Thermal conductivity data acquired previously for the establishment of Standard Reference Material (SRM) 1450, Fibrous Glass Board, as well as subsequent renewals 1450a, 1450b, 1450c, and 1450d, are re-analyzed collectively and as individual data sets. Additional data sets for proto-1450 material lots are also included in the analysis (eleven data sets in total). The data cover the years 1958 to 2009; 52 years of activity by the National Institute of Standards and Technology (NIST) in developing and providing thermal insulation SRMs, specifically high-density molded fibrous-glass board, to the public. Collectively, the data sets cover two nominal thicknesses of 13 mm and 25 mm, bulk densities from 60 kg/m3 to 180 kg/m3, and mean temperatures from 100 K to 340 K. The prevailing generic model for the majority of data sets is the bilinear model in density and temperature. The regression equations are not intended to be, and cannot be, used to "re-certify" any of these previous SRMs. The results of this analysis, instead, aim to enhance our understanding of the original certificate equations derived by previous NIST (formerly the National Bureau of Standards) researchers as well as to improve the development and modeling of future thermal insulation SRMs.