Paul Industries designs and installs compressed air, process gas and utility piping for New Hampshire device, electronics and precision manufacturers. Compressed air is the utility most often treated as free and most often found responsible for a contamination problem nobody could explain. It blows directly onto product during drying and blow-off, which means whatever it carries, oil, water, particles or rust from its own piping, is deposited on the part at the last moment before inspection.
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Three contaminants, specified separately
ISO 8573-1 classifies compressed air purity along three independent axes: solid particles, water content, and oil. A plant asking for clean dry air without saying which classes it needs in each category has not specified anything, and a supplier is free to deliver whatever combination is convenient.
Particles. From the intake, from compressor wear, from desiccant attrition in the dryer, and, most often, from the inside of the distribution pipe. Filtration handles them provided it is positioned after every source rather than only near the compressor.
Water. Air entering a compressor carries humidity, and compressing it raises the dew point so that water condenses out in the receiver, the pipework and eventually at the tool. The measure is pressure dew point, which has to be lower than the coldest temperature the air will encounter. This is where New Hampshire specifically catches people: a system with a pressure dew point that is entirely adequate for an indoor plant will drop liquid water into any run that passes through an unheated space in winter, and a great many plants have a length of main crossing a roof void or an outside wall.
Oil. From lubricated compressors as aerosol and vapor, and as a breakdown product of the lubricant itself. Oil-free compressors remove the source; coalescing filtration and carbon adsorption manage it where a lubricated machine is retained. Oil vapor passes straight through a particulate filter, which is the same distinction between particulate and molecular contamination described on our Oregon cleanroom page.
The verification point worth making is that these must be measured at the point of use rather than at the compressor room. A plant with a good compressor, a good dryer and thirty-year-old galvanized piping has excellent air at one end and something quite different at the other.
The pipework is usually the problem
When we are called to investigate air quality on an established site, the distribution is the cause more often than the plant is.
Corroded steel mains shed continuously. Older systems in black or galvanized steel carry decades of internal corrosion, and every pressure change and flow surge releases some of it downstream. The air leaving the dryer is clean; the air arriving at the blow-off nozzle is carrying rust.
Low points collect water and nobody drains them. A main that dips to cross an obstruction holds condensate, and that slug arrives at a tool as liquid when flow increases. Drain legs at every low point, and traps that are checked rather than assumed.
Take-offs from the bottom of the main. This is the classic and entirely avoidable error. A branch taken from the underside of a horizontal main collects everything settling in that main. Taken from the top, it does not. It costs nothing at installation and it is one of the most common causes of water and debris at a workstation.
Dead legs from removed equipment. Capped branches left when a machine was taken out hold stagnant air and condensate, and they corrode from the inside with nothing to indicate it.
The remedies are unglamorous: replace corroded mains rather than adding more filtration to compensate, install a ring main so pressure is stable and flow direction is not fixed, take branches from the top, drain the low points, and put point-of-use filtration close to critical operations so that whatever the distribution contributed is removed before the air reaches product.
Energy, which is where the other half of the argument sits
| Continuous load | New Hampshire per year | At the 8.13 cent US average |
|---|---|---|
| 25 kW | $35,500 | $17,805 |
| 50 kW | $71,000 | $35,609 |
| 100 kW | $142,000 | $71,219 |
Compressed air is among the most expensive utilities in any plant because the conversion from electricity to useful work at the tool is poor, and at 16.21 cents per kilowatt-hour, 1.99 times the national average (EIA, 2024), that inefficiency costs twice what it does in most states. Four measures consistently repay the effort here.
Fix the leaks. A leak runs every hour the compressor does, and on an untended system leakage frequently accounts for a substantial share of total output. An ultrasonic leak survey with a tagging and repair program is the highest-return energy work available in most plants and it needs no capital at all.
Lower the pressure to what is actually needed. Systems drift upward over years, usually because someone raised pressure to solve a problem that was really a restriction or a leak. Every unnecessary increment is paid for continuously, and the correct answer is normally to fix the local restriction and let the whole system down.
Stop using compressed air where something cheaper works. Blowing, moving and agitating are frequently done with compressed air because a line was already there. A blower delivers the same effect at a fraction of the energy for many of those duties.
Recover the heat. Essentially all the energy into a compressor emerges as heat, and in a New Hampshire winter that heat has somewhere useful to go. Recovering it to space heating or to process hot water is well understood and it is worth substantially more here than in a mild climate.
Process gases, and what changes
Where the plant also distributes nitrogen, argon or other process gases, the requirements tighten and the reasoning shifts from our Oregon high-purity gas page. Purity is specified against the process, distribution is typically stainless with joints made and documented to a defined standard, and the system must exclude atmosphere rather than merely contain pressure, which makes leak testing a purity matter as well as a safety one.
The safety case runs alongside. Inert gases displace oxygen, and a leak into an enclosed or poorly ventilated space is an asphyxiation hazard with no warning properties at all. Oxygen monitoring in rooms where inert gas is distributed, and attention to where a leak would actually accumulate given the gas density and the room’s airflow, belong in the design rather than in a procedure.
We install compressed air generation interfaces, dryers and filtration, ring main distribution in appropriate materials, point-of-use treatment, nitrogen and process gas distribution, leak surveys and heat recovery, and the monitoring that verifies quality where it matters rather than where it is convenient to measure.
Frequently asked questions
Do you install compressed air and gas systems in New Hampshire?
Yes, across Manchester, Nashua, Salem, Portsmouth and statewide: dryers and filtration, ring main distribution, point-of-use treatment, nitrogen and process gas systems, leak surveys, heat recovery, and quality monitoring at the point of use.
What does ISO 8573-1 specify?
