[Neponset, IL] – In a move to help all silica dust-producing operations comply with impending rule changes, a pioneer in industrial dust control is reminding companies that the Occupational Safety and Health Administration (OSHA) respirable crystalline silica (RCS) dust emissions Final Rule [OSHA §1910.1000 Respirable crystalline silica] compliance deadline for general industry and maritime is June 23, 2018. Martin Engineering helps operators safeguard the health of individuals by emphasizing the use of field-proven equipment to minimize dust, forced downtime and potential fines.
Serving customers from mining, aggregates, cement manufacturing to ports and shipping, workplace safety has always been a priority for the company. “We believe that dust control doesn’t need to come at the expense of production or profits, but should support operations and deliver a return on investment,” explained Jerad Heitzler, Foundations™ Training Manager at Martin Engineering. “Although added regulations are always a strain on any business, compliance is an opportunity to assess aging systems and improve efficiency.”
Why the Regulation?
Due to the small size, RCS of PM10 (particulate matter ≤10 microns [μm]) can penetrate the body’s natural defenses (mucus membranes, cilia, etc.), reaching deep into the lungs. Invisible to the naked eye and able to travel long distances on ambient air currents, workers are often unaware of the lingering RCS and take off protective masks, risking exposure and potentially contracting silicosis over time.
Silicosis is a chronic and irreparable disease that affects millions of workers in a wide variety of industries. Without proper protection, workers with extensive exposure can experience a buildup of RCS deep in the lungs, restricting lung capacity. Silicosis can potentially lead to more harmful and life-threatening lung ailments such as pneumonia, pulmonary tuberculosis and lung cancer.
With this in mind, not only does the Final Rule require regular monitoring by the employer, but it also sets personal exposure limits (PEL) and suggests engineering controls and particulate isolation rather than putting the entire onus of wearing uncomfortable respirators on the employees. By doing this, regulators also limit fugitive dust emissions from leaving the site line and exposing the wider public.
“The RCS regulations are touching a wide range of industries,” said Heitzler. “Some operations can implement a single solution, whereas others create dust throughout the entire processes and require unique solutions at each stage.”
Being Compliant
Using a personal dust monitor worn by a trained employee continually monitors the amount of RCS to ensure the exposure is under the average “action level” of 25 µg/m3 (micrograms of RCS per cubic meter of air). Plants must protect workers if they have an amount of RCS dust above the PEL of 50 µg/m3, averaged over an 8-hour day. To control these levels, OSHA gives very general instructions regarding methods of compliance, advising companies to:
Non-compliance could result in fines, disruption in production and legal action by federal or state agencies or workers. If PEL readings are at or above the permissible exposure level, plants must take action with isolation or engineered controls. And fines for first offenses can by steep. For example, following the construction industry deadline of June, 23rd 2017, some general contractors and developers faced fines of $40K- $70K.
Engineering Controls and Isolation
Engineering controls are retrofitted equipment or newly designed systems that reduce or eliminate exposure to RCS. An example of this is Martin Engineering’s modern conveyor transfer chute design, which shapes the flow of cargo, controls transfer speed and minimizes disruption.
Isolation is an enclosed system that seals in dust from escaping. On a fast moving, high volume conveyor, air flow through the settling zone must be controlled and cannot be allowed to escape, otherwise plumes of fugitive dust are released. This can be done from the Tail Sealing Box to the chute exit using specially configured Dust Curtains, which promote quick settling and improve dust capture in top-mounted Dust Bags.
For heavy duty applications with short ducting runs that exceed the volume of a Dust Bag, an integrated Air Cleaner is a compact dust collector located directly above the conveyor transfer point. It captures agitated dust in a filter, then uses a reverse pulse of air to return dust to the main cargo stream.
The system is not sealed if the chute skirting doesn’t retain contact with the belt. Mounted on the outside of the chute with optional quick release clamps for safer access and maintenance, ApronSeal Double Skirting provides a dual seal to prevent the escape of fines and dust. The patented design features a secondary sealing strip that rides the belt to deliver an extra layer of protection against dust emissions and spillage.
For hydrophobic materials, the Surfactant Dust System can apply dust-suppressing surfactant and crusting agents using strategically placed spray nozzles and a fully automated system to avoid waste. Able to be placed almost anywhere within the cargo stream from loading to discharge, the sprayed surfactant agents reduce the surface tension of water, improving its ability to wet surfaces and form fine droplets that reduce dust emissions.
Another concern operators should be aware of is carryback. Without thorough discharge of dry bulk materials, fine material can get caught in cracks and divots on the belt that create dust emissions along the entire return path. Having the proper primary and secondary cleaners is key to reducing carryback. For extra cleaning of tacky or powdery cargo, operators may consider installing a Washbox Cleaning System consisting of a powder-coated steel enclosure equipped with rollers, spray bars, inspection doors and secondary cleaners.
“Compliance not only protects workers, but also protects the bottom line from fines, downtime and lawsuits,” said Heitzler. “Investing in long-lasting and field-proven equipment translates to a sensible ROI and peace of mind over the long term.”