Today’s blog post is sponsored by RPMC Lasers – leading laser distributor in the US, focused on industrial, medical, life science, and defense markets
One of the benefits of lasers are their versatility. They are useful far beyond the bounds of the traditional scientific realm. One of these more ‘non-traditional’ places to find lasers would be in landscaping or construction. Lasers are commonly used in equipment as a guide to indicate where a blade will fall when cutting material. They are are also used as levels in other instances. The following article will explore lasers in landscaping and construction–more specifically, it will cover the common types of laser levels.
Allowable Laser Classes
Lasers used in construction are typically either Class 1 or Class 2, though they are also allowed to extend to Class 3R. This is primarily to protect those at the job site. Since these classes of lasers are typically lower in power, it can sometimes be difficult to see what and where they are marking when using them outdoors on a sunny day. The Occupational Safety and Health Administration (OSHA) in the US Department of Labor has regulations for safe laser operation in the construction industry. While including guidelines for safe operation such as avoiding directing the beam at employees and proper labeling of the laser, there are also exposure limits. For instance, incidental observation of the laser is limited to a maximum irradiance of 1 milliwatts per square centimeter. This limits the powers of the potential lasers being used, but all in the name of jobsite and worker safety.
Laser Levels in Construction
Lasers have been used in one form or another for over the past 50 years in construction. In 1968, Spectra created the first laser used for interior construction. Later in the 1970s, they improved the design by creating both a rotating laser level, as well as a self-leveling laser. This meant the laser level no longer had to be manually based on a traditional bubble level attached to the laser. Improvements continued to be made, until they progressed to the types of lasers used in construction today.
Types of Laser Levels
The optics world likes to categorize lasers. Sometimes we do so by classes like mentioned earlier, sometimes by medium, like semiconductor, gas, or solid-state, or sometimes even in terms of switching, like actively or passively Q-switched lasers. In construction, there is a bit different of a classification. There are three main types of laser levels: Line levels, Rotary levels, and Dot (aka Plumb aka Spot) Laser Levels.
Dot Laser Levels
These types of laser levels are typically more inexpensive than the other two types of laser levels mentioned. They are sometimes called Plumb Levels since they are often used to ensure that walls are plumb. This means that the walls are oriented straight up and down. Dot laser levels project a dot in one direction. This dot is not always a single dot—versions are available that project multiple dots or a cross, instead. These types of levels tend to be self-leveling. To achieve this, one of the internal components is a pendulum. The pendulum is calibrated when it is in its neutral position and adjusts the laser component accordingly to project the beam at the proper angle. Besides putting up walls, some other uses for dot level lasers include in setting foundations and even installing fences.
Line laser levels emit either a horizontal or vertical beam and can usually be pivoted up to 180 degrees. This may be created by using a prism to split the beam so a line is projected extending from the center outward on both sides of the level. Again, the beam itself may be self-leveling through using a pendulum, or they may come where they need to be manually leveled. Since these levels create an entire beam, they are very useful when projects span, say, the length of a wall. This is especially useful when matching heights along multiple planar surfaces. An example of this would be during cabinet installation that spans multiple walls.
These levels are mechanically leveled. A gyroscope and motor are in charge of leveling the beam with respect to the earth. Rotary levels create a beam that spans an entire circle. Internally, there is usually a diode that is then projected onto an angled mirror that rotates. As the mirror rotates, the beam gets projected as a circle. They are widely used when starting a new construction zone. These levels are useful in leveling the ground and determining if material needs to be introduced or removed for a level surface.
Some circumstances, such as increasing distance from the level or bright outdoor conditions can make it difficult to discern the beam. This is due in part to the beam being spread over its large, circular area as opposed to a single narrow focus. In some cases where a wider circumference is necessary, this may mean that a higher power rotary laser may be necessary, or that rotary laser detectors may need to be used. These detectors can extend the range it is possible to use the level, since they can detect the beam at a greater distance where the eye cannot. However, even these detectors tend to only extend the range by 1.5 times that able to be detected by the human eye. To avoid this, there are some newer models of rotary levels that do not use a mirror or prism to bend the beam, but simply use a motor to rotate a diode about the center. This has the same effect of projecting a circle, except it can range over a much longer distance.