Engineering Controls for Silica in Construction – Concrete Grinder. Wet concrete grinding

Engineering Controls for Silica in Construction – Concrete Grinder

Construction workers who perform concrete grinding may breathe dust that contains respirable crystalline silica (RCS). A NIOSH [1] pdf icon study found that workers grinding concrete to smooth poured concrete surfaces were exposed to high levels of dust containing RCS, ranging from 35 to 55 times the NIOSH recommended exposure limit (REL). The Concrete Grinder without Engineering Controls video shows a worker performing a task with a concrete grinder while the overlay shows consistently high levels of respirable dust in the air.

Local exhaust ventilation systems (LEV) can be attached to concrete grinders to reduce RCS exposures. Researchers have found that levels of exposure to RCS were significantly lower when workers used a grinder equipped with an LEV system compared to a grinder used without LEV.

An LEV system consists of a grinder equipped with a ventilation shroud, a length of flexible hose, and a portable electric vacuum cleaner that acts as the fan and dust collector for the ventilation system. Some specifications for an LEV system for a concrete grinder are listed below.

Vacuum Cleaner

The vacuum should have the following features:

• Sufficient flow rate to capture the dust and transport it to the vacuum source.
• A high-efficiency particulate air (HEPA) filter to reduce the chances of releasing dust containing RCS from the vacuum into the worksite.
• A pre-filter or cyclone to increase the length of service of the HEPA filter.
• A filter replacement indicator.
• The ability to clean and replace filters and full collection bowls or bags without exposing the operators to dust.
• A motor that draws at least 10 amps.

Hose

The hose should have a diameter of 1.5- or 2-inches with a relatively smooth interior and a length of no more than 15 feet to provide adequate air flow.

Shroud

The type of shroud to be used depends on the preferences of the cement finisher and the employer, according to the task to be performed.After testing different types of shrouds, NIOSH determined that all were equally effective, reducing dust exposure by at least 90%.

The Concrete Grinder with Engineering Controls video shows a worker using a concrete grinder with a LEV system. The left bar of the graphic overlay of the video shows low amounts of respirable dust when compared to the initial video (above).

Dust controls in the form of local exhaust ventilation (LEV) systems offer several benefits. Those benefits include reducing worker exposure to hazardous dust, potentially allowing for use of less protective respiratory protection; reduced cleanup time; and reduced exposures during cleanup. The LEV dust control may greatly reduce worker exposures to hazardous dust. However, respirators are still necessary to reduce exposure to RCS below the NIOSH REL of 50µg/m 3.

Additional Information

For more information about dust controls for concrete grinders see:

• In-depth survey report of four sites: exposure to silica from hand tools in construction chipping, grinding, and hand demolition at Frank Messer and Sons Construction Company, Lexington and Newport KY; Columbus and Springfield, OH. NIOSH Report No. EPHB 247–15 (2001).
• Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding. [PDF – 280.05 KB] external iconJournal of Occupational and Environmental Hygiene:2010/ 7: 700-711.
• Crystalline silica dust and respirable particulate matter during indoor concrete grinding, wet grinding and ventilated grinding compared with uncontrolled conventional grinding. [PDF – 1.58 MB] external iconJournal of Occupational Environmental Hygiene: 2007 / 4:770–779.
• Protecting tuckpointing workers from silica dust: draft recommendations for a ventilated grinder. external iconThe Center to Protect Workers’ Rights, Silver Spring, MD (2005).
• The efficacy of local exhaust ventilation for controlling dust exposures during concrete surface grinding. pdf icon [PDF – 186.91 KB] external iconAnnals of Occupational Hygiene: 2004 / 48(6):509–518.
• Control of silica exposure from hand tools in construction: grinding concrete. [PDF – 341.43 KB] external iconApplied Occupational Environmental Hygiene: 2002 / 17(7):457–461.
• Respirable crystalline silica dust exposure during concrete finishing (grinding) using hand-held grinders in the construction industry. [PDF – 41.57 KB] external iconAnnals of Occupational Hygiene: 2002/ 46(3):341-346.
• Hazard Review: Health effects of occupational exposure to respirable crystalline silica.NIOSH Publication No. 2002–129.
• In-depth survey report of control of respirable dust and crystalline silica from grinding concrete at Messer Construction, Newport, Kentucky and Baker Concrete Construction, Dayton, Ohio [PDF – 331.84 KB]. pdf iconNIOSH Report No. EPHB 247–21 (2002).
• Alert: Request for assistance in preventing silicosis and deaths in construction workers. NIOSH Publication No. 96–112.
• Control of Hazardous Dust When Grinding ConcreteDHHS (NIOSH) Publication Number 2009-115
• Control del polvo peligroso que se genera durante el pulido de concretoDHHS (NIOSH) publicación N.º 2009-115

