Entries by Andy Biancotti

,

How to Balance Baghouse Performance vs Reducing Operating Costs

Let’s be honest—everyone’s trying to save money. And in the world of dust collection, that often means stretching your filter life just a little bit longer. Maybe a lot longer.

On paper, it makes sense. Filters aren’t cheap, and if you can get 18 or 24 months out of them (or in some applications even longer), instead of changing them every year, that’s real savings for the maintenance budget. But here’s the catch: filters don’t just slowly deteriorate. They clog, leak, harden, tear, and—if ignored too long—can turn your entire dust collection system into a headache.

So how do you actually strike the right balance between baghouse performance and reducing operating costs? Let’s take a walk through the plant floor and talk through what works (and what really doesn’t).

The Smart Way to Know When It’s Time to Change Your Filters

Here’s what we see a lot: some facilities change filters once a year like clockwork. Others wait until filters start leaking like a sieve. A few smart ones monitor differential pressure (DP) and start planning replacement once the readings begin to creep consistently above normal. And then… there are those who wait for disaster—a fire, visible emissions, or a complete loss of suction—before doing anything.

Monitoring differential pressure (DP) regularly and observing its trends will tell you when is best to start planning a filter changeout

Monitoring differential pressure (DP) regularly and observing its trends will tell you when is best to start planning a filter changeout

If you’re only using one of those approaches, you’re probably either wasting money or risking performance. The truth is, the best results come when you combine multiple inputs to guide your decision: schedule, DP trends, emissions monitoring, and even basic visual inspections. If you can, throw in a triboelectric monitoring system to catch leaks early and keep track of overall bag performance. It doesn’t have to be expensive tech—it just has to give you enough data to make a smart call.

Read the article:

What’s the Real Cost of “Saving Money”?

Yes, filters cost money. But what about:

  • 🔴 Downtime when suction drops and production is interrupted?
  • 🔴 Failed inspections that lead to fines or extra paperwork?
  • 🔴 Product quality issues because dust is settling where it shouldn’t?
  • 🔴 Worker exposure to airborne dust when the suction can’t keep up?

These are real, measurable costs—and they often don’t show up until after you’ve stretched your filter life too far. Old filters mean high DP, and high DP means fans work harder, energy bills go up, suction goes down, and eventually, you’ve got clogged machines or exposed workers.

Not worth it.

A Smart Plan: Use a Combination of Clues

Tubesheet and filters inspection

Visually inspect during shutdowns—look for bag hardening, holes, or excessive dust buildup.

There’s no single answer for when to change your filters. But here’s a solid framework that’s worked well for many of our customers:

  1. Set a baseline schedule based on your baghouse size, dust type, and usage patterns.
  2. Track differential pressure. Don’t panic at every spike, but look at the trend.
  3. Visually inspect during shutdowns—look for bag hardening, holes, or excessive dust buildup.
  4. Use leak detection systems to catch issues before they lead to emissions violations, like a triboelectric broken bag detector.

Read the article:

Use Higher-Quality Filter Media

Upgrading to premium filters might feel like an unnecessary cost at first. Why spend more when the cheap bags “get the job done,” right? But here’s the thing: better filters don’t just last longer—they perform better.

investing in PTFE-membrane bags or pleated filter elements can give you lower operating differential pressure (meaning less energy use), better filtration efficiency (which helps keep emissions low), and longer service life (sometimes 2–3 times longer than standard felt bags).

Investing in pleated filter elements can give you lower operating differential pressure, better filtration efficiency, and longer service life

For example, investing in PTFE-membrane bags or pleated filter elements can give you lower operating differential pressure (meaning less energy use), better filtration efficiency (which helps keep emissions low), and longer service life (sometimes 2–3 times longer than standard felt bags).

We’ve worked with plants that doubled their filter life by switching to a more durable media suited for their application, like a bakery using high-temp aramid bags for greasy exhaust, or a steel plant switching to PTFE for sticky fumes. Yes, the initial cost went up, but their cost-per-month of operation actually dropped, and they had fewer changeouts and shutdowns.

So the takeaway? Take a look at your process, your dust, your temperature, and your emissions goals. Sometimes spending a little more upfront saves a lot more down the line.

Train Your In-House Maintenance Staff

Another often overlooked cost-saver: invest in your team. A lot of plants rely on outside contractors for even basic baghouse maintenance—inspections, troubleshooting, filter changes. And while there’s a time and place for bringing in experts (especially for major rebuilds or testing), training your in-house maintenance team can pay off fast.

They can respond to issues faster and learn to spot small issues (like seal leaks or valve failures) before they snowball into expensive downtime. Even just one or two maintenance techs trained in baghouse basics (like checking DP trends, inspecting filters, and doing minor pulse valve repairs) can dramatically reduce long-term maintenance costs.

Training courses, like Baghouse.com training programs, adapt to the time and pace of your personnel.

Don't Let Cost Cutting Cut Into Performance

If there’s one thing we’ve learned from years in the field, it’s this: your baghouse doesn’t need to be the most expensive part of your plant, but it does need to work properly. Trying to save money by squeezing out a few more months of filter life might feel smart today, but it often backfires tomorrow.

Balance is everything. Monitor multiple indicators, make small adjustments, and plan filter changes like you would any other piece of critical equipment maintenance.

,

What Does The New NFPA 660 Standard Mean for Your Facility? —Interview with Matt Coughlin 

New NFPA Combustible Dust Standards 2025

New NFPA Combustible Dust Standards 2025

On December 6, 2024, the NFPA introduced a landmark shift in combustible dust safety standards with the release of NFPA 660: Standard for Combustible Dusts and Particulate Solids (2025). We interviewed Matt Coughlin, Owner and President of Baghouse.com, regarding how these new standards affect multiple industries. 

— "What is NFPA 660, and why should we care?"

Matt: “If your facility handles anything dusty enough to be combustible, this new standard applies to you. NFPA 660 is the new consolidation of six different combustible dust standards. It replaces several older industry-specific standards, like NFPA 654, 61, 484, 655, and 664, and brings them together under one unified framework. The goal is to simplify compliance and create a consistent baseline for dust hazard analysis (DHA), explosion protection, housekeeping, ignition source control, and system design, regardless of the industry.” 

— "So... what exactly does NFPA 660 cover?"

An explosion typically begins when an ignition source enters the dust collector.Matt: “In short: all the requirements for identifying, evaluating, and managing combustible dust hazards. It pulls together everything from hazard analysis to equipment design to training and emergency response. The first 9 chapters are based on what used to be NFPA 652, the old “Fundamentals” standard, while the remaining chapters dive into industry-specific details—like agriculture, woodworking, and metal processing. So whether you make cereal, shape aluminum, or sand furniture, there’s a chapter in the new standard that applies to your facility.”

Here’s a breakdown of the key features of NFPA 660 to help you navigate and understand this transformative standard:

  1. Fundamental Chapters (1–10): These chapters provide core guidelines for combustible dusts and particulates, aligning with the previous NFPA 652 standard (Chapters 1–9). Chapter 10 introduces new content. 
  2. Future Topics (Chapters 11–20): These chapters are reserved for additional fundamental topics such as Fire Protection, Additive Manufacturing, and Nano Materials. 
  3. Agricultural and Food Processing (Chapter 21): This chapter replaces NFPA 61, focusing on the unique requirements for agricultural and food processing industries. 
  4. Combustible Metals (Chapter 22): Representing the previous NFPA 484, this chapter addresses risks and guidelines specific to combustible metals. 
  5. Sulfur Standards (Chapter 23): Derived from NFPA 655, this chapter provides sulfur-related guidelines, now managed by the former NFPA 654 committee. 
  6. Wood Processing (Chapter 24): This chapter supersedes NFPA 664, covering wood processing and woodworking standards. 
  7. Other Material Combustible Dusts (Chapter 25): This chapter consolidates guidelines for all other particulate materials not specified in previous chapters, replacing NFPA 654.  
  8. Committee Oversight: Committees for each specific area (e.g., Fundamentals, Agriculture) remain active to ensure accurate, industry-specific standards. 
  9. Annex Material (A–Z): Expanded annexes offer supplemental information, including explanations, diagrams, and additional guidance. These are for reference only and not mandatory. 
  10.  Commodity-Specific Standards (Chapters 21–25): Include tailored requirements that address the unique risks and operational needs of specific industries, enhancing the foundational guidelines. 

