Only use OEM breathing lines of the same brand and compatible part number with blast hoods. Per NIOSH and manufacturer directions, the respirator for the blast operator starts at the point of attachment, in many cases this is the point of connection off of the CPF filter, and ends with the helmet. To keep your PPE system in compliance only use parts designed for your system. Never use common or general air supply lines for breathing air, these hoses typically release noxious smells and chemicals into the airstream and are breathed in by the blast operator causing harm.