Use Leveling Instruments and Equipment

Comprehensive practice flashcards covering optical, digital, and laser leveling instruments, surveying terminology, leveling procedures, and equipment maintenance from Learning Tasks 1 through 3.

What is an optical level and what is its primary function?

An optical level is a high-powered telescope equipped with crosshairs used to look through and take level readings.

What are the distinguishing features of a Dumpy level?

The Dumpy level (builder's level) is the earliest type of level, featuring manual adjustments with $3$ to $4$ leveling screws, but it is not suitable for fine precision readings.

What leveling bubbles are found on an Engineer's level and what are their roles?

An Engineer's level uses a circular fisheye bubble for rough leveling and a coincidence (split bubble) level for fine, precise adjustments.

How does an automatic level achieve self-leveling line of sight?

It utilizes an internal compensator (hanging prism) suspended by very fine wires or nylon strands that automatically swings and plumbs the line of sight.

What measurement capabilities does a transit level offer?

It measures both horizontal angles and vertical angles, with vertical arcs measuring up to $45^\circ$ from the horizontal.

How do the bucket-type and garden hose-type water levels differ in operation and staffing requirements?

The bucket type uses a single bucket with a hose to mark planes up or down (ideal for ceiling heights) and requires only one person. The garden hose type consists of a long hose with two clear ends, must stay below the water level, and requires two people.

What is a reticule and what field check verifies its position?

The reticule is a piece of glass inside the telescope upon which crosshairs are etched. A peg test is performed to check its position.

What is the function of the knurled adjustment ring on the telescope eyepiece?

The knurled adjustment ring focuses the crosshairs for the user's eye.

What is the purpose of the horizontal tangent screw on an optical level?

It is used to slowly and precisely rotate the instrument horizontally to adjust the azimuth line of sight.

What is the purpose of a sunshade on an optical level?

A sunshade is a short tube attached to the objective lens to eliminate glare caused by the sun.

What materials are leveling rods constructed from and how are metric rods marked?

Leveling rods are made of wood, fibreglass, or aluminum with reflective faces. Metric rods feature cumulative divisions of $10\,\text{mm}$.

What is the purpose of stadia lines on an optical level and are they used for building layout?

Stadia lines are used to determine the distance from the instrument to the leveling rod; however, they are not accurate enough for building layout work.

What historical tool was originally used for surveying chains, and what modern tape lengths are standard?

Surveying was originally performed using Gunter's chain, which was $100$ links long. Modern measuring tapes are typically $15\,\text{m}$ or $30\,\text{m}$ in length.

Where should an optical level ideally be set up relative to the benchmark and station?

The instrument should be set up approximately halfway between the benchmark and the target location/station.

What are the setup parameters for conducting a peg test?

Set stakes into the ground $60\,\text{m}$ apart and place the instrument midway between the backsight and foresight stakes to accurately check elevation transfer.

What is a benchmark (BM) and what elevation is conventionally assigned to an arbitrary benchmark?

A benchmark is a permanent starting reference point of known elevation, typically assigned an arbitrary elevation of $100.000\,\text{m}$.

What is a datum in surveying?

A datum is a series of benchmarks or an established reference surface from which all elevations are measured, such as mean sea level.

What is the difference between a backsight (BS) and a foresight (FS)?

A backsight is a rod reading taken on a point of known elevation to determine the line of sight elevation, whereas a foresight is a reading taken on a point of unknown elevation.

What is a turning point (TP)?

A turning point is an intermediate reference point upon which a foresight is taken to establish its elevation, followed by a backsight to advance the leveling run.

What does Height of Instrument (HI) represent?

Height of Instrument is the absolute elevation of the telescope's line of sight relative to the datum.

What does completing a leveling circuit require?

Completing a circuit requires starting the leveling run at a known benchmark (BM) and working all readings back to close on the original BM.

What does the acronym LASER stand for, and what gases produce the red beam in gas laser levels?

LASER stands for Light Amplification by Stimulated Emission of Radiation; it emits a narrow, bright red beam generated by helium/neon gases.

What type of radiation do electronic levels emit compared to standard visible laser levels?

Electronic levels emit invisible infrared rays.

What are leveling targets made of and what are their typical applications?

Targets are made of clear plastic and are used to establish levels for structural components such as ceiling T-bars, concrete screeds, and drainage pipes.

How is a pipe laser level utilized on a job site?

A pipe laser level is laid directly at the end of a pipe and dialed to a desired slope to install pipes at a constant grade for drainage.

What are the rules for tripod leg spacing and setup on sloped ground?

Tripod legs should be spread approximately $900\,\text{mm}$ ($3\,\text{ft}$) apart (wider in windy conditions), and two legs must always be placed facing downhill on slopes.

What is the proper cleaning procedure for optical level lenses?

Allow the lens to dry completely, then use a camel's hair brush in a circular motion starting from the center and working outward; never rub abrasive materials against the glass.

What handling precautions must be observed when transporting and setting up an optical level?

Always carry the tripod under the arm facing forward, grip the instrument by its base, transport it in its cushioned case over distances, never force or overtighten screws, and never leave it unattended.