About Andy Biancotti

Andy has been working in the maintenance field for over a decade, continuing to learn the secrets of preventive maintenance in the ever growing field of dust collection. Editor and marketing manager.

Entries by Andy Biancotti

Why Interstitial Velocity and Can Velocity Matters in Dust Collector Design?

When designing a pulse-jet dust collector, engineers often focus on the air-to-cloth ratio as the main sizing parameter. However, there’s another equally important factor to consider: interstitial velocity and can velocity. Ignoring this variable can lead to significant performance issues, including poor dust release, higher energy consumption, and reduced filter life.

What is Interstitial Velocity?

Interstitial velocity refers to the upward velocity of air moving through the open spaces between the filter bags inside a dust collector.

This upward air movement occurs in systems that use a hopper inlet. In these configurations, dust-laden air enters through the hopper and flows upward into the filter housing. The clean air passes through the filter bags, while the dust accumulates on the outer surfaces of the bags.

The interstitial velocity can be calculated using the following formula:

Interstitial Velocity = ACFM ÷ ((Length × Width − π × (Bag Dia ÷ 2)² × # of Bags) ÷ 144)

If the interstitial velocity is too high, dust that’s pulsed off during cleaning won’t fall back down into the hopper. Instead, it will remain suspended and be drawn back onto the bags. This leads to a high pressure drop, excessive compressed air usage, and shortened bag life.

What is Can Velocity?

Can velocity refers to the upward air velocity through the entire housing below the filter bags. In other words, interstitial velocity focuses on the air movement between the bags themselves, while can velocity measures the air movement just below them.

The can velocity can be calculated using the following formula:

Can Velocity = ACFM ÷ ((Side L × Side W) ÷ 144)

What Is the Optimal Interstitial Velocity?

There isn’t a single standard value for interstitial velocity. The optimal level depends on several factors, including dust characteristics and operating conditions.

✅ Bulk Density: Dusts with higher bulk density settle more easily, allowing for higher interstitial velocities.
✅ Particle Size: Smaller particles remain suspended longer, so lower interstitial velocities are preferred.
✅ Agglomeration Tendencies: If the dust tends to clump together, it may fall more easily, permitting slightly higher velocities.
✅ Inlet Loading: Both high and low dust loading rates can influence how much upward velocity the system can tolerate.

Each of these factors must be evaluated during the design phase to determine an acceptable range that keeps the collector efficient and prevents re-entrainment.

Optimizing Interstitial Velocity in New Dust Collectors

When designing a new dust collector, engineers typically start by dividing the system’s airflow by the desired air-to-cloth ratio to determine the required filter area. After that, the number, length, and diameter of the filter bags are selected. If the resulting interstitial velocity is too high, several adjustments can be made:

Change Bag Length: Switching from 10-foot to 8-foot bags (or even shorter) can reduce upward air velocity.
Change Bag Diameter: Using smaller-diameter bags (for example, 4½ inches instead of 5¾ inches) increases spacing between bags and lowers interstitial velocity.
Use a High Inlet: A high inlet design introduces dust-laden air into the upper part of the housing, minimizing upward air movement.
Increase Row Spacing: Widening the distance between bag rows (from the standard 8-inch centers to a greater spacing) helps reduce velocity between the filters.

Sometimes a combination of these methods is required. For instance, to achieve an interstitial velocity below 100 feet per minute, you might need to use shorter bags and increase bag spacing simultaneously.

Optimizing Interstitial Velocity in Existing Dust Collectors

Reducing interstitial velocity in an existing dust collector can be more challenging, but several modifications can still be effective:

✅ Switch to Smaller-Diameter Bags: This increases open space in the housing but requires a new tubesheet. Even though the air-to-cloth ratio increases, lowering interstitial velocity can still improve overall performance.
✅ Use Smaller-Diameter, Longer Bags: This maintains the same air-to-cloth ratio while expanding open space. However, housing modifications may be necessary.
✅ Reduce Air Volume: Adjusting the ventilation system to lower airflow (CFM) decreases interstitial velocity directly.
Pleated elements offer much greater filter area, reducing both interstitial and can velocities.

✅ Install Pleated Filters: Pleated elements offer much greater filter area, reducing both interstitial and can velocities. Some rows of filters can even be removed while maintaining or improving filtration efficiency.
These pleated filters are usually 40″ shorter than the bags, doubling the height in the drop-out zone. This increase allows large dust to settle before even entering the filter section, further reducing the load on the filters. When filters “see” less dust, they do not load up as quickly, they are not pulsed as frequently, and they last longer.
✅ Add a High Inlet Section: Retrofitting a high inlet effectively eliminates upward air velocity by changing the airflow path.

Careful consideration of interstitial velocity during the design phase can prevent costly performance issues and maintenance problems later.

For existing collectors, thoughtful retrofits and airflow adjustments can restore performance and reduce re-entrainment problems without requiring a full system replacement.

Keeping interstitial velocity under control is a small design detail that makes a big difference in achieving reliable, efficient, and long-lasting dust collection performance.

November 18, 2025/by Andy Biancotti

Cement Plant Baghouses: Answers to the Most Common Questions

Cement plants deal with some of the toughest dust challenges in any industry: high temperatures, abrasive materials, and nonstop operation. A well-designed and maintained baghouse keeps production efficient and the air clean. Below are some of the most common questions plant and maintenance managers ask us about cement baghouses, along with practical, experience-based answers.

— What exactly does a baghouse do in a cement plant?

Think of the baghouse as the plant’s air filter. It captures fine cement dust from grinding, mixing, and kiln operations before that dust escapes into the atmosphere. Dirty air enters through ductwork, passes through hundreds of fabric filter bags, and exits clean. The dust stays on the surface of the bags until it’s shaken or blown off during the cleaning cycle.

— What types of dust are collected in cement production?

Chemical lime plant dust collection system

Every step of cement manufacturing creates different dust. Handling raw materials like limestone and shale produces coarse particles. Grinding and kiln operations generate much finer dust, sometimes small enough to stay suspended in the air for hours. Then there’s the abrasive mix dust from silos, which needs filters tough enough to resist corrosion and wear. That’s why choosing the right filter media for each stage is key.

— How can I prevent the hopper from clogging when humidity is high?

Some hoppers have an inlet above the discharge. Although many people are tempted to inject the precoat powder through this inlet, it is a very low location, there is not enough air volume to maintain the velocity needed to carry powder to the top section of the filter bags

Dust collector hopper

When humidity rises, dust becomes sticky and bridges over the hopper instead of falling through. A few proven tactics include keeping hopper heaters or insulation active during humid conditions, ensuring your discharge system (like rotary valves or screw conveyors) stays dry, and never letting dust sit idle for long periods. Continuous dust discharge is the best prevention.

— My filter bags keep clogging when humidity increases — what can I do?

filter bags clogged by humidity in dust and air

Humidity in the incoming air causes condensation and blinds the filter bags. The flue gas temperature should be above the dew point before entering the baghouse.

