ISO 11561:1999 PDF

Scope: This International Standard specifies two laboratory test methods, based on slicing and scaling techniques, to determine the long-term changes in the thermal resistance of closed-cell (normally 90 %) cellular plastic materials that contain gases which, through diffusion processes, affect the properties of a foam with time. Using standard methods for the measurement of thermal resistance, method A consists of periodic measurements performed over a short time interval on thin specimens conditioned in a controlled ambient temperature environment. The results of relative change with time are used in conjunction with a mathematical technique to derive the thermal resistance of greater thicknesses of the material as a function of time. Method B describes a simple test to determine a conservative design life-time value (25 years and longer) for an unfaced, closed-cell, cellular plastic product. This method is limited currently to unfaced homogeneous materials. For this method, multiple specimens of the core and surfaces of materials with variations in the slope of the primary stage thermal resistivity and a time relationship of less than 10% within a sample are considered to be homogeneous. Generally, products with natural skins or with density deviations normally found with such products may be considered acceptable for test by this technique.

ISO 11561:1999 Referenced Document

ISO 7345 Thermal performance of buildings and building components — Physical quantities and definitions*， 2018-03-08 Update
ISO 8301 Thermal insulation — Determination of steady-state thermal resistance and related properties — Heat flow meter apparatus AMENDMENT 1
ISO 8302 Thermal insulation; determination of steady-state thermal resistance and related properties; guarded hot plate apparatus
ISO 9346 Hygrothermal performance of buildings and building materials - Physical quantities for mass transfer - Vocabulary*， 2007-10-01 Update

1999 ISO 11561:1999 Ageing of thermal insulation materials - Determination of the long-term change in thermal resistance of closed-cell plastics (accelerated laboratory test methods)