New app set to calculate fire extinguisher fill levels


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Field service technicians can benefit from a new app that calculates the liquid level in fire extinguishers. Using knowledge of the fill weight, the app indicates the fill level of liquid CO2 in the cylinder so that technicians can easily locate the exact liquid/gas boundary using a level checking device.

The level checking device could be a temperature sensing strip for example or an ultrasonic liquid level indicator like the Link Instruments’ ULLC2001.

Developed in-house by Link Instruments, the app is completely free of charge to download and can also be used in reverse to calculate the fill weight if the liquid level is known. Running on laptops, tablets and smartphones, both iPhone and Android, it can be used in the field even when offline.

“The convenience of this app will make servicing easier for field fire safety technicians, including in the marine sector,” said Link Instruments’ Dominique Christie. “We believe the app is the only one of its type.”

It uses the SG factors given in the Link Instruments’ ULLC200 instruction manual, which are based on the company’s extensive experience of testing for calibration checks on a CO2 cylinder of known weight as well as tests using strip sensors and other thermal devices.

Experience indicates the appropriate calculation factor is 1.0 for a cylinder temperature of 15°C, 0.9 for 20°C and 0.8 for 25°C, which is normally the temperature limit for testing CO2. Normally the liquid level is found to be within 5% to 10% of calculations made using these factors.

CO2 cylinders are normally two-thirds full, with adjustments required for temperature and the operating instructions for the level checking instrument. However, using the above factors an approximate level can be produced, which is particularly useful if a 35kg cylinder has been filled with 45kg for example or where a larger cylinder has a lower volume tropical fill.

The app will also be able to work with extinguishers that use other liquid fire suppressing agents such as FM-200 and NOVEC 1230.

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