The term level describes the straightness of horizontal members. The term plumb describes the straightness of vertical members.
Level and plumb members intersect at 90-degree angles, and are used to establish precise horizontal and vertical lines, respectively. There are many of these tools, ranging from simple spirit levels to sophisticated electronic and laser instruments.
Click on each leveling tool to know more:
The most common tool used to check both level and plumb is the spirit level. They are made of wood, aluminum, or a lightweight alloy.
Spirit levels generally contain three bubble vials: the vial mounted at the center of the tool is used to establish true horizontal (and verify level), and one vial is mounted transversely at each end for establishing true vertical (and verifying plumb).
The engineer’s level or plumber’s level can measure slope (angle) as well as plumb and level. One of the vials is adjustable to different angles.
When you adjust the vial and hold the level at the desired angle, the bubble in the vial is centered. Then, one level is checked against another to ensure the reading is correct.
The torpedo level is a small spirit level that is useful in confined areas or for leveling short runs of pipe.
Most torpedo levels have a vial that indicates 45-degree angles. Plumbers often use a torpedo level with a magnetic base.
Plumbers use a line level to make sure that either end of the line level attach to the line at about the midpoint of the reach.
When the air bubble is centered between the markings on the vial, this indicates the trueness of the line to which the line level is attached. That pipe laid between two distant points is level along its entire distance.
By using a line level, you can transfer (determine or calculate) vertical dimensions, such a height or elevation, over long distances without using the larger leveling instrument called a transit.
Precision and Distance Leveling Instruments:
If distances are too great to be measured accurately by the levels mentioned above, or if more accuracy is required, you will need to use a builder’s level (also called a surveyor’s level) or a transit level with a leveling rod.
Builder's Level versus Transit Level
The main difference between a builder’s level and a transit level is that the telescope with the builder’s level is fixed, but the telescope with a transit level can move up and down.
Laser Level Tools
This leveling device projects a thin, 90-degree beam of low-wattage light. More accurate over longer distances, lasers are very easy to use when establishing vertical or horizontal lines and are used for measuring or laying out openings. Using this tool, you can tell immediately if something has been aligned.
Examples of Using Laser Level Tool
• Use this tool as an alignment guide when installing gravity-flow pipelines. Lay the pipe along the beam of light emitted by the laser.
• Cold beam lasers can be used to install and align such building elements as walls, partitions, and access floors.
A plumb bob is a precise, yet simple, measuring tool used to align points vertically, from one floor to another floor below. To establish this exact vertical line, the plumb bob uses the law of gravity.
A plumb bob generally consists of a specially designed weight attached to one end of a nylon thread. Nylon is used because it is more resistant to dampness. A plumb bob is used to find the center point on a pipe run.
A chalk line is used to lay out long, straight lines of chalk on smooth or semi-smooth surfaces.
Pull the chalk line taut between two points, then carefully stretch the line away from the surface and let it snap back to produce a straight line of chalk.
Because of the way most chalk lines are designed, they can be used instead of a plumb bob.