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Public-images-osm logo.svg pipeline = surge_tank
Isawa II power station surge tank and penstock.jpg
A tank designed to absorb water hammer power in a pipeline on valve closing or emergency stops Edit this description in the wiki page. Edit this description in the data item.
Group: Man made
Used on these elements
may be used on nodesshould not be used on waysshould not be used on areasshould not be used on relations
Useful combination
Status: approvedPage for proposal

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.

DIN 4844-2 Warnung vor einer Gefahrenstelle D-W000.svg

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.


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


Photo Aerial view Tagging Note
Isawa II power station surge tank and penstock.jpg

At the center of the shaft or chimney, add a node and use :

On the chimney actual footprint, an area:

A chimney is installed above the pipeline it is supposed to protect
Pipeline underground surgeTank.JPG

At the center of the shaft, add a node and use :

On the shaft actual footprint, an area:

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