Class III Hazardous Areas

The National Electrical Code, or NEC, classifies hazardous areas into three different categories; Class I, Class II, and Class III.  To use equipment in or around these types of areas, caution has to be taken in order to not cause an explosion or fire.  In the U.S., the Underwriter’s Laboratory, UL, can certify products that can be used safely in these hazardous areas.  EXAIR received our UL Classification for our new product line; the HazLoc Cabinet Cooler Systems.  Under certain guidelines, the HazLoc Cabinet Coolers can be used in Class I for gases and vapors, Class II for flammable dust, and Class III for ignitable fibers and flyings.  In this blog, I will be discussing the Class III classified area.

For a fire or an explosion to occur, we need three things as described in the fire triangle; oxygen, fuel, and an ignition source.  For Class III areas, that fuel is a build-up of material like fabric lint and fine wood shavings.  These small fibers can float and collect on equipment in the surrounding areas.  This collection of material can easily ignite and cause a fire from a spark or a heat source, like kindling.  These fibrous materials and flyings are not explosive, but as a collection, they are a fire hazard; the reason for the Class III designation.  This newest hazardous classification is generally located within the textile and woodworking industries.

The ignition source (the second leg of the fire triangle) is generally from electrical equipment, heat, and static.  Arcs and sparks from motors, contactors, and switches can easily ignite Class III materials; as well as high temperatures from equipment.  NEC and UL segregate this hazardous location into two divisions.  Class III Division 1 is in an area where fibers/flyings are handled, manufactured, or used.  Class III Division 2 is where the fibers/flyings are stored or handled other than in the process of manufacturing.  In both divisions, it is important to protect your electrical systems from these small fibers floating in the surrounding air.

EXAIR's Hazardous Location Cabinet Cooler

The EXAIR HazLoc Cabinet Cooler Systems are designed to keep your electrical panels cool within hazardous areas like Class III because system shutdowns from electrical overheating are costly and potentially dangerous.  If you would like to discuss the details about the EXAIR HazLoc Cabinet Coolers, an Application Engineer at EXAIR will be happy to help you.

 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

NEW From EXAIR! The Hazardous Location Cabinet Cooler – For Use In Classified Areas

EXAIR is always focused on releasing new products and improving on existing product lines, and 2018 has been no different! Earlier on this year we introduced the New Super Air Scraper as an accessory to our 2” Flat Nozzles and Safety Air Guns. Just last month, EXAIR has also introduced a new line of products to the Cabinet Cooler family: The Hazardous Location Cabinet Cooler.

hazloc_illLsr-800w

EXAIR’s Hazardous Location Cabinet Coolers are engineered for use with purged (not included) electrical enclosures. The HazLoc Cabinet Coolers are not purged and pressurized control systems and should not be relied upon nor used in place of a purged and pressurized controller. They are meant for use in conjunction with a purged and pressurized control system. These systems have been approved and tested by UL for use in the following areas:

Class I Div 1&2 – Groups A, B, C, and D

  • Class I Areas refer to the presence of flammable gases or vapors in quantities sufficient to produce explosive or ignitable mixtures. Class I Div 1 will have ignitable concentrations of flammable gases present during the course of normal operations. This is level of approval is one that differentiates the EXAIR Hazardous Location Cabinet Coolers from much of the competition. Class 1 Div 2 areas will have flammable gasses or vapors present only in the event of an accident or during unusual operating conditions.

Class II Div 1&2 – Groups E, F, and G

  • Class II areas are locations in which combustible dust may exist. The end user shall avoid installation of the device in a Class II environment where dust may be readily disturbed from the exhausts of the Hazardous Location Cabinet Cooler. Any dust formed in the vicinity of the cooler must be cleaned regularly.

Class III

  • Class III areas are locations that will have ignitable fibers or flyings present. This is common within the textile industry.

The Cabinet Cooler also carries a temperature rating of T3C, meaning it cannot be installed near any materials that could auto-ignite at temperatures in excess of 320°F. For a comprehensive list and description of all of the various Classified areas, check out the UL website.

