Vaporisation of liquid nitrogen causes a 700-fold volume exapnsion, displacing breathable air and presenting a risk of asphyxiation unless an oxygen monitor is fitted
Crowcon has launched a complete gas safety package to protect personnel working with liquid nitrogen from the risk of asphyxiation.
Consisting of an oxygen detector, a control unit and a combined beacon and sounder to raise the alarm, Nitrowarn can provide a life-saving early warning of falling oxygen levels caused by the rapid expansion of nitrogen in the event of spillage.
In addition to all the necessary components including cabling, the Nitrowarn package for customers in the UK includes installation and commissioning by a Crowcon engineer.
One litre of liquid nitrogen vaporises to form around 700 litres of gas.
In the confined space of a laboratory or store room, the sudden release of such a large volume will displace significant quantities of breathable air, creating a serious risk of asphyxiation.
At the heart of the package is Crowcon's recently launched Gasflag control unit.
If the detector registers a dangerous condition, personnel in the vicinity are alerted by Gasflag's built-in warning LED and sounder.
To raise the alarm over a wider area, however, the control unit also triggers a separate flashing beacon and wailing sounder, which can be sited in any convenient, prominent position.
Two alarm levels can be set at the control unit, allowing a 'pre-alarm' warning to be given if the oxygen level falls only slightly. Nitrowarn can also safeguard against a secondary hazard of liquid nitrogen handling: fire due to oxygen enrichment.
Extremely low temperatures may cause highly flammable liquid oxygen to condense from the air.
When the liquid vaporises again, the resulting oxygen-rich atmosphere will allow most materials to burn very readily if an ignition source is present.
To combat this danger, one of the control unit's two alarm levels can be used to warn of rising rather than falling oxygen levels.
Nitrowarn is easy to use, requiring no calibration and having only one push-button on the control unit to reset the system after an alarm.
The simple front panel features just four LEDs - two for each of the alarm levels, one indicating a healthy power supply and one to indicate a fault.