If your bags are blinding due to moisture, start by checking your cleaning system. Pulse valves or compressed air lines that aren’t firing properly can make it worse. Also, look for air leaks that might be pulling in humid ambient air. In some cases, switching to a bag fabric with a moisture-resistant or PTFE membrane finish can dramatically reduce buildup. And if the problem happens during startup, preheat the baghouse to reduce condensation.

— What should I do if I have torn bags but can’t shut down the baghouse?

This is a common challenge in cement plants that run continuously. If shutdown isn’t possible until an overhaul, isolate the compartment where the damage occurred if your system allows it. You can also temporarily plug the tube sheet opening to reduce bypass air. But these are only stopgaps — schedule a full changeout as soon as possible, because running with torn bags not only reduces efficiency but can also damage the fan and downstream equipment.

— How do I deal with corrosion inside the baghouse?

Corrosion usually comes from acidic gases or moisture condensing inside the housing. First, inspect during cooler times of operation — look for rust streaks or pitting around welds and door seals. The fix often starts with controlling condensation by maintaining stable temperature and airflow. For chronic cases, consider upgrading to corrosion-resistant coatings or stainless-steel components in key areas.

— How often should I perform maintenance on a cement baghouse?

In most plants, a visual check should be done weekly, focusing on leaks, bag condition, and hopper discharge. Pulse valves, solenoids, and pressure lines should be inspected monthly for wear or air leaks. At least once a year, a full internal inspection and leak test should be scheduled, preferably during a planned outage.

Download maintenance checklist here.

— How do I know if my baghouse is performing well?

Your best indicator is differential pressure. A stable reading within the manufacturer’s range means airflow and cleaning are balanced. Usually, the normal range is between 3″ to 5″ of differential pressure. If pressure rises steadily, you’re likely dealing with bag blinding, moisture buildup, or a faulty pulse valve. If pressure drops too low, check for leaks or broken bags. Also, keep an eye on visible emissions; a sudden increase in dust escaping the stack is a sure sign something’s wrong.

— What should I include in a baghouse inspection checklist?

A solid inspection form should cover a few essentials:

✅ General info: date, location, production rate, and environmental conditions during inspection.
✅ Visual condition: look for damaged bags, dust buildup, rust, or cracks in the housing.
✅ Operational data: record differential pressure and compressed air pressure.
✅ Observations: note any weak pulse, uneven cleaning, or abnormal sounds from valves or blow pipes.

Keeping consistent records helps you track performance trends and catch issues early.

Download maintenance checklist here.

— What’s new in cement baghouse design?

Modern cement baghouses have evolved. Some systems now feature round bag designs that clean themselves automatically, reducing the need for shutdown maintenance.

IoT sensors are also revolutionizing how maintenance is performed in cement plants. Predictive maintenance (enabled by real-time data from connected sensors) means you can fix stuff before it breaks. This transition not only saves money on repairs and energy but also increases equipment lifespan and improves overall plant efficiency.

Read more about this in the article: Smarter Cement Plants: The IoT Revolution You Can’t Ignore

— Is silicosis a risk in cement manufacturing? What protection should workers use?

Silicosis risk depends on whether your raw materials contain free silica. But even if they don’t, workers should always avoid breathing dust. Proper dust masks or respirators must be worn in dusty areas. The finished cement product itself doesn’t contain free silica.

— Our electrostatic precipitator (ESP) on the long dry kiln (2520 TPD) is not working. A company suggested replacing it with a water fogging system that sprays 10-micron droplets into the kiln riser pipe. They claim it can capture up to 80% of the dust before the ID fan. Do you think this is a good idea? What are the pros and cons?

We don’t see many advantages to this idea. Normally, water spray is used in a conditioning tower to cool and humidify gases before they enter the ESP. In that setup, up to 80% of the dust might fall out in the tower.

However, spraying directly into the kiln riser is very different, it’s not an expansion chamber. Cooling the gases there would also make them contract, increasing the draft at the kiln inlet and possibly causing more dust to escape from the kiln. I don’t recommend this modification. A deeper analysis of the problem is needed before making any changes.

— We produce white cement and are having problems with lumps forming and coating on the silo walls. The cement enters the silo at about 80°C, and we run a bag filter continuously to remove moisture. How can we stop this problem? Would using a polymer liner or insulating paint inside the silo help?

At 80°C, the cement is still hot enough for gypsum dehydration to continue, which causes lumps and buildup. You should cool the cement below 70°C before it enters the silo.

Another solution is to raise the cement mill outlet temperature to around 115°C so gypsum dehydration finishes inside the mill instead of the silo.

— How do I choose the right silo bin vent?

Start by identifying the size and type of silo you’re working with. Most cement and construction materials use standard small or medium silos, and for these, there are well-established bin vent models with proven performance.

If you know your silo’s capacity, that’s often enough to recommend one of our standard bin vents. However, for a more accurate selection, it helps to provide a few key details stated in the following question.

— What information do I need to provide when selecting a silo bin vent?

The more specific your data, the better we can match a collector for your needs. Here’s what helps most:

✔️ Material stored in the silo: Cement, sand, gravel, or other bulk materials. Each has different dust characteristics.
✔️ Required airflow capacity: This depends on your pneumatic pump’s output and how often you load the silo.
✔️ Loading frequency: For example, twice per week or twice per day. This affects both the cleaning method and the filter’s air-to-cloth ratio, more frequent loading requires more filter area.
✔️ Loading pipe size: Ensures the airflow matches the system’s capacity.
✔️ Pressure relief valve: In some cases, you may need an emergency valve to prevent overpressure if the filter becomes blocked.

If you don’t have all this data, that’s fine, we can estimate using a safety margin of 1.2–1.5× to make sure the bin vent performs reliably under all conditions.

— What’s better: a cartridge filter or a baghouse filter?

Cartridge filters are less expensive upfront and suitable for smaller silos or less frequent loading.

This depends on your operation’s workload and budget priorities.

✅ Cartridge filters are less expensive upfront and suitable for smaller collectors or less frequent loading.
✅ Baghouse filters cost more initially but are designed for heavier use. They handle frequent loading and higher dust volumes much better.

In other words, if your collector has regular or high-volume use, a baghouse filter will save you more money in the long run by reducing maintenance and filter replacements.

— Which Filtration Media Is Best for Cement Dust Control?

The first step in deciding which filtration media to use is knowing what is trying to be captured.

Aramid baghouse filters (trade name Nomex) is widely used because of its resistance to relatively high temperatures and to abrasion.

General applications for Aramid felt includes highly abrasive dust and chemical applications with high temperatures

If the application involves fine dust particles in high concentrations, then it would be best to use synthetic fiber filters. Highly concentrated dust particles need a greater surface area for adsorption/collection of smaller-sized particles. Two highly reliable filtration media for concrete dust collection are aramids and Polyester.

Aramids, also known as Nomex, is cost-effective and highly efficient at filtering small particles at high temperatures. Nomex can successfully filter particles down to the 2 micron range. Felted aramids are generally the first choice for pulse jet baghouses used in cement, utility and incineration operations around the world. If a project needs to be able to filter even smaller particles, Baghouse.com offers a Nomex product with the ability to filter particles down to the submicron range.

