If you work in an industry like construction, engineering or land surveying, where accurate and precise measuring is essential to project quality, you need a reliable way to take measurements and ensure level structures.

And on a busy job site or time-sensitive project, when spending time fiddling with fussy equipment could mean the difference between making your clients happy with an on-time completion or having to explain why you’re pushing out the timeline, you need tools that are fast and easy to use. According to a 2016 McKinsey article, for instance, the average construction project goes 20 months over its original schedule, so you need all the tools you can muster to save time where you can.

Every job site where precision, accuracy and timelines are priorities should have an automatic level as part of its toolkit. In this guide, we discuss what these versatile tools are, how they work and some common applications where they are particularly beneficial.

What Is an Automatic Level?

An automatic level, also known as a self-leveling level or a builder’s auto level, is a professional tool that can establish or verify points in the same horizontal plane. Builders, contractors, engineers and land surveyors use these optical levels to plan structures and developments and ensure structural soundness. Construction and surveying sites generally prefer automatic levels to their manual counterparts because they are much quicker and easier to set up.

Many automatic levels have special design features to help them withstand rugged outdoor work environments. They are often safe for work even in dusty or wet conditions and can sometimes even survive accidental submersion.

How Does an Automatic Level Work?

A level works by measuring the difference in elevation between two points or determining the heights of different landscape features or structures. You may have a basic bubble level in your garage or shop to test levelness — an automatic optical level applies the same principle in a more sophisticated way.

Automatic Level Parts and Functions

A typical optical level consists of a tripod, a bubble or circular level and a telescope with a magnifying glass, and it is generally used in combination with a marked stadia rod. The telescope contains crosshairs and a series of horizontal stadia marks, much like the marks on a ruler. The crosshairs establish the level point on a targeted area, with one long horizontal line marking the horizontal plane, and the stadia marks allow for the calculation of distances. Stadia marks often have a scale of 100:1, meaning 0.5 meters between these stadia marks represents a distance of 50 meters to the target.

Both a manual level and an automatic level allow the user to make rough adjustments by moving the level’s components until the bubble level or circular level is in alignment. The difference between a manual level and an automatic level lies in how to make fine adjustments. With a traditional manual level, the user must make manual adjustments to the level’s line of sight by turning the precision leveling screws until the telescope’s rotational plane becomes horizontal. An auto level contains internal components that make those adjustments automatically and do so much more quickly than a human could.

Another component of an automatic level is an internal swinging prism. The swinging prism is known as the internal compensator mechanism, and it allows for tremendous precision because it removes the variation found in manual level measurements. Users can set these levels even on uneven surfaces and be assured of correct readings.

When the level is placed on the ground, gravity and the slope beneath the level cause the suspended prism to tilt, even while the tripod remains stable. The adjustments required to correct for the tilting help the user determine distances, heights and angles.

Advantages and Disadvantages of Auto Levels

What are some of the advantages and disadvantages of auto levels? Automatic levels have many benefits — they are simple and easy to use, offer quick setup and provide accurate and precise measurements. They can be more prone to human error than their more complex cousins, digital levels, because digital levels use a clear digital display and ultra-precise lasers for measurement, whereas automatic levels use graduation markings that humans must interpret. On the whole, though, automatic levels are highly reliable, durable tools.

Uses for an Automatic Level

What is an automatic level used for in engineering, construction and land surveying work? Here are some of its most common uses:

  • Developing drainage systems: Automatic levels help create proper drainage systems for properties by ensuring that laying the pipes in the proposed angles and elevations will allow water to drain effectively. 
  • Fence building: Contractors and land developers can use automatic levels to build straight, level fences.
  • Grading: The automatic levels used in civil surveying are useful for measuring land grades for potential roads and ensuring the correct grades for existing roads. Automatic levels are often used to measure the grade of an area. Surveyors can measure the steepness of a slope to determine whether the site is suitable for development or will need alterations first. Automatic levels are also useful for maintaining the grade of a roadway. Surveyors can use levels to assess whether and how the road has sunk because of ground settling and determine whether it requires regrading.
  • Landscaping: An automatic level is useful in landscaping for developing level grades for planting.
  • Setting foundations: An automatic level can help set the foundation of a new home. Contractors use an automatic level to ensure the foundation is level and the angles set perfectly to provide stability.
  • Subsidence measuring: Automatic levels are also often used in subsidence measuring — that is, determining whether the land has sunk in a way that jeopardizes structures and their foundations. Using an automatic level, surveyors or contractors can check elevations and see whether they have shifted, or they can check to see whether the angles of a structure have maintained their proper alignment.
  • Verifying elevations and angles: In construction, an automatic level helps verify the elevation and angles of critical elements like foundations, floors and footings, as well as the height of doors and walls.

How to Use an Automatic Level

To use an automatic level the user turns the levelling screws on the level until the circular bubble vial is centered. This puts the level into the range of the internal compensator. The user can then look through the telescope while a second person positions a leveling staff, or stadia rod, with its base on a known elevation or reference point. The user then views the location of where the “crosshairs”, (visible to the user in the objective lens), fall on the level rod and notes the reading obtained. After this, additional observations are taken at locations on the project where elevation information is needed. From here the user can determine elevation differences between the reference elevation and the unknown locations by comparing the readings between the observations. The internal compensation mechanism insures accuracy by factoring out any mis-leveling error.

Find Your Equipment at Allen Instruments

To see the benefits of a high-quality automatic level in your construction, engineering or surveying work, make Allen Instruments your trusted source. Our digital and automatic level equipment gives your measurements the accuracy and precision you need to ensure the quality, safety and longevity of your projects. Our automatic levels are quick and easy to set up, and our reliable local experts are always here to answer questions or talk through problems.

You can rent engineering and building levels from us, or you can get in touch to discuss used equipment. Contact us today to learn more.

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