Technical reports: Liquid presence sensing

Measuring Moisture in Insulation

At LAIIER we have carried out a series of tests for our Severn sensors to show their performance for a range of liquids and setups. Here we present a technical report for the detection of moisture through insulation.

Measuring moisture in insulation

Measuring whether the Severn sensor can detect moisture on a saturated section of insulation. Rock Wool pipe insulation was wrapped around a mild steel pipe reflective of industrial supply pipes. We have previously tested the Severn sensor in direct contact with water, but here we want to see if moisture can be detected.


Setup diagram of measuring moisture in insulation

A 2” diameter mild steel pipe was wrapped in 1” thick rock wool pipe insulation. The pipe insulation setup was 39” long where the Severn sensor was adhered in two positions:

  1. On the outside of the insulation, positioned at the side at position A
  2. On the outside of the insulation, positioned at the bottom at position B

A 10mm hole was punctured through the top of the rock wool where 100 ml of water was dispensed. The Severn sensor was connected to the Severn board in order for serial data to be collected. 

Results and findings

  • For sensor position B at the bottom, the initial drop shows the detection of moisture from the saturated insulation. There is a second drop in reading where water is pooling on the surface of the sensor.

  • For sensor position A at the side, the detection of moisture is much later. This is because of the time it takes for the insulation to absorb the water around the side. Over time the reading increases slightly showing that the sensor can detect the insulation becoming less saturated.

  • Position B detected moisture earlier due to the gravitational flow of water.

Graph showing moisture detection on the Severn sensor


The moisture from saturated rock wool insulation can be detected with the Severn sensor where the level of saturation can also be seen. Moisture readings can be distinguished from water pooling on the sensor’s surface.