— "Is this standard wildly different from what we were doing before?"

Matt: “Not wildly. Most of the technical guidance is similar to existing standards, just reorganized, clarified, and modernized. The biggest updates? Clearer language, fewer contradictions, and improvements in the Hazard Management chapter—especially around process-specific equipment. Also, more detail on how to handle metallic dusts.” 

— "Why did NFPA feel the need to consolidate all these standards?"

Matt: “Great question. Imagine trying to assemble IKEA furniture using six different instruction manuals written in different fonts and translated from Swedish by six different people. That’s kind of what combustible dust compliance looked like before. NFPA 660 streamlines the process. Now, you’ve got one clear document, with consistent definitions and guidance. “ 

— "Is NFPA 660 legally enforceable?"

Matt: “Technically, NFPA standards aren’t laws. But when OSHA or your local fire marshal adopts one by reference—or expects you to follow the “most current standard”—then yes, it effectively becomes enforceable. So, if you’ve got combustible dust anywhere in your facility, you should be planning around NFPA 660 going forward. Even if your inspector hasn’t mentioned it yet… you don’t want to be caught off guard when they do. It’s important to note however that your local regulations may differ from the NFPA standards, and you are responsible for complying with local laws regardless of whether they align with the standard. 

— "What does this mean for my Dust Hazard Analysis (DHA)?"

Matt: “If you’ve already completed a DHA under NFPA 652, good news—you’re still covered. NFPA 660 affirms that every facility handling combustible dust must complete a DHA and keep it updated. If you haven’t done a DHA yet? Well… this is your friendly reminder that now’s the time.” 

NFPA regulations require that a Dust Hazard Analysis (DHA) be performed for all operations that generate, process, handle or store combustible dusts or particulate solids.

— "Are there changes to dust collection system design in NFPA 660?"

Matt: “Not major ones. Most of the requirements for dust collection systems remain consistent, with some clarifications around explosion protection, fire isolation, and cleaning systems. If you were already designing to NFPA 652 or 654, you’re pretty close. Just make sure your documentation reflects the new standard and double-check anything specific to your industry. And no, NFPA 68 (deflagration venting) and NFPA 69 (explosion prevention systems) aren’t included in NFPA 660—they remain separate standards, so keep them in your compliance toolbox. And in case you are wondering, we do sell combustible dust equipment that is designed to comply with those standards as well. And if you need help understanding the standards or outfitting your facility to comply, we have a staff of experts who can help you.” 

— "What industries are affected by this?"

Matt: “Pretty much any facility dealing with fine particulate matter that could become airborne—and flammable. That includes agriculture, food processing, wood, metal, plastic, rubber, pharmaceuticals, chemicals, and more.” 

— "How do I start complying with NFPA 660?"

Matt: “Start by reviewing your current safety programs. Ask yourself: Have you done a DHA? Are your mitigation and suppression systems up to date? Are you training your people? Is your documentation current and aligned with NFPA 660? If you want to dig in a bit deeper on your own, you can start with some of our other posts on the basic requirements of combustible dust safety for dust collection systems. If you need help, this is where it pays to talk to experts—your equipment vendors and consultants like Baghouse.com who can guide you as well as provide the equipment 

See case study: Case Study – Combustible Dust Safety in Aerospace Manufacturing 

— "Is this the final version, or should I expect more changes soon?"

Matt: “NFPA standards go through a three-year revision cycle. So yes, NFPA 660 will continue to evolve based on public input and committee feedback. The current version went into effect in December 2024, and we can expect updates in future editions—especially in the “reserved” chapters where new technologies (like additive manufacturing or nanomaterials) might be added. But for now? This is the go-to standard, and it’s worth getting familiar with.” 

Final Thoughts

Standard for Combustible Dusts and Particulate Solids (2025)

Standard for Combustible Dusts and Particulate Solids (2025)

NFPA 660 gives the combustible dust community a clear, consistent roadmap for staying safe and compliant. The intent is not to bury you in paperwork but to help prevent real-world tragedies from something as deceptively harmless-looking as dust. 

So, grab a cup of coffee, open that PDF, and get to know NFPA 660.

You can obtain the NFPA official document following this link. 

, ,

NEW FREE WEBINAR: How to Plan, Budget, and Execute Successful Projects 

Whether you’re upgrading an existing system or planning a new installation, understanding the planning, budgeting, and execution processes is essential to the success of your dust collection project. That’s why we’re excited to invite you to our upcoming webinar, How to Plan, Budget, and Execute Successful Dust Collection Projects.

What to Expect from the Webinar

Baghouse.com technicians talking at a dust collection webinar through zoomThe webinar will provide in-depth knowledge and actionable strategies for effectively managing dust collection projects from start to finish. Our expert speakers will guide you through the essential steps of planning, designing, and executing a dust collection project. Whether you’re a plant manager, process engineer, or maintenance professional, the content is tailored to be super practical and based on real case scenarios.

Program

  • 🔹 Welcome & Overview

  • 🔹 How to Develop Your Dust Collection Scope and RFQ

  • 🔹 How to Lay Out Your Ductwork, Hoods, and Fans

  • 🔹 How to Get the Best Quotes

  • 🔹 How to Manage Critical Spare Parts and Avoid Downtime

  • 🔹 Conclusion & Q&A 

Why Should You Attend?

  1. Gain Practical Knowledge: The webinar is designed to provide real-world strategies for planning and executing dust collection projects. You’ll walk away with actionable insights into creating detailed RFQs, and making smarter equipment decisions.

  2. Optimize Your Dust Collection System: Dust collection isn’t just about buying the cheapest system. It’s about understanding the needs of your facility and selecting the right components to ensure long-term performance and efficiency. This webinar will show you how to make informed decisions that can save you money, time, and headaches down the line.

  3. Avoid Delays and Costly Mistakes: One of the key goals of the webinar is to help you develop a clear and effective RFQ that reduces the risk of miscommunication, delays, and unexpected costs. Knowing exactly what to ask for and how to compare quotes will help you avoid delays and costly mistakes.

  4. Learn from Industry Experts: With years of experience in the field, our expert speakers have worked on numerous projects and are eager to share their knowledge. You’ll get insights from professionals who understand the challenges you face daily.

 

How to Connect

Attending the webinar is simple! All you need to do is register using the link provided below. Once registered, you’ll receive a confirmation email with all the details you need to log in at the scheduled time. Don’t forget to mark your calendar:

📅 Date: Wednesday, May 21st, 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.

Sign up now and take the first step toward mastering dust collection planning, budgeting, and execution.

We look forward to seeing you there!

, ,

Smarter Cement Plants: The IoT Revolution You Can’t Ignore

If you are the kind of professional that is always looking into the latest cutting-edge technology and ways to implement it in your cement and mining applications, well… this article is for you.

IoT sensors are 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.

Besides, you will get the pulse of your plant at all times. 24/7/365!

A typical cement plant goes through several important steps to make cement. First, extractors remove raw materials from the quarry. Then, crushers and mills break down large rocks into smaller pieces. These are mixed in the right amounts using blenders and mixers, and then finely ground in grinders. The mixture is heated and cooled in a large rotating kiln. Finally, the finished cement is packed and sent out using conveyor belts or trucks.

Throughout the whole cement manufacturing process, systems like dust control, silo management, motors, fans, and conveyors play a vital role in keeping everything running smoothly and efficiently.

Throughout the whole process, systems like dust control, silo management, motors, fans, and conveyors play a vital role in keeping everything running smoothly.

Here’s how different IoT sensors can make your dust collection system smarter and more efficient in 2025.

Baghouse.com is teaming up with Senzary to offer advanced IoT sensors that will take your dust collection and plant maintenance to the next level.