The Hazardous Location Cabinet Cooler is available in (8) different cooling capacities ranging from 1,000 Btu/hr – 5,600 Btu/hr. The Cabinet Cooler is the best solution for protecting your sensitive electronics from heat, dirt, and moisture. With Nema 4/4X systems available, the Hazardous Location Cabinet Coolers will keep the cabinet cool without compromising the integrity of the enclosure.

If you’ve got an electrical cabinet installed within a hazardous location, fill out the Cabinet Cooler Sizing Guide and allow an EXAIR Application Engineer to determine the most suitable model for you.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

What’s In My Air, And Why Is It Important?

Everyone knows there’s oxygen in our air – if there wasn’t oxygen in the air you’re breathing right now, reading this blog would be the least of your concerns. Most people know that oxygen, in fact, makes up about 20% of the earth’s atmosphere at sea level, and that almost all the rest is nitrogen. There’s an impressive list of other gases in the air we breathe, but what’s more impressive (to me, anyway) is the technology behind the instrumentation needed to measure some of these values:

Reference: CRC Handbook of Chemistry and Physics, edited by David R. Lide, 1997.

We can consider, for practical purposes, that air is made up of five gases: nitrogen, oxygen, argon, carbon dioxide, and water vapor (more on that in a minute.)  The other gases are so low in concentration that there is over 10 times as much carbon dioxide as all the others below it, combined.

About the water vapor: because it’s a variable, this table omits it, water vapor generally makes up 1-3% of atmospheric air, by volume, and can be as high as 5%.  Which means that, even on a ‘dry’ day, it pushes argon out of the #3 slot.

There are numerous reasons why the volumetric concentrations of these gases are important.  If oxygen level drops in the air we’re breathing, human activity is impaired.  Exhaustion without physical exertion will occur at 12-15%.  Your lips turn blue at 10%.  Exposure to oxygen levels of 8% or below are fatal within minutes.

Likewise, too much of other gases can be bad.  Carbon monoxide, for example, is a lethal poison.  It’ll kill you at concentrations as low as 0.04%…about the normal amount of carbon dioxide in the atmosphere.

For the purposes of this blog, and how the makeup of our air is important to the function of EXAIR Intelligent Compressed Air Products, we’re going to stick with the top three: nitrogen, oxygen, and water vapor.

Any of our products are capable of discharging a fluid, but they’re specifically designed for use with compressed air – in basic grade school science terms, they convert the potential energy of air under compression into kinetic energy in such a way as to entrain a large amount of air from the surrounding environment.  This is important to consider for a couple of reasons:

  • Anything that’s in your compressed air supply is going to get on the part you’re blowing off with that Super Air Nozzle, the material you’re conveying with that Line Vac, or the electronics you’re cooling with that Cabinet Cooler System.  That includes water…which can condense from the water vapor at several points along the way from your compressor’s intake, through its filtration and drying systems, to the discharge from the product itself.
  • Sometimes, a user is interested in blowing a purge gas (commonly nitrogen or argon) –  but unless it’s in a isolated environment (like a closed chamber) purged with the same gas, most of the developed flow will simply be room air.

Another consideration of air make up involves EXAIR Gen4 Static Eliminators.  They work on the Corona discharge principle: a high voltage is applied to a sharp point, and any gas in the vicinity of that point is subject to ionization – loss or gain of electrons in their molecules’ outer valences, resulting in a charged particle.  The charge is positive if they lose an electron, and negative if they gain one.  Of the two gases that make up almost all of our air, oxygen has the lowest ionization energy in its outer valence, making it the easier of the two to ionize.  You can certainly supply a Gen4 Static Eliminator with pure nitrogen if you wish, but the static dissipation rate may be hampered to a finite (although probably very small) degree.

At EXAIR Corporation, we want to be the ones you think of when you think of compressed air.  If you’ve got questions about it, give us a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Air photo courtesy of Bruno Creative Commons License

Troubleshooting a Cabinet Cooler Application: Clogged Filter Elements

Recently I’ve worked with a customer who needed to troubleshoot some of his Nema 12 Cabinet Coolers installed in their plant. They’ve been installed for about 6 years now without issue, but over the summer they noticed a few times where the temperatures inside the enclosures was getting a bit higher than they were comfortable with. Since this hadn’t been an issue since prior to installation, they gave us a call to see what could be the problem.