Compressed air purity along three independent axes: solid particles, water content and oil. An air specification is therefore three class numbers rather than one, and asking for clean dry air without stating all three has not specified anything.
Why is pressure dew point a New Hampshire issue specifically?
Because a dew point adequate for a heated plant will drop liquid water in any run passing through an unheated space in winter, and a great many plants have main runs crossing a roof void or an outside wall. The dew point has to be below the coldest temperature the air will actually meet.
Where should air quality be measured?
At the point of use, not in the compressor room. A plant with a good compressor, a good dryer and old corroded piping has excellent air at one end and something quite different at the other, and only point-of-use measurement reveals that.
What causes most air quality problems?
The distribution rather than the plant. Corroded steel mains shed rust continuously, low points collect condensate that arrives as a slug when flow increases, and branches taken from the bottom of a horizontal main collect everything settling in it.
Why take branches from the top of the main?
Because water and debris settle to the bottom. A branch from the underside collects all of it; a branch from the top does not. It costs nothing at installation and it is among the most common causes of water and particulate arriving at a workstation.
Does oil vapor get removed by filtration?
Not by particulate filtration, which does not address molecular contamination. Coalescing filtration handles aerosol and carbon adsorption handles vapor, or an oil-free compressor removes the source. Assuming a particulate filter covers oil is a common and consequential error.
What is the best energy measure?
Leak repair. Leaks run every hour the compressor does and frequently account for a substantial share of output on an untended system. An ultrasonic survey with tagging and a repair program needs no capital and repays itself quickly, particularly at roughly double national energy cost.
Should we recover compressor heat?
In New Hampshire, usually yes. Essentially all the energy entering a compressor emerges as heat, and through a long heating season that heat has somewhere useful to go, whether space heating or process hot water. It is worth considerably more here than in a mild climate.
How do I get a quote for a New Hampshire air or gas project?
Use the form on this page or call 201-450-8280. Useful inputs are the ISO 8573-1 classes required at each point of use, existing distribution material and age, whether any run passes through unheated space, current system pressure, and whether a leak survey has ever been done.
Oil-free or lubricated compressors for a device plant?
Oil-free compressors where the air contacts product or clean surfaces, because they remove the oil source rather than filtering it, and lubricated compressors with staged filtration where the cost difference matters and the air quality class allows. The class the air must meet decides the compressor type.
How are receivers and storage sized?
For the plant's peak short-term demand so that the compressors run steadily rather than cycling with every tool, with wet and dry receivers placed to serve the dryer and the distribution. Storage is the cheapest capacity a compressed air system has.
In what order are compressed air filters staged?
Particulate first, coalescing for liquid oil and aerosol, then activated carbon for oil vapour, then a final particulate filter, each sized for the flow with pressure drop monitored. Filters out of order load prematurely and pass what they were meant to catch.
What point-of-use conditioning does a tool need?
A regulator set to the tool's requirement rather than the main's pressure, a filter matched to the tool's sensitivity and, for tools that need it, a lubricator, with the assembly drained and inspected. Point-of-use conditioning is where the plant's air meets the process.
Ring main or dead-end distribution?
A ring main, which feeds each point from two directions, holds pressure across the plant and allows sections to be isolated for work, while a dead-end branch starves the far tools and cannot be isolated without losing them. Ring mains are the standard for a plant of any size.
How is compressed air condensate handled?
Through automatic drains at receivers, dryers, filters and low points, discharging to an oil-water separator so that the oily condensate is not sent to the sewer untreated. Condensate from a lubricated compressor is an oily waste and is treated as one.
What piping materials suit clean compressed air?
Aluminium or stainless piping that does not corrode and shed, with push-fit or welded joints, replacing the black steel that rusts internally. Material choice is the largest single air quality improvement in most plants.
What does reducing the system pressure setpoint save?
Compressor power falls with pressure, and leaks and unregulated uses draw less at lower pressure, so every reduction in setpoint saves twice. The setpoint is reduced to the minimum the highest-pressure tool needs, with that tool served by a booster if it is alone.
How is compressed air metered?
With flow meters on the main and on major branches, pressure sensors at the far points and power metering on the compressors, trended so that the plant sees its consumption, its leak load and its cost. Air that is not metered is treated as free, and it is the plant's most expensive utility.
How are process gases different from compressed air?
Nitrogen, argon and specialty gases are supplied at a defined purity and the piping must preserve it, which means clean materials, leak-tight joints and, for high-purity gases, orbital-welded stainless. The purity specification sets the piping standard.
How is air used in device drying and blow-off specified?
As product-contact air, with particle, water and oil classes chosen so that nothing is deposited on the part, and with point-of-use filtration and monitoring. The air is a process input and is treated as one.
How does New Hampshire's energy cost affect compressed air?
Industrial power is well above the national average, which makes leaks, over-pressure and inefficient control expensive. Compressed air is one of the most improvable energy costs in a New Hampshire plant.
How is an air system audited?
By measuring flow, pressure and quality at the compressor and at points of use, surveying leaks, and reviewing the dryer and filtration against the classes needed. The audit usually finds leaks and pressure far above need.
What about laser and welding gases in device shops?
Shielding gas purity and delivery pressure affect weld quality on titanium and stainless devices, and the piping from cylinder or bulk to the machine preserves the purity. Contaminated shielding gas produces rejected welds.
What is the commonest compressed air problem in New Hampshire device plants?
Rusting steel piping and winter condensation depositing water and particles on parts at the last step, blamed on the process rather than on the air. Point-of-use measurement finds it.
Air quality or compressed air costs in New Hampshire?
Tell us whether any main runs through unheated space and when you last surveyed for leaks. Those two cover most of what we find. Call 201-450-8280 or use the form below.