SIST EN 27027:1996
(Main)Water quality - Determination of turbidity (ISO 7027:1990)
Water quality - Determination of turbidity (ISO 7027:1990)
Wasserbeschaffenheit - Bestimmung der Trübung (ISO 7027:1990)
Diese Internationale Norm beschreibt vier Verfahren zur Bestimmung der Trübung von Wasser.
Quantité de l'eau - Détermination de la turbidité (ISO 7027:1990)
Kakovost vode - Ugotavljanje motnosti (ISO 7027:1990)
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kakovost vode - Ugotavljanje motnosti (ISO 7027:1990)Wasserbeschaffenheit - Bestimmung der Trübung (ISO 7027:1990)Quantité de l'eau - Détermination de la turbidité (ISO 7027:1990)Water quality - Determination of turbidity (ISO 7027:1990)13.060.60Preiskava fizikalnih lastnosti vodeExamination of physical properties of waterICS:Ta slovenski standard je istoveten z:EN 27027:1994SIST EN 27027:1996en01-oktober-1996SIST EN 27027:1996SLOVENSKI
STANDARD
SIST EN 27027:1996
SIST EN 27027:1996
SIST EN 27027:1996
INTERNATIONAL STANDARD ISO 7027 Second edition 1990-04-15 Water quality - Determination of turbidity Qualitk de l’eau - Determination de Ia turbidife Reference number ISO 7027 : 1990 (El SIST EN 27027:1996
ISO 7027 : 1990 (El Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bedies). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take patt in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 7027 was prepared by Technical Committee ISO/TC 147, Water guality. This second edition cancels a constitutes a minor revision . nd replaces the first editio In (ISO 7027 : 19841, of which it Annex A of this International Standard is for information only. 0 ISO 1990 All rights reserved. No patt of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-121 1 Geneve 20 l Switzerland Printed in Switzerland ii SIST EN 27027:1996
ISO 7027 : 1990 (El lntroduction Turbidity in liquids is caused by the presence of undissolved matter. In the case of undissolved, finely dispersed matter, the turbidity may be determined by measuring the attenuation of a radiant flux as it Passes through the liquid or by measuring the inten- sity of diff used radiation. The diffusion of radiation is a property of liquids and tan be used to measure turbidity. This International Standard describes both of these methods, together with methods which, although largely superseded since the development of Optical turbidimeters, are still used for semiquantitative determi- nations, for example to obtain information in field work on surface and waste waters. SIST EN 27027:1996
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INTERNATIONAL STANDARD ISO 7027 : 1990 (E) Water quality - Determination of turbidity Section 1: General _ 1.1 Scope This International Standard specifies four methods for the determinations of turbidity of water. Section 2 specifies semiquantitative methods, employed for example in field work: a) method using the transparency testing tube (suitable for pure and lightly polluted water); b) method using the transparency testing disk (especially suitable for surface watet=). Section 3 specifies quantitative methods using Optical turbi- dimeters : a) method by measuring diffused radiation, applicable to water of low turbidity (for example drinking water). Depen- ding on the instrument design, it may also be used for waters of higher turbidity; b) method by measuring the attenuation of a radiant flux, more suitable for highly turbid waters (for example waste or polluted waters). Measurements of turbidity tan be affected by the presence of dissolved light-absorbing substances (substances imparting colour). Such effects tan be minimized, however, by perform- ing measurements at wavelengths greater than 800 nm. Only a blue colour, which may be found in certain polluted waters, slightly affects measurements of turbidity in this region of the spectrum. Air bubbles may also interfere with measurements but such interference may be minimized by careful handling of the samples. 1.2 Normative referbnces The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3864 : 1984, Safety colours and safety signs. ISO 6107-2 : 1989, Water quality - Vocabulary - Part2. CIE Publication No. 17 : 1987, InternationalLighting Vocabu- lary. 1.3 Definitions For the purpose of this International Standard, the definitions given in CIE Publication No. 17, and the following, apply. turbidity: Reduction of transparency of a liquid caused by the presence of undissolved matter. See also 3.1. 1.4 Sampling and samples Maintain all glassware that Comes into contact with the Sample in a scrupulously clean condition. Wash with hydrochloric acid or surfactant cleaning Solution. Collect samples in glass bottles, fit Stoppers, and carry out the determinations as soon as possible after collection. If storage is unavoidable, store the samples in a cool, dark room but not longer than 24 h. If the samples have been stored cool, allow to come to room temperature before measurement. Prevent con- tact between the Sample and air and avoid unnecessary changes in the temperature of the Sample. SIST EN 27027:1996
ISO 7027 : 1990 (El Section 2: Semiquantitative methods 2.1 Method using the transparency testing tube 2.1.1 Apparatus 2.1.1.1 Transparency testing tube, consisting of a colourless glass tube 600 mm + 10 mm long and of internal diameter 25 mm + 1 mm, graduated in divisions of 10 mm. 2.1.1.2 Shield, close fitting, to protect the transparency testing tube from lateral light. 2.1 .1.3 Print Sample, placed under the tube (2.1 .l .l) con- sisting of black print on a white background (height of characters 3,5 mm; line width 0,35 mm); or a test mark (for example a black Cross on white Paper) provided with the apparatus. 2.1.1.4 Constant light Source: 3 W low voltage tungsten lamp, to illuminate the print Sample or test mark (2.1 .1.3). 2.1.2 Procedure Thoroughly mix the Sample and transfer it to the transparency testing tube (2.1.1.1). Steadily lower the Sample level until the print Sample or test mark (2.1.1.3) is clearly recognizable as viewed from above. Read the liquid height from the gradu- ations on the tube. 2.1.3 Expression of results Report the measured liquid height, to the nearest 10 mm, together with the apparatus used (name of the manufacturer). 2.2 Method using the transparency testing disk NOTE - This method is intended primarily for testing bodies of water in sh. 2.2.1 Apparatus The apparatus comprises a transparency testing disk made of cast bronze and coated with white (sec ISO 38641 plastic, attached to a chain or rod. NOTE - A typical design comprises a disk of diameter 200 mm with six holes, each of diameter 55 mm, on a circle of diameter 120 mm. 2.2.2 Procedure Lower the disk, on its chain or rod, into the water until the disk is barely visible when viewed from above. Measure the length of immersed chain or rod. Repeat the Pest several times. Ensure that no interference arises by reflection at the water surface. 2.2.3 Expression of results Report the depth of immersion. For values less than 1 m, report the result to the nearest 10 mm. For values greater than 1 m, report the result to the nearest 0,l m. SIST EN 27027:1996
ISO 7027 : 4990 (E) Section 3: Quantitative methods using opticai turbidimeters 3.1 General principles A water Sample coloured by dissolved substances is a homo- geneous System that only attenuates radiation passing through the Sample. A water Sample containing undissolved substances attenuates the incident radiation and in addition the insoluble particles present diffuse the radiation unequally in all directions. The forward diffusion of radiation by the particles affects the attenuation so that the common spectral attenuation coef- ficient p(d) is the sum sf the spectral diffusion coefficient s(;l) and the spectral absorption coefficient a(A): p(il) = SM) + a(A) To obtain the spectral diffusion coefficient s(A) alone, the spec- tral absorption coefficient a(J.1 must be known. In Order to determine the spectral absorption
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