{"$schema":"nativecad-dfm-pack/1","id":"piping","title":"Piping -- pipe, tube, fittings, flanges, manifolds, O-rings and ducting","sector":"piping","version":"2026-09-03","summary":"Pipe/tube schedules and metric sizes, flange bolt circles (ASME B16.5, EN 1092-1), thread standards (NPT, BSPP/G), manifold and O-ring groove geometry, hose barbs, push-to-connect tube, duct sizes, pressure-wall sizing and the tests a fluid-carrying part is held to.","aliases":["pipe","pipe fitting","manifold","pipe flange","hose barb","o-ring","oring","o-ring groove","npt","bspp","g thread","tube fitting","hvac","duct","valve body","pneumatic","hydraulic","plumbing"],"crossSector":false,"size":"core","sources":[{"id":"asme-b16.5","title":"ASME B16.5-2020 Pipe Flanges and Flanged Fittings, NPS 1/2 Through NPS 24","url":"https://www.asme.org/codes-standards/find-codes-standards/b16-5-pipe-flanges-flanged-fittings","accessed":"2026-09-03"},{"id":"asme-b31.3","title":"ASME B31.3-2020 Process Piping","url":"https://www.asme.org/codes-standards/find-codes-standards/b31-3-process-piping","accessed":"2026-09-03"},{"id":"asme-b1-20-1","title":"ASME B1.20.1-2013 Pipe Threads, General Purpose (Inch) -- NPT","url":"https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch","accessed":"2026-09-03"},{"id":"iso-228-1","title":"ISO 228-1:2000 Pipe threads where pressure-tight joints are not made on the threads -- Part 1: Dimensions, tolerances and designation (G / BSPP)","url":"https://www.iso.org/standard/4258.html","accessed":"2026-09-03"},{"id":"iso-3601-2","title":"ISO 3601-2:2016 Fluid power systems -- O-rings -- Part 2: Housing dimensions","url":"https://www.iso.org/standard/64450.html","accessed":"2026-09-03"},{"id":"en-1506","title":"EN 1506:2007 Ventilation for buildings -- Sheet metal air ducts and fittings with circular cross-section","accessed":"2026-09-03"},{"id":"parker-oring-handbook","title":"Parker O-Ring Handbook, ORD 5700","url":"https://www.parker.com/content/dam/Parker-com/Literature/O-Ring-Division-Literature/ORD-5700.pdf","accessed":"2026-09-03"},{"id":"swagelok-tubing-data","title":"Swagelok Tubing Data -- Tube Fittings, Bend Radius and Selection Guidelines","url":"https://www.swagelok.com/downloads/webcatalogs/en/ms-01-107.pdf","accessed":"2026-09-03"},{"id":"engineering-toolbox","title":"The Engineering ToolBox -- Pipe Flow Velocities, Pressure Drop and Equivalent Length Reference Data","url":"https://www.engineeringtoolbox.com/","accessed":"2026-09-03"},{"id":"matweb-materials","title":"MatWeb Material Property Data (piping metals, plastics and elastomers)","url":"https://www.matweb.com/","accessed":"2026-09-03"}],"entries":[{"id":"pipe-nps-od-series","kind":"dimension","tier":1,"title":"NPS 1/2-4 outside diameters and DN equivalents","summary":"Steel pipe OD runs 21.3, 26.7, 33.4, 42.2, 48.3, 60.3, 73.0, 88.9, 114.3 mm for NPS 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 4 (DN15, 20, 25, 32, 40, 50, 65, 80, 100) -- OD is fixed by NPS, wall thickness by schedule.","applies":["pipe","steel pipe","nps"],"value":{"options":[21.3,26.7,33.4,42.2,48.3,60.3,73,88.9,114.3],"unit":"mm"},"basis":"ASME B36.10 pipe OD series, the fixed-OD convention every NPS schedule wall is cut from","sources":["asme-b31.3"],"tags":["pipe","nps","dn","od"]},{"id":"metric-tube-od-series","kind":"dimension","tier":1,"title":"Metric hydraulic/pneumatic tube OD series","summary":"Metric tube for hydraulic and pneumatic lines is stocked at 6, 8, 10, 12, 16, 20, 25 mm OD with 1-2 mm wall depending on pressure class -- match the fitting's tube-OD rating exactly, tube fittings do not tolerate an oversize or undersize tube.","applies":["tube","hydraulic tube","pneumatic tube"],"value":{"options":[6,8,10,12,16,20,25],"unit":"mm"},"basis":"Swagelok/Parker metric tube catalogue OD series for compression and flare tube fittings","sources":["swagelok-tubing-data"],"tags":["tube","metric","od"]},{"id":"flange-b16-5-class150-nps2","kind":"dimension","tier":1,"title":"ASME B16.5 Class 150 NPS 2 flange (typical)","summary":"An NPS 2 Class 150 flange is 152.4 mm OD, 120.7 mm bolt circle, four dia19.1 mm bolt holes and a 1.6 mm raised face -- the size to reach for when a fitting needs one flange dimension; see pipe-schedule-wall-table for the full NPS 1-4 table.","applies":["flange","nps 2 flange","class 