🔍 Key Concepts

• 46 CFR requirements for boiler blowoff (blowdown) piping design pressure • Relationship between maximum allowable working pressure (MAWP) of a boiler and the required strength of connected piping • Why safety-related piping is often rated above the boiler’s normal working pressure

💭 Think About

• Look in 46 CFR Part 52 for rules on power boilers and find the specific section on blowoff or blowdown piping; what multiplication factor is applied to the boiler’s MAWP? • Ask yourself: does the Coast Guard typically require exactly the same pressure rating as MAWP, or a higher margin for components involved in pressure relief and water discharge? • Compare each choice to 600 psig: which answers reflect a realistic safety factor used in pressure vessel and piping design?

✅ Before You Answer

• Verify in 46 CFR the exact factor (e.g., 1.25 × MAWP, 1.3 × MAWP, 1.5 × MAWP, etc.) that must be applied to the boiler’s maximum allowable working pressure for blowoff piping external to the boiler. • Confirm that the requirement is stated as a minimum design/working pressure for the piping, not a test pressure. • Make sure you are looking at the section that applies to external blowoff piping for power boilers at 600 psig MAWP, not to other types of piping or lower-pressure heating boilers.