After the bottom and side panels have been placed, sheets of plywood are added to the outer surface to prevent damage to the insulation during the backfill process. A cement-bedding mixture is then added to fill the space between the pipe and insulation., 1976-11, PCA0002-3b-39, Folder: PCA0002-3b. Alyeska Pipeline Service Company : Trans-Alaska Pipeline Construction Collection, 1976-1977, PCA 2. Alaska State Library - Historical Collections Finding Aids. https://alaska.libraryhost.com/repositories/2/archival_objects/17669 Accessed February 22, 2025.