FAQ CATEGORY: System Design

System Design

What Is Source Capture Of Dust And Fumes?

Source capture describes dust and fume collection practices that are point solutions. They grab particulates at the source, preventing them from exposing workers, damaging equipment and threatening regulatory compliance. The alternative to source capture is ambient capture, a facility-wide solution to continually clean and turn over air from an entire facility. Source capture offers particular benefits, including the following:

  • More efficient capture - Grabbing particulates at the source much less airflow than ambient capture. This results in lower energy use and, over time, major cost savings.
  • Reduced exposure for workers - When harmful particulates are captured at the source, they don’t have a chance to threaten workers. Many particulates in dust and fumes are breathing hazards for workers, and exposure can lead to serious health effects, including death. Allowing those particulates to travel throughout a facility before capturing them is a health hazard.
  • Improved regulatory compliance - Many substances found in dust and fumes are highly regulated by OSHA. For example, hexavalent chromium, a common byproduct of welding stainless steel, carries a very strict OSHA standard (2.5 micrograms per cubic meter of air). Capturing fumes like these at their source ensures that a manufacturer meets these standards.

What Is The Best Source Capture Solution For Manual Cutting And Grinding?

The best source capture solution in these cases would be a dust collector that provides powerful suction, easy maintenance and low energy use. The best solution depends on your particular operation. Here are the best options:

  1. For a single cutting or grinding station, a portable collector would work well. Units such as the VentBoss collectors go where you need them and offer most of the features of larger units, including compressed-air cleaning and built-in spark arrestance. Portable welding ventilation units can be attached to a wide range of fume arms, providing great flexibility.
  2. Backdraft or downdraft tables are also great source capture solutions for cutting or grinding operations. These tables provide a functional work surface and powerful suction that pulls dust away from the worker’s breathing zone. These tables can include their own filtration units, be connected to a portable collector or can be ducted into a larger collection system.
  3. Large dust collectors like RoboVent’s Senturion collector can provide efficient filtration for an entire facility. A powerful unit like this can be ducted to many different cutting or grinding stations.

No matter what solution you choose, it is vital to control dust and fumes in the workplace, especially if it involves metalworking. Many of these dusts are toxic and pose serious dangers to workers. What’s more, these dusts also carry specific regulations from the Occupational and Safety and Health Administration (OSHA). For example, metals like cadmium, nickel and aluminum have individual exposure limits, set by OSHA.

What Is The Best Dust Collector To Pair With A Fume Arm?

A fume arm is a versatile solution for dust and fume collection and can be attached to a variety of dust collectors including centralized systems, standalone units and portable systems.

Fume arms generally have one of two diameters: 6 inches or 8 inches. The 6-inch arm requires around 600-750 CFM (cubic feet per minute) of airflow, while the 8-inch arm requires 1,000-1,200 CFM.

Fume arms are often connected directly to portable dust collectors, creating powerful solutions such as RoboVent’s PowerBoom device. These systems effectively eliminate fumes at their source, protecting welders and workers throughout an entire facility. The best collectors can be configured to run only when an operation is running, limiting energy use and maintenance costs.

Fume arms can also be ducted to centralized dust collection systems.
The RoboVent Senturion series provides powerful filtration for centralized ducted systems.

Will A Centralized System Extract Dust And Fumes Equally From All Intake Points?

When designed properly, a centralized system will indeed collect fumes equally well from all of its intake points. Air quality engineers are experts in these matters and take many variables into consideration. These variables include:

  • The size of each intake point and how close the intake points are to the collection unit.
  • The number of intake points. More intake points will require more horsepower from the motor.

The gates on a duct system are like valves, and they should be sized according to how close they are to the source of suction (the dust collector)—closer gates will be smaller than ones farther away. Sizing gates in this way, an engineer will balance a system so that every dust- or fume-generating application gets the amount of suction it needs.

What Is The Capture Efficiency Of A Backdraft Or Sidedraft Table?

The capture efficiency of these units depends a lot on surrounding air current patterns. If the area is turbulent, it will cut into the capture rate. For example, if the backdraft table is next to a garage door that is often open, it won’t work perfectly. This turbulence will disturb the suction and could prevent some of the weld fumes from being captured.

On the other hand, a backdraft table that is well placed will perform with a high capture rate. A table that is enclosed in some way could be expected to capture 90-100% of weld fumes.

What Is The Capture Rate Of A Fume Arm?

Fume arms have a long history of effectively abating weld fumes in industrial operations. If a welder is working on a small piece in the same location, over and over, a fume arm, such as PowerBoom, can capture nearly 100% of weld fumes.

If pieces being welded are large, a different solution might be more appropriate. In this situation, a welder is constantly moving, and the fume arm must be continually repositioned. This step is often overlooked, leading to a major drop in capture efficiency. When a fume arm isn’t the right solution, a backdraft table might work, assuming the part fits on the table. When the situation calls for a highly flexible solution, a fume gun is the best way to capture fumes at the source.

Should I Use Individual Dust Collector Units Or A Centralized System To Collect Weld Fumes?

This answer hinges on two key details about your operation: how valuable is your floor space and what is your potential for growth? The size and layout of your operation might play a considerable role, as well. Let’s look at the benefits of both options.

Benefits of a centralized dust collection system:

  • Optimizes floor space - If floor space is precious, then a centralized system located on the ceiling or outside is a great option. A powerful unit such as the RoboVent Senturion dust collector can capture dust and fumes from an extensive centralized system with many intake points.
  • Lowers maintenance costs - Fewer service points, in centralized systems, lead to lower maintenance costs than an array of individual dust collection units.
  • Creates efficiencies - Centralized systems also make it easier to monitor the network, track its performance and make adjustments where necessary. Over time, this data collection, as well as the chance to use more automated controls, can generate major cost savings.
  • Provides flexibility - If you might be changing your layout or expanding your production in the near future, a centralized system would better suit your needs. A well-designed centralized system could hold capacity for many welding stations, and adding these stations would be much easier than if they had to be paired with new individual dust collectors, as well. For example, RoboVent’s Grid Configuration uses modular, standardized ductwork that can be reconfigured easily as your needs change.

Benefits of using individual dust collection systems:

  • Saves money in certain situations - Welding operations that use only a few stations might be able to collect their fumes quickly and efficiently using standalone collectors. Such an arrangement would avoid the need for ductwork and avoid higher installation costs.
  • Avoids overkill - If your operation only produces a modest amount of weld fumes, individual dust collectors, such as RoboVent’s Spire units, could capture them effectively.
  • Saves energy - Centralized systems need to move air throughout an entire facility, which uses a lot of power. If your facility only needs a few individual dust collectors, you could save money on energy.
  • Allows for odd layouts - If your welding stations are few and far apart, a centralized system with lots of ductwork might not make sense. A few well-placed standalone dust collectors would work well in this situation.
  • Provides options for transport - If your dust collectors might be moved to another facility, individual units are obviously the way to go.

I Need Another Collection Point For A New Weld Station. Can I Just Tap Into The Existing Duct Overhead?