Polyester is by far the most widely used fabric as it has good overall qualities to resist acids, alkalis, and abrasion, is inexpensive and has a good temperature range.

Polyester baghouse filter

Polyester is another popular filter media used in concrete plants. Polyester can be clad with a PTFE treatment to maximize its chemical resistance.

How can I train the maintenance personnel at my cement plant?

At Baghouse.com, we offer several flexible training options tailored to cement plants and other heavy-duty operations:

▶️ In-person training: Hands-on, on-site instruction focused on your specific system and challenges. This option includes a system audit with a report on possible improvements to your facility.
▶️ Virtual training: Live sessions led by our experts, ideal for teams at multiple locations.
▶️ Online training course: Self-paced modules covering everything from filter changeouts to differential pressure analysis.
▶️ Combined training: A hybrid approach that blends virtual lessons with an expert, along with the Online training course.

Do you have any additional questions that were not covered in this article?

If you have specific questions about your cement baghouse setup or want expert guidance on maintenance or upgrades, reach out to the team at Baghouse.com. Our dust collection specialists can help you evaluate your system and offer practical solutions tailored to your operation.

October 28, 2025/by Andy Biancotti

Baghouse Training, Dust Collection 101

NEW FREE WEBINAR: Boosting ROI with Smart Sensors & Industrial IoT

If you work in operations, engineering, facilities management, plant management, EHS, or purchasing, you are familiar with the constant pressure to keep production running smoothly while controlling costs. Unplanned downtime, wasted energy, and manual inspections drain resources and put safety at risk. This webinar will show you how IoT sensors and predictive monitoring can change that equation, helping you cut costs, prevent failures before they happen, and clearly demonstrate ROI. It’s a must-attend webinar!

What to Expect from the Webinar

This webinar will show you how integrating IoT sensors into your dust collection system can slash maintenance costs, extend equipment life, and eliminate manual guesswork. Our expert speakers will guide you through the power of predictive monitoring, with practical examples from real-world facilities.

Program

🔹 Welcome & Overview
🔹 What is IoT, and how does it apply to your facility?
Webinar Special Guest – Eric Schummer, CEO of Senzary

🔹 IoT Technology Explained In Depth – Interview with Eric Schummer
- ➡️ What are the building blocks of an IoT platform?
- ➡️ How data gets collected, transmitted, and visualized? What are the basic steps for implementing IoT tools?
- ➡️ What are some IoT sensor types relevant to dust collection and other industrial equipment?
- ➡️ How do IoT platforms interface with existing enterprise systems?
- ➡️ Review ROI cases for common facility types, and case studies.
🔹 How Can I Implement This Technology In My Facility?
🔹 Conclusion & Q&A

Why Should You Attend?

✅ Gain Practical Knowledge: You’ll learn exactly how sensors like particulate, pressure, airflow, and rotary monitoring devices can be integrated into your dust collection system to reduce unplanned downtime and avoid costly failures.
✅ Optimize Maintenance and Energy Use: Traditional “fix it when it breaks” or over-cleaning approaches waste time and money. This webinar will show you how predictive maintenance saves energy, avoids over-cleaning, and extends the life of your filters and fans.
✅ See the ROI Clearly: We’ll walk through real cost comparisons, labor vs. sensors, unplanned outages vs. predictive monitoring, so you can see how facilities are saving thousands each year.
✅ Learn from Industry Experts: With Baghouse.com and Senzary teaming up, you’ll hear directly from leaders who understand dust collection challenges and how IoT can solve them.

How to Connect

Attending the webinar is easy! Simply register using the link below. Once registered, you’ll get a confirmation email with all the details to log in. Don’t miss it:

📅 Date: Wednesday, October 8th, 2025

⏰ Time: 1:00 PM (EST)

📍 Platform: Zoom

🔗 Registration Link: Click here.

The session will be interactive, with a live Q&A at the end, so be sure to come prepared with any questions you may have about dust collection systems and projects.

Questions & Answers Section

During this section, our experts answered some of the live questions our attendees sent.

✅ What types of sensors work best for dust collection?
✅ Where should sensors be installed in a baghouse?
✅ How does predictive monitoring actually reduce downtime?
✅ Can IoT technology be retrofitted into older systems?
✅ How does sensor data integrate with plant operations?
✅ What is the cost-benefit of sensors vs. manual inspections?
✅ How can IoT improve safety and compliance with EHS standards?

Sign up now and take the first step toward smarter, safer, and more cost-effective dust collection.

We can’t wait to see you there!

September 23, 2025/by Andy Biancotti

Baghouse.com News

Federal Agency Says Fatal Fremont Explosion Was Preventable

A federal agency says the deadly July explosion at a Fremont, Nebraska, industrial plant was “a terrible tragedy” that never should have happened.

On Wednesday, the U.S. Chemical Safety and Hazard Investigation Board (CSB) released new information about the July 29 blast and fire at Horizon Biofuels. The accident killed worker Dylan Danielson, 32, and his two daughters, ages 8 and 12.

CSB Chairperson Steve Owens called it “a completely avoidable hazard,” saying early evidence shows it was likely a combustible wood-dust explosion—a well-known risk in wood-processing facilities.

Investigation Still Limited

The CSB investigates serious chemical accidents but does not set regulations. Its work at Horizon has been delayed because the site is too dangerous to enter.

“The facility remains unsafe, with a risk of collapse,” the agency said. Officials have advised keeping a safe distance until the building is stabilized.

What Happened That Day

Shortly before noon, witnesses saw a sudden release of dust or smoke from a tower. Flames appeared, followed by a powerful blast that tore through the structure.

Danielson was working inside. He survived the initial explosion but was trapped. He managed to speak by phone with the plant manager, who was off-site, and with his wife.

Neighbors heard him calling for help and tried to reach him, but unsafe conditions forced them back. Emergency crews arrived, evacuated the area, and could not enter until the next day, when they recovered the three victims.

Dust-Control System At the Plant

The CSB said its investigation will focus on the operations and conditions at the Horizon Biofuels facility, as well as dust-control systems, industry guidance for safe dust operation and regulatory oversight. A combustible dust explosion can occur when certain conditions align at a facility, including dust accumulation, dispersion and ignition within a confined space, potentially triggering a powerful secondary explosion, like the one that occurred at the Horizon Biofuels facility.

The CSB has examined many such disasters. A 2006 study reviewed 281 dust explosions, causing 119 deaths and 718 injuries across industries.

Past Safety Issues

Records from the Occupational Safety and Health Administration (OSHA) show Horizon Biofuels was cited in 2012 for four serious violations and fined $6,000.

The Nebraska State Fire Marshal’s Office, leading the state investigation, also called the incident an “accidental dust explosion” in its preliminary report.

You Can Prevent It

Combustible dust incidents are preventable with proper design, inspection, and maintenance. Baghouse.com helps industrial facilities diagnose hazards, install combustible dust prevention equipment, and identify measures to prevent explosions… protecting both your workers and equipment.

