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Downgrading zone 1 and zone 2 areas
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By installing a gas alarm system, areas classified as zone 1 or 2 can be downgraded. The gas sensors continuously register whether there is any emission of explosive gases or vapours in the room. In the event of a leak registering in excess of 25 % LEL, the power supply will cut out to all equipment not EX-approved – thereby eliminating potential sources of ignition.
The advantages are:
- It is possible to use ordinary electric components, such as switches, etc.
- The staff is warned of a leakage.
- It is not necessary to have constant ventilation.
The alarm system could have functions such as:
| Low alarm A1 (10% LEL propan): |
Activates alarm beacons.
Starts up the ventilation system.
Closes the gate. |
| High alarm A2 (25% LEL propan): |
Cuts off the power supply for any equipment that is not EX-approved.
Activates alarm bell.
Sends alarm signal to staff. |
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Frode Laursen, logistics centre, Åstorp, Sweden
An example of downgrading zone areas by installing a gas alarm system can be demonstrated with the new logistics centre in Åstorp, which Frode Laursen has established for Unilever. Geopal System supplied gas detectors for the ethanol storage as well as the aerosol storage in Åstorp.
In the event of gas leakage, alarm beacons are activated, the ventilation system is turned on, and the gate to fire section two is closed. In case of high gas alarm, the power supply is cut off for any equipment that is not EX-approved.. |
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