Tests

The rate of flow is computed using the continuity equation (Q=VxA). STPS calculates the average velocity by measuring actual velocity profiles rather than assuming theoretical profiles. The area of the pipe is calculated using the true measured inside diameter of the pipe.

Meter Accuracy Tests - Larger meters are tested in place using test meters or by comparison with a Pitometer rod meter. The tests are conducted to determine if customers are being billed properly. If meters are under-registering, this is lost revenue to the water utility.

For smaller meters, a comparison test is performed using a calibrated meter connected in series with the meter to be tested. In order to do this type of test, the meter to be tested has to have a test plug and isolation valves on bothsides of the meter.

Pump Efficiency Tests - Pump efficiency tests provide performance data for a pump and motor operating under actual field conditions. Conditions may have changed since the original installation. Excessive wear of the pump components may be revealed.  The pump tests determine the current head capacity and effiiency characteristics. A wire-to-water efficiency is calculated to provide a basis for electrical energy management and cost-effective scheduling of pumping units. This information is a more accurate representation of the pump`s operating characteristics than a curve from the manufacturer`s catalog. Where possible, the pump is tested at three different rates of flow and at shut off head, including flow rates less than and greater than the normal pumping rate. This allows for the construction of the pump curve that represents actual pump performance.

Loss of Head Hazen-Williams "C" Value Tests - These tests are performed to determine friction characteristics for a variety of pipe sizes, types and ages. A test consists of measuring head loss between two points, the distance between the points, and the diameter and the flow rate through the pipe, from which a roughness coefficient can be determined. The coefficient "C" determines the carrying capacity of a water main and is a basic requirement for developing a calibrated computer model.

Fire Flow Tests - These tests measure water available for fire protection and determine recommended quantities in accordance with the standards of the industry. Flow measurements are taken at key points in the distribution system, to evaluate whether high-demand needs are met. Test results determine locations in the system that may require reinforcement or additional supply.