September 19, 2025/by Andy Biancotti

Dust Collector Maintenance, Operation & Optimization, Dust Collector Troubleshooting

How to Protect Your Filter Bags During Startup (And Why It Really Matters)

New bags take in, that’s why it’s essential to protect them during startup

Starting up a new set of filter bags in your baghouse might seem like a routine step, but it’s actually one of the most critical moments in determining how long those bags will last. Many operators don’t realize that what happens in the first 24 to 48 hours can make or break the long-term performance of the filters.

Here’s the issue: brand-new filter bags are clean and porous. That means air and dust can move through them very easily. If you send the full process flow through them right away, high-velocity dust particles can slam into the bare filter media, embedding deep into the fibers. This leads to premature blinding, where airflow is restricted, the pressure drop rises, and bag life is drastically shortened.

To understand this better, let’s talk numbers. A brand-new bag may have a permeability of 25 to 60 CFM/ft². That’s how easily air flows through it. A seasoned bag with a healthy dust cake may be down to 5 to 10 CFM/ft². A bag that’s blinded? Less than 2. That’s a massive drop. The takeaway: new bags take in a lot more air and dust—if you’re not careful. That’s why it’s essential to protect them during startup.

What’s The Right Way to Start Up a New Baghouse Compartment?

The short version: precoat, restrict, and go easy on the cleaning.

Precoat powder comes in 50-lb bags.

Start by applying a precoat—a compatible fine powder like limestone dust or commercial precoat products. This coats the clean bags with a thin layer of dust that acts like a buffer. It protects the fabric from direct contact with abrasive or sticky dust, and helps absorb moisture or acids that might form when the system is heating up.

Think of this step like preparing a fishing net: imagine you’re about to toss a net into a lake full of small fish. If you send it in empty, the fish will slip right through the holes. But if you first catch a few big fish and they block the holes, they form a barrier—so that even the smaller fish can’t pass through anymore. That’s exactly what a precoat does. The coarse particles land first, fill in the open pores of the fabric, and create a protective layer. When finer, stickier particles arrive later with the process dust, they’re less likely to get embedded in the media because the “big fish” have already blocked their path.

Next, limit the airflow. For reverse gas or shaker baghouses, you can do this by closing inlet or outlet dampers down to about 20% or by slowing down the fan. For pulse jet systems, you can also reduce fan speed or limit compressed air. Remember, the goal is to keep flow near the design air-to-cloth ratio, not wide open. Just enough to ventilate the system.

Finally, reduce or disable the cleaning cycle for the first 8 to 12 hours—or even longer if possible. That dust cake needs time to build. In reverse air systems, stop the reverse gas or shaking. In pulse jets, lower the compressed air pressure going to the pulse header. If you start blasting the bags too early, you’ll strip away the precoat and delay cake formation.

A Few Extra Tips

Turn on the hopper heaters before startup to preheat the compartments to avoid condensation

🔹 If your baghouse has hopper heaters, use them before startup to preheat the compartments. This helps you avoid hitting the dew point and forming condensation.
🔹 Be especially cautious with high-moisture or acidic processes—the precoat is even more important here.
🔹 Always document how the startup was handled. If you notice premature failures later on, it’s helpful to trace things back to how the bags were introduced into service.

The Payoff of a Proper Startup Routine

Taking care of your bags during startup is one of the smartest things you can do to extend their life and avoid expensive issues down the road. A little extra attention now can save you thousands of dollars in early bag replacements, lost production time, and increased energy costs.

Don’t let brand-new filters fail early. Precoat them, limit the airflow and give the filters time to settle in.

Need help with your startup procedure or choosing the right precoat material? Reach out—we’re always here to help!

August 20, 2025/by Andy Biancotti

News

“Our Track Record Says It All” —Interview With David Dal Santo

Interview With David Dal Santo, our Director of Operations

Director of Operations at Baghouse.com, David DalSanto

With decades of experience finding solutions to our customers’ often complex dust collection needs, Baghouse.com has acquired extensive experience overcoming obstacles foreseen and unforeseen.

Read what our Director of Operations, David DalSanto, who has been with the company since its inception nearly four decades ago, has to say about some of the most exceptional projects Baghouse.com has completed.

— "What former projects of Baghouse.com are you the most proud of having been a part of?"

David – “John Deere – Central Foundry – Waterloo, IA – A violent explosion in the furnace did extensive damage to the structure, including the housing, tubesheet and roof structures. We brought in a very large crew and worked around the clock, “improvising and adapting” as the repairs progressed. We sourced many of the needed repair parts, but also fabricated the main parts and structures we needed on site. We had the entire Baghouse system back on line in only nine days.”

— "What were some of the most challenging projects that you have tackled?"

Original condition unit with envelope filters and shaker mechanism

David – “Goodyear Tire & Rubber Co. – Topeka, KS – Old ‘Envelope” style Dust Collectors by W.W. Sly & Pangborn were a “maintenance headache” for the plant. We did multiple Pulse-Jet conversions to the existing Dust Collectors. By removing the inner workings and roof structures, we made room to install modern Clean Air Plenums. We modified the ductwork and installed High Efficiency Cylindrical filter bags and cages to take advantage of the Pulse-Jet cleaning system.”

— "What were the specific problems that you had to face?"

David – “Most units were in the center of a large building, an area that could not be serviced by conventional cranes.”

Follow Up Question — "How did you overcome those problems?"

As we couldnt use traditonal cranes, the collectors had to be installed using Helicopter lifts

David – “New equipment had to be installed using Helicopter lifts. As a licensed pilot/aircraft owner myself, I know well just how dangerous these aerial maneuvers are, and the great skill, and expertise that are needed to execute these operations safely. Despite all of the challenges we faced to get this Baghouse back up and running, downtime for each conversion was only 3 to 4 days each. Again remarkable considering the circumstances.”

— "What do you feel are some of the greatest dangers you know of regarding safety on the job site, and how do you handle them?"

David – “Several dangers present themselves regularly in our line of work. #1 – Harmful gasses leaking into the work area. #2 – Unsafe structures/hazard of falling objects. #3 – Fire hazards during welding/cutting operations. We work with our foremen, safety personnel and plant representatives to identify all of these dangers specific to each job before we begin. We then brief our people accordingly, enabling them to keep a close watch for these hazards and avoid them.”

Identifying all the dangers specific to each job before we begin is one of the most important routines of our team

“The greatest danger we encounter however is; unsafe materials hoisting practices by plant or outside contractor personnel. Because of my personal experience as a Structural IronWorker and Heavy Machinery Mover, I know full well the immense danger to life that this process poses. I have seen first hand the tragedy that results when people who are not qualified to carry out this task, or simply have a disregard for lifting/hoisting safety measures.”

“As such, we prefer to do our own lifting/hoisting. All of which is directly led by a duly trained foreman, with extensive training and experience conducting these lifts safely and properly.”

— "What are some of the biggest mistakes you notice other companies make when servicing a Dust Collector?"

Some of the biggest mistakes we notice other companies make when servicing a Dust Collector is to tension the structural filter bags incorrectly.

