Safety and health newsletter for the Oregon construction industry


August 14, 2012

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Tool box talk: Laser levels

Although laser levels have been used on construction sites for years, their use is increasing with instruments that can define plum, level, and square reference points, and can establish vertical or horizontal planes. But the narrow beam that makes laser levels effective isn’t entirely risk free.

What are they?

Common types of laser levels include:

  • Dot lasers, which project two, three, or five beams of light, allowing the user to establish a point from floor to ceiling, a level reference point, and a 90-degree reference.
  • Line level lasers, which project a single beam of light 180 degrees horizontally and vertically, allowing the user to establish a horizontal or vertical plane.
  • Rotary level lasers, which project a single beam of light 360 degrees, allowing the user to establish a horizontal or vertical plane.

Laser intensity

The intensity of a laser beam is determined by the laser’s power, which is measured in milliwatts (mW) and classified by its power as shown in the table below. Most laser levels use Class IIIA lasers.

Laser class



Class I laser

Doesn’t produce damaging radiation under normal operating conditions. When viewed under magnification, however, the beam can cause eye damage.

Product scanners, CD players, and laser printers.

Class II laser

Isn’t dangerous unless the beam is viewed under magnification.

Laser pointer.

Class IIIA laser

Can produce spot blindness and other eye injuries.

Most laser levels use Class IIIA lasers.

Class IIIB laser

Can damage eyes and burn skin.

Entertainment light shows and lighting effects.

Class IV laser

Can damage eyes, burn skin, and cause fires.

Burning and cutting tools.

Laser levels must have a label that indicates their class. Here’s an example:

Laser level safety precautions:

  • Never stare into a laser beam.
  • Don’t try to repair or disassemble a laser level.
  • Read the instruction manual before you use a laser level.
  • Never point a laser level at vehicles, drivers, people, or pets.
  • Don’t let children play with laser levels.
  • Always turn the laser level off when you’re not using it. Leaving it on increases the risk of someone unintentionally staring into the laser beam.
  • Don’t remove or deface any laser level labels.
  • Don’t operate a laser level near flammable liquids, gasses, or dust.
  • Don’t aim the laser beam at shiny or reflective surfaces; they’re not suitable for laser use.


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