Testing Piezometers for Functionality Prior to Installation

Figure 1. Soil Instruments Standard VW Piezometer

1. Introduction

Upon receiving your Piezometers you should visually inspect your shipment to ensure that no damage has occured in transit.
When leaving Soil Instruments our Piezometers are fully tested to ensure they are functioning correctly however we do recommend testing the Piezometers prior to installation.
This includes taking a base reading on site along with testing during the installation process.

2. Testing the Functionality of the Piezometers

Before taking the Piezometers to site a simple functionality test can be performed to ensure the Piezometers are functioning correctly.

This can be done simply by:
Filling a bucket or an equivalent with water

Connecting the Piezometer to a logger or readout unit and ensure you are getting a stable reading. If you are receiving an unstable reading you may need to cycle through the sweep ranges on the logger to find the correct sweep range. There is also a knowledgebase article on our website that details which sweep range is required for different vibrating wire instruments.

Once you are receiving a stable reading please make note of this reading.

To then test the functionality please lower the Piezometer into the water at measured intervals (see Figure 2.).

You will then need to calculate the values you have into mH20 which are then comparable to the intervals you have measured. The calculations for this conversion can be found in the data reduction section of the W9 Piezometer manual.

    Figure 2. Lowering a Piezometer into a body of water for testing

    3. Possible differences seen

    When conducting these tests you are looking for a stable linear response from the Piezometer showing increasing pressure as the Piezometer is inserted deeper into the water.

    The readings you receive from the piezometer should typically fall within 25 F^2/1000 digits of the values stated on the Piezometers calibration sheet. We say typically 25 F^2/1000 digits as there is a possibility that transital influences may affect the readings you are receiving slightly, however this will not cause any reduction of the Piezometers accuracy.

    Please remember to compensate for any barometric differences that you may be experiencing compared to when the Piezometer was calibrated, calculations for this can be found in the instruments manual.

    4. Functionality tests on Site

    We strongly recommend further tests of the Piezometers on site including taking your base reading.

    If this base reading on site is not taken then once installed you will only be able to measure pressure change from when the Piezometer is first entered into the ground.

    We also recommend testing the Piezometer throughout the installation process to ensure that no damage has occurred to the Piezometer. 

    If your Piezometers readings fall outside the parameters stated above please submit a support Email detailing the differences you are experiencing.