An auto level staff is an essential tool used in surveying along with an auto level instrument. It plays a critical role in obtaining accurate elevation readings of points on the ground. This guide provides a detailed look into the types, uses, and methods of reading an auto level staff.
What Is an Auto Level Staff?
An auto level staff (or leveling staff) is a graduated rod used to measure the height difference between points during a survey. The staff is held vertically on the point to be measured, and the reading is taken through an auto level.
It is made of durable materials such as aluminum or fiberglass and typically features a telescopic design that can extend several meters.
Types of Auto Level Staff
1. Telescopic Staff
- Made up of multiple extendable sections
- Common sizes: 3m, 4m, 5m
- Lightweight and portable
2. Folding Staff
- Hinged sections folded for storage
- Less common than telescopic models
3. Invar Staff
- High precision staff made with Invar alloy
- Used in high-accuracy work
4. E-type Staff
- Printed with E-pattern markings
- Ideal for quick and easy readings
5. Bar-coded Staff
- Used with digital levels
- Offers higher accuracy and automatic readings
Construction and Design
Auto level staffs typically include:
- Graduations: Metric or imperial units, usually in millimeters.
- Color contrast: Black and red markings on a white background for better visibility.
- Bottom base: Flat or rounded base to ensure proper ground contact.
- Telescopic lock: Ensures stability during use.
How to Use an Auto Level Staff
- Place the staff vertically on the point to be surveyed.
- Ensure it stands straight (a circular bubble may be included).
- Look through the auto level telescope.
- Align the horizontal crosshair with the staff and take the reading.
- Note the reading corresponding to the crosshair intersection.
Staff Reading Example
If the auto level shows a reading of 1.275 m at a benchmark point and a 1.925 m at the next point:
- Rise or Fall = 1.275 – 1.925 = -0.650 m (a fall of 0.650 m)
Uses of Auto Level Staff
- Road leveling and gradient setting
- Construction site layout
- Establishing foundation levels
- Topographic surveys
- Earthwork calculation
Tips for Accurate Staff Use
- Hold staff vertically; use a bubble level if needed
- Avoid parallax error by aligning your eye directly with the crosshair
- Use a stable base, especially on uneven terrain
- Record observations carefully
FAQs About Auto Level Staff
What is the standard length of an auto level staff?
Common lengths are 3m, 4m, and 5m, with 4m being widely used for most surveys.
What is an E-type staff?
It is a leveling staff with E-shaped markings for quick optical reading.
Can I use an auto level staff with a laser level?
Yes, but ensure compatibility, especially with digital or bar-coded staffs.
How do I maintain my auto level staff?
Keep it clean and dry, avoid dropping it, and store it in a protective case.
Conclusion
An auto level staff is a vital tool in construction and land surveying, allowing precise height measurements. Understanding its types and correct usage ensures accuracy and efficiency in every project. Whether you’re a student or a seasoned engineer, mastering the staff is key to successful surveying.
