🔍 Key Concepts

• 46 CFR Subchapter F requirements for fuel oil service system piping • Restrictions on use of fittings (unions, bushings, street ells, valves) in fuel oil discharge lines • Differences between threaded/screwed connections and welded/flanged connections in high‑risk systems

💭 Think About

• Which of these fittings is specifically mentioned in 46 CFR Subchapter F as being allowed in fuel oil service discharge piping, and under what limitations? • Which fittings are generally restricted or discouraged in fuel oil systems because of leak and fire risk? • Think about which item would most likely be found in a high‑integrity, high‑temperature fuel oil line on a modern inspected vessel.

✅ Before You Answer

• Verify in 46 CFR Subchapter F which fittings are explicitly prohibited in fuel oil discharge piping (e.g., unions over a certain size, certain screwed fittings). • Check if the regulation allows only one of these items under specific conditions, while the others are not mentioned or are restricted. • Confirm whether any of these fittings are limited by size, type (screwed vs welded), or service (suction vs discharge) in the text of the regulation.