How Dust Testing Can Improve Indoor Air Quality in Manufacturing: A Q&A Guide

Maintaining indoor air quality (IAQ) in manufacturing facilities is essential for worker safety and operational efficiency. Dust generated from various processes can pose significant health risks to workers and negatively affect product quality.

To address these concerns, dust testing is crucial. In this Q&A, we explore which types of facilities have IAQ issues, dangers to workers, how dust testing can improve indoor air quality, the role of dust collectors and the importance of selecting the right filters and protective equipment.

1. Why is controlling dust in manufacturing facilities so important for indoor air quality?

Controlling dust in manufacturing is crucial because it directly impacts indoor air quality. Dust from various processes can contain hazardous particles that, if not properly managed, can harm workers. Some of these dust particles can be toxic and pose significant health risks. A notable example is the aftermath of 9/11, where exposure to toxic dust led to chronic health issues for thousands of residents and first responders.

2. What types of facilities generate dust?

Many industries produce dust through their operations, materials and final products. However, the following facilities create a lot of indoor dust:

• Chemical Processing Facilities: Activities like coating, blending, crushing, milling, mixing and pelletizing create airborne dust that can pose significant health hazards.
• Pharmaceutical Companies: The production of tablets and other solid-dose products often releases toxic dust due to the use of active ingredients.
• Metalworking Plants: Processes such as welding, thermal cutting and sanding can generate tiny, toxic metal particles, including lead, iron, nickel and chromium.
• Woodworking Operations: Sawmills, furniture makers and other wood product manufacturers produce fine wood particles during cutting, routing, chopping and molding, which can pose health risks.
• Food Processing: Dust from solid ingredients like sugar, starch, spices and flour can trigger allergic reactions, especially in those with gluten intolerance.
• Packaging Manufacturers: The production of paperboard, metal and plastic packaging materials results in the creation of dust.

3. What health risks are associated with poor IAQ?

Poor IAQ means the air is filled with dust particles that can settle on surfaces or be inhaled by workers. Depending on their chemical makeup, these particles can cause a range of health issues, including eye irritation, dermatitis and allergic reactions like rashes and asthma. The severity of these health problems often correlates with the duration of exposure.

Inhaled dust can lead to respiratory issues such as coughing, wheezing, bronchitis and even lung cancer. The type of dust plays a significant role in the severity of lung injuries—metals and crystalline silica, for instance, are particularly toxic. If ingested, silica particles can release harmful substances into the body.

Acute exposure to toxic dust can result in chronic diseases over time. For example, a persistent cough could eventually develop into chronic obstructive pulmonary disease (COPD) or gastroesophageal reflux disease (GERD).

4. Does OSHA govern indoor air quality?

Yes, the Occupational Safety and Health Administration mandates that manufacturing facilities maintain safe working environments, free from hazards that could cause harm or injury. Compliance with OSHA standards requires the removal of potentially toxic dust from processing areas to protect workers’ health and safety.
OSHA has set permissible exposure limits (PELs) for workers’ exposure to certain airborne dust during an eight-hour shift. For instance, the PEL for hard and soft wood dust is 5 mg/m³ over an eight-hour time-weighted average (TWA), with a short-term exposure limit (STEL) of 10 mg/m³.

5. How do facilities reduce exposure to dangerous dusts?

High-efficiency dust collectors with cartridge-style filters, designed specifically for your operation, can effectively filter hazardous dust, making the indoor environment safer.

6. What role does dust testing play in selecting a dust collection system?

Dust testing is vital in determining the best dust collection system and filters for your specific application. By analyzing dust characteristics—such as particle size, shape, moisture content and abrasiveness—you can select the appropriate dust collector and filter media. Dust testing is especially valuable when installing a new system, starting a new manufacturing process or when changes in equipment or processes might affect dust characteristics.

Problems with existing dust collection systems can also be addressed with dust testing. If a dust collector is using too much energy, not clearing the air effectively, or requiring excessive maintenance, it may not be designed for the type of dust it is collecting. A dust characteristics analysis can help determine the correct filter housing size, ductwork design and other system components to optimize performance, leading to better air quality and reduced energy consumption.

7. How does the dust hazard analysis mandated by the NFPA relate to indoor air quality?

The National Fire Protection Agency requires that companies producing potentially hazardous dust complete a dust hazard analysis (DHA). The DHA helps to identify potential dust explosion and fire hazards and guides the selection of dust collection equipment that mitigate these hazards.

8. How does dust testing help ensure compliance with indoor air quality guidelines?

Dust testing provides detailed insights into dust characteristics, helping you remain compliant with indoor air quality standards. Your air quality program should include goals based on guidelines from the American Conference of Governmental Industrial Hygienists (ACGIH) and adhere to OSHA’s PELs for the dusts your operation generates. Dust testing ensures that your dust collection system meets these standards.

9. What are the key steps involved in dust testing and sample collection?

Dust testing begins with collecting a representative dust sample, preferably from a dirty filter in an existing dust collector. Avoid samples from the hopper as they may not accurately represent the dust’s particle size distribution captured by the filters. And dust collected from the floor could contain impurities and other materials. The testing lab will analyze the sample for particle size, shape, moisture level and abrasiveness, providing essential data for selecting the right dust collection system and filters.

10. What factors should be considered when selecting dust collector filter cartridges?

When selecting dust collector filter cartridges, consider the dust characteristics and the type of manufacturing process. For example, hazardous dusts like crystalline silica require high-efficiency filters that meet OSHA requirements. Moist or sticky dusts, common in food processing, may benefit from washable polyester filters. For statically charged or metal-containing dusts, grounded cartridges or conductive filter media are recommended by the NFPA.
Particle size analysis is also critical in determining the filtration efficiency required to meet emissions standards and comply with OSHA regulations. The analysis reveals the dust particle size down to the submicron level, allowing you to select the appropriate filter media. Understanding both the count and volume of particles ensures that your dust collection system is tailored to the specific needs of your operation.

11. What is the significance of microscopic analysis in dust testing?

An optical microscope is used to observe the shape of dust particles, and a scanning electron microscope provides elemental analysis and detailed media images. For example, identifying a crystalline structure with jagged edges, like fumed silica, indicates the need for a high-efficiency filter with an additional protective layer of nanofibers or PTFE. Microscopic analysis can also detect oil in the dust, which may require oil-resistant filter media to prevent filter clogging and ensure efficient dust collection.

12. How do abrasion and moisture testing contribute to dust collection system design?

Abrasion testing helps determine the optimal design of dust-handling equipment, including inlets, baffles, discharges and ductwork. For instance, highly abrasive dusts like cast iron grindings require a low inlet velocity to prevent premature wear on filters.

Analysts use a hygrometer to identify the presence of moisture in the dust. This helps to determine equipment design elements like hopper angle and conveying velocities. It also guides the selection of appropriate filter media and equipment design elements to prevent clogging and ensure smooth operation.

Conclusion

Maintaining indoor air quality in manufacturing facilities requires a thorough understanding of the dusts generated by your processes. Dust testing provides essential data that guides the selection of dust collectors, filters and system components, ensuring a safe and compliant work environment. By investing in dust testing and proper equipment, you can protect your employees’ health, improve indoor air quality and improve efficiency of your operations.

Source: OHS Online

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