Air quality management for small and midsized manufacturing shops

2022-11-28 01:18:12 By : Mr. Anthem Zhu

Managing dust effectively can be a challenge for small and midsized shops. Here are the answers to the questions that managers of small to midsized welding shops frequently ask about air quality management. Getty images

Welding, plasma cutting, and laser cutting produce fumes, often referred to as smoke, which consist of airborne dust particles made up of tiny pieces of dry solid matter. This dust can reduce air quality, irritate the eyes or skin, damage the lungs, and become a hazard when settling on surfaces. Hydraulic Filter Element By Size

Air quality management for small and midsized manufacturing shops

Processing fumes can contain lead oxide, iron oxide, nickel, manganese, copper, chromium, cadmium, and zinc oxide. Some welding processes can also produce toxic gasses like nitrogen dioxide, carbon monoxide, and ozone.

It’s important to manage dust and fumes properly in your workplace for the safety of your workers, the equipment, and the environment. The best way to capture dust is with a collection system that removes it from the air, exhausts it outdoors, and returns clean air indoors.

However, managing dust effectively can be a challenge for small and midsized shops because of costs and other priorities. Some of these facilities will try a do-it-yourself approach to control dust and fumes under the assumption that their shop does not need a dust collection system.

Whether you are just starting out or have been operating for many years, you might be interested in the answers to questions that managers of small to midsized welding shops frequently ask about air quality management.

First, be proactive with a health risks and mitigation plan. For example, an industrial hygiene assessment will help you identify harmful elements in your dust and determine exposure levels. This assessment should include evaluating your facility to ensure you are meeting Occupational Safety and Health Administration (OSHA) permissible exposure limits (PELs) for the dust particles that your applications produce.

Ask your dust collection equipment supplier if they can recommend an industrial hygienist or environmental engineering company experienced in identifying dust and fumes specific to metal processing facilities.

Next, create air quality goals for your dust management program based on two resources:

If you are going to recirculate clean air back into your facility, make sure it stays below the actionable limit set by OSHA PELs for contaminants. If you are exhausting air outdoors, remember that you are subject to the Environmental Protection Agency’s (EPA) National Emission Standards for Hazardous Air Pollutants.

Last, when designing your dust collection system, you must make sure you create a safe welding workplace by following the three Cs of dust and fume removal: capture, convey, and contain. This design will typically include some type of hood or method of fume capture, ducting connecting the capture points, properly sizing the ducting back to a dust collector, and selecting a fan that can handle the system’s volume and static.

This is an example of a cartridge-style industrial dust collector that is located outside of a welding facility. Images: Camfil APC

A dust collector system designed specifically for your operation is an accepted and proven engineering control that can capture, convey, and contain hazardous airborne contaminants. Dry media dust collectors containing high-efficiency cartridge filters along with secondary filters are suitable for capturing respirable dust particulates.

Source-capture systems are popular for applications involving small parts and fixture welding. Typically, they include fume-exhaust guns (tip extraction), flexible fume arms, and slotted fume hoods or small exhaust hoods with side shields. These are usually customized to be application-specific with minimal interruption of the workflow.

Enclosures and canopy hoods are often used where the footprint area is 12 ft. by 20 ft. or less. Curtains or hard walls may be added to the sides of the hood to create a booth or enclosure. In the case of robotic welding cells, a full enclosure over and around the application can often be used. This works well for single- and dual-arm welding robots and multiaxis plasma cutting robots.

When your application isn’t compatible with the suggestions previously outlined, then an ambient system can be designed to remove fumes from most if not the entire facility. Keep in mind that as you progress from source capture, enclosures, and hoods to ambient collection, the airflow required increases significantly, as does the system’s price tag.

Many small to medium-size shops tend to react only after they’ve tried to control fumes with money-saving DIY methods, such as opening doors or windows and creating their own exhaust system. The problem is that nuisance fumes eventually become a much bigger problem and often overwhelm these methods while increasing energy costs or creating dangerously high negative pressures in the facility.

The first thing you need to do is figure out where the problems most often arise in your facility. This could be plasma table fumes, free-hand arc gouging, or welding on benches. From there, address the process that creates the most fume first. A portable system may help you get by depending on the amount of fume generated.

The best way to reduce worker exposure to hazardous fumes is to work with a quality dust collector manufacturer who can help you identify and create custom systems for your facility. Typically, this includes installing dust collection systems with primary cartridge-style filters and high-efficiency secondary safety filters.

The primary filter media you select for each application should be based on the dust particle’s size, flow characteristics, quantity, and distribution. A secondary safety monitoring filter, such as a HEPA filter, increases particle capture efficiency to 0.3 microns or larger (capturing a high percentage of PM1) and prevents hazardous fumes from discharging into the air if the primary filter malfunctions.

If you already have a fume management system, carefully monitor your shop for conditions that indicate it’s not working properly. Some warning signs include:

Watch out for a fume cloud that thickens throughout the day and hangs in the air after welding activity ends. However, heavy fume accumulation doesn’t necessarily mean your extraction system isn’t working, it may mean you’ve outgrown your current system. If you’ve recently increased production, you may need to reevaluate your current setup and make changes to accommodate the uptick in activity.

