What is 1 and 2 scrap metal?

Both HMS 1 and 2 comprise obsolete scrap only – iron and steel recovered from items demolished or dismantled at the end of their life. Because both grades guarantee a minimum piece thickness – at least 1⁄4 inch (6.35 mm) for HMS 1, and 1⁄8 inch (3.175 mm) for HMS 2 – consignments have a high density.