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What is the Difference Between an AMU & an MUA?

Maintaining good indoor air quality and balanced air pressure is essential for a safe and healthy working environment in any shop. When you operate a paint booth in your shop, it can create problems with indoor air pressure and quality if you do not take precautions. This is especially true in smaller areas where the pressure changes caused by a paint booth can quickly affect the air in the entire building.

Fortunately, there are two ways to maintain good air quality and proper air pressure: providing make-up air (MUA) to the shop or adding an air makeup unit (AMU) to the paint booth. Understanding the operational differences in these solutions as well as the potential benefits can help you determine which option is right for you.

Paint Booth Operation Causes Negative Air Pressure

During paint booth operation, air is exhausted from the booth. While it is necessary to exhaust air in order to exhaust the overspray from painting, this process can quickly change the volume of air in the booth, causing negative air pressure to develop.

There are several problems that negative air pressure can cause:

  • A vacuum effect that pulls dirt and debris into the paint booth
  • Uneven curing of the finish on painted items
  • Poor indoor air quality
  • Drafts and temperature fluctuations
  • Suction that makes the doors and windows hard to open

To restore balanced air pressure inside the booth, air must be added back in to replace the air that is exhausted.

Make-Up Air Balances Shop Air Pressure

To make up the air pressure inside the paint booth, you need to pull in new air to replace the exhausted air. In some setups, a booth will replace exhausted air by drawing in air directly from the shop’s interior atmosphere. However, pulling the shop’s air into the booth can cause changes to the pressure of the shop at large. In a small building, normal paint booth operations can quickly lead to negative air pressure in the entire shop.

Make-up air (MUA) is intended to replace the air from the shop that is used and exhausted by the paint booth. MUA solutions sometimes function as part of the HVAC system to draw replacement air from the outside. It could also function without a HVAC system to push air into the building. This extra ventilation restores air pressure and improves the overall quality of air inside the shop.

An Air Makeup Unit Provides Additional Benefits

A more popular option is an air makeup unit (AMU) which balances air pressure and improves air quality by providing replacement air into the booth itself. An AMU is designed to provide the right amount of air into the paint booth to balance the volume of air exhausted.

Many AMU models offer the ability to heat the air for a temperature-controlled spraying environment. The heating feature allows the AMU to be put into “cure” mode. When in this mode, the paint is cured (or baked) at a very high temperature and is done in less than an hour. This feature increases the production capacity of any shop.

  • Providing replacement air directly into the booth eliminates negative air pressure in the shop
  • AMUs can reduce the amount of dust and other particles that can ruin the paint finish
  • Temperature-controlled air can reduce the time it takes for a finish to cure, especially in colder environments

In large shops that have more than one paint booth, installing AMUs for each booth provides more functionality than simply getting a single MUA solution for the shop itself.

Deciding Between an AMU and an MUA Solution

Paint booth operation creates air movement due to exhaust, and that air must be replaced to avoid issues caused by negative air pressure. A MUA shop solution provides replacement air to the interior of a shop, improving ventilation and reducing air pressure problems. An AMU provides air within the paint booth itself to balance the air pressure. Heated AMUs control the temperature inside the booth with warm air and can run cure cycles that ensure faster, consistent curing.

Standard Tools designs and builds the Sure-Cure AMU and MUA for these different air replacement circumstances. The units are built to a shop’s specific gas and power, CFM requirements and installation prerequisites. Although Standard Tools is a paint booth manufacturer, the Sure-Cure AMU can be built to be compatible with any brand paint booth. All of our air-replacement solutions improve the air quality and production level of a shop. Contact an expert at Standard Tools to get more information on the Sure-Cure AMU and MUA. The team can help you figure out which solution is best for your shop.


What Are the Benefits of an AMU?

Adding an Air Makeup Unit to a paint booth can provide several unique advantages that increase overall productivity and improve finish quality. While the basic function of an AMU is fairly simple, the number of benefits it offers is impressive. An AMU provides a solution to issues created by the air pressure imbalances that can occur during paint booth operation.

Counteracting Negative Air Pressure

During operation, the exhaust system of a paint booth utilizes and then expels a large volume of air. This significant amount of air movement can quickly create an imbalance of air pressure. When air leaves the inside of a booth without being replaced at the same rate, the internal air pressure quickly becomes lower than the external air pressure. A negative air pressure situation such as this can cause several adverse effects:

  • Strong drafts, especially around windows and doors
  • Low-quality indoor air
  • Imperfect paint curing
  • Malfunctioning exhaust fans
  • Poor temperature control
  • Suction pressure that makes doors difficult to open

The Air Makeup Unit fixes these issues by addressing the underlying cause: negative air pressure. The AMU provides air to a paint booth at the proper rate to replace the air that’s lost through exhaust. Many systems can automatically balance the pressure by making small adjustments to offset pressure changes such as a door opening.