In short, no. The existing ductwork and filtration system presumably have been sized for the current welding needs. To add a port and a new source of fumes would unbalance the system and compromise its integrity.

For example, adding a new port would cut airflow through all of the existing ports; this could affect capture rates. To add a new weld station to a system, an air quality engineer would have to run new calculations for the system and determine the power needed for the new arrangement.

Before adding a new collection point to your existing centralized source capture system, consult with an air quality system designer.

How Do I Know What Size Dust Collector I Need For My Source Capture System?

A source capture solution is sized according to many variables. Dust collector capacity is a function of several factors:

  • CFM: The air speed required for a source capture system—measured in cubic feet per minute (CMF)—is calculated in the design of any system. Operations with a high CFM will need more powerful motors than those with a lower air speed. Too little CFM won’t carry the particulates all the way to the dust collector; too much could drive the particulates too deeply into the filter media, clogging it. Maintaining a high CFM also costs more, due to the increased energy use. Fortunately, air quality engineers understand how to balance these variables and calculate the right CFM for your needs.
  • Filter media: Filter media, measured in square inches, is the second element in dust collector design. The ration of airflow to filter media is called the “air-to-cloth ratio.” It is important to make sure you have enough filter media for the volume of particulates you produce and the total volume of air you are moving. Using too little filter media results in significantly shorter filter life, greater maintenance burden and more wear and tear on equipment.
  • Motor horsepower: Source capture systems with large particulates or high volumes of dust require more horsepower from the dust collector.

Dust collector sizing depends on several factors:

  • Distance from the source to the dust collector - The longer the distance, the more horsepower you will likely need from your motor.
  • Particulate type - Fine particles require much less power and air speed than large particles. A lower air speed, measured in cubic feet per minute (CFM), means that less power is required and that operating costs will be lower.
  • Volume of particulates - Some operations produce a high volume of particulates, requiring a lot of filter media.
  • Pipe or duct diameter - Large particulates require larger diameter pipes and ducts, but there are limits to how large a pipe should be. If it is too large, there is a risk of particulates dropping out of the airflow. If this happens, it becomes a maintenance burden and perhaps a fire hazard.

Obviously, many of these variables are interrelated. For example, particulate type, CFM and motor horsepower are all connected. Professional air quality engineers are able to factor all of these variables into their design for a source capture system.

What Is The Best Source Capture Solution For Robotic Welding?

The best way to capture weld fumes from a robotic welding station is to enclose it and attach the cell to a dust collector. This ensures that workers are protected and that weld fumes are caught at a very high capture rate. Enclosures are neither expensive nor difficult to install, but sometimes there are obstacles to implementing them, such as overhead cranes or other equipment. The best option is often a modular enclosure, such as RoboVent’s Streamline Hood. This hood can be customized to fit over any operation, including multiple robotic welding stations. It also features a low profile that works well with overhead equipment. Air quality engineers are able to advise on the most practical and cost effective way to enclose or partially enclose a welding cell.

RoboVent’s Spire dust collector is a good example of available units with powerful filtration and low running costs that can be attached to welding cells.

If an enclosure is not possible and if a welding arm produces a high volume of weld fumes, especially over a large weldment, the next best solution is to affix a hi-vac extraction system to the robotic arm. This system will capture fumes at the source. Because the robot performs the same task in the same way every time, air quality engineers can design a system that accounts for the robot’s speed and movements, ensuring that the fume extraction point is well placed at all times.

What Is The Best Source Capture Solution For Manual Welding?

The best source capture of weld fumes will attack the two main sources of fumes: those coming off the welding point and residual fumes coming off the hot weld seam. Not all fume capture solutions are able to catch both. However, a backdraft/sidedraft plenum excels at this challenge. For bench welding with large (but not huge) parts and consistent placement on the bench, this solution is able to pull the fumes away from the worker’s breathing zone and capture the fumes with near total efficiency.

Fume arms, another popular air quality solution, can be very effective, too. When the welding piece is small and always in the same location, a fume arm is a great solution. But if the piece is large, a fume arm must be repositioned frequently. Welders are often inconsistent in doing this, leaving many fumes not captured. Residual fumes are very hard to capture.

After backdraft tables and similar devices, the fume gun is another excellent source capture solution for weld fumes. When used correctly, RoboVent’s MIG fume gun can capture up to 95% of weld fumes at the source. These devices are especially useful in unconventional situations, such as welding on very large parts or in places where a welding bench isn’t available.

How Is A High-vacuum (hi-vac) System Different From A Low-pressure One?

Dust collection systems fall roughly into two categories:

  • high volume/low pressure
  • low volume/high pressure

High-volume, low-pressure systems are more common. These are likely what you think of when you picture a dust or fume collector. As a point of reference, they might move up to 10,000 CFM (cubic feet per minute) of air at 10-12 inches of vacuum pressure. Dust collectors used for ambient air filtration operate like this, turning over large amounts of air throughout the day. Source capture systems, including collectors attached to welding hoods like the RoboVent Spire, can use this method as well.

Low-volume, high-pressure systems, also known as hi-vac systems, operate quite differently. They move less air but do it at a higher pressure. A common airflow might be closer to 60 CFM at a vacuum pressure of 80 inches. These systems are attached source capture devices like fume guns, fume arms or robotic tip extractors. High vacuum pressure is needed for these systems to overcome the static pressure that results when pulling weld fumes or dust through small pipes.

How Do I Determine The Diameters Of Hi-vacuum Pipes?

The necessary diameter of your hi-vacuum pipes depends on two main variables: volume of particulates and particulate size. Let’s break them both down:

  • Volume of particulates: To begin, you should consider how many dust-producing devices will be running at once. The greater the volume of particulates, the greater diameter you will need. A large number of vacuum ports will also require more suction, but that is more a question of motor size than pipe diameter.
  • Particulate size: A welding station produces very different particulates than a router or a chop saw. Transporting weld fumes is very different than transporting saw dust. As particle size increases, you will need higher-diameter pipes.

Vacuum pipes have a limit to how large they can be, however. If a pipe is too large, particulates might move too slowly and drop out of the airflow. Over time, these particulates could plug up the pipes. This can cause problems beyond ruining your dust collection efforts. Clogged pipes are a maintenance hassle and a fire danger.

Designing a dust collection system with correctly sized pipes and horsepower takes skill. Professional air quality engineers are able to factor in the most pertinent variables of your operation and build a system that is both efficient and cost effective.

Do I Need Additional Air Filtration If I Use A Fume Gun To Capture Weld Fumes?

The best fume guns capture up to 95% of weld fumes when used properly. In most situations, additional air filtration will not be necessary to protect welders. However, the presence of residual fumes coming off of hot seams means that an ambient capture system is often a helpful accompaniment to a fume gun.

The answer to the question turns into a firm “yes” when a welder is working in a confined space, however. In this situation, any residual fumes will accumulate and overly expose a welder. Ventilating the space or outfitting the welder with personal protective equipment (PPE) is necessary.

