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Sensitivity

The sensitivity of the vial determines how quickly the bubble moves when one end of the spirit level is lifted.

What is a spirit level's sensitivity?

Hultafors - Global

For craftsmen different tasks call for different degrees of precision. This is why professionals often have more than one spirit level, to get different rates of vial sensitivity. A spirit level with standard sensitivity is easy to work with and often good enough. But more demanding tasks call for a spirit level with higher sensitivity.

The vial shape

Higher and lower sensitivity is achieved by changing the shape of the vial. If we take a closer look at a vial we can see that it has a barrel-shaped inner contour. Within the barrel-shape the air bubble searches for the highest point. Had the vial been a straight tube, with no curve, it would have been impossible to level.

Less curve, faster reaction

The curve of the vial can be looked upon as a sector of a bigger circle. The radius of that circle determines how curved the vial is, and therefore how sensitive it is.

A larger radius means that the bubble can move more easily and reacts to smaller movements.

Which sensitivity do you need?

Sensitivity is measured in mm per meter. The rate is based on a spirit level 1 meter long, and how high one end of the level must be lifted for the bubble to move 2 mm.

Ten times as sensitive

The standard for most spirit levels on the market is a sensitivity of 10 mm/meter, the equivalent of a 200 mm radius. Hultafors also offers spirit levels five and ten times as sensitive than standard.

Mounting a door frame is a task that calls for a spirit level with higher sensitivity. For example Hultafors MST or Hultafors Libella 2000.

Sensitivity facts

Sensitivity is determined by the radius of the vial; a larger radius means that the bubble can move more easily. Sensitivity is measured in mm per meter.

The parameter is based on a spirit level 1 meter long, and how high one end of the level must be lifted for the bubble to move 2 mm. Certain applications require a higher sensitivity, which is why we produce spirit levels with varying degrees of vial sensitivity.

Radius(mm) Sensitivity (mm/m) Model
150 13,3 TVP
200 10 HV, PV
1 000 2 Libella 2000
2 000 1 MST 180

If the vial is too sensitive, the level may be difficult to work with. However, the more sensitive the vial, the more accurate your work will be.

More to explore ↓

MST - our most sensitive spirit level.

The MST level is our strongest and most sensitive spirit level. Crush-proof block vials that is UV-resistant and withstands temperature changes with a +30% magnification lens and luminescent reflector for easier reading.

Learn more about MST 180

How accurate is your spirit level?

Manufacturing tolerance is the sum of all possible minor and microscopically small errors during production. Tolerance is thus the divergence from sensitivity, and the smaller the value the better.

Learn more and watch our video

5 facts about our vials

The fluid-filled containers that give you a level reading are called vials. The liquid in the vials is usually oil or alcohol so that the air bubble inside can move freely.

Learn more about the vital vials

Why length matters

The strength of the spirit level is determined by the shape and thickness of the profile, as well as the holes for the vials.

Learn more about the profile and end caps

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