Maximum limits

Note that the RVP is a relative pressure that is a difference compared to the atmospheric pressure. The RVPs for gasolines are generally between 350 and 1000 millibar. The level corresponding to European specifications are shown in Table 5.6 the fuel must be simultaneously within minimum and maximum limits, identical for each type of fuel, gasoline and premium, but... 

Another danger, intoxication by inhalation, is related to the benzene content. A maximum limit is often set for this compound. 

For example, in the case of light Arabian crude (Table 8.16), the sulfur content of the heavy gasoline, a potential feedstock for a catalytic reforming unit, is of 0.036 weight per cent while the maximum permissible sulfur content for maintaining catalyst service life is 1 ppm. It is therefore necessary to plan for a desulfurization pretreatment unit. Likewise, the sulfur content of the gas oil cut is 1.39% while the finished diesel motor fuel specification has been set for a maximum limit of 0.2% and 0.05% in 1996 (French specifications). 

Examples of typical packaging labels from reagent grade chemicals. Label (a) provides the actual lot assay for the reagent as determined by the manufacturer. Note that potassium has been flagged with an asterisk ( ) because its assay exceeds the maximum limit established by the American Chemical Society (ACS). Label (b) does not provide assayed values, but indicates that the reagent meets the specifications of the ACS for the listed impurities. An assay for the reagent also is provided. 

Germanium tetrachloride refined for use in making optical fibers is usually specified to contain less than 0.5 to 5 ppb of each of eight impurities vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc. Limits are sometimes specified for a few other elements. Also of concern are hydrogen-bearing impurities therefore, maximum limits of 5 to 10 ppm are usually placed on HCl, OH, CH2, and CH contents. 

Fig. 2. Maximum limits of average output power P 0 from power sources at average wattages or continuous wave (CW) where A is the soHd state B,...

In addition to considering the external environment, recommendations for the internal environment have been set. Every room in which human activity is required has maximum limits for noise (85—90 dB), carbon dioxide, solvents, radiation, temperature, etc. 

The lower Emit of applicability of the nucleate-boiling equations is from 0.1 to 0.2 of the maximum limit and depends upon the magnitude of natural-convection heat transfer for the liquid. The best method of determining the lower limit is to plot two curves one of h versus At for natural convection, the other ofh versus At for nucleate boiling. The intersection of these two cui ves may be considered the lower limit of apphcability of the equations. 

Many finely divided metal powders in suspension in air are potential e] losion hazards, and causes for ignition of such dust clouds are numerous [Hartmann and Greenwald, Min. MetalL, 26, 331 (1945)]. Concentration of the dust in air and its particle size are important fac tors that determine explosibility. Below a lower Umit of concentration, no explosion can result because the heat of combustion is insufficient to propagate it. Above a maximum limiting concentration, an explosion cannot be produced because insufficient oxygen is available. The finer the particles, the more easily is ignition accomplished and the more rapid is the rate of combustion. This is illustrated in Fig. 20-7. 

In 1980 the Drinking Water Directive was introduced, which specified a maximum limit of 0.1 /rgU for any pesticide in drinking water and 0.5 /rgU for total pesticides. Monitoring was needed for a wide range of pesticides in water and this became the impetus for developing new analytical techniques capable of detecting pesticides at very low levels. Consequently, analytical techniques improved and more pesticides were detected in watercourses and water supplies. 

Elliott reeommends serviees of two witnesses be employed during the instrument ealibration and test. Expenses assoeiated with the field test would be a per diem rate for the serviee engineer, travel and living expenses at eost plus 10% administrative eharge, and a maximum limit of eight man-day eharge for pre- and post-test analysis and report preparation (typieal unit). 

Using Simpson s Rule outlined above, the maximum limit, oo, is dilfieult to work with and an appropriate value refleeting the problem should replaee it. For argument s sake, we will give it a value of 700 MPa. Therefore, the reliability ean be determined given that ... 

The major concern of both output and input filter capacitors is the ripple current entering the capacitor. In this application, the ripple current is identical to the inductor ac current. The maximum limits of the inductor current is 2.8 A for I peak and about one-half the maximum output current or 1.0 A. So the ripple current is 1.8 A p-p or an estimated RMS value of 0.6 A (about one-third of the p-p value). 