IMG_9331

They had (6) total Cabinet Coolers, (2) of the 4340s and (4) 4325s all being fed from the same compressor. The first thing we wanted to determine was whether or not a sufficient volume of air was being supplied to them. Since this was a new problem and we had several years of operation without any trouble, there had to be something that has changed. With a pressure gauge installed directly at the inlet, he observed that the pressure coming into the Cabinet Cooler was only 70 PSIG. Cabinet Coolers are rated at pressures of 100 PSIG but can operate in the range of 80-100 PSIG, so we knew then that not enough air was reaching them.

When troubleshooting any Intelligent Compressed Air Product, we need to know the pressure DIRECTLY at the air inlet to the product. Oftentimes a customer will know the pressure they’re getting out of the compressor, but this isn’t generally the pressure you’ll see at the point of use. Pressure drops can occur due to undersized lines, restrictive fittings (such as quick disconnects), or improper maintenance.

He shared with me some photos of the setup and said that they hadn’t changed anything since the original installation. These units were operating off of their own dedicated compressor, so we weren’t getting a pressure drop due to any additional applications also using the same air supply.

With no moving parts to wear out the Cabinet Coolers are a maintenance-free product, so long as they’re supplied with clean and dry compressed air. In order to ensure that the air supply stays clean and dry, an Auto-Drain Filter should be installed just upstream of the Cabinet Cooler. Inside of any of EXAIR’s Auto-Drain Filters is a 5-micron filter element. If this becomes clogged over time, it can result in a pressure drop just after the filter. This turned out to be the culprit in this case as he placed an order for some replacement filter elements, changed them out, and was back up and running! The pressure at the Cabinet Coolers increased to 90 PSIG and started operating as they had before.

built to last 5 year

EXAIR prides ourselves in delivering a quality product that’s Built to Last. If you have a product that doesn’t seem to be operating at peak performance, give us a call. An Application Engineer is ready to take your call and help make sure you’re getting the most out of our products.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Going Outside The Box With Vortex Tubes

Among EXAIR’s comprehensive line of Intelligent Compressed Air Products, the Vortex Tube stands out as a unique, and fascinating, solution for a variety of applications requiring a flow of cold air:

  • Cabinet Cooler Systems: clean, cold air to protect electrical and electronic components housed in an enclosure.  Installs in minutes; no moving parts; reliable & maintenance free.
  • Cold Gun Aircoolant Systems:  Direct, focused flow of cold air to replace messy coolant in machining, cutting, drilling, grinding, etc., applications.  Integral magnet base for quick & easy installation; single or dual outlet hose kits; standard or High Power to meet any need.  Optimized flow for maximum cooling and freeze prevention.
  • Adjustable Spot Cooler: Similar to the Cold Guns in many ways, but with variable performance for specific applications.  Cold air to -30°F (-34°C) on demand.
  • Mini Cooler: Similar to the Cold Guns and Adjustable Spot Coolers – magnetic base mounting and single or dual outlet hose kits, but more compact.  Lower flows for smaller jobs.

Then there are the Vortex Tubes themselves…at the heart of all of these products, but perfectly capable all on their own.  In fact, in certain situations, “plain old” Vortex Tubes have been used to do the exact same jobs as all of the above products.  They can even be customized, in and of themselves, to meet specific installation, operation, and/or performance needs:

