NFPA Regulation 652 came into effect in the summer of 2015 and its changes affect many businesses in industries including agriculture, woodworking, metalworking, chemical, food production, and other areas where combustible dusts are produced. Complying with NFPA Regulation 652 means ensuring that your dust collection system, housekeeping, ignition source control, explosion prevention and protection, and fire protection all meet standards assigned in Regulation 652 or a specific regulation for your industry. Importantly, there are a few specific changes that you will have to make, as well as specific dust collection system standards that you will have to meet.

Dust Hazard Analysis

If you have not completed a dust hazard assessment, it is crucial that you do so. The NFPA Regulation 652 lists dust hazard assessment as mandatory for all industries where combustible dust is a risk. This includes but is not limited to:

• Grain elevators,
• Food production,
• Chemical manufacturing
• Woodworking facilities,
• Metal processing
• Recycling facilities
• Coal-fired power plants

As outlined in Chapter 7 of the NFPA Regulation 652, the DHA is mandatory as the first step towards combustible dust collection and mitigation. If you have not performed one already, you have until 2018 to integrate new standards. The DHA directly replaces the PHA.

Documented Risk Assessment

It is crucial that you keep a documented record of risk assessment, which outlines the level of risk for each hazard, hazard location, and overall hazard risk at your location. This risk assessment can help you to choose the correct methods for mitigating combustible dusts, and will serve as proof that you have met the standards required for safety in your workplace.

Building Regulations

There are several building regulations that might require that you perform modifications or upgrades to your workplace:

• Building Protection - Each building compartment with a dust explosion hazard must feature explosion protection such as explosion venting.
• Dust buildup prevention – The building must be designed to minimize dust accumulation and to facilitate cleaning and dust collection. This means eliminating structures with ledges, uncovered joists and beams, and other hard to access surfaces.
• Separation – Ensure that it is possible to completely separate combustible dusts from workers and equipment.

Dust Collection System

There are multiple regulations and requirements for any dust collection system. Dust collection systems include pneumatic conveying, central vacuum cleaning systems, etc.

• In an enclosed dust collection system, the components must be designed to prevent dust escape, except for normal intake and outtake. If that is not feasible, the system must include its own dust collection.
• The dust collection system must be designed and installed by qualified persons
• The system must be designed to ensure that the air velocity meets or exceeds the minimum required to keep the piping or ducting interior surfaces free from dust accumulation under all normal operation
• If the dust collection system's air material separator is greater than 8 cubic feet, the enclosure must be protected from a dust explosion. Separators include dust collectors, cyclones, etc.
• Dust collection systems with explosion systems (Almost all) must be provided with isolation devices to prevent explosions from spreading between connected devices.
• Each dust capture hood must be designed to achieve the minimum air velocity required for combustible dust collection, control, and containment. This airflow must be documented based on the system's design.
• Branch ducts must remain connected and should not be blanked off without system changes to maintain the required air velocity and air flow balance.

Specific Dust Collection System Requirements:

Central Vacuuming Dust Collection – A central vacuum system should be capable of maintaining minimum dust conveying air velocity at all times, even when in use by two operators. No more than two hose operators can be on a single tube line at any one time. The system can support more than one tube lines if the system is designed to support them. The systems hoses must be between 1.5 and 2 inches, and a maximum of 25 feet in length. All hoses and tools must be dissipate static or be conductive and grounded.

Air Material Separators – Air material separators should be located outdoors or in an area that is protected from fire and explosion. The separator must be protected from explosion if the dirty-side enclosure is larger than 8 cubic feet. Air can be recycled from the air-material separator, providing that filters and secondary filters or filter-leak detectors are used alongside isolation or fire suppression devices just after the air-material separator.

Housekeeping

It is crucial to develop a threshold level for dust accumulation to establish a housekeeping plan outlining the frequency and methods required to keep dust accumulation at a minimum. The chosen cleaning methods must minimize risks, should not create dust clouds, and should involve dust collection (vacuuming rather than blowing dust around with compressed air).

Ignition Control

Ignition sources such as hot surfaces, hot work, static electricity, bearings, groundings, sources of open flame, etc. do present a risk and must be separated from sources of combustible dust whenever possible.

Handling Combustible Dust

Handling Bulk Bags - Flexible Intermediate Bulk Containers (FIBCs) or Bulk Bags can be hazardous when used to store combustible dust. It is important to choose the right bags to prevent explosions.

Enclosures – Dust collection systems, bucket elevators, silos, and other enclosures with explosion hazards must feature explosion mitigation and management.

The primary goal of the NFPA Regulation 652 is to ensure that you understand your combustible dust risks, are taking steps to mitigate risks, are collecting dust, and that your system is up to date and meets safety standards. If you want to learn more, you can access a free online copy of the regulation here.