Managing dust and fumes properly is crucial for the safety of your workers, the equipment, and the shop environment.

Finally, it is always important to listen to, observe, and question your workers. They can let you know if current engineering controls are effectively managing dust at your facility and also suggest areas for improvement.

OSHA rules for small businesses can be complex, especially when it comes to knowing which rules you must follow and which ones you are exempt from following. Many times, small shops think they can fly under the radar of OSHA regulations—until an employee files a complaint. Let’s be clear: ignoring the regulations does not eliminate the health risks to employees.

Under OSHA’s General Duty Clause, Section 5(a)(1), employers must identify and abate hazards in the workplace. This means employers are required to keep records identifying all the hazards (dust) generated in their facility. If the dust is flammable or explosive, they must follow National Fire Protection Association standards to properly manage the dust, and if not, they need to keep test records.

OSHA also has set PEL thresholds for airborne particle contaminants generated by welding and metal processing. These PELs are based on an eight-hour, time-weighted average for hundreds of dusts, including those contained in welding and metal processing fumes listed in annotated PEL tables. When initial air monitoring reveals exposures above the action level, facility operators need to implement additional requirements per OSHA.

As mentioned previously, fumes can irritate eyes and skin. However, there are more toxic effects that you should be aware of as well.

Particulate matter (PM) with a diameter of 10 microns or less (≤ PM10) can reach the respiratory ducts, while particles 2.5 microns or less (≤ PM2.5) can lodge deep inside the lungs. Inhalable particles with a diameter of 1.0 micron or less (≤ PM1) can cause much more damage because they can penetrate the lung barrier and enter the blood system.

Regular exposure to PM contributes to the risk for developing respiratory diseases, including lung cancer. Many of the particles produced by welding and metal processing reside within this hazardous range, and the nature and severity of the hazard will vary with the type of material being processed. Whether you are working with stainless steel, mild steel, aluminum, galvanized, or another material, the material safety data sheet is a good starting point for identifying health risks.

Manganese, the primary metal in welding wire, can cause headaches, exhaustion, listlessness, and weakness. Prolonged exposure to manganese fume can cause neurological problems.

Exposure to hexavalent chromium (hex chrome), a carcinogenic substance produced during welding on metals that contain chromium, can result in short-term upper respiratory illness and eye or skin irritations.

Zinc oxide, generated by hot work on galvanized steel, can result in metal fume fever, a short-term illness in which severe flu-like symptoms occur after a break from work, such as after a weekend or during a vacation.

If you already have a fume management system, monitor your shop carefully for conditions that indicate it’s not working properly, such as a fume cloud that thickens throughout the day.

Signs and symptoms of beryllium exposure can include shortness of breath, cough, fatigue, weight loss, fever, and night sweats.

In general, watch out for eye, nose, and throat irritation, dizziness, and nausea.

In welding and thermal cutting operations, a well-designed and maintained dust collection system works to prevent respiratory problems in employees and keep facilities in compliance with current air-quality requirements.

Yes. Air that is laden with fumes can coat the heat exchanger and cooling coil, causing the HVAC system to require frequent service. Weld fume can penetrate standard HVAC filters, causing heating systems to malfunction and air conditioning condensation coils to clog. Constant service of HVAC systems can become expensive, but poorly functioning systems can create dangerous conditions for workers.

A simple but important safety rule is to change out dust filters before they become overly laden with dust. Replace the filter if you notice any of the following:

Some long-life cartridge filters can operate for two years or more between changeouts. However, heavy dust-loading applications generally require more frequent filter replacements.

Choosing the right replacement filter for your cartridge dust collector can have a big effect on the cost and performance of your system. Be careful when purchasing replacement filters for your cartridge dust collector—not all filters are the same.

Oftentimes buyers get caught up in the best value. However, the sticker price isn’t the best guide when purchasing cartridge filters.

Overall, protecting yourself and your workers with proper dust collection systems will go a long way in helping your small or midsized business thrive and grow.

Camfil Air Pollution Control (APC)

See More by Jon Ladwig

Read more from this issue

The WELDER, formerly known as Practical Welding Today, is a showcase of the real people who make the products we use and work with every day. This magazine has served the welding community in North America well for more than 20 years.

Easily access valuable industry resources now with full access to the digital edition of The FABRICATOR.

Easily access valuable industry resources now with full access to the digital edition of The WELDER.

Easily access valuable industry resources now with full access to the digital edition of The Tube & Pipe Journal.

Enjoy full access to the digital edition of STAMPING Journal, which serves the metal stamping market with the latest technology advancements, best practices, and industry news.

Easily access valuable industry resources now with full access to the digital edition of The Fabricator en Español.

© 2022 FMA Communications, Inc. All rights reserved.

Air quality management for small and midsized manufacturing shops

Industrial Candle Filter Element 1340014 Not yet registered? Sign up