Enclosure Specification

Inclusion compounds open up a wide area of applications (1,2,17—28). An important aspect in this connection is the specific microenvironment created by the host enclosure of the guest which exerts an influence on the physical, spectroscopic, chemical, and other properties of the guest. 

MultiwaU. shipping sacks are suitable for transport in aU kinds of carriers from tmcks to seafaring vessels. Particular care must be taken to prevent the storage of objects with sharp projections adjacent to the bags in case of doubt, it is advisable to line the enclosure with kraft paper of a basis weight >23 kg. Additional rules for the transportation of multiwaU sacks are contained in appHcable tariff specifications and should be consulted for rail, tmck, and ocean-going shipments. 

Cij = mean specific heat of combustion products from base temperature to leaving-gas temperature Te-C = cold-surface fraction of a furnace enclosure. 

Environmental Enclosures Enclosures for valve accessories are sometimes required to provide protection from specific environmental conditions. The National Electrical Manufacturers Association (NEMA) provides descriptions and test methods for equipment used in specific environmental conditions in NEMA 250. Protection against rain, windblown dust, hose-directed water, and external ice formation are examples of environmental conditions that are covered by NEMA standards. 

To fulfil the above requirements the material inputs for the motor, such as stampings, steel, enamelled copper wire, insulations and varnishes, bearings, enclosure materials and hardware must be subjected to a series of acceptance tests according to norms and standard specifications. For example, enamelled copper wire used... 

Provision and use of appropriate health surveillance, e.g. for signs of dermatitis, asthma, effects of specific solvent exposures. Full use of any spray booth, enclosure, exhaust ventilation or dilution systems, and automatic handling equipment. (The efficiency of all local exhaust ventilation and other control systems should be maintained, and checked by testing.) Where appropriate, atmospheric monitoring of airborne pollution levels. 

The vendor shall be responsible for the selection of proper range, pressure rating, materials of construction and electrical enclosure based on process conditions and electrical area classification. All instruments and controls shall be in accordance with Specification ME-0-JN400. 

Drafts from windows and doors can have speeds that exceed that through the face of the enclosure. This can be especially so where the makeup air does not balance the amount extracted by the endosure(s). Doors should be kept closed unless the room has been specifically designed to operate otherwise. 

The terms zonal model and flow element are also used for the simplified characterization of the flow field in a single enclosure. There, a zone represents a partial volume of air in the enclosure, whereas in the multizone models described here, a zone represents a specific enclosure which is connected to other enclosures by air conductances (see The Airflow Network later). 

Specific leakage Relating to the leakage that takes place from an enclosure due to a pressure difference created either mechanically or naturally. It is the ratio of leakage area in m divided by the floor area in m. ... 

In Division 1 areas, meters, instruments, relays, and similar equipment containing high-temperature or arcing devices must be installed in approved explosion-proof or purged enclosures. Unless such devices are specifically labeled as suitable for Class I, Division 1 areas, it is best to assume they are not suitable. 

FPN No. 2) The explosion characteristics of air mixtures of gases or vapors vary with the specific material involved. For Class I locations. Groups A, B, C, and D, the classification involves determinations of maximum explosion pressure and maximum safe clearance between parts of a clamped joint in an enclosure. It is necessary, therefore, that equipment be approved not only for class but also for the specific group of the gas or vapor that will be present. 

Equipment that has been approved for a Division 1 location shall be permitted in a Division 2 location of the same class or group. Where specifically permitted in Articles 501 through 503, general-purpose equipment or equipment in general-purpose enclosures shall be permitted to be installed in Division 2 locations if the equipment does not constitute a source of ignition under normal operating conditions. 

After an area classification has been established, then anelectrical equipment, instruments, and wiring must adhere to that classification. Therefore, some motor enclosure types would not be electrically acceptable for specific area classifications. 

A dust-ignition-proof machine is a totally enclosed machine whose enclosure is designed and constructed in a manner which will exclude ignitable amounts of dust or amounts which might affect performance or rating, and which will not permit arcs, sparks, or heat otherwise generated or liberated inside of the enclosure to cause ignition of exterior accumulations or atmospheric suspensions of a specific dust on or in the vicinity of the enclosure. 

Granulate, particle-size material specifically manufactured or produced from basic product off-cuts. Supplied by most manufacturers and used for packing or pouring into irregular-shaped enclosures. 

