Skip Navigation

Course 851 - Silica Dust Safety in Construction

Safety guides and audits to make your job as a safety professional easier

Administrative and Work Practice Controls

If engineering controls are not sufficient to reduce exposure limits below OSHA’s PEL, it may be necessary to use administrative and work practice controls that focus on controlling worker behaviors rather than physical hazards of silica dust.

Administrative Controls

It’s always important to include administrative controls no matter what your control strategies are. Policies, program, plans, processes, and procedures all play an important part in making sure the exposure control program functions as intended. Here are some basic guidelines for an effective program:

  • First, develop a written silica dust exposure control program and a respiratory protection plan.
  • Write policies, processes, procedures and safe work practices to control worker behaviors and reduce exposure to silica dust.
  • Develop policies that require the use of respirators if engineering controls are not sufficient to lower exposure levels adequately.
  • Ensure exposed employees are taught how to properly use and maintain respirators.
  • Provide medical examinations for employees who may be exposed to respirable crystalline silica, as recommended by NIOSH, and have X-rays read by a specialist in dust diseases. Develop a plan for reducing exposures of employees whose X-rays show changes consistent with silicosis.
  • Report all cases of silicosis to state health departments and to the Mine Safety and Health Administration (MSHA), and record cases on OSHA logs, as required.
  • Post warning signs to identify work areas where respirable silica is present.
  • Develop effective corrective and preventive equipment maintenance programs to reduce silica exposures and ensures optimal operation of the equipment.
  • Inspect equipment regularly during the workshift. Equipment and dust control devices should be on a routine maintenance schedule.

Operation and Maintenance

Operate and maintain all equipment in accordance with manufacturer's instructions to minimize dust emissions.

Water Flow Rate

For tasks performed using wet methods, apply water at flow rates sufficient to minimize the release of visible dust.

Dust Collection Systems

When using commercially available shrouds and dust collection systems with any equipment, the following should be met:

  • Dust collectors should provide at least 25 cubic feet per minute (cfm) of airflow per inch of wheel diameter, and
  • have filters with 99% or greater efficiency and cyclonic pre-separators or filter-cleaning mechanisms.

Exhaust Systems

For tasks performed indoors or in enclosed areas, provide a means of exhaust as needed to minimize the accumulation of visible airborne dust.

Work While in Enclosed Cabs or Booths

For measures implemented that include an enclosed cab or booth, ensure that the enclosed cab or booth:

  • is maintained as free as practicable from settled dust;
  • has door seals and closing mechanisms that work properly;
  • has gaskets and seals that are in good condition and working properly;
  • is under positive pressure maintained through continuous delivery of fresh air;
  • has intake air that is filtered through a filter that is 95% efficient in the 0.3-10.0 micro meter range (e.g., MERV-16 or better); and
  • has heating and cooling capabilities.

Best Practices for Cutting

  • All saws: When possible, make sure they are equipped with integrated water delivery systems that continuously feed water to the blade.
  • Handheld saws: In addition to water delivery systems, use respiratory protection with an Assigned Protection Factor (APF) when using handheld power saws as follows:
    • when working outdoors for longer than four hours per shift
    • always when working indoors in an enclosed area
  • Fiber-cement handheld saws: When using handheld saws for cutting fiber-cement board outdoors, use saws equipped with commercially available dust collection system. If the above requirements are met, respiratory protection is not required.
  • Walk-behind saws: In addition to water delivery systems, use respiratory protection with an Assigned Protection Factor (APF) when using handheld power saws as follows:
    • when working outdoors for longer than four hours per shift
    • always when working indoors in an enclosed area
  • Drivable saws: For outdoor tasks only, use with integrated water delivery system that continuously feeds water to the blade. When this requirement is met, no respiratory protection is required when working outdoors.

Best Practices when Drilling

  • Rig-mounted core saws or drills: Use tool equipped with integrated water delivery system that supplies water to cutting surface. When adequate water delivery systems are used, no respiratory protection is required.
  • Handheld and stand-mounted drills (including impact and rotary hammer drills). Use drills equipped with commercially available shrouds or cowlings with dust collection systems. Use HEPA-filtered vacuums when cleaning holes. When these requirements are met, no respiratory protection is required.
  • Dowel drilling rigs for concrete: (For outdoor use only). Use shrouds around drill bits with dust collection systems. Use HEPA-filtered vacuums when cleaning holes. Always use respiratory protection with a Minimum Assigned Protection Factor (APF) during the work shift.
  • Vehicle-mounted drilling rigs for rock and concrete. Two primary best practices are recommended by OSHA:
    • Use dust collection systems with close capture hoods or shrouds around drill bits with a low-flow water sprays to wet the dust at discharge points from the dust collectors, or
    • Operate the equipment from within enclosed cabs and use water for dust suppression on drill bits.