150"],"value":{"table":[{"field":"OD","value":152.4},{"field":"boltCircle","value":120.7},{"field":"boltCount","value":4},{"field":"boltHoleDia","value":19.1},{"field":"raisedFace","value":1.6}],"unit":"mm"},"basis":"ASME B16.5 Class 150 dimension table, NPS 2 row","sources":["asme-b16.5"],"tags":["flange","b16.5","class150","nps2"]},{"id":"npt-thread-table","kind":"dimension","tier":1,"title":"NPT taper pipe thread: 1/4 and 1/2 NPT","summary":"1/4 NPT is 18 TPI, tap drill 7/16 in (11.1 mm); 1/2 NPT is 14 TPI, tap drill 45/64 in (17.9 mm) -- both taper 1:16 on diameter, so a straight (non-tapered) hole will not seal an NPT fitting.","applies":["npt","pipe thread","taper thread"],"value":{"table":[{"size":"1/4 NPT","tpi":18,"drillIn":"7/16","drillMm":11.1},{"size":"1/2 NPT","tpi":14,"drillIn":"45/64","drillMm":17.9}],"unit":"in"},"basis":"ASME B1.20.1 NPT thread table (TPI, pitch diameter) and taper convention","sources":["asme-b1-20-1"],"tags":["npt","thread","taper","tap-drill"]},{"id":"bspp-g-series","kind":"dimension","tier":1,"title":"BSPP (G) parallel thread: G1/4, G3/8, G1/2","summary":"G1/4 major dia 13.157 mm at 19 TPI, tap drill 11.4 mm; G3/8 major dia 16.662 mm at 19 TPI; G1/2 major dia 20.955 mm at 14 TPI, tap drill 18.6 mm -- parallel (straight) thread, sealed by a bonded washer or O-ring, not by the thread itself.","applies":["bspp","g thread","parallel thread"],"value":{"table":[{"size":"G1/4","majorMm":13.157,"tpi":19,"drillMm":11.4},{"size":"G3/8","majorMm":16.662,"tpi":19},{"size":"G1/2","majorMm":20.955,"tpi":14,"drillMm":18.6}],"unit":"mm"},"basis":"ISO 228-1 BSPP thread dimension table","sources":["iso-228-1"],"tags":["bspp","g-thread","parallel"]},{"id":"oring-groove-faceseal-as568","kind":"dimension","tier":1,"title":"O-ring face-seal groove depth/width by AS568 cross-section","summary":"Face-seal groove sized to the O-ring cross-section: CS 1.78 mm (AS568 -010/-014/-020) -> depth 1.3, width 2.5; CS 2.62 mm (-113) -> depth 2.0, width 3.6; CS 3.53 mm (-210) -> depth 2.7, width 4.8 mm.","applies":["o-ring","o-ring groove","face seal","flange"],"value":{"table":[{"csMm":1.78,"examples":"-010/-014/-020","depthMm":1.3,"widthMm":2.5},{"csMm":2.62,"examples":"-113","depthMm":2,"widthMm":3.6},{"csMm":3.53,"examples":"-210","depthMm":2.7,"widthMm":4.8}],"unit":"mm"},"basis":"Parker O-Ring Handbook static face-seal groove design tables, ISO 3601-2 housing series","sources":["parker-oring-handbook","iso-3601-2"],"tags":["o-ring","groove","as568","face-seal"]},{"id":"oring-squeeze-stretch-fill","kind":"rule","tier":1,"title":"O-ring squeeze, stretch and groove fill targets","summary":"Design 15-25% squeeze (cross-section compression) on a static groove, 2-5% stretch on a piston/rod bore fit, and 70-90% groove fill by volume -- below the range the seal leaks, above it the O-ring extrudes into the clearance gap or takes a compression set.","applies":["o-ring","o-ring groove"],"value":{"min":15,"max":25,"unit":"%","note":"squeeze; see summary for stretch (2-5%) and fill (70-90%)"},"basis":"Parker O-Ring Handbook and ISO 3601-2 squeeze/stretch/fill design envelope","sources":["parker-oring-handbook","iso-3601-2"],"tags":["o-ring","squeeze","stretch","fill"]},{"id":"barlow-formula","kind":"rule","tier":1,"title":"Barlow's formula for pipe/manifold wall thickness","summary":"Minimum wall t = P*D/(2*S*E) -- pressure times diameter over twice the allowable stress times joint efficiency; e.g. a 10 mm bore at 10 MPa in 6061-T6 (S~69 MPa, E=1 solid block) needs only t~0.7 mm by burst alone, which is why manifold-wall-min (5 mm) governs instead.","applies":["pipe","manifold","pressure vessel"],"value":{"value":"t = P*D/(2*S*E)","unit":"mm"},"basis":"ASME B31.3 wall-thickness design equation (Barlow's formula form)","sources":["asme-b31.3"],"tags":["barlow","wall-thickness","pressure"]},{"id":"manifold-wall-min","kind":"rule","tier":1,"title":"Minimum manifold block wall between a port and an outside face","summary":"Leave >= 5 mm of solid aluminium wall between any drilled port and the block's outside face (or another port) at 10 MPa working pressure -- Barlow's formula alone under-predicts the wall a drilled, threaded, cyclically loaded manifold needs.","applies":["manifold","manifold block"],"value":{"min":5,"unit":"mm"},"basis":"Common hydraulic/pneumatic manifold design-guide minimum wall for a 10 MPa aluminium block, above the Barlow-formula burst