1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 22197-4:2013Fine ceramics (advancedceramics, advanced technicalceramics) Test method forair-purification performance ofsemiconducting photocatalyticmaterials Part 4: Remov
2、al of formaldehydeBS ISO 22197-4:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 22197-4:2013.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this commit
3、tee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 66978 1ICS 81.060.30Co
4、mpliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2013.Amendments issued since publicationDate Text affectedBS ISO 22197-4:2013 ISO 2013Fine ceramics (advance
5、d ceramics, advanced technical ceramics) Test method for air-purification performance of semiconducting photocatalytic materials Part 4: Removal of formaldehydeCramiques techniques Mthodes dessai relatives la performance des matriaux photocatalytiques semi-conducteurs pour la purification de lair Pa
6、rtie 4: limination du formaldhydeINTERNATIONAL STANDARDISO22197-4First edition2013-04-01Reference numberISO 22197-4:2013(E)BS ISO 22197-4:2013ISO 22197-4:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this public
7、ation may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the countr
8、y of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 22197-4:2013ISO 22197-4:2013(E) ISO 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative refer
9、ences 13 Terms and definitions . 14 Symbols 25 Principle 26 Apparatus . 36.1 Test equipment . 36.2 Test gas supply 56.3 Photoreactor . 66.4 Light source . 66.5 Analytical system 67 Test piece 68 Procedure. 68.1 General aspects . 68.2 Pretreatment of test piece . 78.3 Preparation for the test . 78.4
10、Pretest . 88.5 Removal test 89 Calculation 810 Test method for test pieces with lower performance 911 Test report . 9Bibliography .10BS ISO 22197-4:2013ISO 22197-4:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO memb
11、er bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each 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, government
12、al and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directi
13、ves, Part 2.The main task of technical committees is to prepare International Standards. 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
14、casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 22197-4 was prepared by Technical Committee ISO/TC 206, Fine ceramics.ISO 22197 con
15、sists of the following parts, under the general title Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for air-purification performance of semiconducting photocatalytic materials: Part 1: Removal of nitric oxide Part 2: Removal of acetaldehyde Part 3: Removal of toluene Par
16、t 4: Removal of formaldehyde Part 5: Removal of methyl mercaptaniv ISO 2013 All rights reservedBS ISO 22197-4:2013INTERNATIONAL STANDARD ISO 22197-4:2013(E)Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for air-purification performance of semiconducting photocatalytic mat
17、erials Part 4: Removal of formaldehyde1 ScopeThis part of ISO 22197 specifies a test method for the determination of the air-purification performance of materials that contain a photocatalyst or have photocatalytic films on the surface, usually made from semiconducting metal oxides, such as titanium
18、 dioxide or other ceramic materials, by continuous exposure of a test piece to the model air pollutant under illumination with ultraviolet light (UV-A). This part of ISO 22197 is intended for use with different kinds of materials, such as construction materials in flat sheet, board or plate shape, t
19、hat are the basic forms of materials for various applications. This part of ISO 22197 also applies to structured filter materials including honeycomb-form, woven and non-woven fabrics, and to plastic or paper materials if they contain ceramic microcrystals and composites. This part of ISO 22197 does
20、 not apply to powder or granular photocatalytic materials.This test method is usually applicable to photocatalytic materials produced for air purification. This method is not suitable for the determination of other performance attributes of photocatalytic materials, i.e. decomposition of water conta
21、minants, self-cleaning, antifogging and antibacterial actions. It concerns the removal of formaldehyde.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the la
22、test edition of the referenced document (including any amendments) applies.ISO 4892-3, Plastics Methods of exposure to laboratory light sources Part 3: Fluorescent UV lampsISO 6145-7:2001, Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 7: Thermal mass-flow
23、 controllersISO 10677:2011, Fine ceramics (advanced ceramics, advanced technical ceramics) Ultraviolet light source for testing semiconducting photocatalytic materialsISO 16000-3:2001, Indoor air Part 3: Determination of formaldehyde and other carbonyl compounds Active sampling methodISO/IEC 17025:2
24、005, General requirements for the competence of testing and calibration laboratoriesISO 22197-1:2007, Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for air-purification performance of semiconducting photocatalytic materials Part 1: Removal of nitric oxideISO 80000-1, Qua
25、ntities and units Part 1: General3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply. ISO 2013 All rights reserved 1BS ISO 22197-4:2013ISO 22197-4:2013(E)3.1photocatalystsubstance that performs one or more functions based on oxidation and reduction rea
26、ctions under photoirradiation, including decomposition and removal of air and water contaminants, deodorization, and antibacterial, self-cleaning and antifogging actions3.2photocatalytic materialsmaterials in which or on which the photocatalyst is added by coating, impregnation, mixing, etcNote 1 to
27、 entry: Such photocatalytic materials are intended primarily for use as building and road construction materials to obtain the above-mentioned functions3.3zero-calibration gasair that does not contain pollutants (i.e. in which common pollutants are below 0,01 l/l)Note 1 to entry: The zero-calibratio
28、n gas is prepared from indoor air using a laboratory air purification system, or supplied as a synthetic air in a gas cylinder.3.4formaldehyde gasgases of known concentrations used for test and calibration3.5test gasmixture of air and pollutant(s) of known concentration prepared from a standard gas
