OSHA silica rule decision spells three-month reprieve for contractors

Occupational Safety and Health Administration has moved the target for the construction industry to comply with the revised respirable crystalline silica exposure standard from June 23 to September 23, citing a need to conduct additional outreach and provide educational materials and guidance due to the unique nature of employer requirements. The standard reduces the worker exposure threshold from 250 to 50 micrograms of silica dust.

Announcing the delay, the agency nevertheless urges construction industry employers to continue to a) take steps either to come into compliance with the new permissible exposure limit, or implement specific dust controls for certain operations as provided in Table 1 of the standard; and, b) prepare to implement exposure assessments, medical surveillance and employee training requirements.

On behalf of the Construction Industry Safety Coalition (CISC), the Mason Contractors Association of America noted, “The Coalition is pleased OSHA has recognized the need to develop guidance material for the construction industry before enforcing the respirable crystalline silica rule. While CISC appreciates the 90-day delay in enforcement, [it] remains concerned about the overall feasibility of the standard in construction and has requested that the Agency delay enforcement for a year.”

Crystalline silica is a component of concrete that becomes breathable when drilling, sawing, polishing, cutting or crushing concrete, brick, block, rock or stone, notes Bosch Tool. OSHA claims that respirable crystalline silica is capable of crippling or killing workers by causing a range of lung diseases, from silicosis and lung cancer to emphysema, plus kidney disease. The agency estimates that 2.3 million U.S. workers are exposed to respirable silica dust each year on the job.

Prior to the OSHA’s announcement of enforcement delay, construction and plant equipment companies were preparing contractors and concrete producers for June 2017 and June 2018 compliance targets, promoting at World of Concrete and The Precast Show an array of devices Concrete Products samples here.


Model 1040PD central vacuum system is available in 10 hp and 15 hp, supporting one to three operators while conforming to NFPA standards for indoor installation. The model generates 100 percent more vacuum than other small central vac systems with piping runs up to 200 feet, product engineers contend. It features a plug-and-play design with single-point compressed air and three-phase power supply, plus full control panel. All Vac-U-Max central vacs with positive-displacement or regenerative blower vacuum producers are available with secondary HEPA filtration. Typical applications for HEPA-filtered vacuums include precast concrete, cement and aggregate operations. — Vac-U-Max, Belleville, N.J., 800/VACUMAX; www.vac-u-max.com



Company bills the Dust Collection Cart as the industry’s first such device for handheld drills.

Company has added to its concrete dowel drill line the Dust Collection Cart, suited to handheld tools and meeting all engineering and control methods outlined in the OSHA Table 1 requirements for crystalline silica exposure. Fitted with two 600-mm filters to effectively trap dust particles, the cart collection system weighs 215 lbs. and uses the same air compressor as the drill, drawing 40 additional cfm. It effectively collects dust directly from the drilled holes and conveys to a vessel. E-Z Drill designed the cart with 20 feet of 2-in. dust collection hose and a shroud that goes around the bit to ensure the dust is collected at the point of drilling, maximizing the amount of silica the system captures and reducing operator exposure. — E-Z Drill Inc., Perry, Okla.; 800/272-0121; www.ezdrill.com


When used with appropriated filter, the dust collection system for dowel pin drills meets related Table 1 requirements in the OSHA final respirable crystalline silica standard. Filters supplied with the system comply with the agency’s filter efficiency requirement. Featuring Venturi-style suction and manual or automatic purge control, the pneumatic dust collector removes dust from the air as the operator drills. The canister-style unit can be retrofitted to any Minnich on-grade, on-slab, machine-mounted or utility drill model. It can also be adapted to fit other dowel pin drill makes and models.

The dust collection system requires 40 scfm for hydraulically powered drills and 50 scfm for pneumatically powered units, and 60 to 110 psi. Each canister can accommodate up to two drills and offers a 60-square-meter filter area. System shipped with drill rod guide collection boots, 5-gal. pail-type hopper, and up to 20 feet of vacuum hose per drill. — Minnich Mfg., Mansfield, Ohio, www.minnich-mfg.com


Company cites a series of solutions for silica dust control-geared housekeeping, including the S30 Rider Sweeper shown below. Effective in most applications, wet sweeping can be tackled by Tennant rider sweepers, whose continual water spray provides a shield of moisture on side brushes to keep the silica dust moist until it is captured and contained within the hopper. Company’s walk-behind or ride-on scrubbers can be used for water flooding, an effective silica dust control method in certain applications.