We are excited to collaborate with this renowned company, and thrilled with the many possibilities to bring the Internet of Things to create Smart Plants, not only to the cement industry, but also all other dust collection applications.

The Power of Sensor-Driven Maintenance

In modern cement plants and other industries, sensor-based maintenance is transforming equipment upkeep:

  • ✅ Predictive Insights: Advanced sensors continuously monitor your machinery, detecting subtle changes that indicate potential issues before they escalate into costly breakdowns.
  • ✅ Data-Driven Decisions: Real-time data from strategically placed sensors empowers you to make informed maintenance decisions, optimizing your equipment’s performance and lifespan. By identifying maintenance needs precisely, you can schedule interventions during planned downtimes, minimizing disruptions to your operations.
  • ✅ Cost Reduction: Sensor-based maintenance significantly reduces unnecessary repairs and replacements, lowering your overall maintenance costs.

How Does this Technology Work?

In a cement plant, IoT sensors are installed on critical equipment to monitor parameters like temperature, vibration, and pressure in real time. These low-power sensors transmit data wirelessly to gateways using robust radio technologies such as LoRaWAN. The gateways securely send the data to a cloud-based platform like IoTLogIQ, where it’s organized and processed through a network layer. The system then provides actionable insights through a user-friendly dashboard, enabling plant operators to detect issues early, plan predictive maintenance, and reduce unexpected downtime while improving overall efficiency and safety.

How Does IoT Technology Work?

Essential Sensors for Your Dust Collection System

Particulate Matter Sensors (DustIQ)

Undetected leaks in a baghouse can lead to emissions violations and efficiency losses. Advanced sensors can detect leaks early, ensuring that maintenance teams address the issue promptly before it leads to significant performance declines or regulatory fines. 

These sensors continuously monitor the dust concentration in exhaust air. Most leaking baghouse filters begin as small holes or rips that overtime become worse and worse. DustIQ provides real- time monitoring of dust levels and filter performance. 

  • 🔶 It’s simple to install, you just need to place it on your equipment without any wiring or configuration. 
  • 🔶 It’s autonomous, it works for several months without recharging.
  • 🔶 It’s secure by design, its designed for harsh or even explosive environments.
The enLink Air LoRa wireless Air Quality Monitor is a high-precision device that measures up to 14 important environmental conditions.

The enLink Air LoRa wireless Air Quality Monitor is a high-precision device that measures up to 14 important environmental conditions.

The enLink Air LoRa wireless Air Quality Monitor is a high-precision device that measures up to 14 important environmental conditions. These include temperature, humidity, light level, volatile organic compounds (VOCs), carbon dioxide (CO₂), fine and coarse dust particles (PM2.5 and PM10), oxygen, sound level, and barometric pressure. It can also connect to 4 extra plug-in gas sensors, choosing from over 200 different gas types or sensitivity levels. The monitor sends real-time data to the cloud using long-range LoRa wireless technology, so the information can be viewed and analyzed from anywhere.

Auburn Filtersense PM series probes

Auburn Filtersense PM series probes

Virtually any sensor with the capability to send a digital signal can be integrated with the IOT software and system. For example, the Auburn Filtersense PM series probes with 4-20mA outputs can also be integrated if you need this particular style of broken bag detection.

Extensible to Cloud-based dashboards and usage reporting, additional custom alarms, or integration to 3rd party applications
Extensible to Cloud-based dashboards and usage reporting,
additional custom alarms, or integration to 3rd party applications

Differential Pressure Sensors

Monitoring the pressure difference across filter bags or cartridges is important to know how well the filters are working. If the pressure slowly goes up, it usually means the filters are getting clogged. If the pressure suddenly drops, it might mean a filter has failed. Real-time alerts help maintenance teams act quickly—cleaning or changing filters before they create bigger problems. This helps save energy and avoid unplanned shutdowns. 

The EnLink Status-DP uses long-range LoRa wireless to measure and send differential pressure data, even from up to 16 km away.

The EnLink Status-DP uses long-range LoRa wireless to measure and send differential pressure data, even from up to 16 km away.

The EnLink Status-DP makes this easy by using long-range LoRa wireless to measure and send differential pressure data, even from up to 16 km away. It can be used to track pressure before and after filters. It runs on a long-life battery, making installation simple and low-cost. Its special Multi-Range sensor includes up to 7 calibrated pressure ranges, so one Status-DP unit can handle a wide range of pressure monitoring needs.

Airflow Sensors

Airflow sensors help detect blockages in the ductwork or issues with the fan. If airflow drops below the ideal level, operators can respond quickly to fix the problem and keep the system running smoothly.

The enLink Status-AF focuses specifically on airflow, measuring air velocity from 0 to 40 m/s with extremely high accuracy of 0.1%.

The enLink Status-AF focuses specifically on airflow, measuring air velocity from 0 to 40 m/s with extremely high accuracy of 0.1%.

 

The enLink Status-AF focuses specifically on airflow, measuring air velocity from 0 to 40 m/s with extremely high accuracy of 0.1%. Like the other enLink devices, it transmits data using LoRa wireless for easy cloud integration or connection to onsite systems via Modbus IP, enabling performance tracking and real-time alerts.

Temperature and Humidity Sensors

High humidity can cause dust to stick together and clog filters, while very high or low temperatures can shorten the life of equipment. By monitoring these conditions, plants can make adjustments to avoid damage and maintain system efficiency.

The Dragino LSN50v2-S31 is a LoRaWAN wireless sensor designed to accurately measure temperature and humidity in the surrounding environment.

The Dragino LSN50v2-S31 is a LoRaWAN wireless sensor designed to accurately measure temperature and humidity in the surrounding environment.

The Dragino LSN50v2-S31 is a LoRaWAN wireless sensor designed to accurately measure temperature and humidity in the surrounding environment. It uses the SHT31 sensor from Sensirion, which is fully calibrated, temperature compensated, and known for its reliability and long-term stability. The sensor is housed in a waterproof, anti-condensation casing, making it suitable for long-term use. It can also send alerts if temperature or humidity goes beyond set limits. Powered by an 8500mAh Li-SOCI2 battery, it’s built to last up to 10 years depending on usage and update frequency, making it a reliable, low-maintenance monitoring solution for industrial environments.

Rotating Machine Monitoring (RotaryIQ)

RotaryIQ monitors and analyses any rotating machine and helps to automate diagnostics and predict anomalies, wirelessly and non-intrusively, with a simple installation. Sensors communicate through LoRaWan (Long range network) and data is encrypted end-to-end. Senzary’s sensors monitor not only heat and vibration, but ultrasound too, meaning customers have the earliest possible alert of drift – before any damage has occurred.

  • 🔶 Vibrations, temperature, humidity, 3-axial accelerometer: Looseness, imbalance, misalignment, advanced degradation.
  • 🔶 Ultrasounds: Lubrication issues, early signs of rolling degradation, gas leaks.

Typical Issues in a Cement Plant

Ultrasound and Vibration Monitoring

Monitoring Material Inside Silos (SiloIQ)

The high-frequency signals (e.g., 80 GHz) and narrow beam angles (e.g., 15°) enable accurate targeting of the material surface, even with uneven topography or buildup on walls. Radar technology allows for non-intrusive measurement without contact with the abrasive cement material. This eliminates issues like sensor wear, maintenance, and contamination associated with contact-based methods.

Real-time level data from radar sensors provides up-to-date information on material inventory in each silo. This enables better production planning, timely replenishment, and avoidance of costly run-outs or overfills. It also can optimize material usage, production scheduling, and logistics. Radar performs well in challenging silo geometries found in cement plants, including tall and narrow silos, large bunkers, and dome-shaped storage halls.

Real-time level data from radar sensors provides up-to-date information on material inventory in each silo.

