Enclosure degree

Options. Traditional control options for overexposure are material substitution, process change, containment, enclosure, isolation, source reduction, ventilation, provide personal protection, change work practices, and improve housekeeping. A simple way of looking at selection of control options is to find the cheapest option that results in the desired amount of exposure reduction. It is not actually that simple, however, because the various options differ in ways other than cost and degree of control. Some of the other factors to consider in selection of control options are operabiUty, rehabiUty, and acceptabihty. 

The speed of the pickle reaction is also dependent on the concentration and temperature of the pickle, the degree of agitation of either the metal part or the pickle solution, the alloy being pickled, and the acid used. Pickling solutions may be appHed by either spray or immersion techniques. However, because of the noxious fumes emitted, there must be adequate ventilation. Sometimes, particularly when spraying techniques are used, an enclosure to contain the fumes and mist is employed. 

Though this is a quartic equation, it is capable of explicit solution because of the absence of second and third degree terms. Trial-and-error enters, however, because (GSi)r and are mild functions of Tg and related Te, respectively, and aprehminary guess of Tg is necessaiy. An ambiguity can exist in interpretation of terms. If part of the enclosure surface consists of screen tubes over the chamber-gas exit to a convection section, radiative transfer to those tubes is included in the chamber energy balance, but convection is not, because it has no effect on chamber gas temperature. 

Purchase Price Typical purchase prices, including drive motors, of tubular and disk sedimenting centrifuges are given in Table 18-16. The price will vary upward with the use of more exotic materials of construc tion, the need for explosion-proof elec trical gear, the type of enclosure required for vapor containment, and the degree of portability, and this holds for all types of centrifuges. 

Except for areas with fire or explosion hazards (hazardous areas), motor enclosures are designed to provide protection to the internal working parts. The development or improved insiilating materials and finishes has affec ted the required degree of protection and consequently the design and classification of enclosures. Examples of several types of enclosures are shown in Fig. 29-4. 

Roiaiing elecirical machines. Classificaiion ol degrees of protection provided by enclosures for rotating machinery 4691/1985 BS 4999-105/1988 ... 

The enclosure must have a high degree of protection... 

The test equipment is the same as described for degree of protection I. But the enclosure under lest is tilted up to an angle of 15° in respect of its normal operating position successively, in iw o planes at right angles (to cover all four sides). The total duration of the test will be 10 minutes (2.5 minutes each side). The lesl results should be the same as for degree of protection I. 

The enclosure under test is mounted in its normal position on a turntable, the axis of which will be vertical and height variable, located near the centre of the semi-circle formed by the oscillating tube. The table is rotated to spray all parts of the enclosure equally. The enclosure should be kept under a spray of water for 10 minutes. The lesl results should be the same as for degree of protection 1. 

A normal enclosure is meant for a reasonably clean atmosphere and a relative humidity not more than 50% for LT and 95% for FIT indoor enclosures. Where the atmosphere is laden with fumes or steam, saline or oil vapours, heat and humidity, excessive dust and water or contaminated with explosive and fire hazardous gases, vapours or volatile liquids (Section 7.11) a special enclosure with a higher degree of protection is required as in lEC 60529 or lEC 60079-14. For non-hazardous areas, the enclosure can be generally one of those discussed in Tables 1. 10 and 1. 11, and when required can be provided with special treatment to the metallic surfaces. For hazardous areas, however, special enclosures will be essential as discussed in Section 7.11. 

The types and degrees of enclosure protection are generally the same as defined for motors in Section 1.15, Tables... 

AMD 1 Degrees of protection provided by enclosures (IP code) (AMD 7643J dated 15 July 1993. Superseded BS 5490 1977... 

The advantages of low-level hoods are listed in Table 13.17. The first step is to verify that the general principle of local capture of emissions is acceptable and feasible for the process. The next step is to establish the most efficient hood geometry. In most cases, this involves a balancing of the degree of process interference tolerable against the degree of emission source enclosure required. 

Degree of enclosure The actual protection offered by an enclosure in the con tainmenr of a generated contaminant. 

A dripproof machine is an open machine in which the ventilating openings are so constructed that successful operation is not interfered with when drops of liquid or solid particles strike or enter the enclosure at any angle from 0 to 15 degrees downward from the vertical. The machine is protected against solid objects greater than 2 inches. 

The degree of attenuation at the critical frequency can be very large, but this type of silencer has a very narrow bandwidth. This device may be suitable when the machine being dealt with emits sound predominantly of a single wavelength. Lining the chamber with absorbers can expand the absorber bandwidth of a Helmholtz resonator, but this has the effect of reducing the efficiency. The perforated absorber, which forms the basis of many acoustic enclosures and silencers, is a development of the resonator principle. 

Table 13.16 sets out the major waste disposal methods, and potential hazards from toxic waste deposition are indicated in Table 13.17. The range of precautions required at land tips depends upon the risk, e.g. the nature and degree of contamination and the work to be undertaken. It will, however, encompass personal protective equipment a high standard of personal hygiene enclosure, possibly pressurization, and regular cleaning of vehicle cabs vehicle washing facilities site security, and control of designated dirty areas. Air monitoring and medical surveillance may be required.

These require some degree of confinement, usually inside a building or module. The mechanism of pressure buildup is the expansion of hot gas as it burns, exceeding the vent capacity of the enclosure. No significant shock wave is created, because in general the space is too small or there is insufficient gas for the flame front to accelerate to the necessary speed. These explosions can occur with small amounts of gas. 

A weather resistant enclosure intended to provide suitable protection against specified weather hazards. It is suitable for use outdoors. It is designed to provide a degree of protection against rain, sleet, windblown dust, and damage from external ice formation. 

An indoor enclosure with a degree of protection against settling dust, dirt, and noncorrosive liquids Type 6 - Submersible... 

Type 6 enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against the entry of water during occasional temporary submersion at a limited depth. They are not intended to provide protection against conditions such as internal condensation, internal icing, or corrosive environments. 

More complex environmental rigs can be illustrated by an arrangement where pipe line components, seals, valves, etc., are mounted as in service and pressurised cyclically with the service fluid. The rig is contained in an enclosure so that elevated or subnormal temperatures can be applied. The degree of acceleration can be varied for both mechanical and environmental factors. 

Recourse must now be made to the use of a certain hermetically sealed enclosure in order to impede an indefinite diffusion. Flat Men say that they are dealing with un gaz, and they call pression or tension the results of a certain bombardement against the enveloping wall which is carried out by millions of molecules shot out forth in all directions from Plane P. This operation is the only phenomenon captured by the senses of a Flat Man... . They give this operation a specific name, HEAT, and they only experience it through an artificial unity, DEGREE OF TEMPERATURE. . .. Voild, the transformation of the operation into heat, which is the reverse of the preceding operations. 

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