Material specification

A section related to materials sets out, apart from general requirements, that compliance with the material specifications of the directive can be achieved in one of the following forms by using materials which comply to harmonised standards, by using materials covered by a European approval of materials, a subject which will be explained further on, and by a particular material appraisal carried out by the notified body. 

Acetal resins are one of several plastic materials specifically targeted for recycle in at least one soon-to-be-constmcted recycling faciUty (28). 

In the laboratory or process research section a laboratory procedure for a fine chemical is worked out. The resulting process description provides the necessary data for the determination of preliminary product specifications, the manufacture of semicommercial quantities in the pilot plant, the assessment of the ecological impact, an estimation of the manufacturing cost in an industrial-scale plant, and the vaHdation of the process and determination of raw material specifications. 

Testing and Standards. Requirements for extmsion and mol ding grades are cited in ASTM specifications (79) and in Federal specification LP-389A of May 1964 (80). For fabricated shapes, FEP film and sheet are covered by Aeronautical Material Specifications (AMS) 3647 and LP-523 (81). Besides the specifications covered by the Fluorocarbons Division of the Society of the Plastics Industry, Inc. (82), other specifications are Hsted in Reference 83. 

The properties of commercial rigid foamed plastics are presented in Table 2. The properties of commercial flexible foamed plastics are presented in Table 4. The definition of a flexible foamed plastic is that recommended by the ASTM Committee D 11. The data shown demonstrate the broad ranges of properties of commercial products rather than an accurate set of properties on a specific few materials. Specific producers of foamed plastics should be consulted for properties on a particular product (137,138,142). 

Although a torsion test is simple to carry out, it is not commonly accepted as an integral part of a material specification furthermore, few torsion data exist in handbooks. If, as is usually the case, the design needs to be based on tensile data, then a criterion of elastic failure has to be invoked, and this introduces some uncertainty in the calculated yield pressure (8). 

Index ofi Aerospace Materials Specifications, Society of Automotive Engineers, Warrendale, Pa., 1986. 

R. B. Ross, ed.. Metallic Materials Specification Handbook, 4th ed.. Chapman and Hall, London, 1992. 

The designs and varieties of boxes that can be constmcted and used in chemical packaging are many. This flexibiUty in design is possible because boxes are manufactured with minimal tooling expense under specifications that are unique to each order, but which are subject to various material specifications for meeting freight and shipping requirements. 

The other cause of constmction problems is the introduction of badly chosen, or even unauthorized, changes during constmction in order to expedite the work. Any changes in details, material specifications, or erection procedure must be given careful consideration by both the builder and silo designer. 

Table 1. Simplified Hot Applied Membrane Material Specifications...

Standards, SAE (Aerospace Materials Specifications), and the U.S. Department of Defense. ... 

The alloys of titanium utilised in industrial applications have compositional specifications tabulated by ASTM. The ASTM specification number is given in Table 14 for the commercially important alloys. MiUtary specifications are found under MIL-T-9046 and MIL-T-9047, and aerospace material specifications for bar, sheet, tubing, and wine under specification numbers 4900—4980. Every large aircraft company has its own set of alloy specifications. 

A colloid is a material that exists ia a finely dispersed state. It is usually a solid particle, but it may be a Hquid droplet or a gas bubble. Typically, coUoids have high surface-area-to-volume ratios, characteristic of matter ia the submicrometer-size range. Matter of this size, from approximately 100 nm to 5 nm, just above atomic dimensions, exhibits physicochemical properties that differ from those of both the constituent atoms or molecules and the macroscopic material. The differences ia composition, stmcture, and iateractions between the surface atoms or molecules and those on the iaterior of the colloidal particle lead to the unique character of finely divided material, specifics of which can be quite diverse (see Flocculating agents). 

