Page 32 - OHS, April/May 2024

INDOOR AIR QUALITY
Handling Indoor Particulate Hazards with Vacuum Technology
Vacuum conveyors and industrial vacuum cleaners reduce liability exposure to dust produced during the manufacturing process.
BY DOAN PENDLETON
More than 40,000 chemicals are used in U.S. industry today, and a small percentage are regulated, leaving manufacturers in the dark about potential long-term effects. But lack of regulation does not absolve manu-
facturers from liability when workers are exposed to air pollutants.
Fugitive Dusts
Fugitive dust, particulate matter that becomes entrained in ambi- ent air, is part of the manufacturing environment where powders and bulk solids are processed. Fugitive dusts from chemicals, even those considered low-toxicity or nuisance dust, can cause respi- ratory illness, allergen risks and skin irritation (as well as com- bustible dust explosions); therefore, facilities are obligated to use OSHA’s hierarchy of controls to implement safeguards.
OSHA has no indoor air quality (IAQ) standards but holds em- ployers accountable to recognize the source of poor air quality and control workplace hazards under its General Duty Clause. OSHA’s respiratory standard 1910.134 (a)(1) states the primary objective to control respiratory disease is to “prevent atmospheric contami- nation” of harmful dusts. Only “when effective engineering con- trols are not feasible,” are respirators mandated control.
Engineering Controls
Engineering controls change processes to minimize contact with hazardous chemicals. High-efficiency particulate air (HEPA) in- dustrial vacuum cleaners are an acceptable engineering control to support OSHA compliance. Best industrial hygiene practices rec- ommend using HEPA vacs for dusts containing hazardous or toxic materials such as silica, lead, asbestos and beryllium.
OSHA’s revised Standard for Crystalline Silica advises switch- ing to HEPA vacuums may help employers meet current permis- sible exposure limits (PEL). It does “not allow dry sweeping or dry brushing where such activity could contribute to employee expo- sure to respirable crystalline silica unless wet sweeping or HEPA- filtered vacuuming... is not feasible.”
Nearly all regulatory agencies discourage brooms and com- pressed air to control surface dust and recommend industrial vac- uum cleaners to eliminate surface dust, not redisperse it.
Adopting the Right Solutions
Most industrial vacuum cleaners aren’t capital expenditures and cost far less than indirect costs of a single respiratory illness — and much less than proposed OSHA fines for exposing workers.
Most industrial vacuums today are portable. Stationary central vacuums with small footprints and portable vacuums that operate like a central vacuum cleaning systems provide suction to multiple stations. Power options for industrial vacuums include air-pow- ered venturi units, electric powered units (including intrinsically safe options) and PD pump. Combustible dust vacs and submerged
recovery vacs can add HEPA secondary filters.
Industrial vacuums can have 55-gallon drums, continuous bag-
ging options and even 2-yard discharge hoppers, with standard PTFE high efficiency filters; and a HEPA secondary filter.
While vacuum cleaning systems tackle fugitive dusts, vacuum conveying systems prevent loose powders from going airborne.
Manual material handling of powders and bulk solids is the greatest contributor of worker exposure to respiratory hazards in industrial environments. When powders or bulk dry materials are open-dumped, a puff of dust is created, creating fugitive dust.
Preventing Dust at the Source
Vacuum conveying systems are fairly simple and consist of five basic parts: a pickup point where material enters the conveying system; convey tubing that transfers material between equipment; a vacuum receiver (aka filter receiver) which is an intermediate holding vessel for materials; a vacuum source that powers the system; and a control panel that tells the system how to operate.
Air-operated venturi powered vacuum producers are by far the safest vacuum source for vacuum conveyors as they generate no heat or sparks. Where compressed air is not sufficient, or when conveying materials at higher rates and longer distances, positive displacement pumps are preferred for vacuum conveying.
Vacuum conveying systems are also available with HEPA sec- ondary filters and a range of configurations and power options. There are pre-engineered vacuum conveying systems, but most are customized according to a facility’s requirements.
Other Air Quality Considerations
Where facilities transition from manual transfer of materials to fully enclosed vacuum conveying system, workers’ need to wear respirators is eliminated since dust is contained during transfer.
For transferring ingredients that require higher levels of contain- ment, minimizing exposure requires additional scrutiny in conveyor equipment design. Whenever air moves through a vacuum conveyor system, it cycles through filters before being exhausted. One method for additional safety is added HEPA filtration.
Implementing vacuum conveyors reduces manual labor costs, preserves and recaptures materials for reuse and recycling, and de- livers precise measurements to boost quality and consistency.
Most regulatory agencies recognize vacuum technologies as ac- cepted engineering controls to prevent exposure to contaminants that cause respiratory diseases such as silicosis, occupational asthma and chronic obstructive pulmonary disease (COPD).
Doan Pendleton is President of VAC-U-MAX (Belleville, N.J.; www. vac-u-max.com), which specializes in the design and manufacture of pneumatic conveying systems, industrial vacuum cleaning systems, and support equipment.
32 Occupational Health & Safety | APRIL/MAY 2024
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