What Works Better For Weld Fume Collection: Source Capture Or Ambient Air Filtration Systems?

Both source capture and ambient air filtration have their place in weld fume collection. The answers really depend on the volume and toxicity of fumes being produced, the size of the weldments and the layout of the facility.

Source capture is the first line of defense for most high-production welding applications. Source capture offers significant benefits, including:

  • Lower energy and equipment costs, because the equipment does not have to move as much air. The closer to the source weld fumes can be captured, the lower the cubic feet per minute (CFM) of air to be moved. This translates into dust collection equipment with a smaller motor and much smaller energy consumption.
  • Better protection for workers. Source capture keeps weld fumes out of the welder’s breathing zone and out of the ambient air of the facility, providing better protection from toxic elements.
  • Cleaner facilities: capturing weld fumes at the source keeps facility air clean and clear and also eliminates dust and grime that falls out of the ambient air onto floors and surfaces.

Source capture systems include:

  • Hoods and enclosures (for robotic welding)
  • Fume guns
  • Fume arms
  • Backdraft/sidedraft tables

Ambient air filtration systems clean the air for the entire facility. They can be highly effective, but generally require more energy to use and may not provide enough protection for workers directly exposed to weld fumes. Ambient systems are best used for:

  • Situations where source capture is not feasible, such as working with very large weldments or in environments where the use of overhead cranes or other equipment prevents hoods or enclosures from being used.
  • In low-production environments where the overall volume of fumes is small.
  • As a backup system when source capture alone does not meet air quality standards—for example, when residual smoke rising off of hot weld seams cannot be effectively captured using fume guns or fume arms. Hybrid systems using both source capture and ambient air filtration can generally use a smaller ambient system than would be required if ambient air filtration were used as the primary weld fume collection system.

Can Downdraft Tables Be Used For Welding Smoke?

Downdraft tables are well suited for grinding or cutting applications. In these applications, larger and heavier particulates fall out of the air and are captured by the table.

The best solutions for welding smoke account for hot smoke’s tendency to rise. For this reason, a downdraft table is not an ideal solution for welding smoke. A powerful table, however, could most likely capture a large amount of smoke. Downdraft tables are sometimes used in situations where welding and cutting or grinding is conducted on the same work surface.

If the table will be used primarily for high-production manual welding, a better choice is a backdraft or sidedraft table such as the RoboVent Crossflow table, which will capture weld fumes as they rise and pull them away from the welder’s breathing zone. Fume arms are another good choice for manual welding stations.

How Do I Reduce Exposure To Hexavalent Chromium (hex chrome) In Stainless Steel Weld Fumes?

Hexavalent chromium—commonly called hex chrome—is a toxic particulate produced while welding stainless steel. The fine particulates produced in this welding process pose a serious inhalation risk. The substance is known to cause cancer as well as affect the respiratory system, kidneys and liver.

The Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit for hex chrome of 2.5 micrograms per cubic meter of air.

Here are four steps to reduce exposure to hexavalent chromium:

  1. The first step in cutting exposure is to look at process improvements. Changes in process and materials can significantly cut welders’ exposure to hexavalent chromium. These methods are usually less expensive and burdensome than addressing weld fumes after they have been created and released into your facility. The first change recommended by air quality engineers is a change in welding wire. If you are using flux-core wire, a change to solid wire will drastically reduce your weld fumes and reduce welders’ exposure to hex chrome.
  2. Next, use engineering controls such as a dust collection systems to protect welders from hex chrome. For manual welding, source capture systems such as backdraft tables or fume guns capture weld fumes—and particularly dangerous substances such as hex chrome—with a high degree of efficiency. If welding operations involve very large pieces (ones that won’t fit under a hood or on a table), the best solution might be a fume gun combined with a secondary ambient capture system to capture any leftover fumes. Robotic applications should be kept under hoods whenever possible.
  3. Your third step is to consider an ambient dust collection system. This collector will mitigate fumes throughout a facility and could cut exposure to a safe level. While never adequate as a standalone air quality solution, ambient collectors are highly effective when paired with source capture equipment.
  4. If exposure levels are still excessive, look into implementing personal protective equipment (PPE) such as powered air-purifying respirators (PAPR’s) for welders. When used correctly, PAPR systems can protect a welder in nearly any welding situation. Remember that OSHA considers PPE to be a last resort; engineering controls must be used whenever it is technically feasible.

How Do I Reduce Exposure To Beryllium In Weld Fumes?

Beryllium exposure can lead to serious health problems, such as chronic beryllium disease (CBD), a serious lung disease. The element is classified as a human carcinogen, as well, carrying the risk of lung cancer.

Beryllium exposure is so dangerous that it has been the subject of a recent change to regulations from the Occupational Safety and Health Administration (OSHA). The agency has cut its permissible exposure limit (PEL) for beryllium from 2.0 micrograms per cubic meter of air to 0.2 micrograms, a tenfold reduction.

Here are four steps to reduce exposure to beryllium:

  1. Your first step in reducing beryllium exposure is to examine your welding processes. Process improvements can often cut fumes with far less expense and hassle than other methods. Changing your weld wire from flux-core to solid, for example, is a highly effective way to reduce fume volume and to cut welders’ exposure to beryllium.
  2. The next step is engineering controls, such as a dust collection system that will limit workers’ exposure to weld fumes. For manual welding, backdraft tables, fume arms or fume guns can be used to collect weld fumes and keep them out of the welder’s breathing zone. Robotic applications should be kept under hoods whenever possible. High-efficiency dust collection systems, such as the RoboVent Spire dust collector, can filter beryllium and other harmful contaminants out of the air, protecting workers and bringing a facility into regulatory compliance.
  3. Next, consider an ambient dust collector. If a source capture system is already in place and if beryllium exposure levels are still too high, there are still more options available. An ambient source dust collector will clean the air throughout a facility and cut exposure levels to weld fumes.
  4. If engineering controls do not keep exposure levels within PELs, welders should wear personal protective equipment (PPE) such as powered air-purifying respirators (PAPR’s), which filter the air wherever a welder goes. Air quality experts recommend serious training on these devices so that they are used as effectively as possible. Remember that OSHA considers PPE to be a last resort; engineering controls must be used whenever it is technically feasible.

How Do I Reduce Exposure To Manganese In Weld Fumes?

Manganese particulates are a common component of weld fumes. The high temperatures involved with welding create extremely small particulates that can travel deeply into the lungs. These particulates have proven to be a serious health hazard. Studies show that exposure to manganese dust can produce memory loss and other disruptions to the central nervous system. Excessive exposure can cause Manganism, a disorder with symptoms similar to Parkinson’s Disease.

OSHA has set a permissible exposure limit (PEL) for manganese at 5 mg/m3 as a ceiling, meaning particulate volumes cannot exceed this level at any time.

