1. Scope

1.1 This test method covers a procedure for predicting the long-term thermal resistance (LTTR) of unfaced or permeably faced rigid gas-filled closed-cell foam insulations by reducing the specimen thickness to accelerate aging under controlled laboratory conditions (1-5) .

1.2 Rigid gas-filled closed-cell foam insulation includes all cellular plastic insulations manufactured with the intent to retain a blowing agent other than air.

1.3 This test method is limited to unfaced or permeably faced, homogeneous materials. This method is applied to a wide range of rigid closed-cell foam insulation types, including but not limited to: extruded polystyrene, polyurethane, polyisocyanurate, and phenolic. This test method does not apply to impermeably faced rigid closed-cell foams or to rigid closed-cell bun stock foams.

Note 1See Note 7 for more details regarding the applicability of this test method to rigid closed-cell bun stock foams.

1.4 This test method utilizes referenced standard test procedures for measuring thermal resistance. Periodic measurements are performed on specimens to observe the effects of aging. Specimens of reduced thickness (that is, thin slices) are used to shorten the time required for these observations. The results of these measurements are used to predict the long-term thermal resistance of the material.

1.5 The test method is given in two parts. The Prescriptive Method in Part A provides long-term thermal resistance values on a consistent basis that can be used for a variety of purposes, including product evaluation, specifications, or product comparisons. The Research Method in part B provides a general relationship between thermal conductivity, age, and product thickness.

1.5.1 To use the Prescriptive Method, the date of manufacture must be known, which usually involves the cooperation of the manufacturer.

1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

C168 Terminology Relating to Thermal Insulation

C177 Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus

C518 Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus

C578 Specification for Rigid, Cellular Polystyrene Thermal Insulation

C591 Specification for Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation

C1029 Specification for Spray-Applied Rigid Cellular Polyurethane Thermal Insulation

C1045 Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions

C1126 Specification for Faced or Unfaced Rigid Cellular Phenolic Thermal Insulation

C1289 Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board

D1622 Test Method for Apparent Density of Rigid Cellular Plastics

D6226 Test Method for Open Cell Content of Rigid Cellular Plastics

E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process

Other Standards

Keywords

aging; long-term thermal resistance; LTTR; rigid closed-cell plastic foams; scaling factors; thermal insulation; thermal resistance; time-averaged thermal resistance; Polyurethane insulation; Rigid closed cell plastic foams; Rigid thermal insulation; Scaling; Spray-applied thermal insulation; Thermal insulating materials; Aging resistance; Controlled testing conditions/environments; Foamed-in-place thermal insulation; Long-term behavior/performance; Phenolic plastics; Polyisocyanurate insulation; Polystyrene (PS); Thermal resistance/resistivity; Time-averaged thermal resistance; Unfaced thermal insulation

ICS Code

ICS Number Code 83.100 (Cellular materials)

DOI: 10.1520/C1303_C1303M-10

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