Wet and Dry Concrete Polishing

The concrete polishing industry continues to improve rapidly. New methods, tooling and liquids are being introduced regularly to provide the best solution at the lowest cost while reducing waste and the impact on the environment. Wet and dry concrete polishing are two of the main concrete polishing methods.

Dry Concrete Polishing

Dry polishing is how it all started. Contractors figured out that if you densified the concrete and then ground it with your large grinders you could get a nice shine out of the concrete. It typically takes around 6 – 9 steps to get the maximum shine out of your concrete. It really depends on your concrete.

• Dry concrete polishing creates a lot of concrete dust and concrete waste that must be disposed of.
• The dry polish takes longer than a wet polish and will use more tooling.

Wet Concrete Polishing

Wet polishing requires a water source and a plan to manage the slurry. What are you going to do with the concrete sludge that is generated during the process? This can sometimes get tricky. If you have water and can handle the slurry properly then wet polishing is a great option. You eliminate any silica dust concerns and speed up the timeline of the project.

• Wet polishing can be done with the same grinders used for dry polishing.
• Wet concrete polishing can be completed in as little as 4 steps.
• Wet polish keeps the diamond tooling cooler and therefore cuts the concrete better, allowing you to eliminate some early cuts but still giving you the same results.

Wet Concrete Polish with Ride On Concrete Trowels

Another innovative solution is a wet polish utilizing ride on concrete trowels. These can be used in large areas to complete a lot of sq ft in a hurry. In order to use this method, you need larger areas, I would say 50,000 sq ft minimum, and you will need a lot of water. This process uses probably over twice the water as wet polishing with your grinders. The extra water means extra slurry, so you really need to have the manpower and solidifying chemicals to handle the volume. You will also need a forklift on site to move the trowel and lift it for diamond changes.

50,000 sq ft minimum

A lot of water

heavy manpower and solidifying materials

Forklift on.site

If you are considering polishing your concrete give us a call. We are very experienced in all three methods and can help determine what is best for your facility.

Contact Us

Liquid Floors, Inc. offers epoxy coating installation, wet and dry polishing and will help you find the solution that is best for you and your industrial needs. Just give us a call at 704-543-7565 or email us at info@liquidfloors.com and we can set up a free consultation to go over price ranges and enhance your concrete surface and floors.

Concrete Grinding and How Much Can A Grinder Remove?

Most people are searching for what concrete grinding is? Another important question for all newbies is how much will a concrete grinder remove?

Let’s go deeper into details. Concrete grinding is a mechanical treatment process of the surface using special equipment, like Husqvarna or HTC, combined with abrasive diamond tools. The metal segment attachments procure the removal of unevenness on rough concrete surfaces to reveal a smooth finish. In addition, there are grinding diamond tools to help make the process faster.

Have you ever been struggling to remove old mastic or glues, waterproofing membranes, or epoxy coatings from a concrete surface? It’s a bit of a challenge most concrete resurfacing contractors, fluid floor applicators, and even waterproofers have. The main goal is to simplify the methods of removing materials from concrete surfaces. Thus, preparation to reapply a coating, membrane, or adhesive will be enjoyable.

Why It Is The Best Method Of Concrete Floor Prep?