Dry Sweeping with HEPA filtration is an OSHA-allowable solution in applications where other methods, such as wet sweeping or HEPA vacuums, are not feasible. Several Tennant walk-behind and ride-on sweepers are available with HEPA filtration systems; they operate with a dry system that provides a filtration efficiency of 99.97 percent to 0.3 microns. They utilize existing multi-stage filtration systems, adding a final-stage HEPA system to collect and contain smaller particles. — Tennant Co., Minneapolis, 800/553-8033, www.tennantco.com


Company is extending its Dust Extraction System, anchored by M12 Hammervac Universal Dust Extractor introduced in 2012. With the launch of an 8-Gallon Dust Extractor and accessories, the company’s full lineup of rotary hammers and grinders are compliant through either OSHA silica rule Table 1 or Objective Data Requirements.

The 8-Gallon Dust Extractor features an automatic filter cleaning mechanism to allow for sustained airflow at 148 cfm in dust-producing applications. The Extractor’s dual filtration system (complete with HEPA filter) captures 99.97 percent of all particles greater than 0.3 microns. For SDS Max hammers, there is a new dust extraction attachment for drilling holes up to 2-3/4-in. in diameter and a chisel boot for chipping applications. Also available are new cutting shrouds that work with the Extractor to maximize dust collection during concrete cutting with grinders. The accessories join current lineup of Hammervac-dedicated and universal extractors, billed as the most complete system of cordless, battery-powered dust extraction solutions in the industry. — Milwaukee Tool, Brookfield, Wis., 800/SAWDUST; www.milwaukeetool.com


From ½-in. anchor to 18-in. diameter holes in rebar-heavy concrete, the new DD 250 is a rig-based, wet drilling system compliant with Table 1 in the revised OSHA standard for respirable crystalline silica dust exposure. Hilti designed the Diamond coring tool to be smart with a digital display that will help guide the operator during each coring job. The operator can follow the display to accurately level the tool, select the right gear for the jobs, check how much work has been accomplished, receive live status updates and service messages. The tool has an air-cooled, heavy-duty drive unit with four-speed gearing and convenient controls. Rotating speeds across gears 1–4 are 240–2,220 rpm. — Hilti Inc., 800/879-8000, www.us.hilti.com; Hilti (Canada) Corp., 800/363-4458, www.hilti.ca


Company announced at 2017 World of Concrete the first fully integrated worm drive saw designed to score and cut concrete. It engineered the saw with an integrated wet/dry dust management system to control dust, allowing for cleaner cuts, and GFCI protection. Both features extend the life of the saw and protect the user.

The Medusaw features a Cut-Ready adjustable plunge lock that allows users to quickly set and make consistent plunge cuts; integrated rolling foot plate with rubber wheels that help users to move it smoothly across hard surfaces plus rust resistant brackets and fasteners to protect against corrosion; retractable front pointer to accurately guide the saw along the cut line and navigate tight spaces; and, onboard multi-function wrench, making it easy for users to change their blades, oil, brushes, water feed attachment and wheels. — Skilsaw Power Tools/Robert Bosch Tools Corp., www.skilsaw.com


Speed Clean bits are built around an internal channel that sucks up dust while drilling; by virtue of creating less dust, they eliminate 90 percent of airborne silica particles. The bits rely on solid carbide tips, embedded in a steel head, along with robust two-cutter and four-cutter geometry to enhance speed and service life. Each bears a rubber connector that attaches drill bit shaft to a dust extraction system hose. Speed Clean bits deliver a clean hole in concrete up to 50 percent faster than conventional alternatives, product engineers note, netting more specification-grade holes in less time.

Bosch enlisted a certified industrial hygienist in developing Speed Clean bits. Using each type of concrete drill bit, four tests were initiated. Speed Clean rendered undetectable amounts of silica dust in the worker’s breathing zone in all four; for conventional concrete drill bits just the opposite was observed. — Bosch Tools, 877-BOSCH-99; www.boschtools.com, www.bethepro.com