Laser levels and laser measuring devices are great tools when used correctly, they make easy work of setting levels and working out distances, on building sites and around your home, the technology to fit a laser into a small handheld case has really been taken up by the DIY and building industry.
Using a laser to measure and set out for a project really saves time and resources, as you need only one pair of hands to do what used to be a 2 or 3-man job.
But with previous concerns around the use of laser pointers and other laser-powered optical devices are they really safe to use?
Lasers levels and measures use class 2 lasers in the visible to near-infrared range (400-1400nm) and can burn the retina if misused. Laser radiation less than 400 nm or greater than 1400nm is absorbed by the cornea and lens, this causes cataracts or burns. Infrared lasers (700nm – 1mm) are more hazardous, as they don’t trigger the blink reflex.
With that said, laser levels and measuring lines are not all bad, and used in the right way are great tools that help in all sorts of ways. In this article we take a detailed look at the hazards when using a laser level, highlighting the dangers and how to avoid them.
Are laser levels and laser measures dangerous?
The light beam emitted from a commercial laser generally has a small amount of power, however, it can be concentrated enough to damage the human eye.
For example, the Dewalt DW088-XE line-level uses a class 2 laser which is rated at less than 1.3milli Watts (nW), with a laser wavelength of 637nanometers (nm), which puts it in the visible light spectrum and is considered generally very safe, however, class 2 lasers can be dangerous when not used correctly.
This is very similar to laser measuring devices like the Leica Disto range which uses a class 2 laser with less than 1mW of power and a wavelength of 635nm. I often use the pocket-sized Leica Disto D1 or D2 for my DIY projects and surveying as they are easy to use and very accurate.
This type of unit is common in tools used for construction and DIY projects and the human eye is able to provide protection from damage due to its blink reflex.
If a laser beam should be directed at the human eye, it can create a concentrated amount of radiation on the surface of the retina, this is focused by the eye’s lens and would be a very tiny spot that is then heated up by the radiation.
This increased heat can destroy or permanently damage the cells of your eye, in particular the photoreceptor cells that make up your retina.
A 10 Degrees Celsius increase in temperature will destroy retinal photoreceptor cells. If the laser has enough power, it can create radiation and cause permanent damage in a fraction of a second, in some cases this will be faster than the time it takes for a normal human to blink.
In general domestic tools that you can purchase in DIY stores that use lasers are not powerful enough to cause permanent damage when used correctly, but with misuse, they are capable of causing harm to an unprotected human eye.
What are the different classes of laser?
There are a number of different classes for lasers, a laser will be allocated a classification based on several considerations including laser emission characteristic and laser pulse.
Both in the US and UK follow guidelines for the classification of lasers. In the USA OSHA Technical Manual (OTM) Section III: Chapter 6 provides definitions of Laser class and their potential hazards.
While the UK uses standard BS -EN 60825-1:2014 to define the nature and classification for laser equipment.
Generally, they follow the same classes and provide guidance on each type of laser which are as follows:
How to use a laser level Safely and avoid the risks
Anyone that uses a laser level, measure or laser line should understand the risks and how to avoid them and keep everyone safe.
Basic guidelines should be followed such as avoiding staring directly into the beam and using protective eyewear that has the right type of optical filters to protect your eyes from any scattered or reflected laser light.
Take steps to make sure that the area you are working in is clearly signed and that anyone entering is aware of the use of laser equipment and the risks.
To help stay safe always read and follow tool manufacturers’ instructions and we have put together these recommended precautions when you are using a laser level or measuring device:
- Never look or stare directly into the beam.
- Use the correct protective glasses, normal tinted sunglasses don’t offer enough protection from a laser beam.
- Always turn the laser off when it’s not in use,
- Never leave a laser unattended for any period of time.
- Never point a laser at a vehicle with a driver, people, or pets.
- Don’t try to disassemble or repair any type of laser tool, this can result in serious injury.
- Don’t use a line laser unless you’re familiar with how it operates.
- Don’t let children play with lasers.
- Always purchase a line laser that’s compatible with your intended use.
- Remove the batteries before storing the laser to prevent damage.
How to choose the right safety equipment
When using laser equipment eyewear should be selected to match the specific laser classification. It must provide the right level of protection and block or attenuate in the correct wavelength range to suit your laser measure or level.
Protective eyewear for use with lasers is rated according to an optical density (OD), this tells you how well the optical filter can reduce the beam’s intensity.
Look for laser safety eyewear that has been marked with the EN 207 or EN 208 protection level, this should include wavelength range, the CE mark (in the UK and Europe), and be tested and certified by an appropriate notified body.
Also, consider the tint color for protective glasses, do you need to be able to read or identify warning signs? If so, the color of the lens may affect your ability to see certain warnings. Wrap-around frames like these from LaserPair also help to protect from reflected light and are available in different tints.
If direct exposure to the beam is possible, it has to have enough optical density and wavelength rating to withstand a direct hit from the beam without breaking.
When choosing eye protection make sure it is a good comfortable fit because for eye protection to work it must be worn.
For more information on laser levels and laser measuring equipment check out our articles on how to use a laser level and our top pick or laser measuring devices.
This article was written by: Richard Quinton – The DIY Help Desk Owner, Engineer & technical specialist.
Richard is one of the key partners in The DIY Help Desk team. He is a qualified Engineer, writer, and publisher, educated to Master’s level. He is a keen advocate of DIY and home improvements.
Richard enjoys helping others to learn new skills and reach their goals and believes that passing his knowledge and experience on through his writing is an effective way to positively impact the lifestyles and well-being of others on a larger scale.