Firstly, concrete mechanical treatment can be accomplished either dry or wet. Prepping the floors before installing hardwood or tiles is the best way to ensure the floors’ endurance.

It is also important when the concrete will be polished or coated with epoxy, as the quality of the surface will show through.

What are the benefits of Concrete Mechanical Treatment?

• Rebuild concrete surfaces. Removes all inconsistencies and imperfections, resulting in a usable and smooth surface.
• Remove dirt, paint, or mastic. The best way to get rid of different remnants left on the concrete.
• Install flooring (coatings, carpets, or tiles). A contractor can easily install any flooring on a smooth surface. Floor prep is key in the longevity of a new covering option.

How Much Will a Concrete Grinder Remove?

Let’s find out how much will a concrete grinder remove? As a matter of fact, a concrete grinder can remove as much concrete as you wish, but its limitations are:

A small planetary concrete grinder with basic grinding tools will remove around 1/16” of the concrete in 1-2 passes in a normal situation. You might be able to remove more – 1/8’’ if use a heavier concrete grinder and more aggressive PCD tools. In fact, an angle grinder with a cup wheel will do the best job.

It will be easier to grind in the case of soft concrete, especially if you use highly aggressive PCD tools for concrete layer removals like glue, black mastic, or other imperfections.

Lastly, the more pressure you put on the grinder, the more wear you put on the diamond tools. If you need to remove a thicker layer of concrete faster, you may need an extremely soft bond grinding pad.

Finally, concrete grinding is often seen as a finishing or refinishing procedure. But if you have a thick layer to remove, contractors suggest a complete demo and re-pour the slab.

How Long Does Grinding Take?

Do people also ask about how long does grinding takes? As a matter of fact, the time of concrete grinding depends on a few factors:

• How big is the project?
• Whether the area is quite open, or it consists of a lot of small spots?
• What kind of finish do you expect – polishing or sealing?
• How much exposure of aggregate do you want to see?
• What kind of shine do you desire?

How much does it cost to grind concrete?

In fact, concrete grinding contractors normally charge around 0.75-2 per square foot for light concrete sanding. This makes the floor ready to install a new floor covering. over, check out the ranges for different types of glues or mastic removal:

• A thin layer of epoxy paint, VCT glue, or mastic: 1 to 1.2 per square foot.
• Thick coatings 1/8-1/4”: 1.3 to 1.5 per square foot.
• Black heavy mastic (multi-layer): 1.5 to 2 per square foot.
• Check our Concrete Calculator. You can find out How much concrete do you need?

Do you want to know how much will a concrete grinder remove? Here are the answers, along with other commonly asked questions.

Silica dust – controlled cutting of bricks and concrete using water

The beauty of choosing a full exposure aggregate of polished concrete for your space – whether residential or commercial. Is that you got a truly unique floor. No two concrete floors are the same, as it all comes down to concrete quality, technique, and aggregate amount.

However, most people don’t know how to achieve that shiny and refine style. Also, aggregate exposure ranges from minimal to open-stone exposure depending on the depth of the rocks inside the concrete and grinding.

Concrete Grinding Contractors Near Me

Firstly, your best option to find out the floor prep cost in your area is to contact a contractor. Secondly, request a Free Estimate to find out the best competitive price from your Concrete Contractors Near Me. Lastly, if you’re getting into the game of floor renovation, hiring a Pro will most likely help to avoid wasting time and money on your first few jobs.

Consequently, in this article, we learned what ground concrete is? Also, what is the best prep method? And how much will a concrete grinder remove? Feel free to ask our specialist a question.

Facade Systems

What is Concrete Grinding?

Modern concrete is made up of differing proportions of cement, dry sand, dry stone, and water. Each recipe creates a different form of concrete. Each has differing degrees of strength and durability. Depending on the project and its properties, different mixtures of concrete are selected.

WHAT IS CONCRETE GRINDING?