Here are four steps to reduce exposure to manganese:

  1. The first step in cutting dangerous substances like manganese from weld fumes is to consider process improvements. By looking at your processes, you might be able to identify changes you can make which will reduce your fumes without any major expenses or hassles. For example, if you are using flux-core wire, one of the best changes you can make is to shift to solid-core wire. This wire produces much less smoke and fewer dangerous particulates.
  2. Next, consider engineering controls such as a high-efficiency source capture system. For example, a backdraft table or fume gun can capture weld fumes at the source with a high degree of efficiency—usually over 90% if used correctly. These devices can connect to a powerful filtration system, such as the RoboVent Senturion collector. This equipment ensures that manganese particles and other weld fumes don’t travel through a welder’s breathing zone. Robotic applications should be kept under hoods whenever possible.
  3. If source capture alone does not bring particulates down to acceptable levels, consider adding an ambient air filtration system to clean the air throughout an entire facility.
  4. When engineering controls along do not keep manganese exposure within OSHA permissible exposure limits, personal protective equipment (PPE) such as powered air-purifying respirators (PAPR’s) can be used for workers at risk. Proper training and consistent use of these devices are crucial for their effectiveness. Remember that OSHA considers PPE to be a last resort; engineering controls must be used whenever it is technically feasible.

What Is The Best Kind Of Dust Collection System For Automotive Welding?

Much of automotive welding relies on robotic welding cells. For this kind of welding, fume collection depends, in large part, on whether or not the welding cells can be enclosed or not. If so, the fume collection challenge is rather straightforward. If not, the collection takes a bit more effort.

Enclosing robotic welding cells involves installing equipment such as hoods, curtains or partitions. This equipment is relatively inexpensive, but installing it is sometimes limited by a facility’s layout—overhead cranes and other equipment might prevent some enclosures.

An enclosed welding cell extracts weld fumes much more effectively than an open cell. This means a dust collector can operate using much less energy than in an open environment. Enclosed cells are also more effective at protecting workers across a facility, since fumes aren’t given the chance to drift and expose workers. A dust collector such as the RoboVent Spire is a good example of today’s leading industrial air filtration systems. It provides powerful air filtration and runs efficiently due to automated controls and other proprietary technology.

For manual welding of automotive parts, the best dust collection method will depend on the nature of the welding station. If a welding process is repetitive and if the part is small, a fume arm attached to a dust collector will be adequate for mitigating the fumes. If the part is big enough to make a fume arm ineffective, a welding table with a backdraft plenum will collect the fumes without overly exposing the welder. If the part being welded is very large, the best collection system is a fume gun. These devices allow a welder to capture the fumes at the source. Used correctly, a fume gun can collect up to 95% of weld fumes.

What Is The Best Kind Of Dust Collection System For Large Weldments When Overhead Cranes Are Used In The Process?

In situations where welders are working with large weldments, a fume gun is likely the best option. These devices have improved radically in recent years and can offer welders a high degree of protection. The best fume guns can capture up to 95% of weld fumes. Fume guns offer the flexibility a welder needs when moving around a large piece; no other capture system offers the same ability to collect fumes while on the move.

Adding an ambient capture dust collector is a good idea in this situation. It would serve as a backup system that would capture any leftover fumes, preventing a buildup of fumes that could affect workers elsewhere in the facility. This kind of backup ambient system would not require much energy to run as it would not be processing high volumes of particulates.

For robotic welding, robotic tip extraction may be an option. Tip extractors like the RoboVent FlexTrac offer similar benefits as a manual fume gun, collecting fumes at the source as they are generated. The extractor tip is attached directly to the robotic welding arm. A well-designed tip extraction unit doesn’t interfere with the motion of the robotic arm and is able to capture a high percentage of weld fumes.

What Is The Best Kind Of Dust Collection System For A Manual Welding Station?

The optimal air quality solution for manual welding stations is source capture equipment of some kind. This equipment is more effective than ambient capture units at pulling welding fumes away from a worker’s breathing zone. There are many options available, including:

  • Backflow/crossflow tables: The RoboVent CrossFlow table is a good example of an easy-to-use welding bench that captures fumes and protects workers. These tables combine a welding work surface with built-in fume extraction that continually pulls weld fumes away from the welder’s face.
  • Fume guns: For situations where the welder needs to move around or where the weldment is too large to fit on a welding bench, a fume gun is an excellent source capture solution. When used properly, the best fume guns can collect up to 95% of weld fumes.
  • Fume arms or extension booms: Fume arms are positioned over the weld seam to pull weld fumes away from the welder’s face and collect them as they rise. These can be attached to a centralized, ducted system or to a small portable dust collector. Keep in mind that fume arms must be positioned directly over the weld seam to work; for large weldments, this may mean repositioning the fume arm as the welder moves.

If a source capture solution is not possible in a facility, an ambient capture system can help to mitigate fumes throughout the entire facility. Keep in mind that ambient systems do not keep weld fumes out of a welder’s breathing zone. If exposure levels are above OSHA permissible exposure limits (PELs), they must wear personal protective equipment (PPE) to limit their exposure.

OSHA standards lay out the order in which employers should address air quality challenges. First, engineering controls should be attempted. This includes looking at substitutions and other methods of cutting the source of weld fumes. For example, shifting from flux-core wire to solid wire can significantly reduce weld fumes. Next, their rules suggest implementing dust collection equipment, if further measures are needed. Personal protective equipment is always a last resort, in the eyes of OSHA.

What Is The Best Kind Of Dust Collection System For A Robotic Welding Cell?

The ability to collect weld fumes in robotic welding cells primarily depends on one key factor: can the cell be enclosed? If so, the answer is quite straightforward; if not, fume collection is more challenging.

Air quality engineers sometimes put it this way: would you design a home furnace system assuming the windows and doors were always left open? Certainly not. But, if you had no choice, then you would need different equipment and more energy to run the furnace. The same holds for a dust collection system on a robotic welding cell. An enclosed cell is a much easier air quality problem to solve than an open one.

Weld fume capture in robotic welding is primarily performed in three ways. These methods feature both source- and ambient-capture practices. Following is a brief breakdown of these three methods, in order of efficacy.

  • Source capture using a hood or enclosure—Weld fumes from robotic welding cells are best captured when the cell is under a hood or similar enclosure. This equipment performs several functions. It contains the fumes, preventing them from spreading and affecting workers and processes throughout a facility. It also limits the amount of air a dust collection system must process, radically reducing the energy required by the system. RoboVent’s Streamline Hood is a good example of such a system. These hoods can be customized to fit nearly any welding operation. Sometimes overhead cranes or other equipment might preclude a full enclosure. In these situations, a partial enclosure might be all that is possible. Even a simple array of curtains and partitions can surround a welding cell enough to make a difference. None of this equipment is expensive, nor difficult to install, and the long-term benefits are substantial.
  • Source capture using tip extraction—When an enclosure is not possible, tip extraction is a good option. This fume collection device attaches to the tip of a robotic welding arm and captures weld fumes at the source. When well designed, tip extraction can collect up to 95% of weld fumes.
  • Ambient systems—Robotic welding requires intensive methods of fume collection. However, if source-capture options are limited, then ambient systems can be useful. A well-placed and powerful system can mitigate weld fumes effectively. Ambient systems are particularly useful as backup systems, collecting residual fumes that source capture systems might not catch.