The Advantage of Smart Sensors In Your Cement Plant

Choosing an advanced IoT solution for the maintenance needs of your cement plant means benefiting from:

  • ✅ Custom sensor networks aligned with your specific equipment, industry requirements, and operational goals.
  • ✅ AI-powered analytics that translate complex sensor data into actionable maintenance insights.
  • ✅ Sensors and software that integrate smoothly with existing maintenance management systems.
  • ✅ The ability to start with critical assets and expand sensor networks as operational needs grow.
  • ✅ Ongoing assistance from maintenance and IoT specialists to ensure maximum benefits from sensor-based maintenance programs.

Investing in IoT sensors is no longer an option—it’s a necessity for cement plants looking to remain competitive in 2025 and beyond. 

If you’re a plant manager, operator, or engineer committed to pushing your facility to peak performance, now is the time to act. With each connected device, you’re not only protecting your equipment but unlocking the full potential of your plant. Don’t wait for failure—get ahead of it. Invest in intelligence, drive efficiency, and lead your plant into a new era of innovation, reliability, and profitability. The technology is here. 

Let Baghouse.com help you implement this in your facility!

Designing High-Temperature Baghouse Systems

Powder Bulk & Solids

Powder Bulk & Solids – May 2025

This article was published in the May 2025 Edition of the Magazine Powder Bulk & Solids. You can also read it in this link:

Designing High-Temperature Baghouse Systems


It can be difficult to design a baghouse system that meets the unique challenges of operating at high temperatures. Here are some considerations to take into account when designing such a system.

High-temperature airstreams require many substantial design changes. Regardless of whether it is used to control atmospheric pollution, eliminate process contamination, or add profits by recovering product, a baghouse system without the proper filters, collector design, gaskets, etc. will suffer from premature failure, increased emissions, and loss of product control. All of these outcomes result in a higher cost for the operators and less efficiency in creating products and services.

The following are a few items to keep in mind when reviewing the performance of your baghouse system with high-temperature airstreams.

What Exactly Classifies as a “High Temperature Baghouse”?

Engineering an adequate baghouse system is often a challenge. What complicates the situation is that many processes generate dust and other fine particulates suspended in hot gases as part of a normal process flow. These applications are on dust filter media and the vessels that contain them.

For example, baghouses operating in the region between 275°F (135°C) and 1500°F (816°C) are generally considered “high temperature” baghouses. At these temperatures, filter media limitations can be classified as follows:

  • ✦ Level I is 275°F to 400°F (135°C to 205°C)
  • ✦ Level II is 400°F to 500°F (205°C to 260°C)
  • ✦ Level III is 500°F to 1500°F (260°C to 816°C).

Common applications that include high-temperature airstreams such as this include cement kilns, industrial dryers, steel mills, coal-fired power plants, etc.

Some of the specific problems that can occur if a high-temperature baghouse is not designed correctly include:

  1. Moisture in the baghouse and resultant discharge challenges filter failure if the inlet gas temp is allowed to drop below the dew point and condenses.
  2. Early filter failure due to incorrect filter media selection.
  3. Incorrect fits and resultant air leakage, specifically between filters and sealing components (tube sheets) due to thermal expansion at high temperatures.
  4. Corrosion, fatigue, and other temperature-related impacts on baghouse materials.

Options For Cooling the Airstream Before The Baghouse

In many plants, a viable solution to the problems associated with a high-temperature airstream is to install cooling systems upstream from the baghouse. Such treatment options vary greatly, in both design and cost. Some treatment options include heat exchangers, coolers, and quenchers. Sometimes, introducing bleed air into the system is sufficient to cool the gas stream below the design temperatures.

Cooling the dust-laden gases before entry into the baghouse is often the only way to make it possible to use a baghouse for filtration purposes. The cost of operating additional cooling devices should be calculated based on energy usage, maintenance requirements, etc. These costs are often negated by the reduced wear and improved operation of the baghouse due to the lower temperatures (e.g. less heat attack on the filters, less thermal contraction/expansion wear on the collector itself, etc.).

However, it should be noted that over-cooling the inlet gas below the dew point may lead to condensation and moisture in the baghouse, which will cause major problems with filter life and efficiency, difficulty in getting collected dust through the hopper and discharge system, etc. For this reason, engineers should carefully review the inlet gas composition and temperature and design the system to maintain the right temperature, not just the lowest possible temperature.

Selecting The Proper High Temp Filter Media

Baghouse filters damaged by a spike in high temperatures

Choosing the right filter media for your application’s temperature will avoid premature failure from thermal degradation

Choice of media is essential in high temperature applications. High temperature filters themselves often cost as much if not more than the entire baghouse, so protecting the filter media from damage is of vital importance. High temperature operation increases the filter medium’s susceptibility to premature failure from thermal degradation, chemical attack or both, as temperature and chemistry often go hand in hand.

.

.

.

.

.
.

.

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

In recently years a wide range of different fabrics have been developed to meet the needs of high temperature applications. The most popular are polyester, polypropylene, acrylic, for the lower range, aramid, P84, Ryton, fiberglass, Teflon, for the mid-range (up to 500°F), and ceramic, and sintered metal limited ultra-high range (up to 1500°F). In addition to the base fabric material, various treatments and coatings can improve the media’s performance. These include singeing or glazing the material, applying coatings such as silicone or PTFE to improve resistance to acid and alkali substances or improving fine particulate collection and dust cake release.

Filter Medias Infographic

Filter Media Types Infographic

.

Would you like to know what filter and treatment would work best for your application? Download this infographic for free!

.

.

It is also necessary, depending on the kind of baghouse in use, to choose the correct media weight to withstand the baghouse cleaning cycles. A reverse-air baghouse will usually require only a 14 oz./yard fiberglass media, while in the same conditions, a pulse-jet baghouse will need a heavier 22 oz./yard fabric due to the greater strain on the filter fabric during its cleaning cycle compared to a reverse-air type.

Continuous operating temperature of 500°F (260°C) is the limit for traditional fabrics. After 500°F, the only options are to use specialty materials such as sintered metal or ceramics. These materials, while capable of handling temperatures of up to 1500°F (816°C), are much more expensive than traditional fabrics and require special design considerations to ensure they fit and function correctly in their challenging high-temp environment.

The key factors that should influence final media selection are operating temperature (both continuous and peak), abrasiveness of the particulate, chemical makeup of the gas stream, and moisture content.

Baghouse Collector Design Considerations

Even the best filters will be useless if the baghouse itself is not designed for operating in a high temperature application.

One area of concern is wear caused by regular expansion and contraction due to temperature variations. One common solution is to use a circular design. Many baghouse engineers feel this design is superior because most of the unit will expand and contract uniformly outward/inward together. This is however only partially effective since there are usually a number of “hotspots” in the collector where temperatures exceed those in other areas, thus causing uneven expansion/contraction regardless of the shape of the collector.

Insulating the ductwork coming into the baghouse will maintain the temperature above the dew point, avoiding condensation

Insulating the ductwork coming into the baghouse will maintain the temperature above the dew point, avoiding condensation

Additional construction ideas to keep in mind include: using only heavy-duty materials and construction methods, including stiffening elements to mitigate the effects of thermal expansion/contraction, insulate to reduce heat loss and condensation (specifically the baghouse hopper, dirty side housing, and inlet ductwork), and use diaphragm and solenoid valves with copper or stainless-steel piping and Viton diaphragms rated for use in high temp applications.

Maximizing Baghouse Filter Efficiency

Once the system is up and running, maintaining best operating practices can increase your filter life substantially, while also lowering energy usage, increasing collection efficiency and reducing total emissions.

Using stainless steel cages will prevent damage from acidic or alkali gases from corroding the metal

Using stainless steel cages will prevent damage from acidic or alkali gases from corroding the metal

Concern should be taken during startup/shutdown procedures to minimize the effects of crossing through the dew point, which can lead to increased condensation and cause early bag failure. Often this will include preheating the baghouse before introducing the dust-laden process gases to be filtered, and avoid unnecessary shutdowns.

Another good design practice for high temperature systems is to use stronger bag cages with more vertical wires to provide extra support for the filters. If the gas stream includes high levels of acidic or alkali gases, it is often wise to use stainless steel cages.

