Guide values

Sand that is used in filtration must be free of clay, dust, and other impurities. The ratio of lime, lime-stone, and magnesium oxide will have to be lower than 5 weight percent. The standard guide value of the quality of fresh sand is to be below 2% soluble matter at 20 °C within 24 hours in hydrochloric acid of a 20 weight percent concentration. 

Guiding values for particulate material PMjq (aerodynamic diameter. smaller than 10 pm) are given by the United States and the European Union. Major debates are in progress regarding the importance of introducing values for the size PMt j. 

Guide values for normal operations, drop per tray. 

Konings, A. M., Guide Values for the Pouling Resistance of Gooling Water with Different Types of Treatment for Design of Shell and Tube Heat Exchangers, Heat Transfer Eng, V. 10, No. 4.,p. 54 (1989). 

Metals and alloys removal of corrosion products from corrosion test specimens Metals and alloys atmospheric corrosion testing general requirements for held tests Corrosion of metals and alloys. Classification of corrosivity of atmospheres Corrosion of metals and alloys. Guiding values for the corrosivity categories of atmospheres... 

A heat resistance of 200°C for 5 minutes for organic pigments is often taken as a guide value for practical use in PVC, good stabilization of the PVC being a prerequisite. In a high white reduction certain shade changes caused by inadequate heat resistance do however occur in certain cases under these conditions. 

To determine Sb in marine sediments by ETAAS, a direct method was developed based on quantitating the analyte in the liquid phase of the slurries (prepared directly in autosampler cups). The variables influencing the extraction of Sb into the liquid phase and the experimental setup were set after a literature search and a subsequent multivariate optimisation procedure. After the optimisation, a study was carried out to assess robustness. Six variables were considered at three levels each (see Table 2.13). In addition, two noise factors were set after observing that two ions, which are currently present into marine sediments, might interfere in the quantitations. In order to evaluate robustness, a certified reference material was used throughout, BCR-CRM 277 Estuarine Sediment (guide value for Sb 3.5 0.4pgg ). Table 2.13 depicts the experimental setup. 

Since the objective is to obtain the guide value stated on the CRM certificate, i.e. 3.5, Taguchi s term "nominal is best" should be followed and we should proceed in two stages first the selection of the control factor levels in order to minimise the effect of the noise factors and second the selection of the signal factor levels in order to obtain the Sb certified value. 

Lead content of petrol limited to 0.4 gl 1 Introduced to control the transboundary effects of acid rain and to limit emission of acidifying pollutants Air quality limit values and guide values for sulphur dioxide and suspended particles Limit value for lead in the air... 

Limit values and guide values of air quality for sulphur dioxide and suspended particulates. Harmonised measurement methods... 

Evaluation of Indoor Air Contamination by Means of Reference and Guide Values The German Approach... 

Evaluation of Indoor Air Quality with the Aid of Guide Values... 

The aim of toxicologically derived guide values is to provide the user in scientific and official practice with a numerical value which allows him to see from which concentration of the particular pollutant or group of pollutants in the indoor air a health risk to room users could, on the basis of current scientific findings, no longer be excluded with sufficient certainty or beneath which concentration any risk there might be could be ignored. 

Table 9.1 German guide values (RWI and RWII) for indoor air quality (Ad-hoc AG) .

Basic Scheme for Deriving Guide Values for Indoor Air... 

RW II is an effect-related value based on current toxicological and epidemiological knowledge of a substance s effect threshold which takes uncertainty factors into account. It represents the concentration of a substance which, if reached or exceeded, requires immediate action as this concentration could pose a health hazard, especially for sensitive people who reside in these rooms over long periods of time. Depending on the mode of action, guide value II may be defined either as a short-term value (RW II K) or a long-term value (RW II L). 

Figure 9.1 Derivation of guide values according to the basic scheme of the Ad-hoc AC (19%).

What is meant by action here is a need for testing without delay, for example, with regard to decisions to carry out remediation to reduce exposure. It may therefore be necessary for rooms to be closed. If guide value RW II is exceeded this should immediately result in check measurements under normal utilization conditions and-if possible and appropriate-determination of the internal exposure of room users. 

The advantage of these guide values for indoor air is their uniform derivation with its orientation toward risk. Building construction law (building codes) repre-... 

To decide whether a guide value has been exceeded or fallen short of, a check measurement should, as specified in the basic scheme, be taken under utilization conditions before initiating further action. 

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