Revised CalOSHA Regulation on Dust Collection
Cal/OSHA amended Title 8, Section 4324, Dust Collection Systems to reflect changes in the National Fire Protection Association (NFPA) standards. The new NFPA standard clarifies the safe use of dust collectors and allows the indoor use of “enclosureless bag-type dust collectors” (EDCs).
The new regulation, effective December 5, 2007, requires dust collection systems when woodworking machine chips and dust “accumulate so as to endanger employees” through slips and falls, potential explosions, and respiratory illness. The previous regulation required dust collection when there was “accumulation of dust on the floor.” Title 8, Section 5143, General Requirements of Mechanical Ventilation Systems contains more dust collection system requirements.
Cal/OSHA defines dust collection as a system that captures wood dust, chips, and wood particulates from single or multiple pieces of woodworking equipment. The system protects woodworking employees by removing dust and debris from the work area and collecting it for disposal. The system includes the collection hood, the exhaust fan, the dust collector, and all ducts, flexible hoses or other devices used to convey waste material. Small and medium-sized businesses that can’t afford a centralized cyclone or baghouse dust collection system can often install an EDC.
Cal/OSHA defines an EDC as: (1) the filtration is accomplished by passing dust-laden air through filter media, collecting the dust on the inside of the filter media, and allowing cleaned air to exit to the surrounding area. (2) The filter medium is not enclosed in a solid-walled container. (3) The filter medium is hand shaken, not mechanically shaken or pressure-pulsed. (4) The filter medium is under positive pressure. AND, (5) The removal of the collected dust is not continuous or mechanical.
Under the new regulation, EDCs can now be used inside a building if they collect dust only from woodworking or wood processing machinery. Indoor EDCs must not exceed 5000 cfm capacity. They need a totally enclosed, fan-cooled fan motor. Collected dust must be removed daily or more frequently if buildup occurs.
EDCs can’t be used indoors if they collect material from metal grinders, painting, finishing, or other operations that may increase the risk of fire or explosion. EDCs can’t be used indoors if they collect debris from sanders or abrasive planers with mechanical feeds. An exception is that ONE mechanically fed abrasive sander or planer CAN be hooked up to an indoor EDC when special safeguards and work practices prevent sparks and fire.
The sander or planer needs a cut limiting device to prevent thick stock from entering and causing friction and burning of the wood and wood dust. There must be an emergency shutoff to halt the mechanical feed and brake the abrasive belt. The machine operator should visually inspect the stock for any metal objects and remove them before hand-feeding into the machine. The operator must stay close to monitor the machine and activate the emergency stop when necessary.
When indoors, EDCs must be at least 20 feet from the nearest emergency egress route. One EDC with a maximum air-handling capacity of 1500 cfm is allowed in the route if it is 10 feet away from of an emergency exit. EDCs should be at least 20 feet from the nearest employee work station, but a single unit is allowed if it does not exceed 1500 cfm capacity. Multiple EDCs in the same room should be separated from each other by at least 20 feet, but two small units (not exceeding 1500 cfm capacity) can be placed near each other.
All other dust collectors with a maximum air-handling capacity greater than 5000 cubic feet per minute (cfm) need to be kept outdoors or in detached rooms with fire-resistant construction and adequate explosion vents. They can be kept inside a building only if the collectors are liquid-spray type collectors.
Dust collection air and material ducts and flexible hoses should be made of metal or other conductive material that is bonded and grounded to prevent static electricity buildup from the airflow. Nonconductive flexible ducts and hoses may be used for final machine connection if they are the minimum length required to operate the machine, and if bonding to ground is maintained. PVC pipes can’t be used as ducts.
Finally, the new rule requires dust collection system guards to form part or all of the collection hood. Refuse that is too heavy, bulky, or unsuitable to be handled by the dust collection system must be removed manually.
References
The above evaluations and/or recommendations are for general guidance only and should not be relied
upon for legal compliance purposes. They are based solely on the information provided to us and relate
only to those conditions specifically discussed. We do not make any warranty, expressed or implied, that your workplace is safe or healthful or that it complies with all laws, regulations or standards.
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