How Do I Size My Dust Collector For Laser Cutting?

The size of the dust collector required depends on a few variables. Laser cutting is an intensive operation, and accounting for all of these variables is important. Here are some of the major variables:

  • Amount of material being cut. In short, the more material that is being processed, the bigger your dust collector needs to be. The amperage your laser cutter is using impacts how much dust is being produced; the more amperage, the more material is being removed (and the more dust is being produced).
  • Amount of downtime in the cutting process. Many laser cutting operations run for hours at a time. During that period, the dust collector can’t be turned off or serviced in any significant way. If an operation needs to run for many hours at a time, then the dust collector must be sized accordingly—i.e., have a larger containment system and perhaps more filter media.
  • Nature of the dust. Some dusts are easier to address than others. If your operation produces dry dust, it will quickly shed off of the filters, making dust collection easier. If there is moisture involved, then the dust will be stickier and more of a problem. An engineer is able to design the collector accordingly.

A good example of a dust collector suitable for laser cutting is a unit in the RoboVent Plaser Series. These units are designed for the high volumes of dust produced by these operations.

What Are The Benefits Of Ambient Air Filtration Versus Exhausting Contaminated Air To The Outside?

Exhausting contaminated air to the outside carries several risks and costs. Fortunately, those problems are solved by using air filtration equipment. Below are some of the reasons to avoid exhausting your air:

  • Energy Costs: When you exhaust heated or cooled indoor air to the outside, you are blowing money through the roof. Fresh air will need to be re-heated or cooled to indoor temperatures again. This is similar to the effect of running your heater or air conditioner with all of the windows open.
  • Environmental Regulations: The Environmental Protection Agency (EPA) maintains air quality regulations that could be broken if you release too many contaminants into the air in too short a time.
  • Worker Health: Dirty air that travels across a facility on its way to being exhausted comes into contact with many workers along its path. If this air contains harmful substances, workers will be exposed, threatening their health and your facility’s compliance with permissible exposure limits.
  • Community Health: The exhaust could negatively impact the community. In a worst-case scenario, unhealthy air could cause health problems in the community. But even bad smells could cause reputational damage.
  • Water Pollution: Contaminants that gather on the rooftop could get washed away and enter the water system, damaging the environment.

Implementing an ambient capture air filtration system solves these problems by filtering the dirty air and returning it to the facility. Here are some of the obvious benefits:

  • Major energy savings. Because you avoid the need to bring fresh air into the facility, you avoid the need to heat or cool that air. In cold and hot seasons, this leads to major energy savings.
  • Containment. Nothing escapes to the outside where it could cause environmental or community health problems.
  • Improved worker health. Workers are exposed to fewer contaminants. This protects their health and productivity, as well as keeping you compliant with permissible exposure limit regulations.

Can I Connect My Grinding Stations To The Same Dust Collector As My Existing Welding Stations?

Possibly. A grinding station usually produces much heavier particulate matter than a welding station. This means a dust collector must maintain a higher air velocity to address dust from a grinding station. Heavier particulates need faster airflow so that they won’t drop out of the air stream. An air quality engineer would be able to study the dusts involved (and their volume) and advise on what is possible.

Another variable to consider is how many ports your dust collector is currently designed for. Most likely, the existing ductwork and filtration system have been sized for the existing welding needs. Adding a new port would cut airflow through all of the existing ports, affecting capture rates throughout the system. Again, an engineer would be able to consult on this issue.

Types of dust are another factor with this question. For example, you cannot mix aluminum grinding dust with ferrous metals, or a fire/explosion will result.

Why Is The Dust Collector Larger For My Plasma Table Than On My Welding Station?

A plasma table produces far more dust than a welding station. The cutting table removes base metal, and the dust collector captures that material, whereas a welding station produces mostly fumes. These fine particulates don’t require the same amount of airflow or filter media as a dust collector attached to a plasma table.

A good comparison is seen in the two dust collectors:

  • The RoboVent Plaser Series is specifically designed to work with laser and plasma cutting tables. These collectors provide powerful filtration that can handle large volumes of dust.
  • The RoboVent Spire Series is designed to work with a single large welding cell or several smaller welding cells. The system is powerful and can handle a large amount of weld fumes, but it would not be the best choice for a plasma cutting table.

What Is The Best Kind Of Dust Collector For My Batch Mixer?

Every batch mixing operation is different, but most of them share a few traits. Source capture is the preferred method, but most operations require an ambient air filtration solution for a total solution because dust tends to escape and drift. An ambient dust collector treats the air in an entire facility.

  • The RoboVent Vortex Series is a floor-mounted unit that used directional nozzles to create air patterns that move dirty air into the collectors and return clean, filtered air to the facility.
  • The RoboVent Spire360™ Series is a floor-mounted ambient filtration unit that pulls dirty air in at the top and pushes clean air out at the bottom, creating a positive press zone that forces dirty air into the filtration unit.
  • The RoboVent Vista360™ Series mounts ambient air filtration units near the ceiling, freeing up floor space and pulling in contaminated air as it rises.
  • A traditional ducted push-pull system creates air currents using a system of ceiling ducts connected to a powerful dust collector like the RoboVent Senturion Series

If source capture is possible—perhaps where the batch materials are being added to the process—then a hybrid system (ambient + source) would work well. A dust collector like the RoboVent Senturion can be hooked up to hoods or enclosures placed over the dirtiest part of the mixing process to contain dust.

Another factor which batch mixing operators must consider is the tendency for their dust to disperse; when a powder is added, it displaces air, causing dust to fly. Keeping the hopper under negative pressure (by source capture collection) helps to mitigate this effect, and air quality engineers can create that negative pressure with a dust collector. Enclosing your operation as much as possible will obviously make it easier to maintain a negative pressure. When no enclosure is possible, an ambient collection system will likely be necessary for your facility.

When choosing a filter media for your dust collector, it is wise to consider the nature of the specific dust you are handling. An engineer would be able to advise on which filter would be most appropriate. In many batch-mixing operations, a cartridge filter is an optimal solution, providing high efficiency in a compact package.

What Is The Best Kind Of Dust Collector For My Grinding Station?

The nature of your grinding dust might dictate what kind of dust collector you need. For example, a fiberglass grinding booth produces very different dust from an aluminum grinding station. The latter produces dust that is more dangerous to workers and is highly combustible, while the former is more likely to be a much finer dust, which is harder to collect. It is important to match the right dust collector to the application.

Fortunately there are many dust collector options available. For grinding stations where the dust particulates are large and more or less benign, a typical portable dust collector or backdraft table would work well (see examples below). However, grinding operations that produce fine dusts that hang in the air are more of a challenge. If those dusts are combustible, your operation will likely require a hazard analysis of the dust. Testing your dust will tell you how dangerous it is. RoboVent engineers can then factor that information into their work. They understand National Fire Protection Association (NFPA) standards and design dust collection systems to meet them; these include standards such as NFPA #652, Standard on the Fundamentals of Combustible Dust.

