Field facilities construction

Pipe wall thickness and weight, line fill and pressure drop, hydrotest, thermal expansion, tank and vessel volumes, pipeline trench earthworks, cathodic protection.

13 calculators

Pipelines

Pipeline wall thickness (ASME B31.4/B31.8)

Design wall thickness by Barlow's formula with the factors of ASME B31.4 (liquid pipelines) and B31.8 (gas pipelines), the corrosion allowance, and the allowable pressure of the selected pipe.

t_min = P · D / (2 · SMYS · F · E · T) + c

Pipe weight and line fill volume

Weight per metre of steel pipe and of the whole section, the internal (line fill) volume and the mass of the product in the line.

m = π · (D − t) · t · ρ_s = 0.02466 · (D − t) · t [kg/m; D, t in mm]

Pressure drop in a liquid pipeline

Friction loss by Darcy-Weisbach (friction factor from Colebrook-White, 64/Re in laminar flow) plus the elevation change; the flow velocity and Reynolds number.

d = D − 2t; v = 4 · Q / (π · d²); Re = ρ · v · d / μ

Gas pipeline flow capacity

Gas flow rate from the inlet and outlet pressures — the general isothermal flow equation with the Colebrook-White friction factor; gas velocity, average pressure, Reynolds number.

Q_st = (π · d² / 4) · (T_st / P_st) · √[(P₁² − P₂²) · d · R / (λ · L · Z · T · M)]

Pipeline hydrotest: hoop stress

Hoop stress and its percentage of SMYS at the test pressure — at the gauge and at the lowest point of the section, where the water column adds to the pressure.

P_low = P_test + ρ_w · g · Δz

Pipe thermal expansion and restrained longitudinal stress

Free expansion of a section with a temperature change, and the longitudinal stress in a pipeline restrained by the soil, including the internal pressure (Poisson effect); the axial force.

ΔL = α · L · ΔT; σ_T = E · α · ΔT

Tanks and vessels

Vertical tank: volume and mass at a level

Volume and mass of the product in a vertical cylindrical tank at a given level, the fill percentage and the volume per centimetre of level.

V = π · D² / 4 · h; M = V · ρ

Horizontal vessel: volume at a level

Liquid volume in a partly filled horizontal cylindrical vessel (storage tank, drain vessel, separator, settling tank): the cylinder segment plus flat, 2:1 ellipsoidal or hemispherical heads.

A = R² · arccos((R − h) / R) − (R − h) · √(2 · R · h − h²)

Construction works

Pipeline trench earthworks

Excavation of a trapezoidal trench, the soft bedding and padding around the pipe, the backfill with native soil and the spoil volume after bulking.

A(y) = b · y + m · y²; B = b + 2 · m · H

Corrosion protection

Sacrificial anode CP: current demand and anode mass

Mean protective current from the surface area, the current density and the coating breakdown factor, and the net mass of galvanic anodes for the design life — per DNV-RP-B401; the number of anodes.

f_cm = a + b · t_f / 2 (≤ 1)

Corrosion rate from coupon mass loss

Average general corrosion rate from the mass loss of a corrosion coupon over the exposure time, in mm/yr and mpy; the corrosivity rating per NACE SP0775.

CR = 87.6 · W / (ρ · A · t) [mm/yr; W mg, ρ g/cm³, A cm², t h]

Remaining life from the corrosion rate

Corrosion rate from two wall thickness surveys and the remaining life to the retirement thickness; the longest interval to the next inspection.

CR = (t_prev − t_act) / Δτ

Other areas

Pressure vessel shell: wall stresses and thickness

Hoop and longitudinal stresses in the cylindrical shell of a vessel or pipe under internal pressure, the required wall thickness and the allowable pressure per GOST 34233.2 with the weld joint efficiency and allowances.

σ_t = p · (D + s − c) / (2 · (s − c))From Mechanical engineering

Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.