29、or a zero-calibration gas, to be used for the performance test of a photocatalytic materialNote 1 to entry: The flow rate, concentration, etc. are expressed at the standard state (0 C, 101,3 kPa) and dry gas basis (exclusion of water vapour).3.6dark conditiontest condition with no light illumination
30、 by the light source for testing and room lightingsNote 1 to entry: Usually the test gas is supplied for comparison with the illuminated reaction.4 SymbolsFor the purposes of this document, the following symbols apply.f the flow rate of test gas converted into that at the standard state (l/min, 0 C,
31、 101,3 kPa, dry gas basis)Fthe volume fraction of formaldehyde at the reactor exit (l/l)F0the supply volume fraction of formaldehyde (l/l)nFthe removal quantity, by test piece, of formaldehyde (mol)RFthe removal percentage, by test piece, of formaldehyde (%)5 PrincipleThis part of ISO 22197 concerns
32、 the development, comparison, quality assurance, characterization, reliability, and design data generation of photocatalytic materials. The method described is intended to obtain the air-purification performance of photocatalytic materials by exposing a test piece to model polluted air under irradia
33、tion by ultraviolet (UV-A) light. Formaldehyde (HCHO) is chosen 2 ISO 2013 All rights reservedBS ISO 22197-4:2013ISO 22197-4:2013(E)because it is a typical indoor air pollutant that causes the so-called sick-building syndrome. The test piece, placed in a flow-type photoreactor, is activated by UV ir
34、radiation, and adsorbs and oxidizes gas-phase formaldehyde to form carbon dioxide (CO2) and other oxidation products. The air purification performance is determined from the net amount of formaldehyde removed by the test piece (mol). The simple adsorption of HCHO by the test piece (not due to photoc
35、atalysis) is evaluated by tests in the dark. However, some test pieces absorb formaldehyde very strongly, and a stable concentration of formaldehyde may not be attained in the designated time of test. The photocatalytic activity may depend on physical and chemical properties of pollutants mainly due
36、 to the adsorption process involved. For a better evaluation of air purification performance of photocatalytic materials, it is recommended to combine one or more suitable test methods as provided in other parts of ISO 22197.6 Apparatus6.1 Test equipmentThe test equipment enables a photocatalytic ma
37、terial to be examined for its pollutant-removal capability by supplying the the test gas continuously, while providing photoirradiation to activate the photocatalyst. It is the same as that used in the test method for the removal of nitric oxide (ISO 22197-1) and consists of a test gas supply, a pho
38、toreactor, a light source, and pollutant-measurement equipment. Since low concentrations of pollutants are to be tested, the system shall be constructed with materials of low absorption and resistant to ultraviolet (UV) radiation, for example, acrylic resin, stainless steel, glass and fluorocarbon p
39、olymers. An example of a test system is shown in Figure 1. ISO 2013 All rights reserved 3BS ISO 22197-4:2013ISO 22197-4:2013(E)Dimensions in millimetresPP123100897546101150Key1 light source 7 mass-flow controller2 optical window 8 gas mixers3 test piece 9 humidifier4 standard gas (pollutant) 10 anal
40、yser5 air-purification system 11 vent6 compressorFigure 1 Schematic diagram of the test equipment4 ISO 2013 All rights reservedBS ISO 22197-4:2013ISO 22197-4:2013(E)Dimensions in millimetres123599,5 0,55 0,54a) For flat test pieces1246249,5 0,55 0,55799,5 0,53b) For filter-type test piecesKey1 windo
41、w2 test piece3 test gas4 height-adjusting plate5 air layer thickness6 flow channel7 test piece holderFigure 2 Cross-sectional views of photoreactor (axial)6.2 Test gas supplyThe test gas supply provides air polluted with model contaminant at a predetermined concentration, temperature and humidity, a
42、nd supplies it continuously to the photoreactor. It consists of flow regulators, a humidifier, gas mixers, etc. The flow rate of each gas should be within 5 % of the designated value, ISO 2013 All rights reserved 5BS ISO 22197-4:2013ISO 22197-4:2013(E)which is easily attained by using thermal mass-f
43、low controllers with knowledge of temperature and gas type at calibration in accordance with ISO 6145-7. The expression of gas flow rate in this part of ISO 22197 is that converted to the standard state (0 C, 101,3 kPa and dry gas basis). Typical capacities of flow controller for pollutant gas, dry
44、air and wet air are 200 ml/min, 2000 ml/min and 2000 ml/min, respectively. The standard formaldehyde gas in a cylinder, normally balanced with nitrogen, shall have a volume fraction of about 20 l/l.6.3 PhotoreactorThe photoreactor holds a planar test piece within a 50 mm wide trough, with its surfac
45、e parallel to an optical window for photoirradiation. The reactor shall be fabricated from materials that adsorb little test gas and withstand irradiation of near-UV light. The test piece shall be separated from the window by a 5,0 mm 0,5 mm thick air layer. The test gas shall pass only through the
46、space between the test piece and the window. This gap shall be accurately set up according to the thickness of the test piece, for example by using height-adjusting plates with different thicknesses, as shown in Figure 2 a). When a filter-type material is tested, an alternative type of test-piece ho
47、lder shall be used, which holds the test piece while allowing the test gas to pass through the cells of the filter under irradiation Figure 2 b). Quartz or borosilicate glass that absorbs minimal light at wavelengths longer than 300 nm shall be used for the window.6.4 Light sourceThe light source sh
48、all provide UV-A irradiation within a wavelength range of 300 nm to 400 nm. Suitable sources include the so-called black light (BL) and black light blue (BLB) fluorescent lamps, with a maximum at 351 nm, as specified in ISO 4892-3 and ISO 10677. The test piece shall be irradiated uniformly through t
49、he window by the light source. In the case of testing honeycomb-form photocatalysts, the light source shall irradiate one face of the test piece. A light source that requires warming up shall be equipped with a shutter. The distance between the light source and the reactor shall be adjusted so that the UV irradiance (300 nm to 400 nm) at the sample surface is 10 W/m2 0,5 W/m2. The irradiance along the length of the test piece shall also be constant within 5 %. The UV irradiance shall
