ASTM D7990-21 PDF

Full title and description

ASTM D7990-21 — Standard Test Method for Using Reflectance Spectra to Produce an Index of Temperature Rise in Polymeric Siding. This test method defines how to use spectrophotometric reflectance (ultraviolet, visible, and near‑infrared) to calculate an intensity factor that correlates to the temperature rise a polymeric siding color would exhibit under severe solar exposure as predicted by Test Method D4803.

Abstract

ASTM D7990-21 provides a laboratory procedure to measure a specimen’s spectral reflectance and compute a dimensionless intensity factor that represents relative solar energy absorption. The intensity factor is correlated (via a regression equation and Appendix X1) to the temperature rise predicted by Test Method D4803, enabling rapid comparison and categorization of colors and formulations for heat‑buildup susceptibility without performing the full D4803 lamp test.

General information

• Status: Active
• Publication date: April 1, 2021 (approved/published 2021)
• Publisher: ASTM International
• ICS / categories: 83.140.99; 91.060.10
• Edition / version: D7990-21
• Number of pages: 4

Document summary and bibliographic details are published by ASTM International and appear in the D20 (Plastics) book/section. DOI: 10.1520/D7990-21.

Scope

The test method uses reflectance spectra from the ultraviolet, visible and near‑infrared regions to produce an index (intensity factor) of the temperature rise of polymeric siding above ambient caused by solar energy absorption. Appendix X1 provides a method to convert the intensity factor to a predicted maximum temperature rise as correlated to Test Method D4803. The method yields a relative index and is not intended to predict absolute in‑service product temperatures, which depend on installation and environmental conditions.

Key topics and requirements

• Measurement of spectral reflectance (UV–Vis–NIR) of the specimen using a spectrophotometer.
• Calculation of an intensity factor from the specimen reflectance combined with the spectral power distribution of the D4803 heat lamp.
• Correlation of intensity factor to temperature rise via a regression equation derived from D4803 test data (Appendix X1).
• Specimen preparation and backing (use of a black backer to absorb transmitted energy) and minimum specimen size to cover the instrument port.
• Limitations: provides a relative index (compared to a black reference) and does not replace in‑service measurements; environmental/installation variables are not included.

These requirements allow fast, repeatable screening of colors and formulations for heat‑buildup risk in plastic siding products.

Typical use and users

Used by material scientists, product development and color technologists, formulation and compounders of siding materials, QA/QC laboratories, independent testing laboratories, architects and specifiers, and regulatory/code reviewers to categorize colors/formulations for potential heat‑buildup and to decide when to require full product testing (for example, full D4803 heat‑buildup tests).

Related standards

Directly related to and used in conjunction with ASTM Test Method D4803 (Predicting Heat Buildup in PVC Building Products). D7990 provides a spectral‑based index that correlates to the D4803 lamp test results; users should consult the current D4803 edition when applying correlations. Other related standards include spectrophotometry methods such as ASTM E1331 (reflectance and color measurement by spectrophotometry) that describe instrumental measurement practices referenced by D7990.

Keywords

reflectance spectra; intensity factor; temperature rise; heat buildup; polymeric siding; spectrophotometry; UV‑Vis‑NIR; D4803; color screening; thermal distortion.

FAQ

Q: What is this standard?

A: ASTM D7990-21 is a test method that uses measured reflectance spectra to compute an intensity factor that indicates the relative temperature rise a polymeric siding color will experience due to solar energy absorption; it is a laboratory screening tool correlated to ASTM D4803.

Q: What does it cover?

A: It covers spectral measurement procedures (UV–Vis–NIR), calculation of the intensity factor using the D4803 lamp spectral distribution, and the regression‑based correlation (Appendix X1) to predict the D4803 temperature‑rise result. It explicitly notes that predicted values are relative and that field temperatures depend on installation and environment.

Q: Who typically uses it?

A: Material and color formulators, product development teams, QC/test labs, independent testing organizations, architects/specifiers, and standards/code bodies that need rapid color/formulation screening for heat‑buildup risk.

Q: Is it current or superseded?

A: D7990-21 is published and listed as active (2021 edition). A five‑year review/revision work item related to D7990 was opened in 2025, so users should check for any revision ballots or a newer edition since D7990-21 when planning long‑term compliance or test programs.

Q: Is it part of a series?

A: It is part of the ASTM plastic building‑products test suite under Committee D20 (Subcommittee D20.24). It is intended to be used alongside ASTM D4803 (heat‑buildup lamp test) and other materials/installation specifications referenced by the D20 committee.

Q: What are the key keywords?

A: reflectance spectra, intensity factor, temperature rise, heat buildup, polymeric siding, spectrophotometry, UV‑Vis‑NIR, D4803.