To quiet a noise-generating mechanism, the first impulse is often to enclose it. Sometimes an enclosure is in fact the best solution, but not always. If it can be determined what is causing the noise, appropriate action can be taken to be more specific and provide a cost-effective fix. In some cases the problem is caused by a component such as a stepper motor or gear set that does not produce objectionable noise by itself. The trouble typically develops because a small noise is transmitted to a metal frame or cabinet that then serves to amplify the sound using a plastic cabinet can isolate the noise problem. 

Evolution in telescope making since the Palomar has not been limited to the area of optical production. The alt-azimuthal mount has become the established solution since the Bolshoi 6 m telescope, for its superior mechanical performance and the compact, cost-efficient enclosure design it allows. Better understanding of the properties of atmospheric turbulence allowed a more accurate characterization of a telescope properties, a more balanced approach towards specifications and error budgeting and a better understanding of the utmost importance of site selection. Any ground-based telescope of appreciable size will be primarily limited by the effect of atmospheric turbulence, not to mention the proportion of photometric nights allowed by weather conditions. 

This diagram shows the radiation emitted by black-bodies at specific temperature. A black-body is one that has a uniform temperature over all of its surface. One way to make a black-body is to form an hollow enclosure and to heat it to a given temperature. If a small hole is made in the side of the enclosure, radiation characteristic of the temperature will be emitted. 

The heat transfer into the boundary surface of a compartment occurs by convection and radiation from the enclosure, and then conduction through the walls. For illustration, a solid boundary element will be represented as a uniform material having thickness, 6, thermal conductivity, k, specific heat, c, and density, p. Its back surface will be considered at a fixed temperature, T0. 

Pressure detection shall be used for closed enclosure applications. Threshold detectors provide an electric signal when a preset overpressure is exceeded. Dynamic detectors provide an electric signal to the control and indicating equipment (CIE). Typically they have both rate-of-rise and pressure threshold triggering points that can be configured specifically to the application conditions. Although this type of detector minimizes spurious activation of the isolation system (due to pressure fluctuations other than explosion pressure rise), care shall be taken to set up such detectors to meet appropriate detection response criteria for the particular application and protected enclosure geometry. 

Since detectors are by definition exposed to combustible gases they should be rated for electrically classified areas, such as Class I, Division I or 2, the specific gas groups (normally groups C and D), and temperature ratings. It should be noted the UL presently does not specifically test combustible gas detector sensor heads for use in classified areas, although they do tests enclosures for control and data acquisition circuits. Several other international standards do evaluate combustible gas detectors for use in classified areas (e.g., BS 6020). 

A Type 6 enclosure is suitable for application where the equipment may be subject to temporary submersion. The design of the enclosure will depend upon the specific conditions of pressure and time. It is also dust tight and sleet (ice) resistant. 

Specifically note that Type 7 (explosion-proof) enclosures and their associated conduit systems are neither gas or liquid tight. Consequently, corrosive gases such as hydrogen sulfide and water from rain or internal condensation can accumulate with the enclosure. Premature failure of electrical devices and interconnections often results when preventive measures such as drains, air purges, and dual rated enclosures are not used to remove or exclude these corrosive elements. Type 7 enclosures are intended for indoor use. 

Describe in the first column of the table what specific materials and quantities could be combined, how they could be combined, and for how long. Use the second column to indicate whether or not ambient, unconfined conditions apply (ambient temperature, atmospheric pressure, noninerted and nonenriched atmosphere with 21% oxygen, and no enclosure or confinement). Assume published compatibility data will be valid only if ambient, unconfined conditions apply, unless the data indicate otherwise. Use the third column to indicate that, for this scenario under these conditions, a chemical reaction will occur that has the potential for any of your predetermined undesired consequences. Document any comments and the source of your information in the last column. 

Standardized aboveground enclosures are available in a wide variety of materials, sizes, and configurations. Many options and security features are also available for each type of enclosure, and this allows system operators the flexibility to customize an enclosure for a specific application and/or price range. In addition, most manufacturers can custom-design enclosures if standard, off-the-shelf enclosures do not meet a user s needs. 

Many of these enclosures are designed to meet certain standards. For example, the American Society of Sanitary Engineers (ASSE) has developed Standard 1060, Performance Requirements for Outdoor Enclosures for Backflow Prevention Assemblies. If an enclosure will be used to house a backflow preventer, this standard specifies the acceptable construction materials for the enclosure, as well as the performance requirements that the enclosure should meet, including specifications for freeze protection, drainage, air inlets, access for maintenance, and hinge requirements. ASSE 1060 also states that the enclosure should be lockable to enhance security. 

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