Removing Air Particulates

SureCure Vertical AMU

The pressure and quality of the air inside a paint booth can have a significant effect on the overall finish of the coating. When there is negative air pressure inside the booth, it is easy for dirt and debris to be pulled in when a draft occurs. If the air inside the booth becomes contaminated with particulates, it can severely impact the condition of the final product.

An AMU provides clean, filtered air to a paint booth, improving the overall air quality and reducing particles and debris that can compromise the finish of the coating. This setup may also improve the overall air quality in the building itself, because there is no longer a need to draw unfiltered outdoor air inside to address pressure inequalities.

Reducing Curing Time

An AMU can improve productivity by reducing the time it takes to complete a project. It can take an inordinately long time for a finish to cure in cold air. Some AMU models have a heating option that can provide warm air to the booth, creating the ideal environment for optimal curing efficiency. A heated AMU may be especially helpful during the winter months to eliminate prolonged curing times due to cold temperatures.

Improving the Working Environment

An AMU can significantly improve the operation of a paint booth, enhancing both efficiency and finish quality. In addition, there are other advantages that an AMU can provide:

  • Faster curing time
  • Reduced load on a building’s HVAC system
  • Improved indoor air quality
  • Lower energy requirements
  • Less risk of personnel injuries from pressurized doors

Managing shop conditions and ensuring finish quality is easy when there is an AMU system controlling pressure and air quality.

Choosing the Right AMU

Adding an AMU to your paint booth is a simple way to improve your productivity, cut production costs, and ensure exceptional quality on all your finishes. There are several models available, and each one has unique advantages. Contact us to learn about all the options and determine which one is the best solution to your needs. You can give us a call at 888-312-7488 or email us at sales@paint-booths.com.

TOP 10 THINGS TO THINK ABOUT BEFORE ORDERING YOUR PAINT BOOTH.

When looking to buy a paint booth, there are a lot of factors to consider. It may seem overwhelming, but we’re here to help! Here’s our top ten things to consider when buying a paint booth. Considering these things will help you to determine what booth is right for you and will save you a lot of money and heartache by considering them BEFORE you buy your booth.

1. What are the dimensions of the building? We need to know the dimensions of the space you plan to put the paint booth. How tall are the ceilings?

2. What type of booth you are interested in? We have different styles of paint booths. From open-faced booths to large and enclosed truck booths. We have different air flow styles as well, from cross flow and side-down draft or semi-down draft or down draft … if you have a type or style you’re looking for, be sure to let us know. If you don’t know what type or airflow style would work best for you, no problem… our sales folks can help you determine the best booth to meet your painting needs.

3. What phase and/or voltage run through your building? We need to know the kind of power you have so we can make sure that your paint booth and/or your air makeup unit is designed to work in conjunction with it. Did you know that the majority of the time you can contact your power company and they can give you this information if you are unsure?

Packaged booth additions4. Do you need ductwork? Do you know how much ductwork will you need? One of the reasons we need to know the height of your building is because we need to determine how much ductwork is needed from the top of your paint booth straight out of the roof, plus some! In most states it is required that there is 6’ of ductwork exhausting up from the roof.

5. Are you adding heat to your booth? There are several benefits to decide on a heated paint booth. Heat makes it a more comfortable environment in the winter, but that is not why the majority of our customers decide to add heat. Sometimes, there isn’t enough airflow in the business to provide for the booth. (Click here to see if that applies to you). When you have a Sure-Cure AMU, you are able to significantly increase your production. You are able to paint, cure and cool in less than an hour, making your new booth the hardest working part of your business!

6. Have you contacted your city to find out what is required in your city or in your state? It’s important that you know before you order your booth what is required from your city or in your state. Find out what permits you will need and if there are special requirements, like and ETL-listed booth that you have to comply with. For example, if you have to have an ETL-listed booth, but you order a non-ETL booth, you will either have to order a new booth (that we offer already with ETL) or you will have to pay big bucks to have someone come and certify it. To be absolutely safe, you can always request that a fire marshal come and do a walk-through to advise you what you need to consider prior to ordering your booth.