Here are some good dust collecting options for grinding stations:

  • Backdraft or downdraft tables. These provide a functional work surface and a powerful airflow that pulls particulates away from a worker’s breathing zone.
  • Portable dust collectors. These go-anywhere units can ensure that none of your grinding stations go without an air quality solution. A unit like the RoboVent VentBoss offers most of the features of larger units, including compressed-air cleaning and built-in spark arrestance.
  • Centralized dust collectors. A unit like a RoboVent Senturion collector can provide dust collection for a number of grinding or cutting stations.

What Is The Best Kind Of Dust Collector For My Laser Or Plasma Cutting Table?

Dust collectors for laser or plasma cutting tables must take into account the high volume of dust produced by these processes as well as the dust’s extremely fine particulates. Capturing this dust quickly and completely is crucial for protecting workers and for guaranteeing that your laser cutting equipment works properly. (Accumulating smoke and dust can interfere with the laser beam.) Also, because many metallic dusts are combustible, dust collection is necessary to avoid potentially catastrophic fires and explosions.

The RoboVent Plaser Series of dust collectors is tailor-made for these applications. These units offer powerful performance with low operating costs, using automated systems to run only when they need to. The units are also designed to reduce the risk of fires. The optional Delta3 Spark Arrestor kills sparks before they can ignite filter media.

Many of the metals involved in laser and plasma cutting create toxic dust and smoke, and the Occupational Safety and Health Administration (OSHA) has set permissible exposure limits (PEL’s) for many of these substances. Below is a list of just a few of them:

Exposure to these substances is associated with a wide variety of very serious health problems, from respiratory irritation to cancer. Implementing a rigorous air quality solution is necessary both to protect workers and to keep your facility in regulatory compliance.

What Is The Best Kind Of Dust Collector For Carbon Black Dust?

Carbon black dust poses an air quality challenge because of the very small nature of its particulates. These sub-micron-sized particulates can drift across a facility if not captured at the source. Working with an air quality engineer will help you optimize dust capture. When source capture is not possible or is not enough to do the job, an ambient capture system can filter the air in your entire facility and make sure the problem is contained.

Here are some good options for collecting carbon black dust:

  • RoboVent Vortex Series dust collectors create a circulating airflow to capture dust and fumes across an entire facility. This air is filtered and returned to the plant, using eight to twelve nozzles that can be adjusted directionally to maximize the airflow throughout the space. Among the unit’s many benefits is its lack of a need for ductwork, which lowers installation costs.
  • RoboVent Senturion Series dust collectors can collect carbon black dust and filter it. This dust collector can be set up as either a source capture or an ambient capture unit.

Capturing carbon black dust is an urgent need for any facility that handles it. The material is an inhalation risk that carries many dangers for workers’ respiratory and pulmonary systems. The Occupational Safety and Health Administration maintains a permissible exposure limit (PEL) of 3.5 mg/m3 in order to protect workers. Meeting this standard will not only ensure legal compliance but will protect workers from serious health problems.

What Is The Best Kind Of Dust Collector For Glass-making Dust?

Protecting workers from exposure to glass-making dust is more urgent than ever. Changes in the standard for respirable crystalline silica in 2016 have pushed industry to take a new look at their air quality controls. The new regulation by the Occupational Safety and Health Administration (OSHA) limits worker exposure to 50 micrograms per cubic meter of air (μ/m3). This tight standard means that most manufacturers will need to take active measures to address silica dust.

Choosing the best dust collector for this application will likely require input from an air quality engineer. Variables such as particulate size and dust volume dictate the final design of a collection system, including how much power and filter media are needed. For example, larger particulate sizes will require more horsepower than fine particulates, and large volumes of dust will require a lot of filter media in order to handle the load.

Here are two powerful solutions for operations of very different sizes:

  • RoboVent Senturion series dust collectors can provide filtration to address dust from multiple sources. Automated controls and efficient blower motors help make the Senturion highly efficient, saving money and maintenance time.
  • RoboVent PowerBoom portable dust collectors are perfect for individual workstations that produce dust. This powerful collector comes with a boom arm with a reach of 17 feet. The PowerBoom can be wheeled wherever necessary, ensuring that you have adequate dust collection while remaining flexible.

While the dangers of exposure to silica dust often require a source capture solution for the dust, an ambient capture dust collector is a smart secondary system. An ambient system will ensure that leftover dust does not drift and expose workers throughout a facility. Air quality engineers are highly trained in balancing the needs of source and ambient capture.

Which Capture Method Is Best For Weld Fumes?

Welding Exhaust Systems

Removing weld fumes to protect workers and other resources

The need to control weld fumes is more serious than ever. Substances in weld fumes such as hexavalent chromium, beryllium, cadmium, cobalt, and nickel have proven to be dangerous inhalation hazards. The Occupational Safety and Health Administration (OSHA) issues air quality regulations for these substances and many others. Fortunately, affordable welding exhaust systems exist to mitigate these fumes.

Exhaust and Makeup Air vs. Filtration

Welding exhaust systems comprise a wide variety of air quality solutions. The simplest systems exhaust contaminated air to the outside. This option might be attractive for small operations with irregular welding volumes. The method has downsides, however, including high energy bills caused by the need to re-heat or re-cool make-up air. In addition, exhausting welding fumes to the outside sometimes runs into environmental air quality regulations.

The way to avoid those problems is to filter your contaminated air. This avoids any potential breaches in air quality regulations, while saving money on energy bills. The higher startup costs that come with air filtration are more than offset in the long run by energy savings. In addition, facilities with filtration systems tend to have cleaner rooftops and grounds.

Source Capture vs. Ambient Air Quality Control

Choosing between source and ambient capture comes down to the welding application involved and the facility’s physical constraints. The more toxic the fume, the more likely a source capture solution is needed. These solutions grab fumes at the source, preventing them from lingering in a worker’s breathing zone or spreading throughout a facility. Applications that produce a high volume of weld fumes are good candidates for source capture, as well.

Some applications make source capture of fumes difficult. For example, welders working on large parts often find it difficult to reposition fume arms to capture fumes. Sometimes facility constraints—such as overhead cranes—make source capture solutions difficult to implement, as well. In these situations, ambient capture solutions can mitigate a large amount of dust and fumes. These units are facility-wide solutions that churn the air through an entire building in order to run the air through filters.

Best Welding Exhaust System Options for Manual Welding

Manual welding operations require particular attention to workers’ breathing zones and the direction of airflow. The best air quality solutions pull fumes away from the breathing zone while making sure the welder can work without interruption. Systems like RoboVent’s CrossFlow Table provide a convenient work surface while sucking weld fumes away from the welder. Fume arms are another good source capture option. These can be repositioned easily to capture fumes where they are produced.

For welding situations that are unconventional or inconvenient, a fume extraction gun might is a good solution. Recent innovations have improved fume guns and made them a strong alternative for these situations. A good MIG fume gun creates a perfect weld while pulling fumes away from the welder.