Concrete grinding is the process of smoothing rough concrete surfaces. During the concrete grinding process, an abrasive tool with diamond attachment smooths the rough surface. All coatings, stains, and surface cracks are removed along with the top layer of concrete during the first step in the process.

Deeper cracks must be evaluated. If they can be patched, this is the time to do so. Professionals use a pressure washer to blast dirt, rocks, and concrete chunks out of the crack. This creates a clean for the application of an epoxy patch.

Concrete can be ground either wet or dry. Many businesses prefer wet applications to prevent concrete dust from getting everywhere. This is both for cleanliness and safety. Rough concrete dust can find its way into workers’ lungs.

Rough grinding begins with a coarse metal bond tool, usually around 40-grit. After the surface is ground, finer grinding can begin. Generally, this is with 80-grit and finished with 120-grit tools. Each step requires at least 2 passes over the entire area to ensure the proper smoothness.

To harden the concrete after grinding, professionals will apply a liquid chemical. Using a broom, the entire surface is saturated with the chemical. At least 30 minutes is needed to let the chemical steep in. But, most workers wait an entire day before undertaking the final polish. If you’re looking for a high gloss finish, 3000-grit does the job.

WHAT KIND OF EQUIPMENT IS USED IN CONCRETE GRINDING?

Concrete grinding requires high-powered concrete grinders. High-powered concrete grinders are circular devices equipped with heavy-duty, diamond-clad rotating polishers. Industrial-strength washers and vacuum cleaners are also used during various steps in the process.

Parts of the process do require more specialized tools. Angle grinders, straight-wheel grinders, and vertical grinders are also used during certain steps. For clean cuts, cut-off tools are useful to make even cuts where needed.

BENEFITS OF CONCRETE GRINDING

• Saves Time Money. Concrete grinding saves time and money over other floor refurbishment processes. Not only does this make a home project less time-consuming, but saves your wallet some heat as well.
• Increases Safety. Concrete grinding can turn a rough, damaged surface into a smooth, hard surface. This makes it safe for homeowners and visitors to walk on without risk of injury. On driveways, concrete grinding can make for a quieter, and more skid-resistant surface for cars.
• Preps For Projects. Old concrete can become uneven over the years. If a contractor is installing wood or tile floors over a concrete floor, it helps for it to be smooth. Also, the new flooring won’t need constant repairs as gapping occurs.
• Epoxy Floor Finish. Concrete grinding is an excellent way to prepare a floor for an epoxy floor finish. These floors are bright, durable, and easy to clean. They resist water and oil stains, making them last longer than traditional flooring.
• It’s Customizable. Grinding will remove old oil stains easily by skimming off the top layer of concrete. Grinding can be customized to leave a specific amount of texture. Different epoxies need different textures to hold and set.
• Better for the Environment. Concrete grinding produces less pollution and waste than alternate flooring options. It uses fewer raw materials and no harmful chemicals. Due to its longevity, it is a more sustainable option.

CONCRETE GRINDING FOR FLOORING

Homeowners can enjoy beautiful floors with deep concrete grinding. When looking into flooring options, professional grinders will expose the stones in the mix. This reveals the potential look to the homeowner. They’ll do this several times to give the homeowner options. From here, you can decide which flooring type to choose.

Silica Exposure

The homeowner can opt for certain exposure levels. The concrete grinder will remove the top level of the old concrete to the desired level. Partial exposure can give the floor an attractive salt and pepper look. With other flooring, this would be far more expensive.

A deep, full-stone exposure concrete grinding process can be more expensive. It involves removing up to 6 millimeters of concrete. As compared to other grinding options, the final product reveals more of the stones. Polished deep grinding can make the concrete look like a riverbed.

FOR BEST RESULTS, CONSULT YOUR CONCRETE GRINDING PROFESSIONAL

Homeowners can rent concrete grinders and do the work themselves. But for best results, we recommend you select a reputable concrete grinding firm in your area. Check out local concrete businesses for quotes on your next project.

If you have any questions or concerns about your garage floor, pool deck, patio, basement floor, or sidewalk, give us a call.