7. Does your state require you to have fire suppression? It is extremely important to know the answer to this question so you can properly plan. Call your local authorities and get informed. We offer Fire Suppression systems from PyroChem or you may be able to provide a sprinkler system.

STE_SD1000WC8. Do you want your booth powered-coated booth? Not only will your booth be a lot brighter, but it will also stand out and have a professional look to it. See how our booths are powder-coated.

9. Get everything you need in one quick swoop. We offer light bulbs for all of the booth’s light fixtures, as well as the electrical wiring kits that your electrician will need to wire your booth. Get everything ordered and shipped to you to setup and start using your booth. Easily add a supply of intake or exhaust filters to your order so that when they need to be changed, you have them on hand.

10. What other features can I add to my booth? Is there something you want on your paint booth like drive-thru doors, a connected mixing booth or extra lights? One thing that Standard Tools and Equipment does well is our ability to produce custom paint booths. Our engineers can design a booth to fit your needs. If you want your booth taller, wider or brighter… just let us have the opportunity to design your booth for you.

How to determine if a make-up air system is required: It’s simple math

Anytime a paint booth is installed in a building, the amount of exhausted air must be a consideration.

For example, a booth exhausting 13,000 cubic feet per minute installed in a building measuring 50 x50 x 15 (37,500 cubic feet), the air will change every two minutes. This produces a negative pressure condition on the building that can cause safety issues. If the building is equipped with gas-fired unit heaters, the negative pressure condition can actually pull gas from the pilot valves and put raw gas into the room. NFPA-33 addresses this with a calculation.

NFPA-33 A.7.3 “If the volume of the room or building where the exhaust system is located is not at least equal to 20 times the volumetric capacity of the fans (three air changes per hour), then additional make-up air should be provided.”

Going back to the 13,000 cfm exhaust fan. 13,000 x 20 = 260,000 cubic feet. The room would have to be 110’ x 110’x 20’ (264,500 cubic feet).

The rule of thumb is to provide the same amount of air being exhausted with some adjustment in the unit to provide the customer with the proper pressure he requires. Some may want slightly more positive pressure while some may want a neutral pressure building.

Sure-Cure Air Makeup Unit
Sure-Cure Air Makeup Unit

Make-up air units can be placed outside or inside as long as the intake air is drawn from the outside. The control panels are mounted inside the building and can be interlocked to the paint booth to operate simultaneously. If you want more information on the Sure-Cure units from Standard Tools and Equipment, visit us online.

The ductwork is simple, the discharge duct should be equipped with a diffuser to help distribute air more evenly into the room.

If you have any questions, give us a call and we’ll gladly assist in determining if more makeup air is needed. 800-312-7488.

MANIFOLDING SPRAY BOOTH DUCTWORK AND IMPROPER AIRFLOW

Spray booth exhaust ductwork

In this photo, an installer has chosen to manifold three spray booth exhaust duct runs. (A manifold is a pipe or chamber branching into several openings.)

This layout probably looked great on paper and reduced the number of roof penetrations from three to just one.

Reality is such as nasty teacher.   The static pressure (resistance to the flow of air) was greater in the top portion of the ductwork than in the spray booths.  The ductwork downstream from the manifold point (above the joints) should be much larger than what is in the photo.   The air ventilated out of one booth actually flows into its neighbor.

Our booths are designed to meet specific airflow needs and we design them with ductwork. The spray booths in the photo were designed to have individual exhaust ductwork runs; they were not installed according to the design or instructions provided by Standard Tools.

Manifolding of exhaust ductwork is allowed by NFPA-33 only if devices exist in the ductwork that detect improper airflow.  The static pressure within the spray booth will change as the overspray builds up in the exhaust filters and as the obstruction within the booth changes (based on size and shape of parts in the spray booth).  This can be very technical and overly-complex.  The simple rule, and what Standard Tools recommends, is no manifolding of exhaust ductwork.  Keeping ductwork simple is the least expensive and best performing strategy in the long run. We suggest that you install your booth, and your ductwork, according to our recommendations to ensure proper airflow within your booth.

A Bigger State-Of-The-Art Air Makeup Unit

Leading North Carolina paint booth manufacturer announces the big brother to their Sure-Cure® Air Makeup Unit Line

SureCure26K-500February 20, 2015 – GREENSBORO, N.C.—Standard Tools and Equipment Co. has been designing and manufacturing paint spray booths since 1997 and has built over 18,000 paint spray booths. In October of 2013, the company announced the release of their own air makeup unit (AMU), the Sure-Cure® AMU Ignite, available in 10K – 14K CFM with ETL certification.