Best Welding Exhaust System Options for Robotic Welding

The air quality challenges stemming from robotic welding come from the toxicity of the weld fumes and their high volume. Vigorous and well-designed systems are needed to mitigate these fumes. To begin, a good system will confine the weld fumes in order to prevent them from spreading. Next, a welding exhaust hood should provide enough suction to capture the contaminated air and send it through a collector.

For robotic welding applications which don’t fit under an exhaust hood, a tip extraction system is a good alternative. This technology has made leaps in recent years, and today’s systems produce perfect welds while pulling away up to 95% of weld fumes. These units promise to make robotic welding even more effective over the coming years.

SOURCES:
Components of Weld Fumes: https://www.osha.gov/Publications/OSHA_FS-3647_Welding.pdf

Which Exhaust Hood Is Best For Robotic Welding?

Welding Exhaust Hoods

Source capture solutions provide the most efficient and cost-effective remediation of weld fumes

Welding Exhaust Hoods for Robotic Welding

Many substances found in weld fumes have proven to be dangerous, and robotic welding facilities produce a high volume of those fumes. Welding exhaust hoods are an ideal solution for capturing fumes before they can propagate throughout a facility, putting workers at risk and threatening regulatory compliance. A hood encloses a robotic welding cell and provides the most efficient way to evacuate fumes produced by the process.

The use of robotic welding is expanding in manufacturing, and plant managers are looking for the best way to address weld fumes. As long as the parts being welded can fit under a hood, this solution is proving to be both powerful and efficient. Because the exhaust hood is collecting and filtering air from a confined area, it uses less energy than ambient capture solutions.

Confining weld fumes and evacuating them as fast as possible is also the best way to ensure worker health and safety. Weld fumes are a well-documented health risk, and substances like manganese and hexavalent chromium are heavily regulated. Failure to comply with Occupational Safety and Health Administration (OSHA) regulations can lead to heavy fines and other legal troubles.

Considerations in Selecting a Welding Exhaust Hood

Making sure a welding hood is properly sized for the application is the best way to ensure that it is meeting your goals. A hood should be the right size and no larger. The right size and a tight containment around your application means less energy use and more cost savings.

A system should also be easy to install and move. In today’s world of fast-moving product cycles, factory floors must be more flexible than ever. Plant managers don’t have time to stop production and build a new air quality solution for the new layout. Welding exhaust hoods should be modular and easy to manipulate, like RoboVent’s Streamline Hood. Recent changes have made the hood slimmer and more efficient, producing more benefits while taking up less space. The hood can be sized to fit over any application.

Choosing a Dust Collector for Welding Exhaust Hoods

There are many options available for dust collectors to attach to your exhaust hood. If a single filtration unit is all you need, RoboVent’s Spire collector provides a powerful solution in a small footprint. Built for low maintenance and energy efficiency, this unit is a flexible solution for a robotic welding cell. For an array of welding cells, a centralized collection system might be required. Collectors in RoboVent’s Senturion Series can handle a number of welding cells and can be located inside or outside the facility. Senturion collectors feature cutting-edge technology, such as intelligent controls and particulate monitoring. The Senturion Series can be scaled up, as needed.

Many of RoboVent dust collectors come in different configurations. The Grid Configuration connects multiple collectors in an array that saves energy and cuts maintenance costs.

Other Source Capture Options for Robotic Welding

When a welding exhaust hood isn’t appropriate for your application, there are other options. If the pieces being welded are too large to fit under a hood, for example, you might consider robotic tip extraction. This technology has radically improved in recent years. Today’s units produce a perfect weld combined with finely tuned tip extraction of weld fumes. The ability to capture 90-95% of weld fumes at the point of creation without the need for hoods or ducted systems could have a major impact on robotic welding in the future.

Regardless of the method used, the mitigation of weld fumes is a pressing need in manufacturing. Workers’ health depends on a vigilant approach to air quality, and regulatory compliance requires it, as well. Fortunately, there are many powerful and affordable options to solve the problem.

SOURCES:
Components of Weld Fumes: https://www.osha.gov/Publications/OSHA_FS-3647_Welding.pdf

Are Welding Fumes Dangerous?

Flexible air quality solutions for manual welding

Protecting Welders From Dangerous Weld Fumes with Welding Booth Ventilation

Welding booths provide a flexible welding workstation with built-in weld fume source capture for manual welders. When combined with a ventilation or filtration system, they continually pull weld fumes away from the welder’s breathing zone while providing a convenient welding surface for small-to-medium size parts.

Welding booth ventilation is especially crucial for safeguarding welders working with substances that emit dangerous weld fumes. For example, welding stainless steel produces weld fumes that contain hexavalent chromium—particulates that have proven to be highly toxic when inhaled. The Occupational Safety and Health Administration (OSHA) has declared hexavalent chromium carcinogenic to humans, and exposure to the fumes has been linked with cases of cancer, as well as damage to the respiratory system, liver and more. Effective air treatment measures can ensure workers avoid inhaling these particulates.

Ventilation or filtration solutions are important for complying with air quality regulations, as well. Many specific components of weld fumes carry individual OSHA regulations, each of which must be addressed. These substances include hexavalent chromium, manganese, beryllium, cadmium, cobalt, nickel and more. Failure to comply with OSHA standards can lead to serious fines and other legal problems.

Advantages of Welding Booth Ventilation

A good welding booth protects both the welder and nearby staff. The walls of the booth prevent sparks from flying and much of the fumes from spreading, in addition to providing eye protection for those nearby. A good booth provides a convenient work surface for welding—one that is both ergonomic and also connected to a fume collector.

Welding booths would be an ideal solution for situations like welding schools or fabrication shops where welders are working side-by-side. In these situations, the irregular nature of the manual welding—going on and off as welders come and go—makes this particular kind of source capture highly effective and efficient.

Options in Welding Booth Ventilation

No two welding operations are the same, so choosing an air quality solution can sometimes seem challenging. When deciding between exhausting fumes to the outside versus filtering them, a plant manager has a few factors to consider. Depending on the volume of fumes, air quality regulations from the Environmental Protection Agency (EPA) might prohibit exhausting too many particulates into the air. Filtering the air solves that problem. Additionally, exhausting contaminated air to the outside means you constantly have to bring fresh air in, and that air needs to be heated or cooled. This results in a major energy expense. Running weld fumes through filtration units is a money saver, in the long run.

Welding booths coupled with air filtration offer the best of both worlds. Booths are highly flexible solutions that allow for shifting floor plans, irregular welding times, unpredictable fume volumes and other such variables. Filtration options guarantee that welders and surrounding staff are safe and that air quality regulations are met.

RoboVent has almost three decades of experience mitigating weld fumes to protect workers and to improve manufacturing. Our engineers have designed welding booth ventilation systems of every size and layout. Systems like the CrossFlow Table are affordable, flexible air quality solutions for manual welding operations.

What Is The Best Kind Of Dust Collector For Fiberglass Dust?