Next, decide the natural resonance frequency of the tank circuit. For the available quasi-resonant controller ICs on the market, the range is between 1 and 2 MHz. This limit should be considered the maximum limit within conventional QR designs. So 1 to 1.5 MHz is a typical choice. Lower frequencies can be used and some efficiencies can be gained. The equation for the resonance frequency is... 

The early concept was that these were values which must not be exceeded in other words, they were truly maximum values. As the understanding of limits and the development of the philosophy for such limits grew, it was realized that short-term exposures to somewhat higher concentrations could be permitted without undue harm if the total exposure during the day was sufficiently below the maximum limit. This led to the development of the concept of Threshold Limit Values (TLV s) by the ACGIH. 

Another objective of gas processing is to lower the Btu content of the gas by extracting heavier components to meet a maximum allowable heating limit set by a gas sales contract. If the gas is too rich in heavier components, the gas will not work properly in burners that are designed for lower heating values. A common maximum limit is 1100 Btu per SCF. Thus, if the gas is rich in propane and heavier components it may have to be processed to lower the heating value, even in cases where it may not be economical to do so. 

Select a velocity represented by Fj factor between minimum and maximum limits. 

The value of this relation is that it serves as a maximum limit that may he expected from a designed unit when comparing design Q/A versus Equation 10-139. 

Figure 4-492. Maximum limit of evaporation as defined by TDS (NaCI) [228].

Maximum Exposure Limit MEL) Maximum limits of concentration of airborne toxic contaminants, listed by the Health and Safety Executive which must not be exceeded. 

All compressed air systems that use a positive displacement compressor must be fitted with a pressure relief or safety valve that will limit the discharge or inter-stage pressures to a safe maximum limit. Most dynamic compressors must have similar protection due to restrictions placed on casing pressure, power input and/or keeping out of surge range. 

The method of establishing and using alert/alarm limits varies depending on the particular vibration monitoring system that you select. Normally these systems will use either static or dynamic limits to monitor, trend and alarm measured vibration. We will not attempt to define the different dynamic methods of monitoring vibration severity in this book. We will however provide a guideline for the maximum limits that should be considered acceptable for most plant mechanical equipment. 

To maximize control in setting tolerances there is usually a minimum and a maximum limit on thickness, based on the process to be used such as those in Tables 3-6 to 3-9. Each plastic has its own range that depends on its chemical structure, composition (additives, etc.), and melt-processing characteristics. Any dimensions and tolerances are theoretically possible, but they could result in requiring special processing equipment, which usually becomes expensive. There are of course products that require and use special equipment such as polycarbonate compact discs (CDs) to meet extremely tight tolerances. 

Imposing maximum limitations on TDS and certain specific ions or salts (such as hydroxyl ions or chlorides)... 

Where corrosion problems exist, rates may vary considerably throughout the system, but total metal loss may typically exceed 0.25 ppm M (where M = Fe/Cu/Ni) in the condensate without the use of amine. This compares badly to recommended maximum limits of 0.05 ppm M for up to 580 psig/40 bar boilers, 0.03 ppm M for up to 870 psig/60 bar, and 0.02 ppm M beyond that. 

The LDPE reactor is sometimes termed heat transfer limited in conversion. While this is true, the molecular weight (or melt index)—conversion relationship is not since this work shows that a selected initiator can allow conversion improvements to be made under adiabatic conditions for a specified molecular weight. The actual limitation to conversion is the decomposition temperature of the ethylene and given that temperature as a maximum limitation, an initiator (not necessarily commercial or even known with present initiator technology) can be found which will allow any product to be made at the rate dictated by this temperature. Conceptually, this is a constant (maximum) conversion reactor, runnirg at constant operating conditions where the product produced dictates the initiator to be used. 

TLV-STEL, THRESHOLD LIMIT VALUE — SHORT TERM EXPOSURE LIMIT (uSA) A maximum limit... 

From results of conductance measurements it has been found that although the conductance of an electrolyte becomes progressively smaller with decreasing concentration, the values of equivalent conductance increase as the concentration decreases or the solution dilution increases until a maximum limiting value is finally obtained. The limiting value of the equivalent conductance which is attained with decreasing concentration or increasing solution dilution is termed the equivalent conductance at infinite dilution, and is denoted Aq-... 

Inequality constraints, expressing minimum or maximum limits on various parameters. 

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