BS EN ISO 11844-1 pdf free download

BS EN ISO 11844-1 pdf free download. Corrosion of metals and alloys – Classification of low corrosivity of indoor atmospheres.
4 Symbols and abbreviated terms IC indoor corrosivity r corr corrosion rate derived from mass‑loss measurement after an exposure of one year r mi rate of mass increase after an exposure of one year 5 Classification of corrosivity 5.1 General The corrosivity of indoor atmospheres can be classified either by a determination of the corrosion attack on standard specimens of selected standard metals as given in Clause 6 or, where this is not possible, by an estimation of corrosivity based on the knowledge of humidity, temperature and pollution conditions as described in Clause 7 and Annexes B, C and D. Estimation of corrosivity as described in 7.2 and Annexes C and D can lead to wrong conclusions. Therefore, the determination of corrosivity by the measurement of the corrosion attack on standard specimens is strongly recommended. 5.2 Categories of indoor corrosivity For the purpose of this document, indoor atmospheres are classified into five corrosivity categories denoted IC 1 to IC 5. The classification is given in Table 1. 6 Determination of indoor atmospheric corrosivity The determination of corrosivity of indoor atmospheres is based on measurements of corrosion attack on standard specimens of five reference metals after an exposure for one year in accordance with ISO 11844‑2. From the mass loss or mass increase, the indoor corrosivity category for each metal is determined from Table 2. In indoor environments when the all conditions (temperature, humidity, air pollutions) vary only in range of ±5 % from average value, the exposure period should be shorter, e.g. one month only. Preferably, this month should represent the most corrosive period of the year. Metals complement each other in the classification of indoor corrosivity for a given environment. 7 Characterization of indoor atmospheres with respect to indoor corrosivity 7.1 General Environmental characteristics are informative and allow assessment of specific corrosion effects with regard to individual metals and metallic coatings. The ISO 16000 series deals with indoor air measurements describing the sampling strategy, including the conditions to be observed for particular substances or groups of substances, such as the dependence of indoor air pollution concentrations on atmospheric humidity or temperature or other effects. ISO 16000‑1:2004, Table A.1, summarizes the most important types of indoor environment and gives examples of the sources that can be encountered in them. The list is not, of course, fully comprehensive because of the large number of possibilities. ISO 16000‑1:2004, Table B.1, shows the sources of indoor air pollutants and the most important substances emitted. ISO 16000‑1:2004, Table C.1, lists substances frequently detected and their possible sources. The ISO 16000 series does not cover all indoor air pollutants significant for indoor atmospheric corrosivity. Methods for the characterization and measurement of environmental parameters of indoor atmospheres are given in ISO 11844‑3. This method of corrosivity estimation is, in many cases, oversimplified and can give misleading results. An estimation of corrosivity is based on: — climatic influences (outdoor situation including pollution); — indoor microclimate influences; — indoor gaseous and particle pollution. The corrosivity of an indoor atmosphere increases with higher humidity and depends on the type and level of pollution. Important characteristics are frequency of variation of relative humidity (RH) and temperature (T) in intervals, and frequency and time of condensation. An indoor environment is rarely static, since the concentration of any substance can be constantly altered by the strength of the source, human activity, ventilation rate, external or internal climatic conditions, chemical reactions and possible sinks (e.g. sorption by surfaces and furnishings). In addition, the composition of indoor air can vary within and between rooms, and be less homogeneous than the outdoor air surrounding the building. Indoor atmospheres are polluted by the components from external and internal sources. Typical pollutants are SO 2 , NO 2 , O 3 , H 2 S, Cl 2 , NH 3 , HCl, HNO 3 , Cl ‑ , NH 4 + , organic acids, aldehydes and particles (see Annex B). Due to the permanent exchange between indoor and outdoor air caused by infiltration and ventilation processes, it may be important to supplement indoor air measurements with a simultaneous measurement of the outdoor air [if possible, at the same level (floor) of the building]. The outdoor air samples should be taken in the vicinity of the building but not closer than 1 m. In making such measurements, it should be remembered that vertical concentration gradients can occur, e.g. for the components of vehicle exhaust gases in street canyons.BS EN ISO 11844-1  pdf download.