NCCER Pipefitter cheat sheet

Nominal pipe size (NPS) and schedule: wall thickness increases with schedule number for a given NPS; outside diameter stays constant across schedules, so fittings interchange while inside diameter changes.

Take-out (fitting allowance) for a 90° butt-weld elbow equals the center-to-face dimension minus the pipe radius; for a 45° elbow, take-out ≈ 0.625 × NPS (butt-weld long radius), and the face-to-face dimension is used directly for socket or threaded fittings.

Travel, run, and set: travel = run ÷ cos(angle); set = travel × sin(angle); for a 45° offset, set = 1.414 × run and travel = 1.414 × set.

Rolling offset: true offset = √(vertical² + horizontal²); the fitting angle is found from tan(angle) = horizontal ÷ vertical, and the cut length uses the true offset with the standard take-out.

Pipe slope: 1/4 inch per foot equals 2.08% grade; 1/8 inch per foot equals 1.04%; minimum drainage slope for gravity sanitary lines is typically 1/4 inch per foot for pipe 3 inches and smaller.

Bending and expansion: thermal expansion ΔL = L × α × ΔT, with α ≈ 6.5 × 10⁻⁶ in/in·°F for carbon steel; expansion loops and offsets absorb movement between anchors.

Hydrostatic test pressure for new piping is typically 1.5 times the design pressure, held for a minimum of 2 hours, with test gauges calibrated and located at the low point of the system.

Weld fit-up: root gap and land depend on the joint design; a 37.5° bevel per side produces a 75° included angle, and alignment is checked with a hi-lo gauge before tacking.

Isometric drawings show pipe runs in three dimensions using a north arrow and line numbers; the line number encodes size, service, sequence, and insulation or tracing class.

Nominal pipe size (NPS) and schedule: wall thickness increases with schedule number for a given NPS; outside diameter stays constant across schedules, so fittings interchange while inside diameter changes.

Take-out (fitting allowance) for a 90° butt-weld elbow equals the center-to-face dimension minus the pipe radius; for a 45° long-radius elbow, take-out ≈ 0.625 × NPS, and face-to-face dimensions are used directly for socket or threaded fittings.

Travel, run, and set: travel = run ÷ cos(angle); set = travel × sin(angle); for a 45° offset, set = 1.414 × run and travel = 1.414 × set.

Rolling offset: true offset = √(vertical² + horizontal²); the fitting angle is found from tan(angle) = horizontal ÷ vertical, and the cut length uses the true offset with the standard take-out.

Pipe slope: 1/4 inch per foot equals 2.08% grade; 1/8 inch per foot equals 1.04%; minimum drainage slope for gravity sanitary lines is typically 1/4 inch per foot for pipe 3 inches and smaller.

Bending and expansion: thermal expansion ΔL = L × α × ΔT, with α ≈ 6.5 × 10⁻⁶ in/in·°F for carbon steel; expansion loops and offsets absorb movement between anchors.

Hydrostatic test pressure for new piping is typically 1.5 times the design pressure, held for a minimum of 2 hours, with test gauges calibrated and located at the low point of the system.

Weld fit-up: root gap and land depend on the joint design; a 37.5° bevel per side produces a 75° included angle, and alignment is checked with a hi-lo gauge before tacking.

Isometric drawings show pipe runs in three dimensions using a north arrow and line numbers; the line number encodes size, service, sequence, and insulation or tracing class.

Nominal pipe size (NPS) and schedule: wall thickness increases with schedule number for a given NPS; outside diameter stays constant across schedules, so fittings interchange while inside diameter changes.

Take-out (fitting allowance) for a 90° butt-weld elbow equals the center-to-face dimension minus the pipe radius; for a 45° long-radius elbow, take-out ≈ 0.625 × NPS, and face-to-face dimensions are used directly for socket or threaded fittings.

Travel, run, and set: travel = run ÷ cos(angle); set = travel × sin(angle); for a 45° offset, set = 1.414 × run and travel = 1.414 × set.

Rolling offset: true offset = √(vertical² + horizontal²); the fitting angle is found from tan(angle) = horizontal ÷ vertical, and the cut length uses the true offset with the standard take-out.

Pipe slope: 1/4 inch per foot equals 2.08% grade; 1/8 inch per foot equals 1.04%; minimum drainage slope for gravity sanitary lines is typically 1/4 inch per foot for pipe 3 inches and smaller.

Bending and expansion: thermal expansion ΔL = L × α × ΔT, with α ≈ 6.5 × 10⁻⁶ in/in·°F for carbon steel; expansion loops and offsets absorb movement between anchors.

Hydrostatic test pressure for new piping is typically 1.5 times the design pressure, held for a minimum of 2 hours, with test gauges calibrated and located at the low point of the system.

Weld fit-up: root gap and land depend on the joint design; a 37.5° bevel per side produces a 75° included angle, and alignment is checked with a hi-lo gauge before tacking.

Isometric drawings show pipe runs in three dimensions using a north arrow and line numbers; the line number encodes size, service, sequence, and insulation or tracing class.