Standard Tools and Equipment began 2015 with the release of the Ignite’s big brother, the Sure-Cure® AMU Inferno. Available in 17K – 26K CFM, it is also ETL certified and available for larger paint booths and truck booths.

Both units are designed, manufactured and sold by Standard Tools and Equipmen­­t from the Greensboro, North Carolina plant.

“The launch of the Sure-Cure AMU Ignite in 2013 was successful, we were selling units before we even announced the development. We got such positive feedback from our customers on our unit and our shipping times, that we got right to work designing the larger unit,” said Standard Tools and Equipment Co. CEO Michael Kestler.  “We continue to offer products to our customers that meet our high standards of excellence at an affordable price. Our AMU line provides them a safe and reliable unit with all the bells and whistles included in the marketed price. With the addition of the Inferno unit, we can provide a unit for any size booth they may have.”

One of the gaps in the market that the company noticed was the extremely long production times in ordering an AMU. We could design, customize, build and ship a paint booth in less than 10 days but our customers were waiting months for their air makeup units, which were sourced out at the time.

After some research, Standard Tools and Equipment decided that they wanted to start developing their own units. They were determined to make their air makeup units safer and quicker …  to meet the needs of their customer.

“We have built an extraordinary unit that can be built to the customer’s specifications, and shipped within just 2-3 weeks,” John Mauney, Director of Manufacturing at Standard Tools and Equipment Co. “We’re offering our customers the opportunity to be up and running quicker. We understand that they have a business to run and we want to help them do that.”

For Standard Tools and Equipment, that’s exactly how they began to make paint booths back in 1997. “We noticed a major need and as a player in the industry for many years, we already had all the right components to meet that need,” Kestler said.  “We have used our experience to develop over 18,000 booths that are unsurpassed in performance and value for our customers.”

As one of the largest Paint Booth manufacturers in the United States, Standard Tools and Equipment Company pulled together everything they had learned over the last 15+ years to develop air makeup units. Safety was important as the company started to plan out how their unit would be different than others on the market. Many safety features complete this AMU, including flame failure reset, multi-service disconnect and a low-flame auto setting at the loss of power. Their units are designed to be the safest available on the market today.

For more information on the Sure-Cure AMU products, visit https://www.paint-booths.com/category/paint-booth-air-make-up-units.html

Baby Its Cold Outside!! — Air Makeup Units

A favorite song of the winter holidays is ‘Baby, Its Cold Outside’.  The crooners of the 1960s like Dean Martin, Andy Williams and Ann-Margret make this a fun song to hear.  The fellow in this song reminds his girl of all of the problems of a cold winter night as she keeps trying to talk herself into leaving.

As we are bracing for this “Arctic Blast” about to hit us on the East Coast, we’re thinking of all those painters that have to open the building doors when the spray booth is used … and Baby, Its Cold Inside Too!!

At Standard Tools, we make heated air makeup units that can be added to your current system.  Spray booths with intake plenums (or intake canopies) can be directly ducted to our Sure-Cure AMU system. Cross-flow or open-face booths can be supplied with Sure-Cure AMU systems designed to put heated air right into the building.

  • The Sure-Cure direct-gas-fired units can be heated with liquid propane or natural gas.
  • The units are ETL-listed to USA and Canadian safety standards and are designed to provide tempered air (for spraying) and up to 160-F for curing.
  • When ordering your unit, there are many options about power, layout and orientation.
  • Systems are available from 10,000 cfm to 26,000 cfm.
  • We offer ducting components and wiring harnesses.

The best part is that your unit can be built to your specifications and ready to ship to your facility in just a few weeks.

Stop opening the building doors to bring in the freezing air.  OSHA requires a permanent spray area to be at least 65-F.  Most coatings do not work well at colder temperatures, which can lead to poor quality and poor productivity.

Visit our website or call our Sales team for more information.

Air Makeup Units (AMUs) Are HUMMIN’

AMU production 1014 (2)amu production 1014It’s going to be 85 in Greensboro, NC today, but cooler weather is just around the corner!  How do I know that?  Well, I just walked through our Sure-Cure air makeup unit (AMU) production shop, and things are hummin’.  We have four units on the bench in process and several more in the queue this week. These Sure-Cure AMU’s are in big demand.  ETL-certified and tested, they are among the safest units on the market today.

The Sure-Cure will provide gas-heated warm air inside your spray painting booth to speed curing time, even on the coldest days!  With a guaranteed 80 degree rise over ambient air temperature, if it is 0 degrees outside it will be 80 degrees inside your booth!  No more waiting hours or days for dry time.  Plus you can put it into cure mode at the end of the day and go home.  The unit will shut off automatically when the paint is cured.