The shortest answer is this: it depends. The fact that fiberglass-handling operations vary so widely means you will likely have to seek out the advice of an air quality engineer. The main variable in determining which dust collector you need is the particulate size of your fiberglass dust. Some particulates can be very large, and these might call for extra measures within the filtration system. Engineers can even design grinders to install between the collection point and the dust collector in order to reduce the size of particulates. This prevents large particulates from accumulating and clogging the filter media.

The good news with fiberglass dust is that it is not toxic. However, it can cause skin, eye, nose, throat and lung irritation. Small fibers that are inhaled deep into the lungs may aggravate asthma or bronchitis or lead to other chronic lung problems. The dangers of the dust are serious enough that the Occupational Safety and Health Administration (OSHA) has issued permissible exposure limits (PEL) for it. Currently, the limit for respirable dust is 5 mg/m3, and the PEL for total particulates is 15 mg/m3. In order to comply with these regulations, manufacturers need to directly address fiberglass dust.

Here are some good options for collecting fiberglass dust:

  • RoboVent Senturion series dust collectors. This unit can be configured for a wide variety of operations. For example, if a process involves a high volume of dust, engineers can provide more filter media to handle the load.
  • RoboVent PowerBoom portable dust collectors. This unit can collect a high volume of fiberglass dust from a single grinding or cutting station. Its boom arm has a reach of 17 feet, giving workers extreme flexibility.

Consulting with an air quality engineer will ensure that you get the right system designed for your specific needs. In the long run, this system will save you money, because it will be just the right size, no larger. Most importantly, it will ensure that your workers are protected.

What Is The Best Kind Of Dust Collector For Respirable Silica Dust?

While respirable silica dust can be addressed with both source capture and ambient capture equipment, it is best to solve the dust problem at the source, if at all possible. Source capture ensures that you’re collecting the dust—which is often very fine and susceptible to floating away—as soon as possible and preventing it from affecting workers.

The diverse nature of respirable silica dust makes collecting it challenging. Silica dust can vary by particulate size, moisture level and volume—all depending on the process being used. Air quality engineers are able to advise you on the type of dust you have and the best way to mitigate it. For example, high-volume processes often lead to a short filter life among many dust collectors. This problem could lead to major filter replacement expenses, as well as an unnecessary burden put on maintenance staff. RoboVent engineers have decades of experience solving air quality challenges like these.

Here are a couple of the best options for collecting your respirable silica dust:

  • RoboVent Senturion Series dust collectors. This unit provides powerful filtration to address silica dust from multiple operations, if needed. It uses automated controls and other means to run efficiently, saving money and maintenance time.
  • RoboVent PowerBoom portable dust collectors. This unit has a boom arm attached that is capable of capturing dust at the source. With a reach of 17 feet, the unit is a powerful, flexible solution for dust capture.

Capturing respirable silica dust is more important than ever. In 2016, the Occupational Safety and Health Administration (OSHA) changed its standards for a worker’s exposure to crystalline silica dust. The new rule limits exposure to 50 micrograms per cubic meter of air (μ/m3), a very rigid requirement that demands attention from facilities working with respirable crystalline silica.

Air-to-Cloth Ratio: What Is It, And Why Does It Matter?

Sizing your dust collector appropriately for your application and particulate volumes is one of the most important considerations in air quality system design. A big part of that equation comes down to the air-to-cloth ratio, also known as filter velocity. Here's what you need to know about air-to-cloth ratio when it comes to dust collector sizing and selection.

How Dust Collectors Are Sized

There are two important elements to consider when it comes to dust collector sizing:

  • Cubic Feet per Minute (CFM): This is a measure of airflow, or how much air the dust collector is able to move each minute. Your CFM requirements are determined by the size of the enclosure that it must clean and the volume of dust you produce. In general, source capture solutions—such as hooded robotic cellsfume gunsfume arms or crossflow tables—require lower CFM than ambient air filtration solutions, which must turn over air for the entire facility. But the speed with which you are producing particulates matters, too: high-production facilities that generate large volumes of fumes or dust will need to turn the air over faster than facilities with relatively little particulate in the air. A dust collector with higher CFM requires larger blowers and motors, resulting in higher up-front costs as well as higher energy costs over the life of the machine.
  • Area of filter media: This is how much total filter media is in the dust collector, generally measured in square feet. The higher the CFM, and the more particulates you are generating, the more air filtration cloth media you will need.

How to Calculate Air-to-Cloth Ratio

Air-to-cloth ratio (or filter velocity) is simply the amount of air going through each square foot of filter media each minute. It is calculated by dividing the amount of airflow (CFM) by the amount of filter media in the dust collector. For example:

  • A dust collector with airflow of 4,000 CFM and 2,000 square feet of filter media has an air-to-cloth ratio of 2:1.
  • A dust collector with 2,000 CFM and 2,000 square feet of filter media has an air-to-cloth ratio of 1:1.
  • A dust collector with 1,000 CFM and 2,000 square feet of filter media has an air-to-cloth ratio of .5:1.

Determining Air-to-Cloth Ratio Requirements

In general, applications producing large volumes of particulates will require more filter media than those producing fewer particulate. Expressed another way, we can say they require a lower air-to-cloth ratio.

  • For high-production robotic welding, look for an air-to-cloth ratio between 1.5:1 and 2.1:1
  • Most manual welding applications will require air-to-cloth ratios between 2.5:1 and 3.5:1.
  • For most laser cutting applications, manufacturers should look for an air-to-cloth ratio between 1:1 and 1.6:1. Processes that produce heavier particulate loads—thicker materials, continuous production or higher velocity—may need even lower ratios, between 0.5:1 and 0.75:1.

The more particulates are in each cubic foot of air coming through the collector, the lower the air-to-cloth ratio will need to be. Source capture systems will usually require a lower air-to-cloth ratio than ambient systems, because particulates are more concentrated.

The Importance of the Right Ratio

It's important to get the air-to-cloth ratio right when selecting a dust collector. If you have more filter media than you really need, you may be spending more on your dust collector than you need to. But skimping on filter media can have serious adverse impacts on filter life, equipment life, and the overall efficiency and effectiveness of your system.

When air-to-cloth ratio is too high (e.g., not enough filter media for the airflow and volume of particulates you are producing), dust is driven deeply into the filters faster than it can be pulsed off by the filter pulsing system. As dust accumulates, negative pressure builds up on the clean side of the filter, which makes it even harder for the pulsing system to push dust out of the filter and into the containment bin. This causes rapid filter clogging, significantly reducing filter life. Facilities will find that the costs of frequent filter replacements, in terms of both consumable costs and maintenance time, will rapidly outweigh any savings gained by choosing a dust collector with less filter media.

A RoboVent solutions director can help you determine the optimal air-to-cloth ratio for your application type, the size and volume of dust you produce, and your facility's characteristics. RoboVent's VentMapping Engineering Process uses computer modeling to optimize complex air quality system. Getting air-to-cloth ratio right will ensure that your air quality system delivers the performance you expect while minimizing your equipment and operating costs.