ISO 17168-4:2018

Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for air-purification performance of semiconducting photocatalytic materials under indoor lighting environment — Part 4: Removal of formaldehyde

This document specifies a test method for the determination of the air-purification performance, with regards to the removal of formaldehyde, of materials that contain a photocatalyst or have photocatalytic films on the surface, usually made from semiconducting metal oxides such as titanium dioxide or other ceramic materials, by continuous exposure of a test piece to the model air pollutant under illumination from indoor light. This document is intended for use with different kinds of materials, such as construction materials in flat sheet, board or plate shape, which are the basic forms of materials for various applications. This document also applies to materials in honeycomb form, and to plastic or paper materials containing ceramic microcrystals and composites. This document does 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 contaminants, self-cleaning, antifogging and antibacterial actions.

Titre manque — Partie 4: Titre manque

General Information

• Status: Published
• Publication Date: 18-Sep-2018
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206/WG 9 - Photocatalysis
• Current Stage: 6060 - International Standard published
• Start Date: 19-Sep-2018
• Completion Date: 19-Sep-2018

RELATIONS

• Revised: ISO 22197-4:2013 - Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for air-purification performance of semiconducting photocatalytic materials — Part 4: Removal of formaldehyde
• Effective Date: 01-Jun-2013

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 17168-4
First edition
2018-09
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Test method for air-purification
performance of semiconducting
photocatalytic materials under indoor
lighting environment —
Part 4:
Removal of formaldehyde
Reference number
ISO 17168-4:2018(E)
ISO 2018
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ISO 17168-4:2018(E)
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© ISO 2018

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ii © ISO 2018 – All rights reserved
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ISO 17168-4:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 2

5 Principle ........................................................................................................................................................................................................................ 2

6 Apparatus ..................................................................................................................................................................................................................... 2

6.1 Test equipment ....................................................................................................................................................................................... 2

6.2 Test gas supply ........................................................................................................................................................................................ 3

6.3 Photoreactor ............................................................................................................................................................................................. 4

6.4 Light source ............................................................................................................................................................................................... 6

6.5 UV sharp cut-off filter ........................................................................................................................................................................ 6

6.6 Analytical system .................................................................................................................................................................................. 6

7 Test piece ...................................................................................................................................................................................................................... 6

8 Procedure..................................................................................................................................................................................................................... 6

8.1 General aspects ....................................................................................................................................................................................... 6

8.2 Pretreatment of test piece ............................................................................................................................................................. 7

8.3 Preparation for the test ................................................................................................................................................................... 7

8.4 Pretest ............................................................................................................................................................................................................. 8

8.5 Removal test .............................................................................................................................................................................................. 8

9 Calculation .................................................................................................................................................................................................................. 8

10 Test method for test pieces with lower performance .................................................................................................... 9

11 Test report ................................................................................................................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................11

© ISO 2018 – All rights reserved iii
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ISO 17168-4:2018(E)
Foreword

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bodies (ISO member bodies). The work of preparing International Standards is normally carried out

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electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
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ISO 17168-4:2018(E)
Introduction

Photocatalyst is a substance that performs decomposition and removal of contaminants, self-

cleaning, antifogging, deodorization and antibacterial actions under photoirradiation. Its application

has expanded considerably in recent years. The application of photocatalysts for indoor spaces

has increasingly been sought as a solution to indoor environmental problems. Since conventional

photocatalysts are responsive only to ultraviolet light, studies have been made to develop an indoor-

light-active photocatalyst that makes effective use of indoor light, which room lights mainly emit, and

thus demonstrates high photocatalytic performance indoors. The development has recently led to the

commercialization of various indoor-light-active photocatalytic products, and there has been demand

for the establishment of test methods to evaluate the performance of this type of photocatalyst.

This document, with ISO 22197-1, ISO 22197-2 and ISO 22197-3 as the basis, is intended to provide a

testing method to determine the performance of indoor-light-active photocatalytic materials with

regards to the removal of formaldehyde, one of the most interesting aromatic volatile organic compound

(VOC)-caused sick-house syndromes, enabling swift distribution of photocatalytic products and thus

contributing to a safe and clean environment.
© ISO 2018 – All rights reserved v
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INTERNATIONAL STANDARD ISO 17168-4:2018(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Test method for air-purification performance
of semiconducting photocatalytic materials under indoor
lighting environment —
Part 4:
Removal of formaldehyde
1 Scope

This document specifies a test method for the determination of the air-purification performance, with

regards to the removal of formaldehyde, of materials that contain a photocatalyst or have photocatalytic

films on the surface, usually made from semiconducting metal oxides such as titanium dioxide or other

ceramic materials, by continuous exposure of a test piece to the model air pollutant under illumination

from indoor light.

This document is intended for use with different kinds of materials, such as construction materials in

flat sheet, board or plate shape, which are the basic forms of materials for various applications. This

document also applies to materials in honeycomb form, and to plastic or paper materials containing

ceramic microcrystals and composites. This document does 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 contaminants, self-cleaning, antifogging and antibacterial actions.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 6145-7, Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods —

Part 7: Thermal mass-flow controllers

ISO 14605, Fine ceramics (advanced ceramics, advanced technical ceramics) — Light source for testing

semiconducting photocatalytic materials used under indoor lighting environment

ISO 16000-3, Indoor air — Part 3: Determination of formaldehyde and other carbonyl compounds in indoor

air and test chamber air — Active sampling method

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

ISO 17168-1, Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for air

purification performance of semiconducting photocatalytic materials under indoor lighting environment —

Part 1: Removal of nitric oxide
ISO 80000-1, Quantities and units — Part 1: General
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 17168-1 apply.

© ISO 2018 – All rights reserved 1
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ISO 17168-4:2018(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Symbols

f flow rate of test gas converted into that at the standard state (0 °C, 101,3 kPa)

ϕ formaldehyde volume fraction at the reactor exit (µl/l)
ϕ formaldehyde volume fraction at the reactor exit under dark conditions (µl/l)
ϕ supply volume fraction of formaldehyde (µl/l)
n removal quantity, by test piece, of formaldehyde (µmol)
R removal percentage, by test piece, of formaldehyde (%)
5 Principle

This document deals with the development, comparison, quality assurance, characterization,

[1]

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 illumination by indoor light. Formaldehyde (HCHO) is chosen because it is a

[2]

typical indoor air pollutant that causes the so-called sick building syndrome . The test piece, placed

in a flow-type photoreactor, is activated by indoor light illumination, and adsorbs and oxidizes gas-

phase formaldehyde to form carbon dioxide (CO ) and other oxidation products. The air purification

performance is determined from the amount of formaldehyde removed by the test piece (μmol). The

simple adsorption of HCHO by the test piece (not due to photocatalysis) is evaluated by tests in the dark.

However, some test pieces are very absorbent, and a stable concentration of formaldehyde may not be

attained in the designated test time. The photocatalytic activity may depend on physical and chemical

properties of pollutants, mainly due to the adsorption process involved. For a better evaluation of air

purification performance of photocatalytic materials, it is recommended that one or more suitable test

methods are combined, as provided in other parts of the ISO 17168 series.
6 Apparatus
6.1 Test equipment

The test equipment enables a photocatalytic material to be examined for its pollutant-removal capability

by supplying 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 (see ISO 17168-1) and consists

of a test gas supply, a photoreactor, a light source, a UV sharp cut-off filter 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 f
...