Concluding Thoughts

Designing a baghouse dust collection system for use in a high temperature application is no easy task. Proper care and attention must be taken to ensure the proper filter media is selected and that the system itself is engineered and constructed to withstand the effects of high temperature applications.

This guide is by no means an exhaustive list of all the things that must be considered when designing a high temp system. But this information is a good place to start when considering the design of a new system, or looking for ways to improve the operation of existing systems.

When selecting a baghouse supplier/engineering firm like Baghouse.com, work closely with them to ensure all of these considerations are taken into account. By doing so, higher efficiencies, less energy usage, and increased service life will be yours.

,

3 Baghouse Maintenance Tasks for Your Next Shutdown/Outage

When management hear of the plan to shut down the Baghouse system for routine maintenance, they begin to ask questions and usually get a little nervous. After all, when a Baghouse system is not operating, more than likely the plant is not either. No Baghouse, No Plant, No Production, No Income.

However, planned shutdowns of Baghouse systems are a necessary part of routine maintenance, therefore it is essential to plan well in advance in order to minimize downtime and maximize efficiency.  

What tasks should be completed during your next planned shutdown?  Usually the main task of a shutdown is to replace the baghouse filters, which have deteriorated over the course of normal operation. However,  there are other items that should be inspected and tasks that need to be addressed in order to prevent future unplanned outages and issues.

Let’s examine some of these tasks in further detail.

Inspect and Review The Condition Of The Entire System

Exposure to rain, snow and sun can result in a breakdown of exterior components, water ingress and corrosion of the system. 

Rain, snow, and sun can cause corrosion of the baghouse and its components

Normal operation and constant exposure to the weather can result in various parts of a Baghouse system deteriorating and or being damaged. For example, exposure to rain, snow and sun can result in a breakdown of exterior components, water leakage and corrosion of the system. Thus, a planned outage is the perfect time to inspect and review the condition of the entire system and to replace or repair any necessary items.

Check for rust and other corrosion, especially near doors, hatches, and other ports. Insulate against cold or heat where necessary to prevent hot/cold spots that can cause condensation issues. Ensure all door and hatch gaskets are in good condition, and replace worn out ones immediately.

Holes in the ductwork lead to loss of vacuum (i.e. loss of suction). Additionally, holes allow for outside air to enter into the baghouse. Hot, cold or moist air can cause problems inside the unit such as corrosion, acid flashes or sticky dusts. Finally, holes in the structure allow dust to escape, where it can accumulate nearby, disperse to nearby working areas, or into the filtered gas steam and show up as increased emissions.

Inspect All Movable Parts

Diaphragms should be given regular maintenance

Diaphragms should be given regular maintenance and repair if needed

All movable parts should be fully inspected during a shutdown. These include fans, bearings, brushes, belts, gears, etc, to mention just a few. Constant operation can lead to these items being worn or damaged. Therefore, during the shutdown, these items should be repaired or replaced. 

Poorly maintained diaphragm pulse valves have a dramatic effect on the efficiency and effectiveness of a pulse jet baghouse. Leaking diaphragms waste huge amounts of (often very expensive) compressed air. More seriously, worn out diaphragms decrease the effectiveness of the cleaning pulses, which results in poor bag cleaning. Inadequately cleaned bags create higher operating differential pressure, increasing operating costs and lowering suction throughout the system (product dropout and damage to vented equipment).

Keeping the diaphragm valves in good working condition is fairly simple and relatively inexpensive. Extra diaphragm repair kits should be kept on hand so malfunctioning valves can be repaired without delay.

Conduct A Leak Test

Even the most efficient and well-maintained dust collection systems will occasionally experience leaks, compromising their effectiveness and putting worker health at risk.This is why implementing effective leak detection strategies is crucial.

Even the most efficient and well-maintained dust collection systems will occasionally experience leaks, compromising their effectiveness and putting worker health at risk.This is why implementing effective leak detection strategies is crucial.

A planned shutdown is also a perfect opportunity to conduct a leak test of the entire system. This is to ensure the Baghouse system is operating to its optimum performance. 

Conducting a dye test is not only for filter bags that have been in operation for an extended period of time. Newly installed ones can (and should) also undergo leak testing. 

It is also a great time to test the system to see if it will continue to meet environmental standards as well as meet any future requirements.  

All the stress and anxiety of a planned outage can be alleviated by contacting a professional before your next planned shutdown. Baghouse.com can provide expert advice, advance planning, review system and provide any necessary suggestions.

, , ,

A New Tool Empowering Your Personnel: An Online Dust Collection Course

JANUARY 30, 2025 – After more than two years of writing, designing and field testing, we are excited to announce our new, first-of-its-kind online training course on dust collection systems. This is the online version of the in-person training our experts have provided for more than 40 years throughout Mexico, United States and Canada. However, much of its content is updated and revised with the latest best practices in dust collection. This course is meticulously designed for Plant & Maintenance Managers, Engineers, Project Managers, Environmental, Health and Safety Managers, and Purchasing Managers.

Would you like to see a sneak peak of our training courses? 

Watch the video below!

A Dynamic Learning Experience

 

The course is designed to be engaging and dynamic, ensuring that learning is not only informative but also enjoyable

The course is designed to be engaging and dynamic, ensuring that learning is not only informative but also enjoyable

Our programs are structured into eight lessons, each featuring easy-to-understand diagrams and graphics, videos, downloadable materials, links to related articles, and interactive quizzes. The first lessons lay the groundwork with the simplest concepts, and the following lessons continue to build with the more deep and complex dust collection parameters. The first lesson of this Dust Collection Training Course is available free of charge, giving you a preview of the valuable knowledge and insights you’ll gain throughout the program. Check it out now!

Our Four Training Programs

At Baghouse.com, we understand that every business has unique needs when it comes to dust collection training.

That’s why we offer four flexible training programs to fit your team’s schedule and learning style:

► In-Person Training

  • ✧ This option combines a hands-on inspection of your dust collection system with an engaging class led by our experts. It’s perfect for teams that want personalized guidance right at their facility.

► Virtual Training

  • ✧ Join a live instructor on Zoom for interactive sessions designed to address your specific concerns. It’s as close to in-person as you can get, without leaving your office.

► Self-guided Online Training

  • ✧ Learn at your own pace with their self-guided courses. This option allows you to access expert knowledge anytime, anywhere, making it ideal for busy schedules.

► Combined Training

  • ✧ This unique program blends self-guided online learning with live Q&A sessions at the end of each lesson. It’s the best of both worlds—flexibility with expert support.

 

Our training provides insights into the principles of dust collection systems, equipping you and your personnel with the knowledge and skills necessary to optimize your facility’s operations. Here’s a snapshot of what you and your team will gain:

  • ✦ Recognize Each Baghouse Type and Describe Its Basic Function
  • ✦ Describe Different Styles of Baghouses and Their Suitable Applications
  • ✦ Understand Filter Options
  • ✦ Identify Key Design Parameters
  • ✦ Troubleshoot Common Operational Issues
  • ✦ Conduct System Inspections and Audits

Does It Have Group Discounts?

Yes! To make it even more accessible, Baghouse.com offers discounted pricing for group enrollments, making it an ideal opportunity for facilities looking to train multiple employees. If you enroll 5 or more employees, you’ll receive a 10% discount. For groups of 10 or more, they have a 20% discount. And for facilities with 20 or more participants, we offer a substantial 30% discount. This package pricing ensures that your entire team can benefit from their expert training while optimizing your investment. Ask about a discount for your company.

Why Enroll in This Course?

By the end of this course, you’ll be armed with practical knowledge and skills that can be immediately applied to your facility’s dust collection system. Whether you’re looking to optimize performance, reduce maintenance costs, or ensure regulatory compliance, this course is tailored to meet your needs. It’s an investment in your professional development and your facility’s future.

Enroll today and take the first step towards mastering dust collection systems with Baghouse.com’s expert training course!

,

Case Study –  Turning Challenges into Solutions at a Woodshop

Do you have a woodshop and you are having dust collection problems?

  • ■ Not enough suction at the pickup points?

