Series-STRAConfiguration

Supported Applications

The Series STRA Duct Mounted Airflow Measurement Station is designed for HVAC applications requiring accurate airflow measurement in duct systems with highly turbulent conditions at the point of measurement. The station utilizes an airflow averaging element that generates a differential (velocity) pressure signal, similar to orifice and venturi primary elements. It consists of single or multiple factory-mounted airflow elements pre-piped within a casing configured for flanged connection to ductwork.

Operating Conditions & Performance

The Series STRA operates with an accuracy of Within 2% of actual flow when installed in accordance with published recommendations. The measurement range covers 100 to 10,000 fpm (0.51 to 51 m/s). Process temperature limits are defined as 350°F (177°C) for continuous operation in air and 400°F (204°C) for intermittent operation in air. The station supports humidity levels from 0 to 100% non condensing.

Configuration Options

The series is available with standard materials consisting of a G90 galvanized casing, 6063-T5 anodized aluminum flow sensors, and a 3003 aluminum air flow straightener. The airflow straightening section incorporates a honeycomb design featuring a 1/2 inch opening by 3 inch depth.

Configuration options include:

• Housing Configurations: Rectangular (code R) and Oval (code O).
• Sizing Envelope: Circular stations range from 8" to over 73"; rectangular and oval dimensions are available in various height and width combinations up to 120".
• Pressure Connections: Standard process connections utilize 1/4" compression fittings. Internal pressure connections (suffix -IM) are an option for rectangular stations only.
• Oval Mounting Options: A flange option (suffix -F) is available specifically for oval mount stations.

The station size determines the casing length and flange dimensions. For circular flanges, sizes 8" to 15" have a casing length of 8", while sizes 73" and over require a 12" casing length with a 2" flange.

Key Product Differences

The Series STRA is distinguished by its integration of multiple sensing ports that sample total and static pressures. Upstream ports average total pressure in an isolated chamber, while static sensing ports (located where the influence of velocity head is zero) are averaged in a second isolation chamber. Multiple elements are manifolded together for connection to external differential measurement devices such as gages or transmitters.

Model numbering follows the format STRA- x -. For oval flow stations without a flange, the casing length is fixed at 8". Pressure taps on rectangular and oval stations are located on the longer of the two dimensions.