Tag:pipeline=surge_tank
 pipeline = surge_tank
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| Description |
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A tank designed to absorb water hammer power in a pipeline on valve closing or emergency stops. 
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| Group: pipelines |
| Used on these elements |
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| Useful combination |
Status: approved
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| Tools for this tag |
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A surge tank is designed to absorb excessive water hammer power in a pipeline on valve closing or emergency stops.
Depending on the upstream pipeline's length and diameter, such a tank can be pretty huge shafts like 200m of depth and 20m of diameter - often found in the middle of nowhere.
How to map
As a strategic function of a pipeline system, often near the valve that could cause a water hammer, we map them as nodes with pipeline=surge_tank, like pipeline=valve.
Despite such tanks can be huge shafts or chimneys, pipeline=surge_tank should be used on a pipeline node located at the tank's place.
Overground building can exist sometimes and it may be useful to map it with building=service
Also consider drawing an area for the exact footprint of man_made=chimney or man_made=shaft depending on the actual structure of the tank.
 | Surge tanks may be hazardous places. Depending on the hammer force to disperse, particularly during emergency stops, water may rise over the shaft/chimney and overflow around. Stay away from them, never ever fall inside. Always pay attention to directions and warnings to remain safe during surveys. |
Tagging
| Key | Value | Comment | Recommendation |
|---|---|---|---|
| pipeline | surge_tank | It's a pipeline surge tank | mandatory |
| location | <tank location> | Location of the surge tank. Can be outdoor, underground | recommended |
| diameter | <tank diameter> | The internal diameter of the tank | optional |
| height | <tank height> | The internal height of the tank, from the pipeline axis to the very top | optional |
| ele | <tank bottom elevation> | The bottom elevation of the tank | optional |
| capacity | <tank capacity> m3 | The capacity of the tank, if applicable | optional |
| operator | <surge tank operator> | Name of the company operating the surge tank | optional |
Examples
| Photo | Aerial view | Tagging | Note |
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At the center of the shaft or chimney, add a node and use :
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A chimney is installed above the pipeline it is supposed to protect |
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At the center of the shaft, add a node and use :
On the shaft actual footprint, an area:
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Here is an underground shaft acting as a surge tank for a penstock located 170 metres below. The shaft outlet is about 18 metres wide |