minimum","sources":["engineering-toolbox"],"tags":["manifold","wall","minimum"]},{"id":"port-spacing-rule","kind":"rule","tier":1,"title":"Minimum port-to-port spacing in a manifold","summary":"Space adjacent manifold ports at least 1.5x the larger port's diameter, centre to centre, so the wall between two drilled/tapped holes has enough material to resist cracking under pressure and tapping torque.","applies":["manifold","port"],"value":{"min":1.5,"unit":"ratio","note":"multiple of the larger port diameter"},"basis":"Common hydraulic manifold design-guide minimum port spacing to avoid thin webs between drilled/tapped holes","sources":["engineering-toolbox"],"tags":["manifold","port","spacing"]},{"id":"thread-min-engagement","kind":"rule","tier":1,"title":"Minimum pipe/port thread engagement","summary":"Engage a tapped pipe or port thread at least 1x the nominal thread diameter in length -- NPT also needs full hand-tight-plus-turns engagement for its taper to seal; shallower engagement strips under torque or leaks past incomplete taper contact.","applies":["npt","bspp","thread","port"],"value":{"min":1,"unit":"ratio","note":"multiple of nominal thread diameter"},"basis":"Common pipe-thread engagement guidance for tapped ports in metal (ASME B1.20.1 practice)","sources":["asme-b1-20-1"],"tags":["thread","engagement","npt"]},{"id":"hose-barb-sizing","kind":"rule","tier":1,"title":"Hose barb OD sizing","summary":"Size a hose barb's OD 10-15% larger than the hose's nominal inside diameter so the hose stretches on and grips -- undersize and it weeps under pressure, oversize and the hose splits or won't push on.","applies":["hose barb","hose"],"value":{"min":10,"max":15,"unit":"%","note":"barb OD oversize versus hose nominal ID"},"basis":"Common hose-barb fitting design guidance (Parker/Swagelok barb catalogues)","sources":["swagelok-tubing-data"],"tags":["hose","barb","sizing"]},{"id":"flow-velocity-guideline","kind":"rule","tier":1,"title":"Target flow velocity: liquid vs air lines","summary":"Size pipe/tube bore for 1-3 m/s liquid velocity (water, hydraulic oil) and 10-20 m/s for compressed air/gas -- undersizing either raises pressure drop and noise/erosion, oversizing wastes material and slows response.","applies":["pipe","tube","duct","pneumatic","hydraulic"],"value":{"table":[{"service":"liquid","minMs":1,"maxMs":3},{"service":"air/gas","minMs":10,"maxMs":20}],"unit":"m/s"},"basis":"Engineering ToolBox recommended flow-velocity ranges for liquid and compressed-gas piping","sources":["engineering-toolbox"],"tags":["flow","velocity","sizing"]},{"id":"duct-round-sizes","kind":"dimension","tier":1,"title":"Round HVAC duct sizes (EN 1506)","summary":"Round sheet-metal duct is stocked at 100, 125, 150, 200, 250 and 315 mm diameter -- pick from this series rather than an arbitrary bore so off-the-shelf elbows, tees and dampers fit.","applies":["duct","hvac"],"value":{"options":[100,125,150,200,250,315],"unit":"mm"},"basis":"EN 1506 standard round sheet-metal duct diameter series","sources":["en-1506"],"tags":["duct","hvac","round"]},{"id":"material-6061-manifold","kind":"material","tier":1,"title":"6061-T6 aluminium for manifold blocks","summary":"6061-T6 is the default manifold/block material for hydraulic and pneumatic circuits under ~20-25 MPa: yield 276 MPa, density 2.70 g/cm3, machines and anodizes cleanly, and takes a drilled/tapped port without cracking at the wall minimums in this pack.","applies":["manifold","manifold block"],"value":{"table":[{"property":"yield","value":276,"unit":"MPa"},{"property":"density","value":2.7,"unit":"g/cm3"}]},"basis":"MatWeb 6061-T6 property data, the standard machined manifold alloy","sources":["matweb-materials"],"tags":["material","6061","aluminium","manifold"]},{"id":"material-316l","kind":"material","tier":1,"title":"316L stainless for wetted fittings and valve bodies","summary":"316L stainless (yield ~170 MPa annealed, density 8.0 g/cm3) is the default corrosion-resistant wetted material for fittings, valve bodies and process tube where the fluid or environment attacks carbon steel or brass.","applies":["fitting","valve body","tube"],"value":{"table":[{"property":"yield","value":170,"unit":"MPa"},{"property":"density","value":8,"unit":"g/cm3"}]},"basis":"MatWeb 316L stainless property data, the standard corrosion-resistant process-fluid material","sources":["matweb-materials"],"tags":["material","316l","stainless"]}]}