David – “#1 – Incorrect handling/installation practices on specialty filters such as Fiberglass and PTFE Membrane media. #2. Incorrect tensioning procedures on structural filter bags. #3 – Incorrect start up settings/procedures and Incorrect operations procedures.”

“In many cases we are called to fix another company’s mistakes. We often find that a rushed operation, or an overall lack of technical expertise & attention to detail on account of the contractor has caused many problems. These shortcomings later on, needed to be corrected by Baghouse.com during subsequent maintenance visits.”

— "What would you say makes Baghouse.com different from your competitors?"

David – “We care about our customers and we do everything possible to help get their operation running as efficiently as possible or get them back up and running quickly after problems do arise.”

“We have a long history of successfully responding to emergency breakdown situations in which we were able to get the customer back into operation quickly with minimal downtime and lost productivity. This is no easy task, and you will be hard-pressed to find another company capable of duplicating our successes in this area.”

“We also have initiated many Regular Maintenance Programs, Environmental Emissions & Energy Audits, that to this day continue saving our customers money through avoiding violations and unplanned downtime, and increasing efficiency.”

“At the end of the day, we don’t just fix problems – we fix them fast, efficiently, and with a little bit of creativity…It’s not always glamorous, but hey, someone has to get the Baghouse back up and running!

We’ve seen it all, done it all, and if we don’t know the answer right away, we’ll find it. We are always ready for the next challenge.”

July 29, 2025/by Andy Biancotti

Dust Collection 101, Dust Collector Maintenance, Operation & Optimization

Precoating: A Simple Step To Boost Performance In Filters

Why Consume Expensive Downtime To Precoat Your Dust Collector’s New Filters?

One good reason: Dust and fine particles 0.5 microns or smaller can leak right through a new bag or cartridge filter’s pores, working their way deep into the media to the point of clogging the filter and slowing or stopping airflow through your collector.

So if your dust particles are smaller than 10 microns, taking the time to precoat your new filters’ surface with a dry precoating material is the smart thing to do.

Precoat powder is a fine, inert material—typically made of substances like cellulose or diatomaceous earth—used in dust collection systems to protect and enhance filter performance. It is applied as an initial layer on new filter bags or cartridges before the system begins collecting process dust.

Common pre-coat materials include:

Expanded Perlite

Expanded Perlite: Absorbs sticky residues and hydrocarbons while providing a porous barrier.

Diatomaceous Earth

Diatomaceous Earth: Known for its fine particle capture and moisture-absorbing properties.

Calcium Carbonate

Calcium Carbonate: Neutralizes acidic contaminants and provides an effective protective layer.

Benefit: Longer Filter Life

When your dust stream contains a significant percentage of submicron particles, precoating can reduce or prevent the premature failure of your new filter media. Precoating material will build up an initial dust cake on the filter, preventing dust particles from flowing into and clogging the media.

Typical service life for bag filters without precoating is 1 to 3 years and for cartridge filters is 3 to 12 months. Depending on the application, precoating can extend the filter’s life substantially providing enormous cost savings in replacement filters and changeout labor.

Precoating material will build up an initial dust cake on the filter, preventing dust particles from flowing into and clogging the media.

Precoating new filters provides other benefits, too. By keeping particles on the filter surface, precoating improves the initial filtering efficiency at startup. Precoated filters are easier to clean and provide better dust cake release for applications with process air that contains moisture, hydrocarbons, or both. Precoating materials, which don’t burn, can be applied to filters made of fire-retardant media to help reduce explosion risks in spark-producing processes, such as milling.

So, as a review, the main benefits can be summed up as follows:

✅ Sets up consistent porous dust cakes throughout all the filters.

✅ Absorbs moisture and oils that can shorten bag life.

✅ Safe to handle, lightweight powder remains on the filter bags.

Pore Opening Size and Particle Size

Now that we have analyzed the benefits, there are two additional factors you should know when deciding to precoat your filters:

🔶 The pore openings in bag filter media are usually larger than in cartridge filter media, so precoating is required more commonly for bag filters than for cartridge filters. For example, the pore openings in a 16-ounce polyester bag filter are 19.675 microns, significantly larger than the 10.253-micron pore openings in a comparable 80-20 polyester blend (80 percent cellulose, 20 percent polyester) cartridge filter.

🔶 The smaller your dust particles are, the more important it is to consider precoating your filters. And depending on the kind of size analysis used for determining your dust’s size distribution, the particles may be smaller than you think.

The true filtering surface is not the bag itself, but the dust layer or filter cake. When adding a precoating material, you make sure that even the smallest particles are captured by the filter.

Instructions For Precoating Your Filters

The method for precoating new bag or cartridge filters is relatively simple and doesn’t require any special equipment. After installing the new filters in your dust collector, you simply run the collector fan at a low volume to draw precoating material into the collector and onto the filters. For a baghouse or large cartridge collector, this process typically takes 3 to 4 hours; for a small cartridge collector, it can take just 30 to 60 minutes.

The method for precoating new bag or cartridge filters is relatively simple and doesn’t require any special equipment.

Step by step

Whether you’re precoating bag or cartridge filters, the procedure is the same. After installing your new filters in your baghouse or cartridge collector, follow these steps:

For Collectors With A Full Set Of New Bags:

With the fan running, the cleaning mechanism off, and the process off, inject Baghouse.com precoat powder into the system.
With the cleaning mechanism remaining off, bring the process online.
Operate under normal conditions and allow differential pressure to reach 4” to 5” w.c.
Monitor differential pressure across the collector. It may be possible to reduce the frequency and/or duration of cleaning and maintain adequate differential pressure. This may extend filter bag life.

Some hoppers have an inlet above the discharge. Although many people are tempted to inject the precoat powder through this inlet, it is a very low location, there is not enough air volume to maintain the velocity needed to carry powder to the top section of the filter bags

For Bag Recovery And Spot Changing Online Cleaning Collectors (Pulse-Jet Only):

Turn off the fan and run the system through the cleaning cycle two or three times to purge the excess particulate. Turn off the cleaning system after purging the collector and leave it off through step 5.
With the process off, restart the fan and inject Baghouse.com precoat powder into the system.
With the cleaning mechanism remaining off, bring the process back online.
Operate under normal conditions and allow differential pressure to reach 4” to 5” w.c.
Turn the cleaning system on. Monitor differential pressure across the collector. It may be possible to reduce the frequency and/or duration of cleaning and maintain adequate differential pressure. For better cleaning on pulse-jet applications, stagger the row pulsing to prevent re-entrainment of particulate onto the bags.

Off-Line Cleaning Collectors (Reverse Air, Shaker, And Pulse-Jet)

Individually isolate the inlet and outlet of the compartments that will receive the injection and manually run through the cleaning cycle two or three time.

Turn off the cleaning mechanism in each compartment and leave it off until step 6.
The outlet of the compartment should be opened on negative systems. On positive systems, both the inlet and the outlet to the compartment should be opened.
Inject Baghouse.com precoat powder into your system.
With the cleaning mechanism still locked out, the isolated compartment should be returned to service. The pressure drop should be allowed to build up to the normal operating differential pressure before the cleaning mechanism is reactivated.
Turn the cleaning system on. Due to increased airflow and decreased differential pressure, it may be possible to reduce the frequency and/or duration of cleaning. This may extend filter bag life.

