussed. Emphasis is given to design considerations dictated by the use of large numbers of fume hoods. 

T or many years scientists and engineers have attempted to modify the properties of sulfur so that it might be of value as a construction material, but until recently these random efforts lacked direction. Frequently the objectives of work described in many published papers could not be reconciled with the experimental design. For example, authors cited availability, low cost, and low toxicity as reasons for evaluating sulfur as a construction material. The same authors would then proceed to modify sulfur with additives which were in short supply, expensive, and highly toxic. The aging characteristics of sulfur concretes beyond a 28-day period were never examined, and durability outside the laboratory environment was seldom considered. With these limitations, the data were of little value to the construction industry. 

In some cases, for example, toxic characteristics of the material may prohibit shipment of test quantities to vendors laboratories and/or contamination of laboratory buildings and equipment may be irreversible. In other cases, particularly in hot agglomeration, the material must be tested in statu nascendi because cooling and reheating a sample after shipment does not recreate the original material characteristics and the actual binding mechanisms. In those cases, construction of a pilot plant on the project site or other suitable location must be considered which may be equipped with purchased or rented machinery. If this solution is selected, the above remarks on scale-up must still be kept in mind. 

Microcosms are laboratory systems generally consisting of tanks such as fish aquaria containing natural sediment and water, or soil. In those which have been most extensively evaluated for aquatic systems, continuous-flow systems are used. In all of them, continuous measurement of 14C02 evolved from 14C-labeled substrates may be incorporated, and recovery of both volatile and nonvolatile metabolites is possible so that a material balance may be constructed (Huckins et al. 1984). It should be pointed out that the term microcosm has also been used to cover much smaller scale experiments that have been carried out in flasks under anaerobic conditions (Edwards et al. 1992), and to systems for evaluating the effect of toxicants on biota (Section 7.4.2). Some examples are given to illustrate different facets of the application of microcosms to study various aspects of biodegradation. 

Other equipment specifically designed, built or instchemical weapons production facility, as distinct fi-om a facility constructed according to prevailing commercial industry standards such as equipment made of hi nickel alloys or other special corrosion resisfimt material special equqiment for waste control, waste treatment or air filtering special containment enclosures and safety shields non-sfirndm-d laboratory equipment used to toxic chemicdesigned process control p[Pg.162]

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