  • ■ Contaminated recycled air into the facility?

  • ■ Danger of combustible dust in ducts/baghouse?

You will find this article super interesting!

Background

old dust collector at a woodshop

Poor suction, inefficient dust collection, and loads of resources spent on maintenance were some of the problems this plant was experiencing

The US Army’s Aberdeen Proving Ground woodshop was working with an aging dust collection system that could no longer meet their needs. Their existing cyclone and baghouse setup suffered from poor suction, inefficient dust collection, and loads of resources spent on maintenance.

To make matters worse, the return air system consisted of a makeshift, home-built plenum that was not functioning effectively. These issues created a challenging work environment and prompted the woodshop to seek a reliable, long-term solution.

Scope Of Work

The goal was to replace the outdated system with a modern, efficient solution while addressing the following challenges:

  • ● Poor suction and collection performance.
  • ● Difficulty with the maintenance of the equipment
  • ● Inefficient and noisy return air management.

Baghouse.com was tasked with designing and installing a new dust collection system that integrated seamlessly with the existing ductwork.

Solution

Baghouse.com dispatched a technician to assess the woodshop’s existing setup and understand its operational needs. A thorough inspection was conducted on-site, and standard sizing factors were used to engineer a tailored solution. 

Baghouse.com personnel installing a new cyclone and a cartridge collector

Baghouse.com installed a new cyclone and a cartridge collector

The proposed system included:

  • A new cyclone separator for pre-separation.
  • ● A 3-12 cartridge collector for fine dust collection.
  • ● High-performance rotary airlocks to eliminate dust discharge issues.
  • ● An engineered return air plenum to replace the makeshift one, reducing noise and improving airflow efficiency.

The new system was carefully integrated into the existing ductwork while addressing spatial constraints during installation. The project was completed within three months of the proposal’s approval.

Conclusion

New dust collection system

Some of the immediate improvements the new dust collection system delivered were better suction and airflow performance

The new dust collection system delivered immediate improvements. The woodshop experienced significantly better suction and airflow performance. The engineered return air plenum also reduced noise levels. 

From initial evaluation to final installation, Baghouse.com provided high quality customer service, proving they are a trusted partner for even the most demanding projects.

, ,

Top Load Snap Band Baghouse Filter & Cage Measuring Guide

Purchasing and maintenance people commonly call Baghouse.com requesting assistance to figure out what kind of filter bags they need for their top load baghouse. Often, they do not know which measurements they need to identify the filter size and configuration required to quote replacement filters for their baghouse. 

This short article will explain the key features of the most common baghouse filter style: the top load, snap band style baghouse filter.

Description of a Top Load Baghouse

Airflow in a baghouse from the dirty air plenum to the clean air plenum passing through the filters

Top load baghouses are known for their efficiency, reliability and ease of maintenance, making them a popular choice for many industrial applications.

A top load baghouse has a housing with the filter bags arranged so that they hang vertically. The dirty air ductwork usually connects to the baghouse hopper, allowing the dirty air to enter from the bottom of the filters.

The dust particles are captured on the outer surface of the filter bags (falling to the hopper), while the clean air passes through the filters and then travels up through the bag and out the top of the housing. 

In top load pulse jet baghouses, the filters are installed into the tubesheet from above. The tubesheet is a metal plate in the baghouse where the filters are installed, separating the clean air from the dirty air. On a pulse jet baghouse, the tubesheet is near the top ¼ of the baghouse and it is a smooth steel sheet with uniform holes into which each filter is installed.

To allow access to the filters, smaller units will generally have removable doors or hatches on the top of the unit surrounded by railings while larger units will have  a walk-in clean air plenum which allows entry to the baghouse through a door in the side.

Snap Band Filters for Top Load Baghouses

View of a snap band before its covered with material and attached to the filter bag

Cut view of the ring (snap band) and the layer of sown fabric around it that allows for a tight fit against the tube sheet

The snap band is a metal ring sewn into the top of the bag and covered with fabric. The snap band is used to secure and seal the filter bags to the tube sheet.

The pressure from the band pushing against the sides of the hole (when aligned correctly) forms an airtight seal.

The pressure from the band pushing against the sides of the hole (when aligned correctly) forms an airtight seal.

To install a snap band bag, the bag is inserted into the round tube sheet hole. The snap band is deformable, allowing the user to manipulate its shape and insert the band into the tubesheet hole. When released, the snap band “snaps” into place, tightly locking the filter into the hole.

Once installed, a metal wire cage is inserted into the cage to hold it open during operation. Then the blowpipes are installed above the filters. 

 

Why Are Snap Band Filters So Popular?

Snap bands ensure a tight fit at the connection points between the filter bag and the tubesheet, preventing air or dust from bypassing the filter bag. Additionally, they are easy to install and more reliable than older methods that require the use of hold down hardware or clamps to secure the bags into the tubesheet.

Snap Band Filter Bag & Cage Terminology

The relationship between snap band size, bag diameter, and cage diameter has to be carefully calculated, since each component plays a crucial role in ensuring the effective installation, sealing, and performance of filter bags.

Here is a brief explanation of each one of these dimensions:

●  Tubesheet Hole size/Snap Band Size 

An accurate measurement of the tubesheet hole will ensure that the snap band of the filter will have a tight fit

An accurate measurement of the tubesheet hole will ensure that the snap band of the filter will have a tight fit

The tube sheet hole size refers to the diameter of the opening in the tubesheet where the filter bag’s snap band is inserted. This size must match the snap band diameter to ensure a tight fit and prevent leakage or bypass of dust-laden air. Snap bands are sized down to 1/32” so this measurement should be taken with calipers if possible. Always measure across the center of the hole in a straight line from one edge to the opposite edge.

●  Bag Diameter 

The bag diameter refers to the width of the filter bag body

The bag diameter refers to the width of the filter bag when laying flat

The bag diameter refers to the width of the filter bag body (NOT the snap band at the top of the bag, which is considered a separate piece). Since we cannot accurately measure the true diameter of the bag outside of a proper jig in the factory, we usually ask customers to measure the flat width instead, which is the width of the bag when laid flat. The bag diameter is almost always slightly smaller than the snap band/tubesheet hole size. 

 

● Cage Diameter 

The cage diameter is the outside diameter (OD) of the cage body that goes inside the filter bag.

The cage diameter is the outside diameter (OD) of the cage body measured at the center of the cage

The cage diameter is the outside diameter (OD) of the cage body that goes inside the filter bag. The cage diameter will always be slightly smaller than the bag diameter, usually ¼” smaller. If the bags fit too tightly to the cage, the cages will be very difficult to install and remove, and the bags will not flex properly when pulsed and the cleaning power will be reduced, thus contributing to poor operation of the system. 

So, when looking to get replacement filters and/or cages for your pulse jet baghouse, you need to gather the following information: (1) tubesheet hole diameter, (2) the bag flat width and length and (3) the cage body outside diameter (OD) and length. 

If you are unable to shut the unit down to take the hole measurement, we can still quote you the bags with only the bag flat width and length. Then, once you place an order, we can confirm the exact tube sheet hole size by having you send us a used bag to test fit at our facility. Alternatively, we can send you a pre production sample bag to test fit before we release your order to production.

Instructions to Measure Snap Band Filter Bag & Cage Size Step by Step

Common Sizes of Top Load Bags and Cages

With so many different baghouse manufacturers, there is no “standard” size for top load bags. However, there are some common sizes/configurations that are used by multiple OEMs. Common size combinations include:

Small diameter bags: 4” and 5”

  • 5” tubesheet hole, 4.5” bag diameter, 4.25” cage diameter 

  •  5” tubesheet hole, 4.625” bag diameter, 4.5” cage diameter 

  •  5” tubesheet hole, 4.875” bag diameter, 4.5” cage diameter 

Large diameter bags: 6”

  •  6” tubesheet hole, 5.875” bag diameter, 5.5” cage diameter 

  •  6” tubesheet hole, 5.875” bag diameter, 5.625” cage diameter 

  •  6.2” tubesheet hole, 5.875” bag diameter, 5.5” cage diameter 

  •  6.25” tubesheet hole, 5.875” bag diameter, 5.5” cage diameter (Most common)

  •  6.25” tubesheet hole, 6” bag diameter, 5.875” cage diameter 

Measuring Pleated Filters For Top Load Baghouses

Pleated filters can be used in top load baghouses, often as retrofits for units originally designed to take traditional bags and cages. Some units are designed from the factory to use pleated filters. This is most common with small bin vent style units. Would you like to know if pleated filters would be a good option for your baghouse? Contact us to review your application.

