The standard, titled "Pipe Hangers and Supports – Selection and Application," is a critical industry guideline for the engineering and installation of piping systems. While historically significant, modern practitioners should note that it has been officially withdrawn as an active standard . Its technical content was fully integrated into the more comprehensive ANSI/MSS SP-58 standard starting with the 2009 edition. Core Purpose and Scope
But Maya had downloaded a scanned PDF from the company archive — a 2004 revision with handwritten notes in the margins, left by a retired engineer named Walt Hennessey. Next to Type 41, Walt had scrawled: "Do NOT use above 750°F without lateral restraint — see field failure, Edmonton, 1999." mss sp 69 pdf