Foreword

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

This second edition cancels and replaces the first edition ( ISO 17168-2:2018 ), which has been technically revised.

The main changes are as follows:

normative reference to ISO 24448 added to Clause 2 and 6.4.

A list of all parts in the ISO 17168 series can be found on the ISO website.

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 .

Introduction

A 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 17168-1 and ISO 22197-2 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 acetaldehyde, a representative lower aliphatic volatile organic compound (VOC), enabling swift distribution of photocatalytic products and thus contributing to a safe and clean environment.

1 Scope

This document specifies a test method for the determination of the air-purification performance, with regards to removal of acetaldehyde, 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 applicable 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

3 Terms and definitions

4 Symbols

5 Principle

6 Apparatus

6.1 Test equipment

6.2 Test gas supply

6.3 Photoreactor

6.4 Light source

6.5 UV sharp cut-off filter

6.6 Analytical system for acetaldehyde

6.7 Analytical system for CO₂

7 Test piece

8 Procedure

8.1 General aspects

8.2 Pretreatment of test piece

8.3 Preparation for the test

8.4 Pretest

8.5 Test of acetaldehyde removal and CO₂ conversion

8.6 Test of acetaldehyde removal (when CO₂ concentration cannot be measured)

9 Calculation

9.1 Calculation method

9.2 Removal percentage and removed quantity of acetaldehyde

9.3 Conversion to CO₂

10 Test method for test pieces with lower performance

11 Test report

Bibliography