If you have an Air Makeup Unit that is more than 10 years old you may be a candidate for a new high-efficiency Sure-Cure AMU.  Many of the old style Air Makeup Unit’s contain heat exchangers that can crack over years of use.  This greatly reduces the ability of the unit to heat the air to the desired temperature.  It could also result in dangerous fumes being emitted into your booth or painting area!

Our units are popular because Standard Tools is committed to a 2 to 3 week turnaround in producing these units, even in the winter months.  Other manufacturers take 8 to 12 weeks to ship an AMU!  So get your order in today, and be ready for the cold when it gets here!

PAINT BOOTH AIR FLOW: HOW IT WORKS

During spray jobs in a paint booth, the exhaust system must draw substantial quantities of air out of the shop in order to operate. These volumes must be replenished with equal volumes of air coming into the booth.

STE_AMU Full CornerAIR MAKE-UP (AMU) is defined as…a mechanical means of replacing air that has been exhausted out of the booth.

It’s simple…. it’s all about paint booth air flow. How much air in being put into the booth and how much is being taken out. Airflow while spraying takes the over-spray away from the paint job and out of the booth.

Air in – Air out. Air in – Air out. Air in – Air out. Air in – Air out. That’s it. With the Sure-Cure Air Makeup Unit, you control the amount of air pushed into your booth. Why would you need to push air into your booth?

NEGATIVE AND POSITIVE BOOTH PRESSURE
When the exhaust fan of the booth is turned on, it creates a “negative” air pressure in the booth cabin (taking out more air than is being put in). When there is a negative air pressure, the booth will try to suck in as much air as possible, including dirt and debris from outside the booth. THINK VACUUM CLEANERS.

To counter this “negative” pressure, an Air Makeup Unit (AMU) unit is used to supply air to replace the air being exhausted. If the AMU is designed to force more air into the booth than is exhausted…the booth is said to have “positive” air pressure. In this case, the booth has more air than outside the booth and when a door is opened, dirt and debris is pushed away from the booth. THINK STANDING IN FRONT OF A FAN. Continue reading PAINT BOOTH AIR FLOW: HOW IT WORKS

Should you replace your Air Makeup Unit? Things to consider.

So, you have a heated booth, had it for years. Does it still work? If it does, is it working like it should? Maybe it’s time to look at a new heater and take advantage of the latest technology that will not only save you time, but money as well. (Have no idea what I am talking about? Read our post here about what makeup air is).

A heater that was manufactured ten years ago will not have the same technology or controls as a new unit because there have been many advances in the last decade. (Imagine using a cell phone from 10 years ago to do what you needed today…).

Can you control the temperature? New units have digital temperature read outs for the desired and measured temperatures. This is important information that can save you money. If the outside temperature is 75 degrees, then the burner may not be required. Without the temperature reading, your painter may be turning on the heat out of habit not necessity.

Does your unit have a cure mode? If so, is the airflow reduced during the cure cycle or are you helping to heat your town and fund the gas company? New units will reduce airflow by as much as 50% to increase burner efficiency and keep the heat in the booth longer to provide more even heat flow around the product.

Timers. New units will also have timers in the cure mode so the flash, cure, and cool down are controlled automatically, and at the end of the cure process, the booth and heater shut off automatically. This alone will save a shop 10% in fuel costs.

How are your burners? If the heater you have has a cast iron burner, chances are that the orifices are partially rusted, preventing your burner from operating to its maximum efficiency. Some burners may be closed by as much as 50%. If your booth takes a long time to heat or does not reach temperature on very cold days, this may be AMU-OutsideDoublethe problem. Most new burners, including ours, have aluminum burners that will not rust over time.

Do you know your booth pressure? Do you have control over the exhaust fan motor, or does it run full speed all the time? New heaters are designed with variable frequency drives that lets you control the speed of the exhaust fan with the turn of a knob and a pressure gauge will display the actual pressure in the booth. This system translates into longer run times between filter changes and more control over the booth pressure.

If you have an older booth and you want to update your heater, or add a heater to a currently un-heated booth… give us a call and we will walk you through up-fitting your booth with the Sure-Cure Air Makeup Unit (the newest AMU to hit the market. Manufactured by a leading paint booth manufacturer.) Our Sure-Cure AMU has a ton of safety features as well as all the latest technology to provide you with an efficient heated booth. Let our design team get to work for you.

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