Contamination. Manufacturers of cosmetics must be careful to guard against chemical and microbial contamination. Chemical contamination, which may result from the presence of undesirable impurities in raw materials, is avoidable by adhering to rigid specifications for raw materials. Compendial specifications and pubHcations by the CTFA and other professional societies form the basis of most intracompany raw material specifications. Moreover, all packaging components must meet not only physical and design specifications but also such chemical requirements as extractables and absence of dust and similar contaminants (see Packaging, cosLffiTics and pharmaceuticals). 

Specifications. EZ compounds meet class EK in the SAE automotive mbber classification J200. Line callouts have been developed for 50, 70, and 80 durometer materials. Specific compounds meet requirements for O-rings for military aerospace appHcations identified in MIL-P-87175,... 

Material group Materials (specification—grade) See Notes... 

Material Specification P no. (23) Grade Class F actor, E Minimum tensile strength, kip/in- Minimum yield strength, kip/in- Notes Minimum temperature (IS) Minimum tempera-tnre to 100 ... 

Material Specification Grade Class Notes temperature (IS) tnre to 100 200 300 400 500 600... 

Material Specification Grade Temper Size range, in kip/in- kip/in" Notes (IS) ... 

Certain forms of this material, as stated in Table 10-57, must be impact-tested to qualify for service below -29 C (-20 F). Alternatively, if provisions for impact testing are included in the material specification as supplementary requirements and are invoked, the material may be used down to the temperature at which die test was conducted in accordance with the specification. 

The minimum temperahire shown is tliat design minimum temperature for which the material is normally suitable without impact testing otlier tlian that required by the material specification. However, the use of a material at a design minimum temperature below -29 C (-20 F) is established by rides elsewhere in the code, including any necessary impact-test requirements. 

NOTE These toughness-test requirements are in addition to tests required hy the material specification. 

Among the topics of the TEMA Standards are nomenclature, fabrication tolerances, inspeclion, guarantees, tubes, shells, baffles and support plates, floating heads, gaskets, tube sheets, channels, nozzles, end flanges and bolting, materi specifications, and fouhng resistances. 

Specifications for molding powders vary widely, from a No. 8 to a No. 60 sieve product generally the coarser products are No. 12, 14, or 20 sieve material. Specifications usually prescribe a minimum of fines (below No. 100 and No. 200 sieve). Molding powders are produced with hammer mills, either of the screen type or equipped with air classifiers. 

Second, most membrane materials adsorb proteins. Worse, the adsorption is membrane-material specific and is dependent on concentration, pH, ionic strength, temperature, and so on. Adsorption has two consequences it changes the membrane pore size because solutes are adsorbed near and in membrane pores and it removes protein from the permeate by adsorption in addition to that removed by sieving. Porter (op. cit., p. 160) gives an illustrative table for adsorption of Cytochrome C on materials used for UF membranes, with values ranging from 1 to 25 percent. Because of the adsorption effects, membranes are characterized only when clean. Fouling has a dramatic effect on membrane retention, as is explained in its own section below. 

Once a decision has been made to recover materials and/or energy, process flow sheets must be developed for the removal of the desired components, subject to predetermined materials specifications. A typical flow sheet for the recovery of specific components and the preparation of combustible materials for use as a fuel source is presented in Fig. 25-63. The light combustible materials are often identified as refuse-derived fuel (RDF). 

Consequence Phase 3 Develop Detailed Quantitative Estimate of the impacts of the Accident Scenarios. Sometimes an accident scenario is not understood enough to make risk-based decisions without having a more quantitative estimation of the effects. Quantitative consequence analysis will vary according to the hazards of interest (e.g., toxic, flammable, or reactive materials), specific accident scenarios (e.g., releases, runaway reactions, fires, or explosions), and consequence type of interest (e.g., onsite impacts, offsite impacts, environmental releases). The general technique is to model release rates/quantities, dispersion of released materials, fires, and explosions, and then estimate the effects of these events on employees, the public, the facility, neighboring facilities, and the environment. 

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