Standard Practices for Pump Testing

Purpose

To maintain a high degree of accuracy, consistency, safety, and professionalism, Henschel Pump Test has established the following standard practices for conducting and reporting pump efficiency and performance tests.

These standards are intended to provide a uniform testing procedure, establish minimum instrumentation requirements, define reporting expectations, and establish qualification standards for pump test technicians.

These Standard Practices are organized into three sections:

  • Section 1 – Equipment and Instrumentation Standards

  • Section 2 – Pump Test Methods and Reporting Standards

  • Section 3 – Pump Test Technician Qualification Standards

Section 1 – Equipment and Instrumentation Standards

1.1 Water Flow Measurement

Water flow may be measured using one or more of the following methods or instruments:

  • Pitot tube

  • Ultrasonic flow meter

  • Orifice

  • Venturi tube

  • Water meter

  • Weir

  • Volumetric measurement

Flow-measurement instruments shall have an accuracy class of ±2% or better, where applicable.

The pump test technician shall determine the most appropriate method of measuring flow based on the configuration of the pumping system, available access, operating conditions, pipe characteristics, and the accuracy required for the test.

The selected method shall be appropriate for the existing field conditions and capable of producing repeatable and reliable measurements.

1.2 Pump Discharge Head Measurement

Pump discharge pressure shall be measured using a calibrated test pressure gauge with an accuracy class of ±0.5% or better.

For low-head pumping systems, a water column and calibrated tape or measuring device may be used when appropriate.

Pressure measurements shall be taken at a location that accurately represents pump discharge conditions.

1.3 Pump Suction Head Measurement

Pump suction pressure or vacuum shall be measured using a calibrated pressure or vacuum gauge with an accuracy class of ±0.5% or better.

The measurement location shall be selected to accurately represent the suction conditions of the pump.

1.4 Static and Pumping Water Levels in Wells and Sumps

Static and pumping water levels shall normally be measured using an electric well sounder or other suitable electronic water-level measuring device.

The sounder line may be permanently marked or graduated at appropriate intervals to facilitate accurate measurement.

A properly installed and calibrated air line may also be used to determine water levels in wells or sumps. When an air line is used, pressure shall be measured with a calibrated test pressure gauge with an accuracy class of ±0.5% or better.

Water-level measurements should be recorded to the nearest 0.1 foot whenever field conditions and instrumentation permit.

1.5 Motor Power Input – Kilowatts

Pump motor electrical input shall be measured or determined in kilowatts (kW).

Motor kW input may be determined by:

  • Timing a utility-installed billing or revenue meter, when the meter and installation allow for reliable determination of power input; or

  • Using a portable kW/power analyzer with an accuracy class of ±2% or better.

The method used to determine electrical input shall be documented on the pump test report.

1.6 Pump Speed Measurement

Pump or motor rotational speed may be measured using:

  • Electronic tachometer

  • Optical or laser tachometer

  • Stroboscopic tachometer/strobe light

  • Pole-slip method, when appropriate

Pump speed shall normally be reported in revolutions per minute (RPM).

1.7 Voltage Measurement – Systems 600 Volts and Below

Voltage on electrical systems rated at 600 volts or below shall be measured using an appropriate voltmeter or electrical test instrument with an accuracy class of ±1% or better.

Electrical measurements shall be performed in accordance with applicable safety requirements and only by personnel qualified to perform the measurement.

1.8 Current Measurement – Systems 600 Volts and Below

Electrical current shall be measured using an appropriate clamp-on ammeter, power analyzer, or equivalent instrument with an accuracy class of ±2% or better.

Current shall normally be recorded in amperes for each available phase.

1.9 Voltage and Current Measurement – Systems Above 600 Volts

For systems operating above 600 volts, pump test technicians shall not make direct electrical contact with energized high-voltage conductors solely for the purpose of conducting a pump test.

Voltage, current, and other electrical information shall be obtained from properly installed panel-mounted instrumentation, approved metering equipment, or other safe and authorized sources.

All electrical measurements shall comply with the facility's electrical safety procedures and applicable regulations.

1.10 Instrument Condition and Calibration

All test equipment shall be maintained in good working condition and inspected before use.

Where calibration is applicable, instruments used to obtain critical pump test measurements shall have a current calibration or calibration verification appropriate for the instrument and its intended use.

Calibration records shall be maintained by Henschel Pump Test.

Section 2 – Pump Test Methods and Reporting Standards

2.1 Classification of Pump Tests

Pump testing may generally be classified into the following categories:

Shop Tests

Shop tests may also be referred to as laboratory tests, manufacturer's tests, or factory acceptance tests.

These tests are normally conducted at a pump manufacturer's or testing facility under controlled conditions. Because the test environment, instrumentation, piping configuration, and operating conditions can be closely controlled, shop tests are generally capable of providing highly accurate performance data.

