General AWWS | A series of defined parameter thresholds which may affect general offshore operations. |
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HeliOps AWWS | A series of defined parameter thresholds which may affect helicopter flight operations. |
Crane AWWS | A series of defined parameter thresholds which may affect operation of cranes on offshore installations. |
Site Specific | Parameters thresholds defined for individual sites. If site not defined behaves as General AWWS. |
Parameter | Scheme | Warnings | ||
QNH Air Pressure (hPa) | All | < 910 or > 1100 | N/A | N/A |
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QFE Air Pressure (hPa) | All | < 910 or > 1100 | N/A | N/A |
Dry Air Temperature (°C) | All | < 0 | N/A | N/A |
Wet Air Temperature (°C) | All | < 0 | N/A | N/A |
Wind Chill (°C) | All | < -3 | < -1 | N/A |
Relative Humidity (%) | All | > 95 | > 90 | N/A |
Visibility (m) | All | < 250 | N/A | N/A |
Cloud Base (ft) | All | < 300 | < 600 | N/A |
Wind Speed (kts) | General | > 40 | > 30 | N/A |
Crane | > 40 | > 30 | > 20 | |
Heliops | > 60 | > 45 | > 40 | |
Wind Gust (kts) | General | > 50 | > 40 | N/A |
Crane | > 40 | > 40 | > 30 | |
Heliops | > 70 | > 60 | > 50 | |
Significant Wave Height (m) | General | > 7 | > 5.5 | N/A |
Crane | > 4 | > 3 | N/A | |
Heliops | > 7 | > 5.5 | N/A | |
Maximum Wave Height (m) | General | > 12 | >9 | N/A |
Crane | > 7 | > 5 | N/A | |
Heliops | > 12 | > 9 | N/A | |
Wave Crest Height (m) | General | > 7 | > 5.5 | N/A |
Crane | > 4 | > 3 | N/A | |
Heliops | > 7 | > 5.5 | N/A | |
TZ Wave Period (s) | General | > 15 | > 10 | N/A |
Crane | > 15 | > 10 | N/A | |
Heliops | > 15 | > 10 | N/A | |
TP Wave Period (s) | General | > 20 | > 15 | N/A |
Crane | > 20 | > 15 | N/A | |
Heliops | > 20 | > 15 | N/A |
Parameter | Description |
Wind Dir (°) | 10 minute mean wind direction. |
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Wind Speed (kts) | 10 minute mean wind speed. |
Wind Gust (kts) | 10 minute maximum of 3 second mean wind speed. |
Hs (m) | Significant wave height (mean of highest 33% of waves). |
Hmax (m) | Largest single wave. |
Tz (s) | Mean zero crossing period. |
Air Temp (°C) | 10 minute mean dry air temperature. |
Dew Point (°C) | 10 minute mean dew point. |
Cloud Level 1 (ft) | Height of 1st cloud base. |
Cloud Level 2 (ft) | Height of 2nd cloud base. |
Visibility (m) | 10 minute mean horizontal visibility. |
QNH (hPa) | 10 minute mean calculated sea level air pressure. |