Applied only to rows with no catalogue wall or inside diameter. A bore or wall typed on a row replaces it for that row. When this box is empty, a matching interim ASME B36.10 wall is used for those rows. Catalogue wall and inside diameter are used when the catalogue record has them.
Leave the margin blank when you do not want one. A margin is added to the flow before velocity and minimum size are calculated. The maximum flow of a chosen size stays the velocity limit times the area. With a margin, the page also shows the flow that leaves that margin spare.
Method and limitations
Sources
Inside diameter is the stored inside diameter, or the stored outside diameter minus twice the stored wall thickness, from the PipingDesigners pipe data. When those wall and inside-diameter facts are absent, and the NPS and schedule match a row in the interim ASME B36.10-2022 Table 2-1 extract used by the pipe schedule tool, the wall box is filled from that row in the unit already selected. The number is converted if you then change the unit. A wall or a bore you type replaces that fill. A result that uses a wall or a bore you typed is marked as user-entered. When the catalogue later stores a wall or an inside diameter, that stored value is used and the typed wall or bore is not. Interim data from ASME B36.10-2022 Table 2-1 numeric extract, not licensed ASME text. Verify against the current edition of ASME B36.10 before use.
Mean velocity is volumetric flow divided by the internal area. Maximum flow is the velocity limit times that area. Unit factors match the PipingDesigners unit converter: 1 in = 0.0254 m, 1 ft = 0.3048 m, 1 US gallon = 0.003785411784 m3, 1 lb = 0.45359237 kg, 1 ft3 = 0.028316846592 m3, 1 cP = 0.001 Pa·s.
Reynolds number is density times velocity times inside diameter, divided by dynamic viscosity. Laminar is below 2300, transitional is 2300 to 4000, and turbulent is above 4000. Those are the conventional Moody-diagram bands, not a code limit.
API RP 14E erosional velocity is Ve = C / sqrt(rho), with rho in lb/ft3 and Ve in ft/s. C is a user input. The starting value is 100. Confirm C against the edition you use. This page converts density into lb/ft3 and reports Ve in ft/s and m/s. It does not switch C to a metric coefficient.
Density and viscosity are user entries. This page does not store a fluid table.
The velocity limit is yours. The typical velocity ranges above are advisory guidance, not a code requirement. A service choice fills the velocity limit, and you can change it. An optional future-flow margin adds a percent to the flow used for velocity and for the minimum size. It does not change the relation between flow, area and velocity.
Optional pressure drop uses the Darcy–Weisbach equation over 100 m. The friction factor is the Swamee–Jain explicit approximation of Colebrook–White (Swamee and Jain, Journal of the Hydraulics Division, ASCE, 1976), used only for Reynolds number 5000 to 100,000,000 and relative roughness 0.000001 to 0.01. It is not an iterated Colebrook solution. The roughness box starts at 0.045 mm, the rounded commercial-steel value 0.00015 ft. It is a user input. The stored pipe records have no roughness value. Confirm it against the roughness table you use.
Catalogue values are unverified supplier data.
