IGU的玻璃热性能中心是玻璃类型、涂层、腔隙尺寸和气体填充的函数。本文件仅涉及这些领域，不涉及IGU边缘条件。本文件的原始版本于2016年获得批准并发布。该版本的文件于2022年7月更新并发布。

The center of glass thermal performance of an IGU is a function of glass type, coating, and size and gas fill of cavity gap. This document will address these areas only and does not address IGU edge conditions. The original version of this document was approved and published in 2016. This version of the document was updated and published in July 2022.