[ VCF = \exp\left[-\alpha_15 \Delta t (1 + 0.5\alpha_15 \Delta t + \frac16\alpha_15^2 \Delta t^2 + \dots)\right] ]
' API 11.1.4 standard polynomial ASTM_Table54_VCF = Exp(-alpha * dt * (1 + 0.5 * alpha * dt + (1 / 6) * alpha ^ 2 * dt ^ 2)) End Function astm table 54 excel
=EXP(-B5 * (B3-15) * (1 + 0.5*B5*(B3-15) + (1/6)*B5^2*(B3-15)^2)) This third-order expansion is accurate to 6 decimal places for Δt ≤ 50°C. Assuming Density15 in A1, TempObs in A2, Type in A3: [ VCF = \exp\left[-\alpha_15 \Delta t (1 + 0