Compressed Air Use in the Construction Industry

My drive to work involves passing through a growing neighborhood in the northeast suburbs of Cincinnati, Ohio. Over the past few weeks, I’ve seen a wooded lot get cleared & graded for construction of a new house. A week or so ago, heavy earth-moving equipment was digging the basement foundation…and adding to the traffic as huge dump trucks carried the dirt away. Fast-forward to this morning, when I saw that the 2×4 framing of the walls and the placement of the roof joists were almost complete. The backhoes and dump trucks on the lot have been replaced by a small fleet of carpenter’s work trucks, a ‘porta-potty’ (a real plus, considering the number of workers spending 8–10 hours a day on a site that was the utility equivalent of a primitive campsite)…and an air compressor.

Compressed air has been used in construction since ancient times, when manually operated bellows devices were used to stoke fires to increase the temperature inside furnaces that were used to make metal tools and building materials. The first large scale industrial use of compressed air on a construction project was the building of the Mt. Cenis tunnel in Switzerland. Tunnel construction began in 1857 and was expected to take at least 25 years, with some estimates projecting a timeline of over 70 years. However, technical innovations – like the development of pneumatic drills that replaced steam-operated machinery – allowed them to complete it in only 14 years.

In addition to the pneumatic nail guns and impact drivers being used at the new home site along my daily commute, compressed air has a number of other uses in the construction trades. It’s used for excavation, to power de-watering & sludge pumps, hoists, and even material conveyors. For example, a contractor that was building a large fence on sandy terrain used a Model 150200 2″ Heavy Duty Line Vac to remove sand from the hollow fence posts after using hammer drills (which are also air operated, so you know) to anchor them in place. Another user got a Model 151250 2-1/2 NPT Threaded Heavy Duty Line Vac to remove light dirt & sand from holes they dig to set posts in. Both power their Line Vacs with diesel-fueled 185 CFM tow-behind compressors.

Heavy Duty Line Vac: Hardened Alloy Construction and High Performance

EXAIR Air Knives are also used by construction companies. One of our customers bought a Model 110218 18″ Aluminum Super Air Knife Kit to blow an air curtain onto a conveyor to separate filter fabric out of recycled asphalt. Many lumber & building material manufacturers use them to blow off sawdust and loose debris from plywood, OSB board, roofing shingles, etc.

Top: 108″ Super Air Knife is supported & aimed via an array of Model 9060 Universal Air Knife Mounting Systems.
Bottom: Mounting Systems can be ‘overkill’ for some smaller applications, especially when the user is creative. Yes, that’s a door hinge. No, it wasn’t my idea, but I kind of wish it was.

Another customer uses a Model 6901 Spill Recovery Kit with their Model 6395 55 Gallon Premium High Lift Reversible Drum Vac System for cleaning up spills of hydraulic oil from their equipment at construction job sites. The ability to vacuum it up without dragging an electric cord from a shop vac through the puddles of oil is a real plus for them.

The EXAIR Reversible Drum Vac System converts a drum and dolly into a mobile pumping system.

And back to the Line Vacs, an electrical contractor uses a Model 6086 3″ Aluminum Line Vac to pull wire through stretches of underground conduit that are too long for standard fish tapes. They can pull the fish line through 120 feet of conduit in about 30 seconds. The Line Vac also removes any debris that might have accumulated inside the conduit between installation and wire pulling.

If you’re in the construction industry – or any industry, really – and would like to discuss a potential application for engineered compressed air products, give me a call.

Russ Bowman, CCASS

Application Engineer
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Line Vac Solves Long Distance Fish Line Installation Problem

An electric contractor contacted us about a problem that they had with installing the initial pull string (fish line) that is used to pull the primary service entrance wires to a power transformer through underground conduit. For short runs, they use a regular “fish tape” with no problem. However when it comes to longer runs (say over 50 ft), the solution becomes a little more difficult.

In the past, the contractor said that they used a small electric vacuum to try and pull the string through but that was a real hassle, took a bit of time and once the string made it to the suction point, it just kept going on into the vacuum cleaner itself and got tangled quite easily.

Another issue they face is actually clearing the conduit if it has been in the ground for any period of time. Small rodents, birds, snakes, water, etc all can find their way into the conduit over time. All of that has to be cleared before the local utility can pull the primary wires through.

After discussing the usual conduit sizes, we eventually settled on a 3” Aluminum Line Vac that would be able to produce a high enough airflow velocity to clear the debris and also pull the fish line through. Following are some photos of the Model 6086 3” Aluminum Line Vac attached to the conduit. Also shown is a fabricated conduit “pig”, a round piece of foam that is secured to the end of the fish string and inserted into the pipe. This piece allows the Line Vac to exert considerable pulling force onto the line. In this application, the conduit was over 120 ft. long and the job of blowing the string through took less than 30 seconds. Problem solved.

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3″ Line Vac sits on top of the conduit before feeding the fish line through

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Homemade “pig” to help clear large debris out of the conduit

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Exit of the 120′ conduit, showing the fish line has come through all the way

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Fish line is fed into the conduit by the power of the Line Vac

Neal Raker
Application Engineer
nealraker@exair.com