TOOL TYPE
GEOGRAPHY
MODEL
PROCEDURE
US
LAST REVIEWED
09/4/13
SOURCE:
WOODSHOLE
OCEANOGRAPHIC
INSTITUTE
COMBUSTIBLE DUST SAFETY PROCEDURE
PROBLEM: You need to be on guard against dust explosions if you use products and materials
that emit combustible dusts. Examples: candy, sugar, spice, starch, flour, feed, grain, tobacco,
plastics, wood, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, dyes, coal,
aluminum, chromium, iron, magnesium, zinc and fossil fuel power generation. The force from
such explosions can cause death, injury and destruction like the 2008 sugar dust explosion at a
Georgia plant that killed 14 workers.
HOW TOOL HELPS SOLVE THE PROBLEM: One way to prevent dust explosions is to
create and implement safe work procedures for handling combustible dusts. Here’s a Model
Procedure that you can adapt for your own workplace and add to your fire prevention program.
COMBUSTIBLE DUST SAFETY PROCEDURE
1.0 Purpose
Some machining and processing activities involving metals, woods, plastics and other materials
may have the potential to generate combustible dusts. The combination of combustible dusts and
ignition sources creates the potential for ignition and explosion of combustible dusts. This
Procedure is designed to prevent explosions caused by the ignition of combustible dusts.
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1.1 Scope
This Procedure applies to all operations with the potential to generate combustible dusts and
describes how combustible dust hazards should be identified and controlled. Combustible dusts
are defined by the National Fire Protection Association (NFPA) as “any finely divided solid
material…that presents a fire or explosion hazard when dispersed and ignited in air."
2.0 Roles and Responsibilities
2.1 Supervisors & Department Heads are responsible for identifying and controlling
combustible dust hazards in their operations, and ensuring that all affected personnel are aware
of the combustible dust hazards and controls.
2.2 The Environmental Health and Safety (EHS) Manager will assist with evaluation of
combustible dust hazards and controls, conduct training, assist with specific concerns/requests,
and conduct inspections.
3.0 Combustible Dust Hazard Analysis
Supervisors and Department Heads must conduct a hazard analysis of their work activities and
work areas to identify dust explosion hazards. Any area or location with more than a 1/8 inch
build‐up of combustible dust is considered hazardous. In carrying out this combustible dust
hazard analysis, Supervisors and Department Heads will:
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Consider multiple factors including the fact that a variety of materials can be combustible
when finely divided, including dusts generated from the machining/processing of wood,
plastics, and combustible metals (e.g., aluminum, titanium, and iron);
Use proper equipment and safety procedures when inspecting elevated spaces/surfaces;
Examine open areas where combustible dusts may build up, including floors and
horizontal surfaces (e.g., girders and beams);
Examine enclosed and hidden areas where combustible dusts may accumulate, including
dust collectors, ductwork, plenums, and enclosed ceiling spaces;
Evaluate the mechanisms that have the potential to disperse dust in air and create a
potentially explosive concentration (e.g., ventilation systems, air guns, dry sweeping);
and
Identify the existence of potential ignition sources such as grinding, welding, open
flames, and electrical equipment.
3.1 Combustible Dust Hazard Controls
After the combustible dust hazards are identified and assessed, appropriate controls will be
identified and implemented to control/prevent combustible dust fires and explosions.
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4.0 General Dust Control Practices
Where feasible and as appropriate, a combination of engineering controls (such as mechanical
dust collection systems) and administrative controls (such as routine cleaning, inspection,
maintenance) will be implemented, which may include:
* Measures to minimize escape of dust from dust control equipment and ventilation
systems;
* Use of approved and properly designed dust collection systems and filters;
* Selection/use of surfaces that minimize dust accumulation and facilitate cleaning;
* Provision of safe access to enclosed/hidden spaces to permit inspection for combustible
dust buildup;
* Routine evaluation of dust buildup in open and hidden areas;
* Cleaning of combustible dust residue at regular intervals to prevent dust buildup (do not
allow more than 1/8 inch build‐up of combustible dust to accumulate);
* Avoiding cleaning with methods that may create dust clouds where combustible dusts
may be present; and
* Developing and implementing a written combustible dust inspection, testing,
housekeeping, and control program.
4.1 Control of Ignition Sources
Steps will be taken to control ignition sources, such as open flames, grinding, hot equipment,
electrical equipment, and static electricity that may be exposed to combustible dust
concentrations. When operating, servicing, and maintaining equipment, steps will be taken to
ensure that proper grounding is in place, e.g., that hoses, ducts and nozzles used to collect,
convey, or blow combustible dusts are bonded and grounded to safely dissipate static electricity.
4.2 Cleaning
A checklist shall be created that identifies all areas that may accumulate combustible dust. A
routine cleaning schedule to remove combustible dust from floors, ledges, beams, equipment, or
other surfaces will be established that provides for a cleaning frequency that is sufficient to
prevent significant buildup of combustible dust. Where possible, cleaning methods that do not
generate dust clouds, e.g., use of high‐efficiency vacuums that are grounded, wet cleaning
methods, etc., will be used. Proper equipment will be used and safety procedures followed during
cleaning of elevated spaces/surfaces.
4.3 Mitigation Measures
Based on the hazard assessment and if appropriate, measures will be taken to minimize the
danger and damage from a combustible dust explosion. This may include various design factors,
including isolation, distance, barriers, explosion venting, explosion prevention systems, etc.
Please note that damage control precautions may only be appropriate for high‐hazard operations
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involving highly combustible dusts. In general and unless reviewed/approved by the EHS
Manager, these operations should be avoided.
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