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 The backhoes and dump trucks on the lot have been replaced by a small fleet of carpenter’s work trucks, a ‘porta-potty’ (a real plus, considering the number of workers spending 8–10 hours a day on a site that was the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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Finding the Right Intelligent Compressed Air Product

I had the pleasure of talking with a customer who had purchased a Model 6063 1-1/2″ Stainless Steel Line Vac the other day. They were building chemical processing machinery, and needed to move vapor into a condenser for reclamation of the fluid. The Line Vac was doing exactly what they needed it to do, and with a supply pressure regulated down to 12psig, at that. Their question was, how do they quantify the flow rate?

Because the Line Vac generates a moderate level of vacuum head with a moderate vacuum flow, they’re ideal for drawing in bulk solid material and conveying it from one place to another. They’ll do the same with airborne dust, vapors, and gases, but…

Because they’re made for conveying bulk solids, our published performance data for the Line Vacs doesn’t address total developed airflow. However, because our Air Amplifiers are made for moving air (and anything that might be suspended in the air or already airborne), we DO publish airflow performance data for them. And it provides a GREAT segue for situations like this, when the only thing that can do a better job than one EXAIR product is another EXAIR product!

…Air Amplifiers, while similar in function to the Line Vacs, generate a high vacuum flow with a low vacuum head. This makes them the better choice for moving air & airborne dust, vapors, gases, etc.

In this case, the machine designer replaced the 1-1/2″ Stainless Steel Line Vac with a Model 6040 3/4″ Stainless Steel Adjustable Air Amplifier. It’s got a 1-1/2″ OD inlet plenum, so it was a ‘drop-in’ replacement for the 1-1/2″ Line Vac, which was plumbed in with a 1-1/2″ ID hose. When they regulated the supply pressure to 25psig, they were able to replicate the vapor carryover to the condenser at the specified rate, and even cut the already low compressed air consumption from 9.3 SCFM @12psig (for the Line Vac) to 3.7 SCFM @25psig (for the Air Amplifier).

As an EXAIR Application Engineer and a Certified Compressed Air Systems Specialist, I’m here to make sure you get the most out of your compressed air system. If that involves using a product other than the EXAIR Intelligent Compressed Air Product that you may have initially selected, I’m not going to be shy about telling you that. But, there’s a good chance that the more ideal solution is going to be another EXAIR Intelligent Compressed Air Product. If you want to talk about compressed air…so do I! Give me a call.

Russ Bowman, CCASS

Application Engineer
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So, You Want To Calculate Line Vac Flow… Or Do You?

As an EXAIR Application Engineer (and one with almost 14 years under my belt, to boot), I’m well versed in all the standard calculations regarding compressed air, including: converting ACFM or ICFM to SCFM, determining compressed air consumption rates at different inlet pressures, return on investment from using more efficient products, receiver tank sizing, and cost of compressed air generation. I know many formulas, by heart, that relate to certain applications involving our products, like how to calculate the heat load for Cabinet Cooler Systems, the amount of air flow from a Super Air Nozzle, Super Air Knife, Air Amplifier, etc., to cool an object from a starting to a desired temperature (and how long it’ll take to do it), and humidity formulas for Atomizing Spray Nozzle applications.

I’ve loved math all my life, so all that stuff above is one of my favorite parts of this job. There are, however, things we can’t do the math on…and calculating the flow through a Line Vac is one of them. Maybe two. I say “Maybe two” because there are two common questions we get regarding Line Vacs, and neither have answers that can be calculated:

  • How fast can I move [insert description of bulk material here] with a Line Vac?
  • How much air flow is generated by a Line Vac?

There are a LOT of variables that can affect conveyance rate, so the first question is difficult to put a number on, unless it’s something we’ve tested here before, or if a customer has provided reliable data from their Line Vac conveyor setup. For our latest Catalog, #35, we compiled this into a Conveyance Data table. You can access it here (registration required), request your very own print copy, or just contact me, and I’ll email it to you.

Likewise, the second question doesn’t have a mathematical formula to give us an answer either. When we get questions about a Line Vac’s total developed air flow, we’ll say that, very generally speaking, a Line Vac will entrain 2-3 times its compressed air consumption in vacuum flow. That’s based on some informal testing we’ve done in the shop on a few specific Line Vacs. And that’s ALWAYS followed up with some questions of our own:

  • Are you looking for a specific amount of air flow? And,
  • What is the nature of the application?

Oftentimes, we find out that the customer just needs to move air – as opposed to conveying bulk product – and THAT’S a job for our Air Amplifiers. We DO publish formal performance data on those, and if air movement is all that’s needed, the Air Amplifiers are going to do that WAY more efficiently than a Line Vac. They’re capable of entraining air at rates of up to 25:1.

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.

If you have questions about a potential application, or about a specific product, give me a call. I’m here to make sure you get the most out of our products, and that starts right at the beginning, with finding the best one to suit your needs.

Russ Bowman, CCASS

Application Engineer
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Special Line Vacs for Special Applications

EXAIR’s Line Vacs are a great option for replacing your ‘bucket and ladder‘ operation. There are many factors that need to be considered when selecting the best option – how far are you looking to convey? What conveyance rate are you looking to achieve? Is your material abrasive? – to name a few.
Using data we have gathered from our controlled in-house testing, we can almost always recommend a stock-option Line Vac that will meet your application’s needs.

There are some instances however, when your needs will be better met with a custom solution. In this blog I wanted to highlight a few custom Line Vacs that we have produced for customers in the past:

This Special Mini Line Vac was designed with barbed fittings (unlike the hose or threaded fittings) for easier installation for a manufacturer of integrated circuit chips. It was used to remove microscopic debris. The small body and high vacuum flow made it a perfect fit for the confined working space.


This 1 ½” Flanged Line Vac was designed using PVDF to provide a superior chemical resistance. In this case, the unit was going to be exposed to a chloride wash which would corrode all versions of steel, including stainless steel. The QF Flanges were also added to provide easy disassembly when the Line Vac was scheduled for cleaning.

This Special Flanged Line Vac was used to convey a measured granulated material into a pouch. The funnel side was loaded with the pre-measured material and pushed into a mesh pouch when the air was activated.


This Special Flanged Refumigation Line Vac was used to retrofit existing machinery to remove acidic vapors resulting from surface etching of a silicon wafer. Where this would typically be a nice fit for a Stainless Steel Air Amplifier, the existing exhaust piping was lengthy with many bends that would have caused back pressure on any Air Amplifiers. In this case, they needed additional force from the Line Vac to overcome this downstream resistance.

This Special Threaded 1″ Aluminum Line Vac was used to remove fumes from a welding application, and needed to be threaded into a flame retardant filter bag. The custom threads allowed them to screw the filter bag directly onto the line vac with the added insurance of a threaded connection to prevent sparks from escaping the bag.

As you can see, we have many examples of non-stock Line Vacs (as well as special items from other product lines). If you have an application you would like to discuss, feel free to give me a call!

Al Wooffitt
Application Engineer

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