ISO 13788:2012 建築コンポーネントと建築要素の湿熱性能—臨界表面湿度と間質結露を回避するための内部表面温度—計算方法 | 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. 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 Directives, 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 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 13788 was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment, Subcommittee SC 2, Calculation methods in cooperation with CEN/TC 89, Thermal performance of buildings and building components.

This second edition cancels and replaces the first edition (ISO 13788:2001), which has been technically revised.

Introduction

Moisture transfer is a very complex process and the knowledge of moisture transfer mechanisms, material properties, initial conditions and boundary conditions is often limited. Therefore this International Standard lays down simplified calculation methods, which assume that moisture transport is by vapour diffusion alone and use monthly climate data. The standardization of these calculation methods does not exclude use of more advanced methods. If other sources of moisture, such as rain penetration or convection, are negligible, the calculations will normally lead to designs well on the safe side and if a construction fails a specified design criterion according to this procedure, more accurate methods may be used to show that the design will pass.

This International Standard deals with:

• a) the critical surface humidity likely to lead to problems such as mould growth on the internal surfaces of buildings,
• b) interstitial condensation within a building component, in:
  • heating periods ここで, the internal temperature is usually higher than outside;
  • cooling periods ここで, the internal temperature is usually lower than the outside;
  • cold stores ここで, the internal temperature is always lower than outside.

• c) an estimate of the time taken for a component, between high vapour resistance layers, to dry, after wetting from any source, and the risk of interstitial condensation occurring elsewhere in the component during the drying process.

1 Scope

This International Standard gives simplified calculation methods for:

• a) The internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity. The method can also be used to assess the risk of other internal surface condensation problems.
• b) The assessment of the risk of interstitial condensation due to water vapour diffusion. The method used does not take account of a number of important physical phenomena including:
  • the variation of material properties with moisture content;
  • capillary suction and liquid moisture transfer within materials;
  • air movement from within the building into the component through gaps or within air spaces;
  • the hygroscopic moisture capacity of materials.

  Consequently, the method is applicable only where the effects of these phenomena can be considered to be negligible.

• c) The time taken for water, from any source, in a layer between two high vapour resistance layers to dry out and the risk of interstitial condensation occurring elsewhere in the component during the drying process.

2 Normative references

The following referenced documents are indispensable for the application 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.

Bibliography