NOTE: DO NOT SHUT OFF THE COLLECTOR FAN FOR A MINIMUM OF 8 HOURS AFTER THE PRECOAT POWDER INJECTION!
The precoat powder may dislodge and fall into the collection hopper if the fan is shut off.

Calculating and Applying Precoat Powder

Precoat powder comes in 50-lb bags.

A good rule of thumb is to use one pound of pre-coat for every 20 square feet of baghouse filter media. Operate the system at 50% of the design airflow to the baghouse. This results in an inlet duct velocity of approximately 2000 FPM. Avoid dropping the velocity below this threshold.

The material should not be “dumped” into a system. Use a pre-coat feed rate of 1/3 pound per minute per 1000 CFM of reduced airflow. For instance, for a 25,000 CFM reduced airflow system, the feed rate would be 7.5 lbs./minute.

Calculations for Application

Bag Diameter (inches) x 3.1416 = Circumference

Circumference (inches) x length (inches) = Inches² Per Bag

Inches² / 144 = Feet² Per Bag

Feet² x Total Number of Bags = Total Feet²

Total Feet² x .042 lbs = Precoating agent (pounds) Required

Inspecting and Verifying Precoat Coverage

After applying the pre-coat, isolate each filter compartment and inspect the filter bags to confirm they’ve developed a uniform coating

After applying the pre-coat, isolate each filter compartment and inspect the filter bags to confirm they’ve developed a uniform coating—ideally about 1/16 inch thick. It’s also important to check the dust collector hopper to ensure there hasn’t been excessive pre-coat material dropout, which could indicate uneven distribution or overfeeding.

Once the inspection is complete and coverage is confirmed, gradually increase the airflow to the system’s design-rated volume. At this point, you can reactivate the dust discharge equipment, such as the airlock. However, hold off on restarting the filter bag cleaning system until the differential pressure across the bags reaches 3 to 4 inches. This delay allows the pre-coat to settle and form a stable dust cake on the filter media before the first pulse cleaning cycle begins.

Conditioning Feed Of Precoat Powder

After the initial injection, Baghouse.com precoat powder can be added on a continuing basis as a conditioning feed to improve overall long-term collection efficiency and absorb damaging moisture. This provides improved porosity of the dust cakes, resulting in better airflow while reducing bag blinding and depth penetration that can shorten filter bag life.

Although every case is site-specific, the following formula applies for conditioning feed:

Conditioning Feed = 10% of Precoat Powder Initial Control Layer Per Day

The extended life, improved efficiency, and energy savings when precoating your media filters is always a very cost effective solution.

Do you have any additional questions regarding the precoating powder use for your specific application?

July 15, 2025/by Andy Biancotti

Baghouse Design, Dust Collection 101

Our Free Baghouse Design Calculators Are Live!

We’re excited to announce something that’s been a long time coming—a full set of free online calculators designed to make dust collection system design and troubleshooting way easier.

If you’ve ever had to stop what you’re doing to run a quick air-to-cloth calculation, estimate how much precoating powder you need, or figure out what duct diameter to order… this is for you. These calculators were built for people like you: engineers, operators, maintenance personnel, and even purchasing staff… to quickly get answers without digging through spreadsheets or flipping through manuals.

Here’s what we’ve launched:

✧ Air-to-Cloth Ratio Calculator – See if your system is sized right or running outside the ideal range. Great for both design and troubleshooting.
✧ Interstitial Velocity Calculator – Quickly check if the air between the bags is flowing fast enough to keep dust suspended and prevent dropout.
✧ Can Velocity Calculator – Measure the vertical airflow between the baghouse housing and filters.
✧ Total Filter Cloth Area Calculator – Determine how much filter media your system needs to support your airflow volume efficiently.
✧ Leak Testing Powder Calculator – Get an accurate estimate of how much fluorescent leak test powder you’ll need for a given baghouse.
✧ Precoating Powder Calculator – Find out how much precoating agent to apply before startup to protect your filter bags from blinding.
✧ Air Velocity Calculator – Helps ensure you’re maintaining the right conveying velocity in your ductwork to avoid dust dropout or wear in your ducts.
✧ Duct Sizing Calculator – The goal is to select a duct size that allows for proper dust conveyance without excessive friction loss or particle dropout.

These tools are already proving useful in day-to-day work, from initial design to routine maintenance, even quoting and system retrofits. The goal is to take the guesswork out of some of the most common calculations we all deal with in the field.

Of course, these are reference tools, not one-size-fits-all answers. Real-world systems can be messy—airflow changes, system resistance fluctuates, dust loads vary, and what looks good on paper might not work in practice. That’s why we always recommend reaching out to an expert (like us at Baghouse.com) to review your results before making big decisions.

But if you need quick numbers, you’re in the right place.

Try the calculators out today and see how much time (and stress) they can save you.

At Baghouse.com, we believe that knowledge is power, especially when it comes to investing in equipment as critical (and expensive) as a dust collection system. That’s why we’re making these calculators available for free. Our goal is to help people make informed decisions by understanding the numbers behind the quotes they receive.

Whether you’re an engineer comparing different system designs, a plant manager reviewing proposals, or a purchasing agent trying to get the best value, these tools give you the ability to ask better questions and spot red flags. In an industry where it’s all too easy to get sold a one-size-fits-all system out of a catalog, we want to empower you to choose the solution that’s right for your application—one that performs reliably for years to come.

June 19, 2025/by Andy Biancotti

Baghouse Design, Cement and Construction Materials, Dust Collector Maintenance

Asphalt Production & Dust Collectors Design and Maintenance (Part 3)

As we have seen in the previous two articles, when you’re running a hot mix asphalt plant, your dust collector isn’t just another piece of equipment—it’s the beating heart of your dust control system. But for many plant operators and maintenance teams, baghouses are still a bit of a mystery. What makes them work well? Why do they suddenly clog up or burn through filters? And how can you keep yours running for years, not just months?

Why Asphalt Plants Need Dust Control

Regulations are only getting stricter. Hot mix plants must meet tight emissions limits for dust, for sulfur dioxide, and other volatile compounds.

Hot mix asphalt plants are regulated under both federal and local environmental laws, particularly for air emissions. These plants must use effective dust collection and pollution control systems to meet standards for:

♦️ Particulate Matter (PM): Baghouses (fabric filters) or scrubbers must capture fine dust generated in drying, mixing, and conveying.
♦️ Volatile Organic Compounds (VOCs) and Hydrocarbons: Released during asphalt heating and mixing. Controlled through burner tuning, proper operating temps, and vapor capture systems.
♦️ Sulfur Dioxide (SO₂), Nitrogen Oxides (NOx), and Carbon Monoxide (CO): Emissions from combustion systems, regulated especially when using fuel oil, coal, or RAP (Reclaimed Asphalt Pavement).
♦️ Opacity Limits: Visible emissions (smoke/dust) from the stack must remain below specific opacity percentages (often 20% or lower).