When either of these two requirements has been met, no respiratory protection is required.

Best Practices for Hammering

  • Jackhammers and handheld powered chipping tools: Two primary strategies may be used to reduce exposures:
    • Use tools with water delivery systems that supply a continuous stream or spray of water at the point of impact.
    • Use tools equipped with commercially available shrouds and dust collection systems.

For both strategies, when used outdoors, and when exposure is less than or equal to 4 hours during the workshift, respiratory protection is not required. However if exposure is greater than 4 hours during the work shift, AFP 10 respiratory protection is required. When used indoors, AFP 10 respiratory protection is always required. This strategy may be used indoors or outdoors.

Best Practices for Blasting

Sandblasting – Metal Construction
Click to play video
  • Handheld abrasive blasting equipment: Several strategies are possible for blasting tasks:
    • Use less toxic abrasive material like ground walnut shells or plastic beads.
    • Use abrasives that can be delivered with water (slurry) to reduce dust.
    • Use barriers and curtain walls to isolate the blasting operation.
    • Use exhaust ventilation systems in containment structures to capture dust. See video.

Always use appropriate HEPA-filtered vacuuming. If exposed to silica dust levels above the action level, be sure to use appropriate air supplied respirators

.

Best Practices for Grinding

Example of a Hand Grinder Dust Shroud
Click to play video
  • Handheld grinders for mortar removal (i.e., tuckpointing): Use grinders equipped with commercially available shrouds and dust collection systems. Always use AFP 10 respiratory protection when using this equipment.
  • Handheld grinders for uses other than mortar removal: There are two primary control strategies used to reduce exposures:
    • When used outdoors only, use grinders equipped with integrated water delivery systems that continuously feed water to grinding surfaces, or
    • Use grinders equipped with commercially available shrouds and dust collection systems.

When the requirements of either of these two strategies are met while working outdoors, no respiratory protection is required. If working indoors or enclosed areas for more than 4 hours per work shift, use APF 10 respiratory protection.

  • Walk-behind milling machines and floor grinders: Two strategies for this equipment may be used:
Example: Walk-behind floor grinder
Click to play video
  • Use machine equipped with integrated water delivery system that continuously feeds water to the cutting surface, or
  • Use machines equipped with dust collection system recommended by the manufacturer.

When used indoors or enclosed areas, use a HEPA-filtered vacuum to remove loose dust in between passes.

When the above requirements for walk-behind milling machines and floor grinders are met, respiratory protection is not required.

Best Practices when Milling

  • Small drivable milling machines (less than half-lane): Use a machine equipped with supplemental water sprays designed to suppress dust. Water must be combined with a surfactant. When this requirement is met, respiratory protection is not necessary.
  • Large drivable milling machines (half-lane and larger): For cuts of any depth on asphalt only, use machines equipped with exhaust ventilation on drum enclosures and supplemental water sprays designed to suppress dust. For cuts of four inches in depth or less on any substrate:
    • Use machines equipped with exhaust ventilation on drum enclosures and supplemental water sprays designed to suppress dust, or
    • Use a machine equipped with a supplemental water-surfactant spray system designed to suppress dust.

Best Practices when Crushing

  • Use equipment designed to deliver water spray or mist for dust suppression at crusher and other points where dust is generated (e.g., hoppers, conveyers, sieves/sizing or vibrating components, and discharge points).
  • You may also use a ventilated booth that provides fresh, climate-controlled air to the operator, or a remote control station.

When the above methods for crushing are used, no respiratory protection is required.

Best Practices when Abrading, Fracturing, or Demolition

Abrading or fracturing includes hoe-ramming and rock-ripping.

  • Operate equipment from within an enclosed cab.
  • When employees outside of the cab are engaged in the task, apply water and/or dust suppressants as necessary to minimize dust emissions.

Best Practices When Grading and Excavation

These best practices include equipment used for grading and excavation, but not including equipment used for abrading, demolishing, or fracturing silica-containing materials.

  • Apply water and/or dust suppressants as necessary to minimize dust emissions, or
  • When the equipment operator is the only employee engaged in the task, operate equipment from within an enclosed cab.
When the above requirements for grading and excavation are met, no respiratory protection is required.

Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. If engineering controls are not sufficient to reduce exposure limits below OSHA’s PEL, it may be necessary to _____.

2. Administrative and work practice controls focus on controlling _____.

3. What is the APF value required for respirators when they are used for reducing exposure to silica dust?

4. Which of the following is an engineering control for limiting exposure while using hand-held abrasive blasting equipment?

5. OSHA requires employers to use engineering controls first, if possible to reduce exposure to silica dust. Which control strategy is an engineering control for limiting exposure while blasting?


Have a great day!

Important! You will receive an "error" message unless all questions are answered.