The International Association of Classification Societies (IACS) brings the major classification societies: ABS, DNV, Lloyd’s Register (LR), Bureau Veritas(BV), ClassNK, RINA and others. IACS rules establish a set of minimum technical standards. Unified Requirements (UR) are the backbone of that system, incorporated into each member’s own class rules.
For piping, the core reference is UR Part P – Pipes and Pressure Vessels, covering classification, materials, wall thickness, welding and testing for fuel, steam, hydraulics, bilge, ballast and cargo systems. Related requirements also appear in Part F (fire-rated penetrations), Part E (earthing) and Part M (machinery).
This page collects the UR clauses that matter for piping design, so you can go straight to the one you need.
UR M (Machinery)
- M11 – Protective devices for starting air mains
- M12 – Fire extinguishing systems for scavenge manifolds
- M64 – Design of integrated cargo and ballast systems on tankers
- M65 – Draining and Pumping Forward Spaces in Bulk Carriers
- M84 – Capacity and availability of compressed air for essential services
UR F (Fire Protection - In Practice "Piping for Tankers")
- F16 – Bow and stern loading and unloading arrangements on oil tankers
- F20 – Inert gas system
- F22 – Direct loading pipes to oil tanker cargo tanks
- F24 – Temperature of Steam and Heating Media within the Cargo Area
- F46 – Low pressure CO2 piping system
UR G (Gas Tankers)
- G3 – Liquefied gas cargo and process piping
- G2 – Liquified gas cargo tanks and process pressure vessels
- G5 – Fail-close action of Emergency Shut Down (ESD) valve