  • High Temperatures: It should come as no surprise that cold air is often needed because a heat-sensitive item is located in a high heat environment.
    • Vortex Tubes come standard with plastic Generators and Buna o-rings, which are good for ambient temperatures up to 125°F (52°C).
    • High Temperature Vortex Tubes are fitted with brass Generators and Viton o-rings for environments where the temperature can reach 200°F (93°C).
High Temperature Vortex Tubes are suitable for use in environments up to 200F (93C).
  • Preset temperature & flow: Many times, the ability to adjust the performance of a Vortex Tube is a big benefit, but occasionally it’s a liability.
    • I know none of your co-workers are like this (nor are mine) but I’ve heard of people who think they “know better” and are prone to tampering with something that is (or WAS) working just fine, thank you very much.
    • Perhaps you actually DO know better, through experimentation and experience, the optimal performance setting for your application.  Let’s say, for example, you install Vortex Tubes on a line of your products, and a technician has to “dial it in” to a specific Cold Fraction.
    • Any Vortex Tube can be fitted with a drilled orifice (or “Hot Plug”) to replace  the Hot Valve, which presets performance to a specific, non-adjustable value.  If you know the Cold Fraction you need, it’s as easy as that.  If not, it’s as easy as getting a stock Vortex Tube, setting the Cold Fraction where you want it, securing the Hot Valve in position (piece of tape works just fine,) and sending it in.
Preset Vortex Tubes feature a fixed plug, replacing the Hot Valve shown in this picture.

If you’ve got any other specific requirements – special materials, fittings, custom flow/temperature parameters, etc., give me a call; let’s talk.

Russ Bowman
Application Engineer
EXAIR Corporation
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Special Cabinet Cooler Options – High Temperature, Non-Hazardous Purge and Type 316 Stainless Steel

Recent blog discussions about the EXAIR Cabinet Cooler Systems have covered many topics including correctly sizing one, the NEMA ratings, and how-they-work.  In this blog I will review three special options that are available for the most extreme environmental conditions- high temperatures, dirty environments, and harsh or corrosive areas.

High Temperature – For enclosures that reside in high temperature ambient conditions such as near furnaces, boilers, or ovens, EXAIR offers a High Temp version, with special internal components designed to withstand the elevated temperatures.  Cabinets near sources of high heat certainly need to be kept cool, and the EXAIR High Temperature Cabinet Cooler is specially suited to for use in these locations.

ht2ccPR_559pxwide
High Temperature Dual Cabinet Cooler System

Non-Hazardous Purge (NHP) – Cabinet Cooler Systems with this feature provide a continuous positive purge within the enclosure to prevent contaminants from entering through small holes or conduits.  Especially suited for dirty and dusty environments, the NHP Cabinet Cooler Systems provide a slight positive pressure inside the enclosure. This is done by passing 1 SCFM (28 SLPM) of air through the cooler when the the solenoid is in the closed position. When the thermostat reaches the set-point temperature and energizes the solenoid, the full line pressure of air is delivered to the Cabinet Cooler providing the full cooling capability, and still keeping the positive pressure.  When the internal temperature cools to the set-point, the solenoid closes and the system returns to the 1 SCFM (28 SLPM) of air flow condition.

nhpcc_300x
Non-Hazardous Purge Cabinet Cooler for Dirty, Dusty Environments

Type 316 Stainless Steel NEMA 4X Cabinet Coolers – For enclosures that are in food service, pharmaceutical, harsh, and/or corrosive environments, and any application where 316 stainless steel is preferred, the Cabinet Coolers are available in the Type 316 stainless material. The systems are UL Listed for wash down environments, ensuring the enclosure electrical contents remain cool and dry under any condition. Noted applications include on ocean going ships, power plants, medical device manufacturing facilities, and bakeries.

316SSCC_sq800
Type 316 Stainless Steel NEMA 4X Cabinet Cooler System

Please note that the High Temperature, Non-Hazardous Purge and Type 316 Stainless Steel Cabinet Coolers are each available from stock!  No waiting for these special models.

To discuss your application and how a Cabinet Cooler System or any EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR, myself, or one of our other Application Engineers. We can help you determine the best solution!

Brian Bergmann
Application Engineer

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Let’s Size A Cabinet Cooler System!

I can’t remember the last time I put an exclamation point in the title of my blog, but it was probably the last time I got to talk about doing math. Or write about heat transfer.  Insert your favorite engineer joke here…I’m sure I have it coming.