Field Tests

Field tests are conducted with the pumping unit installed in its actual operating environment.

The reliability and accuracy of a field test depend on several factors, including:

  • Instrument accuracy

  • Instrument installation

  • Measurement locations

  • System configuration

  • Operating stability

  • Field conditions

  • Testing procedures

  • Technician experience

When agreed upon by the appropriate parties, field testing may also be used for acceptance or performance verification purposes.

Index Tests

Index testing is a form of field testing used to establish a repeatable basis for comparing pump or pumping-system performance over time.

Index tests may be used to evaluate:

  • Pump wear

  • Changing operating conditions

  • Loss of efficiency

  • System deterioration

  • Maintenance requirements

  • Pre- and post-repair performance

  • Overhaul effectiveness

Whenever practical, index tests should be conducted using the same procedures, measurement locations, instrumentation, and testing methodology as previous tests.

Detailed records should be maintained so that changes in pump and system performance can be accurately compared over time.

Model Tests

Model tests are generally conducted before construction or final design of a full-scale pumping system or prototype.

They may supplement field testing and may be appropriate for very large pumping units, complex hydraulic applications, comparative design evaluations, or situations requiring advance verification of expected prototype performance.

The purpose and requirements of model testing should be established during the design and specification process.

Classification terminology adapted from Igor J. Karassik, Pump Handbook, Section 13.2, "Pump Testing."

Scope of These Standards

The Henschel Pump Test Standard Practices primarily address field testing and index testing of installed pumping systems.

Section 2.2 – Pump Test Report: Measured Values

A pump test report shall document the significant field measurements used to evaluate the performance and efficiency of the pumping system.

2.2.1 Total Lift – Booster Pumps

For booster pumps, the report shall include the measured:

  • Discharge pressure/head

  • Suction pressure/head or vacuum

  • Difference in elevation between measurement points when applicable

Pressure may be recorded in pounds per square inch (psi) and converted to feet of head.

Calculated head values should normally be expressed to the nearest 0.1 foot when measurement accuracy permits.

Unless otherwise specified, the applicable datum shall be clearly identified, with the centerline of the pump discharge pipe used where appropriate.

2.2.2 Total Lift – Well Pumps

For well pumps, the report shall include:

  • Static/standing water level

  • Pumping water level

  • Discharge pressure

  • Discharge vacuum, when applicable

  • Applicable elevation or datum information

Water levels should normally be measured and reported to the nearest 0.1 foot when field conditions permit.

Discharge pressure shall be recorded in psi and converted to feet of head as necessary.

The datum used for water-level and total-lift calculations shall be clearly identified.

2.2.3 Fluid Flow

Pump discharge flow shall normally be expressed in gallons per minute (GPM).

Other units may be used when appropriate for the application, including:

  • Cubic feet per second (CFS)

  • Million gallons per day (MGD)

  • Gallons per day (GPD)

  • Acre-feet per day

The method used to determine flow should be identified in the test report.

2.2.4 Motor Power Input

Electrical power input to the pump motor shall normally be measured and reported in kilowatts (kW).

Where required for performance calculations, electrical input may also be converted to equivalent horsepower.

2.2.5 Pump Speed

Pump or motor rotational speed shall be measured and reported in RPM whenever required for evaluation of pump performance.

2.2.6 Additional Electrical Measurements

When applicable, the test report may also include:

  • Voltage

  • Current/amperage

  • Power factor

  • Frequency

  • Phase-to-phase voltage

  • Phase current balance

  • Motor load

These measurements may be used to identify electrical or motor conditions affecting pumping-system performance.

Section 2.3 – Pump Test Report: Calculated Values

Depending upon the type of pumping system and purpose of the test, the following calculated values should be included in the final pump test report:

  • Total dynamic head/total lift

  • Drawdown

  • Specific capacity for well pumps

  • Hydraulic horsepower

  • Motor input horsepower or equivalent input power

  • Estimated brake horsepower, when appropriate

  • Percent motor load

  • Overall pumping plant efficiency

  • Energy consumption per unit of water pumped

  • Kilowatt-hours per acre-foot

  • Therms per acre-foot, when applicable

  • Gallons of fuel per acre-foot, when applicable

  • Acre-feet pumped per 24-hour day

  • Estimated annual energy use, when applicable

  • Estimated annual pumping cost, when applicable

For well pumps, the elevation relationship between the discharge reference point and the water-level measurement datum may also be documented.

2.4 Test Conditions

A pump test should be conducted under stable operating conditions whenever practical.

Before final measurements are recorded, the technician should allow sufficient operating time for flow, pressure, water level, electrical demand, and other applicable operating conditions to stabilize.

Any condition that could materially affect the accuracy or interpretation of the test shall be documented.