Design Requirements

🔹 Design: Since many asphalt plants are portable, dust collection systems must also be rugged and easy to transport. The compactness of the design and ease of maintenance are all key considerations.

🔹 Filter Media: Asphalt production involves high temperatures. The baghouse installed on the dryer end of the system must be able to handle continuous operating temperatures up to 375°F (190°C) — and sometimes even higher during spikes.

For this reason, aramid filter media (commonly known by the trade name Nomex®) is the go-to choice. It’s a heat-resistant material that performs well under the high-temperature, high-dust conditions of asphalt operations.

To improve performance in space-constrained systems, pleated filter elements made with aramid media are gaining popularity. These offer increased surface area in the same or smaller footprint, which helps overcome the limitations of older, compact baghouse designs. However, pleated filters come with some temperature limitations and should be used where appropriate.

If you choose membrane-coated bags to cut down emissions, be warned—hydrocarbon contamination from the mix or burner can blind those bags fast.

Knockout boxes or cyclones reduce dust loading on the bags and help stabilize pressure drop, which makes the whole system easier to maintain and run.

🔹 Dust Cake and Precleaners: A good cyclone can pull out 80–90% of large aggregate dust before it ever hits the bags. This helps build a healthy dust cake and cuts wear on the filters. We also sometimes install knockout boxes or cyclones when space or volume demands. These reduce dust loading on the bags and help stabilize pressure drop, which makes the whole system easier to maintain and run.

🔹 Fan Sizing and Air-to-Cloth Ratio: Too many asphalt plants are still running baghouses with poor air-to-cloth ratios—sometimes 5:1 or more—which leads to overloaded filters and early failure. Can velocity and fan performance need to be dialed in carefully to avoid high differential pressure (DP) and re-entrainment. We recommend staying between 3.5–4.5:1 for most applications.

🔹 Cleaning System: It’s almost always pulse-jet cleaning in the asphalt world. Most systems run at 60–70 psi, which is usually enough. Cranking it up to 90–100 psi often just shreds bags faster without actually solving the problem.

Your cleaning should be on-demand with a magnehelic or photohelic set to trigger between 3–5 inches W.C. Don’t space out cleaning pulses too far apart—if you wait too long between row cleanings, air takes the easiest path and some bags end up doing all the work.

Conveyor belts are used to move a large amount of material between different parts of the asphalt plant

🔹 Discharge System: Reusing the dust you collect (as we talked about in the previous articles) makes the whole operation more profitable. To handle the bulk material collected, you need one of the following options:

✧ Rotary Airlocks, especially for coarse or abrasive dust.
✧ Slide gates are cheap and simple, but they’re prone to leaking and jamming.
✧ Conveying Systems: Screw conveyors are standard, but some plants are now implementing conveyor belts or even pneumatic systems for faster, cleaner transfers.

Asphalt-Specific Challenges

One big challenge in asphalt baghouses is hydrocarbon vapors. These can migrate into the baghouse, coat the bags, and lead to blinding—especially if you’re using membrane filters. It’s a common issue when burners aren’t tuned properly or during heavy recycling (RAP) operations. Make sure your burner system is dialed in and your bags are suited for the environment.

Condensation is also a frequent challenge in this industry.

When hot gases hit cold metal (or filter bags), moisture condenses. This turns dust into a kind of mud that eats through metal and fabric alike—especially when sulfur in the fuel creates an acid flash.

That’s why preheating the baghouse is critical. We recommend:

✧ 20+ minutes at 350°F during startup.
✧ Make sure the tubesheet, bags, and ductwork are all above the dew point—especially in cold or wet conditions.
✧ Even during midstream restarts, don’t rotate the drum until preheat is complete.

Nomex can handle up to 400°F continuously (spikes to 450°F), but you want to avoid running too cold. The sweet spot is usually around 250°F. Running cold causes condensation, but overheating can destroy the bags. Train your operators to monitor temperature and pressure closely to prevent problems before they start.

What Should An Asphalt Plant Baghouse Inspection Sheet Include?

A good inspection checklist can help you spot issues early, keep your production up, and avoid costly downtime. Here are the key things to keep on your baghouse inspection sheet:

1. Is it the right size?
A baghouse that’s too small will choke your production. One that’s too big can make it tough to hit the right temps. The sweet spot? Around 200 CFM per ton of asphalt mix, assuming about 5% moisture content. So, if you’re running a 400-ton-per-hour plant, you’ll need something around 80,000 CFM.

2. Any leaks?
Make sure everything from the drum seals to the ductwork is airtight. Think of your dust collector like a big vacuum—if there’s a hole in the hose, it won’t suck up anything properly.

3. How are your filter bags holding up?
Worn-out bags lead to high pressure drops, poor cleaning, and lower production. Keep them in good shape by checking temperatures, tuning the burner right, and making sure everything stays in the recommended range. Bags aren’t cheap, so taking care of them will save you serious money—and make your system more attractive if you ever decide to sell it.

Other things to check regularly:

🔹 Total number of bags and their individual ID numbers
🔹 Bag damage (tears, holes, or thinning material)
🔹 When bags were installed, cleaned, or replaced
🔹 Airflow readings (CFM) and velocity (FPM)
🔹 Are airflow and pressure drop within normal range?
🔹 Check airlocks and dampers for proper function
🔹 Log pressure drops across the baghouse and individual compartments
🔹 Investigate weird pressure readings
🔹 Exhaust gas temperatures
🔹 Humidity levels inside the baghouse
🔹 Size and type of dust being collected
🔹 Any signs of system leaks

Invest Some Now or Invest a Lot Later!

Smart plant managers know that a little upfront investment in dust collection pays off big down the line.

Spend on quality filter bags rated for your operating temps, install a proper precleaner like a cyclone to reduce dust loading, and make sure your cleaning system uses demand-based controls. Don’t skimp on preheat systems either—they prevent condensation and extend bag life. Even setting up a solid inspection and maintenance schedule with trained personnel can prevent costly shutdowns.

The key takeaway from this series of three articles is that having the right equipment, the right process, and the right support makes the difference in how efficient (and profitable) your plant is.

Would like to go over some of the information in the previous two articles? Here are the links!

Would like some help designing or upgrading the dust collection system of your asphalt plant?

June 10, 2025/by Andy Biancotti

Baghouse Design, Cement and Construction Materials

Asphalt Production & Baghouse Fines (Part 2)

In the first part of this series, we looked at how an asphalt plant works and why it needs a dust collection system. Now, in part two, we’ll go a step further and talk about baghouse fines (BFs)—what they are, how they’re recycled, and the role they play in asphalt quality. If you’re working at an asphalt plant or managing dust collection equipment, understanding this topic can help you get more out of your system. Also, in addition to helping the environment, you’re also saving money. Reusing fines cuts down on material costs and can actually make your asphalt stronger and more durable, which means fewer problems down the road and less money spent fixing them.