We’re in the dog days of summer (in the Northern Hemisphere) for sure…or, as we call it, “Cabinet Cooler Season.”  If you’re having heat related problems with a control panel, give us a call; we can help.  If you’d like to know what we’re going to talk about, read on.

Heat can cause real problems for electrical and electronic components, in a hurry…we all know that.  Fortunately, we can also specify the right Cabinet Cooler System for you in a hurry too.  And since we keep them all in stock, we can get it to you in a hurry as well.

You can access our Cabinet Cooler Sizing Guide online, here.  You can fill in the blanks and submit it, or you can call in your data.  We do it over the phone all the time, and it only takes a minute.  Here’s what we’re going to ask for, and why:

Enclosure dimensions.  We need the length, width, and height of your enclosure to calculate the heat transfer surface, and the volume of the enclosure.

Current Internal Air Temperature.  How hot is it inside your enclosure?  This is the starting point for figuring out the internal heat load…how much heat the components inside the box is generating.  This needs to be the air temperature – don’t use a heat gun, or you’re going to give me the surface temperature of something that may or may not be close to what I need.  Just put a thermometer in there for a few minutes.

Current External Air Temperature.  How hot is it in the area where the enclosure is located?  We’re going to compare this to the internal air temperature…the difference between the two is actually proportional to the heat load.  Also, if there’s anything cooling the enclosure right now (like circulating fans; more on those in a minute,) this reading is key to figuring out how much heat they’re removing.

Maximum External Air Temperature.  How hot does it get in the area on, say, the hottest day of summer?  We’ll need this to calculate the external heat load…how much heat the enclosure picks up from its surroundings.

Maximum Internal Temperature Desired.  Most electrical and electronic component manufacturers publish a maximum operating temperature of 104F (40C) – it’s kind of an “industry standard.”  Based on this, a lot of us in the enclosure cooling business set our products’ thermostats to 95F (35C) – if we’re maintaining the air temperature a decent amount cooler than the components are allowed to get, history and practice has shown that we’re going to provide more than adequate protection.  If your enclosure houses something with more sensitive temperature limitations, though, we can work with that too…that’s the only time you’re going to want to put something other than 95F (35C) in this field.

Cabinet Rating.  This is all about the environment…we offer three levels of protection, per NEMA standards:

NEMA 12 – oil tight, dust tight, indoor duty.

NEMA 4 – oil tight, dust tight, splash resistant, indoor/outdoor duty.

NEMA 4X – oil tight, dust tight, splash resistant, corrosion resistant, indoor outdoor duty.

The NEMA rating does not affect the cooling capacity at all.

Other:  If the enclosure is mounted to the side of a machine, or a wall in the plant, you really don’t need to put anything here.  If it’s outside and exposed to direct sunlight, tell us what the surface finish (i.e., polished metal, painted grey, etc.) is so that we can account for solar loading too.  If anything else is unusual or peculiar about the application, let us know that too.

My Cabinet Is…Not Vented, Vented, Wall Mounted, Free Standing, Fan(s).  We’ll use what you tell us here to verify heat transfer surface (a wall mounted cabinet’s back surface isn’t a radiative surface, for example.)  Also, I mentioned fan cooling before, so without further ado…

Fan diameter or SCFM.  If there are fans circulating air into (and/or out of) the enclosure, they’re providing a finite amount of cooling right now.  Proper installation of a Cabinet Cooler System is going to require their removal.  Running a Cabinet Cooler System on a vented enclosure is just like running your air conditioner with the windows open.  So, if we know the size (or the SCFM…sometimes there’s a label on those fans, and we LOVE those folks who do that) then we can use that, and the temperatures you gave us above, to take the fan cooling into account.

Once we have all this information, it’s down to the math. Like I said, we do this all the time (especially during “Cabinet Cooler Season”) – give me a call.  Your heat problem isn’t waiting; why should you?

Before I go…here’s a nice little video, walking you through the Cabinet Cooler Sizing Guide.  Yes, I just made you read the book before watching the movie…feel free to tell me which one you liked better.

Russ Bowman
Application Engineer
EXAIR Corporation
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