Examples include:

  • Unstable pumping water levels

  • Changing system pressure

  • Variable-speed operation

  • Flow-control valve adjustments

  • Air entrainment

  • Cavitation

  • Excessive vibration

  • Sand production

  • Meter irregularities

  • Electrical fluctuations

  • Inaccessible measurement points

  • Suspected instrumentation problems

2.5 Repeatability and Index Testing

When a test is intended to compare current pump performance with previous results, technicians should make every reasonable effort to duplicate the original testing conditions and methodology.

This includes using consistent:

  • Measurement locations

  • Flow-measurement methods

  • Pressure-measurement locations

  • Water-level reference points

  • Electrical measurement methods

  • Operating conditions

  • Calculation methods

Significant differences from previous testing procedures shall be documented in the report.

Section 3 – Standards for Pump Test Technicians

3.1 Technician Qualification Levels

Henschel Pump Test recognizes four levels of pump test technician qualification:

  1. State-Qualified or Recognized Technician

  2. Apprentice Pump Test Technician

  3. Journeyman Pump Test Technician

  4. Pumping Systems Analyst

3.2 State-Qualified or Recognized Technician

A technician shall be considered state-qualified or recognized when the individual has successfully completed any applicable training, certification, licensing, or qualification requirements established by the state, utility, agency, or governing program under which pump testing services are being performed.

Where no formal state qualification exists, Henschel Pump Test's internal technician qualification standards shall apply.

State or agency qualification does not replace Henschel Pump Test requirements for demonstrating competency with the equipment, procedures, calculations, and safety practices required for the work being performed.

3.3 Apprentice Pump Test Technician

A technician shall be considered an Apprentice Pump Test Technician while completing required field training and experience.

Apprentice status shall normally continue until the technician has completed:

  • A minimum of two years of pump-testing experience, and

  • Participation in or completion of at least 500 pump tests.

Apprentice technicians shall receive appropriate supervision and shall demonstrate progressive competency in field measurements, equipment operation, calculations, reporting, and safe work practices.

3.4 Journeyman Pump Test Technician

A technician may be designated a Journeyman Pump Test Technician after completing:

  • A minimum of two years of pump-testing experience;

  • At least 500 pump tests;

  • Demonstrated competency in pump testing instrumentation and procedures;

  • Demonstrated ability to accurately complete pump test calculations and reports; and

  • Successful completion of an oral, written, practical, or combination examination administered or approved by Henschel Pump Test.

A Journeyman Pump Test Technician should be capable of independently conducting standard field and index pump tests and producing complete, accurate, and professional pump test reports.

3.5 Pumping Systems Analyst

A technician may be designated a Pumping Systems Analyst after completing a minimum of five years of pump-testing experience and demonstrating advanced knowledge of pumping and hydraulic systems.

The individual shall demonstrate competency in evaluating complete pumping systems used in applications including:

  • Agricultural pumping

  • Municipal water systems

  • Groundwater wells

  • Booster pumping systems

  • Industrial pumping systems

  • Commercial pumping systems

A Pumping Systems Analyst should demonstrate advanced knowledge in areas including:

  • Pump hydraulics

  • Pump efficiency

  • Total dynamic head

  • Flow measurement

  • Well performance

  • Electrical power consumption

  • Motor loading

  • Pump performance curves

  • Energy efficiency

  • System losses

  • Pump wear and deterioration

  • Troubleshooting

  • Performance trending

  • Repair and replacement evaluation

The Pumping Systems Analyst should be capable of interpreting pump test results beyond basic field measurements and identifying conditions that may warrant additional investigation, maintenance, repair, operational changes, or further system analysis.

Section 3.6 – General Technician Responsibilities

All Henschel Pump Test technicians shall:

  • Follow established company testing procedures.

  • Use appropriate and properly maintained test equipment.

  • Verify that instruments are suitable for the measurements being performed.

  • Follow applicable electrical and jobsite safety requirements.

  • Record field measurements accurately and completely.

  • Document unusual or adverse testing conditions.

  • Avoid altering or omitting field data in a manner that could misrepresent pump performance.

  • Perform calculations using approved methods.

  • Maintain professional conduct while working at customer facilities.

  • Protect customer equipment and property.

  • Clearly identify assumptions or limitations affecting test results.

  • Maintain the integrity, consistency, and repeatability of Henschel Pump Test procedures.

Standard of Practice

The objective of every Henschel Pump Test field test is to provide the customer with an accurate, repeatable, understandable, and professionally documented evaluation of pumping-system performance.

Where field conditions prevent a measurement from meeting these standards, the technician shall document the limitation and use the most appropriate alternative measurement method available without compromising personnel safety or the integrity of the test results.

These standards represent minimum internal practices. Customer specifications, contractual requirements, manufacturer requirements, utility standards, governmental regulations, or other applicable standards may establish additional or more stringent requirements.