Conductor Calculations

Objective This module will calculate the Cv of a conductor and the flow through that conductor for a given upstream and downstream pressure. It will also take into consideration the number of 90 degree elbows in the conductor.

Required Data Upstream Pressure, Suggested Delta P, Specific Gravity for Air, Air Temperature, Conductor Length, Conductor Inside Diameter, Conductor Friction Factor & K-Value and Number of 90 Degree Elbows in Conductor.

Input Item Descriptions Upstream Pressure (PSIG) - The minimum pressure that is available at the inlet of the conductor. Suggested Delta P (PSI) - Pressure drop from one end of the conductor to the other. If a Delta P is above a critical flow that is entered, the calculated answer will assume critical flow. Specific Gravity for Air - The specific gravity for air is 1 at standard conditions. This can be affected somewhat by humidity and temperature. These have a minimal effect and therefore a specific gravity of 1 is normally used. Air Temperature (°F) - The air temperature is in degrees Fahrenheit. Standard conditions use 68 degrees Fahrenheit. Conductor Length (in) - The length of the entire conductor. Add sections between elbows together to arrive at total length. Conductor I.D. (in) - The inside diameter of the conductor. Friction Factor - The friction factor for the particular conductor chosen. No. of Elbows in Conductor - The number of 90 degree elbows in the conductor. Count each Tee as one elbow if airflow makes a 90 degree turn. Conductor K Value - Fitting value established for a type of conductor and fitting.

Calculated Item Descriptions

Air Temperature (°R) - The air temperature in degrees Rankine. Upstream Pressure (PSIA) - The upstream pressure state in absolute terms. Delta P Maximum Flow (PSI) - The pressure drop calculated for critical flow condition. Delta P Used (PSI) - The pressure differential used to calculate Cv. This automatically takes into account whether or not critical flow is achieved. Flow (SCFM) - The flow through the conductor under the parameters described. Downstream Pressure (PSIA) - The pressure at the outlet of the conductor in absolute terms. Downstream Pressure (PSIG) - The gage pressure at the outlet of the conductor. Equiv. Fitting Length (in.) - The length of a conductor necessary to equal the Cv of the 90 elbows in the conductor. Conductor Volume (cu. in) - The volume of the conductor in cubic inches. Conductor Cv - The Cv of the conductor and elbows.