Similar to bags and cages, when looking for replacement pleated filters, we will need to know the tube sheet hole size along with the filter diameter and length.

The Dangers of Size Drift

Size drift in top load baghouses can be quite risky to the efficiency of your dust collector. This happens when measurements are taken inaccurately, and over time, the bags end up being a bit too big or too small for the system. 

This can lead to various issues, like: 

  • ● Reduced filtration efficiency
  • ● Compromised dust capture
  • ● Increased emissions
  • ● Potential damage to equipment components

To prevent these problems, it’s important to measure accurately and keep an eye on things to catch any drift early.

Additional Tips When Changing the Filters

Any cages that are bent, rusty, or have shape edges should be discarded and replaced. Filters that are installed onto damaged cages will suffer early filter failure.

Any cages that are bent, rusty, or have shape edges should be discarded and replaced. Filters that are installed onto damaged cages will suffer early filter failure.

  • ● Before removing the filters, the blow pipes must be removed to allow access to the tube sheet.
  • ● If reusing cages, these must be carefully removed and set aside so as not to damage them before putting new filters on them and inserting them back into the tube sheet. 
  • ● When reusing existing cages it’s usually best to remove only a section of filters at once, since there is only limited space to stack the cages at the top of the baghouse. 
  • ● Any cages that are bent, rusty, or have shape edges should be discarded and replaced. Filters that are installed onto damaged cages will suffer early filter failure.

 

 

Understanding the dimensions and components of a top load baghouse will help us order the exact replacement pieces, proper installation, sealing, and long filter life.

Do you have any questions or need the advice of an expert in dust collection?

Are you ready for your next filter changeout?

, ,

Combustible Dust Hazards: Prevention & Protection Technologies

Combustible dusts present both fire and explosion risks. What technologies can help you prevent them?

What is Combustible Dust?

Many manufacturing processes create very small particles of dust that settle on surfaces throughout the plant. Eventually these particles not only create a housekeeping issue, but if the particles are combustible, they can represent a potential fire or explosion hazard. Combustible dusts generally present both fire and explosion risks so it may help to consider the management of these risks separately.

Fire triangle and explosion pentagon

Fire triangle

Fire management strategies traditionally focus on the control or elimination of one of the three key elements necessary for a fire — often represented by the “fire triangle.”

Explosion Pentagon

The explosion pentagon includes two additional elements necessary for an explosion: dispersion of a “Dust Cloud” and “Confinement” of dust. The management or removal of one or more of the elements in the explosion pentagon can reduce the explosion risk. 

What is a Dust Explosion and How Does It Begin?

A dust explosion can be defined as: Any solid material that can burn in air will do so with a violence and speed that increases, with increasing degree of subdivision of the material. In other words, when a combustible material is in dust form it has the potential to not only burn but also under the right conditions explode with great force. This is true even of some materials that may not normally be thought of as combustible when in solid form such as food products like wheat flour or metals like iron.

An explosion typically begins when an ignition source enters the dust collector.

An explosion typically begins when an ignition source enters the dust collector

An explosion typically begins when an ignition source enters the dust collector. This ignition source can come from many things and in most cases is never identified. When a pulse cleaning event occurs, a suspended cloud of combustible dust is present in high concentration within the collector. This completes the five elements of a dust explosion and initiates the explosion.

Many dust explosions that occur in process plants are relatively small, leading to limited damage. However, under the right circumstances, even small explosions can escalate into major incidents. This is most commonly the case when secondary dust explosions happen. The typical scenario is that a small “primary explosion” raises a dust cloud, often from dust deposited over time on plant surfaces, and ignites the resulting dust cloud. This “secondary explosion” takes place where often people are present, placing them in immediate danger. Secondary dust explosions can form a chain reaction that can run through a facility as long as fuel is present, leading to injuries and damage to property. 

Mechanism of dust explosions

dust stream with particles of different sizes

Even materials that are traditionally thought of as non-flammable, such as aluminum, or slow burning, such as wood, can produce a powerful explosion when finely divided, and can be ignited by even a small spark

Dusts have a very large surface area compared to their mass. Since burning can only occur at the surface of a solid or liquid, where it can react with oxygen, this causes dusts to be much more flammable than bulk materials. For example, a 1 kg sphere of a material with a density of 1g/cm3 would be about 27 cm across and have a surface area of 0.3 m2. However, if it was broken up into spherical dust particles 50µm in diameter (about the size of flour particles) it would have a surface area of 60 m². This greatly increased surface area allows the material to burn much faster, and the extremely small mass of each particle allows it to catch on fire with much less energy than the bulk material, as there is no heat loss to conduction within the material. When this mixture of fuel and air is ignited, especially in a confined space such as a warehouse or silo, a significant increase in pressure is created, often more than sufficient to demolish the structure.

Even materials that are traditionally thought of as non-flammable, such as aluminum, or slow burning, such as wood, can produce a powerful explosion when finely divided, and can be ignited by even a small spark.

Explosive Materials & Equipment

The following materials are prone to dust explosions:

The following materials are prone to dust explosions: • Coal • Fertilizer • Cosmetics • Pesticides • Plastic & plastic resins • Wood • Charcoal • Detergents • Foodstuffs (sugar, flour, milk powder, etc.) • Ore dusts • Metal dusts • Graphite • Dry industrial chemicals • Pigments • Cellulose

Materials that are prone to dust explosions

— Coal

• — Fertilizer
• — Cosmetics
• — Pesticides
• — Plastic & plastic resins
• — Wood
• — Charcoal
• — Detergents
• — Foodstuffs (sugar, flour, milk powder, etc.)
• — Ore dusts
• — Metal dusts
• — Graphite
• — Dry industrial chemicals
• — Pigments
• — Cellulose


Typical industrial equipment that requires explosion protection.
• — Dust Collectors
• — Dryers
• — Cyclones
• — Crushers
• — Grinders
• — Silos
• — Pulverisers
• — Conveyors
• — Conveyor ducts
• — Screw conveyors
• — Bucket Elevators
• — Furnaces
• — Hoppers
• — Bins

Dust Collection Systems to Control Combustible Dust Hazards

A properly designed, operated and maintained dust collection system is the great defense against combustible dust hazards in your facility.

A properly designed, operated and maintained dust collection system is the great defense against combustible dust hazards in your facility

Many process requirements may make elimination of combustible dust, mist, or fume impractical. However, it may still be very possible to manage the dispersion of dust within your plant by using an appropriate and effective industrial ventilation system including dust collection. A well designed, maintained, and operated industrial ventilation system including good hoods, proper duct sizes, and properly selected collection equipment can provide effective dust control and can therefore help manage the presence of dispersed dust. This not only reduces housekeeping frequency and expense, but could also help you reduce the risk of dust explosions in your facility, particularly the destructive secondary explosions, by helping reduce the presence of dispersed fuel in your facility. A properly designed, operated and maintained dust collection system is the great defense against combustible dust hazards in your facility.

Who Sets Standards for Combustible Dust Safety?

The three key entities involved in combustible dust issues: OSHA, NFPA and AHJ

The three key entities involved in combustible dust issues are OSHA, NFPA and AHJ

In general there are three key entities involved in combustible dust issues, each with its own particular area of responsibility: (1) The National Fire Protection Agency (NFPA), (2) OSHA and your (3) local Authority Having Jurisdiction (AHJ). In addition to these agencies, others such as the US Chemical Safety Board (CSB) may assist with investigation of combustible dust accidents and advise on the setting of standards for specific industries.

