ISO 8291:1986 ガラス質および磁器のエナメル—セルフクリーニング特性のテスト方法 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member 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, governmental and non-governmental, in liaison with ISO, also take part in the work.

Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting.

International Standard ISO 8291 was prepared by Technical Committee ISO/TC 107, Metallic and other non-organic coatings.

Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated.

0 Introduction

0.1 The combustion of oil or fat coming into contact with the enamelled walls of self-cleaning roasting and baking devices is an oxidation process. The porosity of the wall, resulting in a larger total surface area of the coating, enables the oil or fat to spread out into a thin film and facilitates the action of oxygen.

As combustion at 250 °C cannot be complete, non-oxidizable combustion residues build up in the pores during operation, resulting in the formation of a visible glossy coating. The test method specified in this International Standard is more severe than this process as a testing oil is applied directly to the cold coating and the quantity of the oil on the surface is greater than that seen in practical use.

0.2 Household refined soya oil serves as the testing oil. The composition of commercial grades of this oil is well defined. The freshly prepared soya oil may be supplied by the producer.

0.3 The test method specified in this International Standard can serve only as a comparative method, for the following reasons:

• a) the combustion process is dependent on the draught conditions in the oven — these vary from oven to oven ;
• b) soya oil which is old or of different composition may give different results;
• c) the assessment of the gloss is subjective — the surface roughness of self-cleaning vitreous and porcelain enamels and the patchiness of the gloss do not allow objective measurement.

0.4 It is recommended that specifications should contain the following statement:

1 Scope and field of application

This International Standard specifies a method of test for the determination of the self-cleaning properties of vitreous and porcelain enamelled walls of roasting devices, grills and baking devices; self-cleaning consists in the capacity first to absorb oil or fat in droplet form, and then to volatilize the greater part of the fat or oil by the sequential processes of distillation, decomposition, and combustion (referred to collectively as “combustion" in the following text).

This International Standard is not applicable to pyrolytically cleaning vitreous and porcelain enamels.

2 References

3 Definition

For the purpose of this International Standard, the following definition applies.

continuously self-cleaning enamel finish: Porous enamel finish which absorbs splashes of fat given off during roasting or baking, and simultaneously allows the fat to burn without subsequent increase in temperature.