DUST MITIGATION PLAN - EXAMPLE 1
For Low Complexity Operating Environments
Assessment of Combustible Dust in Hazardous Locations
PURPOSE
The purpose of this document is to support wood processing facilities with the implementation
of their own approach for assessing combustible dust hazardous locations and for developing
relevant and effective mitigation strategies to prevent future incidents. This document is meant
to benefit primarily wood processing facilities whose operating environments do not demand a
high degree of sophistication from an asset management and/or human resourcing perspective.
While this document reflects a collection of practices being used in other mills, the process and
the content of this document is consistent with the recommendations in the ‘NFPA 664
Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking
Facilities’ and ‘NFPA 499 Recommended Practice for the Classification of Combustible Dusts and
of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas’.
Wood processing facilities may use this document as a starting point or as a good framework to
begin the process. It is important to understand that this document does not address all the
specifics of your site. Therefore, this document must be adjusted accordingly to suit the needs
of your operation.
REQUIRED ACTIONS
Safety Order SO‐EL‐GA 2013‐02 requires owners and operators of wood processing facilities to
perform an assessment of their facilities for hazardous locations, due to the presence of
combustible dust. Where gas and electrical equipment is installed within a hazardous location,
a plan to suitably mitigate the combustion risk must be documented.
Follow this link to BC Safety Authority’s website for details on required actions and compliance
deadlines.
http://www.safetyauthority.ca/sites/default/files/combustible_dust_hazard_in_wood_processi
ng_facilities_so-el-ga_2013-02_.pdf
Mitigation Plan for:
Assessment of Combustible Dust in
Hazardous Locations
PREPARED FOR:
Enter Company Name
PREPARED BY:
Enter Name of Qualified Individual and Title
DATE PREPARED:
Enter Date
1
SUMMARY OF PLANT OPERATION
In this section describe the following:




Types of materials being processed
Types of processes
Size of mill in terms of employees, square footage, number of buildings
Hours of operation i.e. shifts
2
SITE MAP
In this section include a site map identifying the buildings or processing areas and the equipment within:
 Buildings or processing areas
 Equipment
 Unique identifier either a number or a letter to denote area designation corresponding to hazard assessment
LEGEND:
Area 2
Area 3
Area 1
Area 4
Area 5
Area 6
Area 1: Electrical Room &
Panel
Equipment list
a.
b.
Area 2: Wood Shop
Equipment list
a.
b.
Area 3: Chip Dump Pit
Equipment list
a.
b.
Area 4: Chip Screen
Equipment list
a.
b.
Area 5: Conveyors
Equipment list
a.
b.
Area 6: Etc.
Equipment list
a.
b.
3
AREA ASSESSMENT
In this section describe the following:
1. The approach used to conduct the assessment, including:
a. Who conducted the assessment (i.e. qualified individual or team approach – list
participants and their area of expertise)
b. FSR names and numbers
c. Reference materials or standards used
2. Operating permit numbers for electrical, gas, and boiler equipment or systems
3. Date of assessment
The mitigation strategies should consider the following options:
1.
2.
3.
4.
Eliminate dust at source
Relocate equipment outside the hazardous location i.e. remove ignition sources
Install equipment rated for hazardous locations
Manage the dust accumulation to non-hazardous levels
For each area assessed include the following:
1. General location (this could be just a number or letter that corresponds to the site map)
2. Operation hours specific to area
3. Area classification (this comes from the standard e.g. NFPA-499 Table A.6.7 page 24)
a. Dust type descriptors
 Heavy
 Chunky
 Fine
 Super fine
b. Dust size
 Accumulation and distribution (depth and spread)
 Measurement descriptions from the standard
o Moderate to dense dust cloud. Dust layer greater than 3.0 mm (¹⁄₈
in.)
o No visible dust cloud. Dust layer less than 3.0 mm (¹⁄₈ in.) but
surface color not discernible.
c. Source
 Dry
 Green
 Wet
 Raw log
 Processed lumber (re-manufacturing plant)
 Wood waste (chips, bark, etc.)
 Species
o Fir
o Cedar
4
d.
e.
f.
g.
h.
i.
j.
k.
o Hemlock
o Pine
o Etc.
Ignition sources in the area
 Type of motors (e.g. totally enclosed, explosion proof, etc.)
 Lighting
 Gas equipment (e.g. flame, heat)
 Electrical equipment (e.g. transformers, motor starters, motor control
centers, etc.)
Friction sources in the area
Dust clouds present? Y/N
 If yes, imminent hazard (i.e. the mitigation strategy is ventilation or rated
equipment; this applies to all dust clouds that require workers to wear
PPE, regardless of confinement)
If less dense dust cloud or if it’s an accumulation i.e. a pile, is the dust confined?
Y/N
Is the equipment approved? Y/N
Is the equipment in good condition? Y/N
 Motors: totally enclosed vs. open style
 Lighting: sealed vs. unsealed; original, replacement in kind or completely
different bulb? Y/N
 Is there accumulation of dust on equipment that raises the operating
temperature of the equipment? Y/N
If equipment not in good condition:
 Sealed (e.g. motor control centers i.e. gasketed type or positive pressure
type)
 Vented to non-hazardous areas
 Filters, if they apply, in good condition
 Is the equipment clean i.e. no dust accumulation? Y/N
Dust management procedure for the area and other mitigation strategies
 Housekeeping – cleaning procedures
o Method
o Frequency
o Documentation i.e. logbook
 Physical controls
o Dust collectors
o Dust conveyors
o Misting
 Period inspection (weekly, monthly, annually)
 Routine inspections to ensure all of the above conditions are being
implemented and are effective
5
IMPLEMENTATION
In this section describe how this plan was implemented. Include a description of the training
program provided to your workforce.
SAFE WORK PROCEDURES
1.
2.
3.
4.
Hot permit program
Cigarette smoking
Emergency preparedness and response
Any other safe work policies and procedures specific to the site
REVIEW OF ASSESSMENT AND DUST MANAGEMENT PROCEDURES
In this section describe how this plan and the ongoing management of activities will be reviewed
to ensure mitigation strategies remain effective over time.
1. Responsible management function to sign off on review and changes
2. Conditions when the review needs to take place
 When equipment changes
 When product type changes
 When dust management procedures are found ineffective
 When environmental conditions change
 When structural changes are made to the building
3. Frequency of period review/evaluation
4. De-energizing equipment during clean-up procedures
6