Combustible Dust Control Strategies

Combating combustible dust hazards effectively in your facility requires dedication and a comprehensive approach. In the following section we will discuss several common combustible dust explosion prevention and protection strategies and technologies as they relate to dust collection systems.

Dust Hazard Analysis Required

NFPA regulations require that a Dust Hazard Analysis (DHA) be performed for all operations that generate, process, handle or store combustible dusts or particulate solids. The standard specifies that the facility owner or operator is responsible for determining if the handled materials are combustible or explosive, and if so, characterizing their properties for the DHA.

NFPA regulations require that a Dust Hazard Analysis (DHA) be performed for all operations that generate, process, handle or store combustible dusts or particulate solids.

NFPA regulations require that a Dust Hazard Analysis (DHA) be performed for all operations that generate, process, handle or store combustible dusts or particulate solids

Hazards associated with combustible dusts and dust collection systems include the following:

  • ● Explosion hazards in the right concentrations and conditions.
  • ● Ignition sources such as open flames, electrostatic discharge, lift truck activity, moving chains, hot surfaces, and rotating equipment with bearings can ignite accumulated or airborne dust, causing a deflagration.
  • ● Downstream through a dust collector’s ducting if not isolated, posing fire, pressure-wave, and noxious-gas hazards.
  • ● Dust buildup on floors, elevated surfaces, and in hidden areas can be disturbed by a primary explosion, become airborne, and contribute to a secondary explosion.
  • ● Dust buildup inside ducting due to deficient filter performance or poor design can contribute to flame or pressure propagation through the duct and into the workspace.
  • ● Metal dusts can have high rates of pressure rise and pressure maximums during a deflagration, causing an improperly designed dust collector to explode and produce shrapnel. • Metal dusts can be reactive with other dust oxides and liquids such as water and produce explosive gases that are highly ignitable.
  • ● Metal dust fires are more difficult to extinguish and can be worsened with the use of improper extinguishing agents.

Explosion Protection and Prevention Technologies

There are many types of devices and systems used to comply with NFPA standards for the explosion protection of dust collection systems, but they fall into two general categories: Passive systems react to the event, while active systems detect and react prior to or during the event.

The goal of a passive system (also called protection) is to control a fire or an explosion so as to keep employees safe and minimize equipment damage in the plant. An active system (also called prevention), by contrast, can prevent an explosion from occurring. An active system involves much more costly technology and may require periodic recertification.

Passive Devices (Protection)

  • ● Explosion venting: Designed to be the “weak” link of the dust collector vessel, an explosion vent opens when predetermined pressures are reached inside the collector, allowing the excess pressure and flame front to exit to a safe area. It is designed to minimize damage to the collector and prevent it from blowing up in the event of a deflagration, thereby reducing the safety hazard. In addition, a flameless vent extinguishes the flame front exiting the vented area, not allowing it to exit the device. This allows conventional venting to be accomplished indoors where it could otherwise endanger personnel and/ or ignite secondary explosions.
  • ● Passive float valve: Designed to be installed in the outlet ducting of a dust collection system, this valve utilizes a mechanical barrier to isolate pressure and flame fronts caused by the explosion from propagating further through the ducting. The mechanical barrier reacts within milliseconds and is closed by the pressure of the explosion.
  • ● Back draft damper: A mechanical back draft damper is positioned in the inlet ducting. It utilizes a mechanical barrier that is held open by the process air and is slammed shut by the pressure forces of the explosion. When closed, this barrier isolates pressure and flame fronts from being able to propagate further up the process stream.
  • ● Flame front diverters: These devices divert the flame front to the atmosphere and away from the downstream piping. Typically, these devices are used between two different vessels equipped with their own explosion protection systems. The flame front diverter is used to eliminate “flame jet ignition” between the two vessels that could overpower the protection systems installed. 


Active Devices (Prevention)

  • ● Chemical isolation: Designed to react within milliseconds of detecting an explosion, a chemical suppression system can be installed in either inlet and/or outlet ducting. Typical components include explosion pressure detector(s), flame detector, and a control panel. This system creates a chemical barrier that suppresses the explosion within the ducting and reduces the propagation of flame through the ducting and minimizes pressure increase within connected process equipment.
  • ● Chemical suppression: Whereas chemical isolation is used to detect and suppress explosions within the ducting, chemical suppression protects the dust collector itself. It is often used, together with isolation, when it is not possible to safely vent an explosion or where the dust is harmful or toxic. The system detects an explosion hazard within milliseconds and releases a chemical agent to extinguish the flame before an explosion can occur.
  • ● Fast acting valve: Designed to close within milliseconds of detecting an explosion, the valve installs in either inlet and/or outlet ducting. It creates a mechanical barrier within the ducting that effectively isolates pressure and flame fronts from either direction, preventing them from propagating further through the process.
  • ● High-speed abort gate: The gate is installed in the inlet and /or outlet ducting of a dust collection system and is used to divert possible ignition hazards from entering the collector, preventing a possible explosion from occurring and preventing flame and burning debris from entering the facility through the return air system. A mechanical barrier diverts process air to a safe location. Abort gates are activated by a spark detection system located far enough upstream to allow time for the gate to activate.

Additional Prevention Devices and Strategies

  • ● Maintain air velocity safety above the minimum conveying velocity: One of the most common sources of potential fuel for combustible dusts is found in the dust collector ductwork. Accumulated dust in ductwork often provides the fuel for devastating secondary explosions or fires. Maintaining the air speed inside the duct safety above the minimum conveying velocity will prevent material buildup.
  • ● Spark arrestor: A mechanical device designed to extinguish spark and embers. They are installed in the ductwork on the inlet side of the dust collector (the dirty air line coming into the unit) upstream from the last pickup but downstream of the collector.
  • A few variations exist, but the device causes the embers to burn out by a combination of the following: Turning vanes that cause the dust-laden air to change direction rapidly and forcing it to take a tortuous path that allows more time for the spark to burn out; screens that break up the ember into smaller pieces that then burn out; a housing larger than the ductwork to reduce the air velocity causing particles large enough to burn to fall out of the airstream; forcing the dust-laden air to impact a flat surface, causing the larger particles to fall out. For proper functioning of the spark trap, the length of duct between the spark source and the spark trap should be at least one duct diameter, and between the spark trap and the dust collector should be at least ten times the duct diameter. A shorter distance will prevent the spark trap from working correctly and is not recommended. Finally, be careful not to confuse a knockout box like device or a cyclone dust collector with a spark arrestor. These devices cannot guarantee 100% spark removal.
  • ● Special Filter Media: While there is no such thing as a “Fire proof filter” certain filter medias provide a level of added resistance to sparks and embers such as flame retardant coatings. Others use conductive materials within the fabric and can assist with static dissipation.
  • ● Sprinklers: Per local building codes you may be required to install traditional water sprinklers inside certain parts of the process, including inside the dust collector incase of fire.
  • ● Choice of filter style: For applications with high dust loading, heavy dusts or “sticky” dusts the use of cartridges may create an additional hazard. With horizontally-mounted cartridges, dust becomes trapped in the pleats in the upper third of the filters This trapped dust can burn even if the filter media is fire retardant.
  • ● Hopper discharge devices: Normally the choice of a discharge varies depending on the process needs and budgetary concerns. With combustible dust applications however the choice of a discharge device can have a major impact on safe operation. Rotary airlocks rated for combustible dust applications work best. Rotary valves enable quick and continuous emptying of the hopper, eliminating the potential for material in the hopper to serve as fuel for a potential explosion or fire. Discharge to a seal drum or hopper can also work well if they are rated to withstand potential explosion pressures. But these must be constantly replaced in order to prevent material backing up into the hopper. Finally, double dump valves rated for combustible dust applications can prove useful in applications with combustible dust but also larger pieces that could potentially jam rotary valves.

 

So, now that we have seen more clearly what are the hazards you might face and the pasive and active approaches to make your facility safer… its time to make an honest review of what needs to be adjusted in order to minimize risks.