A Closer Look At Baghouse Fines

Baghouse fines are the fine particles your dust collector captures during asphalt production. They’re often seen as just a byproduct, but they can actually be a valuable resource. With sustainability becoming a bigger priority in construction, more producers are finding ways to reuse these fines in hot mix asphalt (HMA)—without sacrificing pavement performance.

Most asphalt plants today try to reuse as much of the collected dust as possible (around 80–90% of baghouse fines end up back in the mix.)

In fact, most asphalt plants today try to reuse as much of the collected dust as possible. Industry estimates say around 80–90% of baghouse fines end up back in the mix. That not only helps reduce environmental impact but also fills the mineral filler requirements for certain asphalt designs. Still, a small percentage of producers—probably under 10%—are either disposing of the extra fines in settling ponds or returning them to a quarry. And at plants that use wet scrubbers instead of baghouses, the captured material usually gets washed away and discarded.

Physical and Chemical Properties of Baghouse Fines

In batch plants, the aggregates are first dried in a rotary dryer, then screened into different sizes and stored in bins. These materials are then fed, batch by batch, into a pugmill mixer, where asphalt cement is added and mixed with the hot aggregate.

Most BFs are reused on-site, right at the plant where they’re collected. That’s partly because fines can vary a lot from one plant to another. Their characteristics—like particle size, chemical makeup, and specific gravity—depend on things like the type of aggregate being processed, moisture content, and whether it’s a batch or drum plant. The dust collection setup also plays a big role. Plants with cyclones usually collect finer particles, with up to 90–100% passing the No. 200 sieve (0.075 mm). Those without cyclones may end up with coarser material, with less than 50% passing that same sieve.

In general, baghouse fines are made up of particles smaller than 0.6 mm. Some are coarse, some are ultra-fine. Fines collected after a cyclone tend to be better suited for reuse in asphalt. Most BFs have low plasticity—usually a plasticity index (PI) under 4—and low moisture absorption (typically less than 2%). Organic impurities are rare, except sometimes in oil-fired plants.

Chemically, BFs tend to be alkaline, with pH levels ranging from 7.2 to as high as 12.4, depending on the parent aggregate. Their chemical composition basically mirrors whatever aggregate the plant is crushing—granite, limestone, traprock, or something else.

How Are BFs Recycled?

Depending on the setup, the fines can go straight back into the process or be stored in silos for later. When reused, BFs serve as mineral fillers, replacing materials like hydrated lime or stone dust. These fillers are important. If your mix has too little, it can lack cohesion. Too much, and it might get brittle.

That’s why some producers are careful about how much BF they use. Even though they’re a recycled material, BFs can meet AASHTO (American Association of State Highway and Transportation Officials) and other highway specs for mineral fillers—if the parent aggregate is high-quality and the fines are well-graded.

How Do BFs Affect Asphalt Performance?

Using BFs in the mix does affect performance. For example, bumping up the fines-to-asphalt ratio from 0.2 to 0.5 tends to stiffen the mix by decreasing binder penetration and increasing viscosity. Lab tests show that Marshall stability improves with more fines, peaking when fines make up about 55% of the binder’s volume. The resilient modulus also goes up, which means a stiffer, stronger mix. But there’s a limit—too much fine material (especially over half the binder volume) can cause moisture sensitivity and lead to durability problems in the field.

That’s why proper mix design is so important. Most mixes using BFs can be designed using standard methods like the Marshall immersion-compression test (ASTM D1075). Good designs usually keep the fines content below 50% of the binder’s bulk volume, use well-graded particles, and include plenty of very fine material (smaller than 0.010 to 0.020 mm). It’s also key to keep your fines-to-asphalt ratio consistent—any changes in BF composition can affect pavement performance.

If you’re blending cyclone dust with baghouse fines, be sure to know the proportions and mix them properly. The type of aggregate matters, too. Dust from hard, angular rocks like traprock or granite may stiffen the mix more than softer, carbonate-based materials.

In short, BFs aren’t just filler—they actually act like active components of the mix. They need to be accounted for from the start, not thrown in at the end.

Handling and Production Considerations

For structural design purposes, asphalt mixes with BFs can be modeled using standard AASHTO methods—no special tweaks needed, as long as the fines are integrated correctly.

How fines are handled depends on the type of plant. In batch plants, they can be reintroduced at several points, including the hot elevator, hot bin No. 1, or the weigh box. Introducing fines earlier in the process usually leads to better mixing and more consistent properties. In drum plants, they can be added at the cold feed conveyor, drum inlet or outlet, or—ideally—where the liquid asphalt is injected. That last option helps ensure better coating and reduces the risk of fine particles escaping with exhaust gases.

You can stick with standard mixing and compaction techniques, although mixes with a higher filler/asphalt ratio can be tougher to compact due to stiffness. Quality control doesn’t change either: use AASHTO T168 for sampling, ASTM D2726 for specific gravity, and ASTM D2950 for in-place density.

Over the years, plenty of research has been done on how BFs perform in the field. Early studies—like one by PennDOT in the late 1970s—warned of brittle pavement and compaction problems when fines were added inconsistently. But more recent evaluations are much more positive. Caltrans, for example, found that adding up to 2% BFs improved cohesion. The Asphalt Institute concluded that BFs work well as mineral fillers—as long as the aggregate is high-quality. Other studies (like those from West Virginia and NCHRP) also found that very fine fractions of BFs can boost performance, especially when particles smaller than 0.020 mm are present.

How Baghouse.com Can Help

At Baghouse.com, we’re more than just parts suppliers—we’re your partner for keeping your dust collection system running strong. Whether you need a site inspection, troubleshooting, filter replacements, or a full system rebuild, we know how much dust collector performance affects your ability to reuse baghouse fines effectively.

We can help you to:

✧ Make sure your baghouse is collecting fines that meet gradation specs
✧ Spot issues like uneven airflow or leaking bags that mess with BF quality
✧ Retrofit or upgrade your system to boost performance and cut down on downtime
✧ Train your crew on best practices for handling and recycling BFs

Your baghouse it’s part of your production line. When it’s well-maintained, it gives you a steady source of reusable material and helps you control asphalt quality from start to finish.

In the third and last article of this series, we will take a look at the best design and maintenance practices for asphalt dust collectors.

Need help with your dust collector? Let’s talk.

Image Credits

By Silverije – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=37085244

June 3, 2025/by Andy Biancotti

About Andy Biancotti

Entries by Andy Biancotti

🔹 Welcome & Overview

🔹 What is IoT, and how does it apply to your facility?

🔹 IoT Technology Explained In Depth – Interview with Eric Schummer

➡️ What are the building blocks of an IoT platform?

➡️ How data gets collected, transmitted, and visualized? What are the basic steps for implementing IoT tools?

➡️ What are some IoT sensor types relevant to dust collection and other industrial equipment?

➡️ How do IoT platforms interface with existing enterprise systems?

➡️ Review ROI cases for common facility types, and case studies.

🔹 How Can I Implement This Technology In My Facility?

🔹 Conclusion & Q&A

Contact Us

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About Baghouse.com