SOLAS Pipefitting flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hierarchy of controls

Order of hazard control from most to least effective: elimination, substitution, engineering controls, administrative controls, and personal protective equipment. PPE is the last line of defense, not the first.

Confined space oxygen range

Acceptable entry oxygen concentration is between 19.5 and 23.5 percent by volume. Below 19.5 percent is oxygen deficient; above 23.5 percent is oxygen enriched and raises fire risk.

Hot work fire watch

A fire watch is posted during hot work and maintained for at least 30 minutes after work stops. Combustible gas is tested below the lower explosive limit before and during the work.

Zero energy verification

After lockout and tagout, stored energy is released and the isolation is verified by attempting to start the equipment or by testing with a meter. A tag alone does not prove isolation.

SOLAS piping requirement

SOLAS Chapter II-1 Regulation 26 requires piping systems essential to ship safety to be designed, constructed, and installed to the Administration's satisfaction, with class rules supplementing it.

Hydrostatic test pressure

The hydrostatic test pressure is typically 1.5 times the design pressure. The system is vented of air, pressurized in steps, and held for at least 10 minutes.

Design pressure definition

Design pressure is the maximum allowable working pressure of the system at the design temperature. Components and valves selected must be rated at or above this value.

Nominal pipe size

NPS is a dimensionless size designation. Outside diameter is fixed for each NPS, while wall thickness is set by the schedule number, so bore varies with schedule.

Schedule number meaning

Schedule number roughly equals 1000 times internal pressure divided by allowable stress. For a given NPS, a higher schedule means a thicker wall and higher pressure rating.

Gate versus globe valve

A gate valve is used for isolation because it offers low resistance when fully open. A globe valve is used for throttling because its flow path allows controlled partial opening.

Check valve function

A check valve permits flow in one direction only and closes automatically on reverse flow. It protects pumps and prevents backflow between systems.

Spiral wound gasket use

Spiral wound gaskets with graphite or PTFE filler suit high pressure and temperature flanges. They require proper bolt load and are matched to the flange facing and pressure class.

Long radius elbow takeout

The takeout for a 90 degree long radius elbow equals 1.5 times the nominal pipe size. Subtract fitting takeouts from center-to-center distance to find the cut length.

45 degree offset formula

For a 45 degree offset, travel equals offset divided by 0.7071, which is offset times 1.414. The run equals the offset. Verify with field measurement before cutting.

Thermal expansion formula

Change in length equals original length times coefficient of expansion times temperature change. Carbon steel coefficient is about 0.012 millimeters per meter per degree Celsius.

Weld bevel preparation

Standard V-groove bevel is 30 degrees plus 5 minus 0 degrees with a 1.6 millimeter root face. Surfaces within 25 millimeters of the bevel are cleaned to bare metal.

Socket weld gap

A socket weld leaves about 1.6 millimeters clearance at the bottom of the socket. The gap allows thermal expansion and prevents root cracking during cooling.

Threaded joint sealant

Sealant is applied to the male tapered thread, leaving the first two threads bare. Sealant on the female thread can enter the line and contaminate the system.

Flange bolt tightening

Flange bolts are tightened in a star or crisscross pattern in stages to the specified torque. The gasket is centered on the flange face before tightening begins.

Brazing temperature range

Brazing uses filler metal that melts above 450 degrees Celsius but below the melting point of the base metal. Soldering filler melts below 450 degrees Celsius.

Support spacing rule

Typical carbon steel water line support spacing: NPS 1 about 2.1 meters, NPS 2 about 3.0 meters, NPS 4 about 4.3 meters, NPS 6 about 5.2 meters.

Anchor versus guide

An anchor restrains translation and rotation at one point and directs expansion to loops or offsets. A guide permits axial movement only and prevents lateral displacement.

Spring hanger purpose

A spring hanger carries pipe weight while allowing vertical movement caused by thermal expansion. It differs from a rigid support, which restrains vertical movement.

Expansion loop function

An expansion loop absorbs thermal growth by flexing its legs. Loop leg length is sized so developed stress stays within the allowable range for the material.

Pneumatic test pressure

Where pneumatic testing is permitted, test pressure is typically 1.1 times design pressure. The area is barricaded because stored energy makes failure hazardous.

Dye penetrant inspection

Dye penetrant detects surface-breaking defects on non-porous materials. It does not detect internal volumetric defects, which require radiography or ultrasonic examination.

Radiography purpose

Radiographic examination reveals internal volumetric weld defects such as porosity, slag, and lack of fusion. Film density and coverage must meet the applicable code.

Bilge system principle

Bilge branches from each compartment lead to a bilge main. Non-return valves prevent water from flowing back into compartments from the main.

Steam line drain traps

Steam lines require drain traps at low points and at the end of mains. Inadequate drainage causes water hammer when condensate slugs hit fittings.

Relief valve set pressure

A relief valve set pressure does not exceed the maximum allowable working pressure of the protected system. It opens automatically to prevent overpressure.

Isometric line number

Line numbers typically combine size, service code, sequence number, material class, and insulation code, for example 4 inch FO 102 A1A. The isometric identifies the run.

Piping specification role

The piping specification defines material class, pressure rating, gasket, and bolting for each service. The isometric must agree with it; the specification governs on conflict.