🔍 Key Concepts

• 46 CFR requirements for main propulsion boiler fittings • Purpose of a surface blow (continuous blow) connection on water-tube boilers • How boiler design pressure ranges affect required safety fittings

💭 Think About

• Think about why a surface blow connection is especially important at certain boiler pressures. At what approximate pressure range do boilers commonly operate on large propulsion plants? • Compare each pressure choice with typical low-pressure vs high-pressure marine water‑tube boiler classifications. • Ask yourself: as design pressure increases, do regulations usually become stricter or more relaxed about required fittings like blowoffs?

✅ Before You Answer

• Locate the specific table or paragraph in 46 CFR that lists required fittings for main propulsion water‑tube boilers by design pressure range. • Verify which single threshold pressure in the options matches the minimum design pressure where a surface blowoff becomes mandatory. • Double‑check the units: confirm the psig value and its corresponding kPa match the regulation text for that pressure threshold.