Utility Construction Lasers

Make an Informed Purchase by Understanding Pipe Lasers Quality Basics

Pipe lasers, also known as utility construction lasers, are the primary grade and alignment positioning tool used by utility contractors who install gravity flow pipe in the ground.  If you are new to this type of work or are considering a new or used unit, this article provides basic information can help you make an informed purchase.

As tough environmental conditions are often found in pipe trenches, quality pipe lasers are a combination of a precision instrument inside an enclosure that is tough, shock resistant, waterproof and corrosion resistant. Utility construction lasers can be set up on their own legs, on a tripod (for over the top set-ups), or a base plate and pole with adapter plate. The most common set-up is on its legs resting on the invert inside of a pipe, used with target sets sized to correspond to the diameter of the pipe being installed.  Usually pipe lasers include sets of legs of varying lengths to correspond with a specifically sized target set.

Pipe lasers are typically aligned with the use of a transit, sometimes mounted on a manhole transit tower, so that the laser beam is aligned with the sighting line to where the pipe is being routed (such as the next manhole).

The following is a summary of utility construction laser performance information and features that may be available (depending on manufacturer, model and age) to help you decide what is important based on the type of pipe installation work performed and jobsite conditions that may be encountered.

• Grade range defines the slope range that the pipe laser can achieve (-15% to +40% is a common range).  Some units have steep slope capability that allows grades to be manually set up to 100%.
• Self leveling range defines how far out of level an instrument be set and still allow the self-leveling process to occur.
• Leveling accuracy defines the precision achievable for auto-leveling and thus the accuracy of grade projections.
• Working range defines how far away from the pipe laser the laser beam can reach its target (usually 500 to 700 ft away through the pipe).
• Line adjustment range – a wider lateral range provides the most flexibility during set-up.
• Line center feature shows the beam position relative to its lateral adjustment range.
• Strobe mode is a feature on some units that flashes the laser beam to improve visibility.
• Grade compensation is a feature that automatically finds and corrects grade errors.
• Operating temperature range means the pipe laser will function properly within the specified range of temperature, with a broader range providing more user flexibility in extreme temperature conditions.
• Automatic beam intensity is a power saving feature that adjusts the beam intensity for ambient light conditions.
• Waterproof standard – As pipe lasers are often subjected to tough conditions such as dust, mud and water, most are sealed and over-pressurized with nitrogen so they are water- and dust-proof, capable of submersion in several feet of water without leaking.
• Controls (line and grade adjustment, line set) are important as are clear menu and command functions.
• Memory – useful to support next day set-up by allowing recall of the prior day settings.
• Remote control capability is important to adjust the line (left or right); some units will also allow the grade to be adjusted (up and down) remotely.
• Display visibility – screen resolution, character size and backlighting can be important, particularly in bright sunlight.
• Grade indication is the numerical accuracy of grade setting [often down to one thousandth of a percent (.001%)].
• Unit Size – Most pipe lasers are about 6” high and wide, but some are small and can fit into a 4” pipe.
• Resistant to chemicals and salts – As trench soil can sometimes contain corrosive or otherwise degrading constituents, most pipe laser enclosures and seals are made of materials and coatings that resist chemical degradation. 
• Set-up flexibility and versatility: Pipe lasers and targets are equipped with base extensions and targets faces for entering in various diameter pipes.  Most pipe laser sets include legs of various lengths and target with short and tall lenses to facilitate set-up in different size pipes.  Accessories such as large invert base plates and large targets are available to facilitate installation of large diameter pipe.
• Power supply – Rechargeable battery packs are the most common, but some units come with a 12v power cord and some will accommodate standard alkaline batteries.  Low power indication is a feature on most units.

Advanced Features

• Automatic targeting and alignment is an advanced feature that supports next day set-up where, with a special target, the laser beam will seek and lock onto the center of the target.
• Temperature compensation is a feature that automatically adjusts the encoder so that consistent readings are provided when there are temperature variations over the operating duration.
• Line alert is a feature that visually warns the user that the set-up line has been disturbed so that costly rework is avoided.
• Line and grade lock is a feature that allows the set-up values to be locked in to prevent inadvertent changes.
• Plumb reference beam allows the laser to be set-up precisely over a point.  The laser or LED plummet beam is a feature on some pipe lasers.
• Line set capability allows the beam to be raised outside the trench for easy line setup or alignment checking.  There are units with a vertical laser to achieve this.
• Green beam – red wavelength is most common and adequate in most cases, but some manufacturers offer green beam laser; about four times more visible in daylight conditions, but at substantially higher cost.

The highest quality, durable time-tested pipe lasers are made by Spectra Precision, Topcon, Sokkia, Leica, Apache, AGL, David White and CST/Berger, and well maintained used units by these manufacturers from reputable dealers are generally a good value.