Standard Interpretations - Table of Contents|
| Standard Number:||1910.1200(d); 1910.1200|
|December 27, 2013|
|MEMORANDUM TO:||REGIONAL ADMINISTRATORS|
Acting Deputy Assistant Secretary
|FROM:||Thomas Galassi, Director
Directorate of Enforcement Programs
|SUBJECT:||Classification of Combustible Dusts under the Revised Hazard Communication Standard|
This memorandum provides guidance for compliance safety and health officers (CSHOs) to use in determining whether manufacturers or importers have properly classified their products1 for combustible dust hazards under the revised Hazard Communication Standard (HCS). This guidance shall be used when inspecting manufacturers and importers, usually from referrals concerning inadequate or inappropriate labels or SDSs are conducted, not inspections of downstream users. Until OSHA addresses these issues through rulemaking, CSHOs shall use this document to determine if manufacturers and importers (from now on "classifier") are in compliance with the obligations of 1910.1200(d) for combustible dust. CSHOs may direct any questions that arise in applying this guidance to the Directorate of Enforcement Programs or the Salt Lake Technical Center (SLTC).
On March 26, 2012, OSHA amended the HCS to align with the Globally Harmonized System for the Classification and Labelling of Chemicals (GHS). However, the GHS does not contain a classification for combustible dust hazards, and to maintain coverage of this hazard under the HCS, OSHA amended the standard's definition of "hazardous chemical" to include "combustible dust2 ." Noting ongoing efforts at the United Nations (UN) and in the Agency's own combustible dust rulemaking, OSHA did not adopt a definition of the term combustible dust in the final rule. Rather, as an interim measure, OSHA stated that it had already provided guidance on combustible dust, including the Combustible Dust National Emphasis Program (NEP), which "includes an operative definition." 77 FR 17705. OSHA also noted that a number of voluntary consensus standards exist, "particularly those of the NFPA," which provide further guidance. Id.
Under the HCS, classifiers are required to "evaluate chemicals produced in their workplaces or imported by them to classify the chemicals in accordance with this section." 29 CFR 1910.1200(d)(1). Any such classification must "identify and consider the full range of available scientific literature and other evidence concerning the potential hazards." 1910.1200(d)(2). However, there "is no requirement to test the chemical to determine how to classify its hazards." Id. The classifier must consider not only the hazards of the chemical in the form it is shipped, but also consider the hazards that arise under normal conditions of use and foreseeable emergencies. When performing inspections of classifiers, CSHOs must ensure that the requirement to consider normal conditions of use and foreseeable emergencies is followed by the classifier.
The combustible dust NEP defines combustible dust as a solid combustible material, composed of distinct pieces or particles, that "presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape." A number of voluntary standards prepared by the National Fire Protection Association (NFPA), FM-Global, and ASTM International suggest various tests, data, and criteria that may be used to determine whether a material presents a combustible dust hazard.
As noted above, classifiers must consider any hazards posed by the product in normal conditions of use and foreseeable emergencies, and must consider the full range of available information about those hazards. For combustible dusts, often the best information is actual experience with the product. If the classifier knows that its product has been involved in a deflagration or dust explosion event, the classifier should classify the product as a combustible dust unless the classifier can show that the conditions surrounding the event are not expected in normal conditions of use or foreseeable emergencies. In the absence of information on a deflagration or dust explosion event, classifiers may use one or more of the following approaches in determining whether such hazards exist, depending on the information that is available.
In summary, when conducting inspections of classifiers, CSHOs should determine how classifiers have handled the available evidence about a product's explosibility. Where there is evidence that the product has actually been involved in a deflagration or dust explosion event, it should be classified as a combustible dust. Similarly, where results of accepted tests on the product are available, the dust should be classified in accordance with those results. Finally, in the absence of actual events or test data on the product, the classifier may either rely on the published test data on similar materials or use the available information about particle size to determine the combustible dust hazard of the product.
This guidance is not intended to be exclusive, and classifiers may have other reliable methods to establish whether their product does or does not present a combustible dust hazard in normal conditions of use and foreseeable emergencies. CSHOs should consider such claims carefully, and in such cases consultation with the Directorate of Enforcement Programs and/or the SLTC is strongly encouraged.
1 The Hazard Communication Standard's classification requirements apply to "chemicals," 29 CFR 1910.1200(d)(1), which is defined as "any substance or mixture of substances," 1910.1200(c). The word "product" in this memorandum is intended to be understood as a synonym of "chemical" as defined in the standard.
2 While the GHS requires dust explosion hazards to be noted on the safety data sheet, it does not include a chapter or classification criteria for combustible dusts.
3 ASTM E1226: Standard Test Method for Explosibility of Dust Clouds.
4 ASTM E1515: Standard Test Method for Minimum Explosible Concentration of Combustible Dusts.
5 NFPA 61: Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities.
6 NFPA 68: Standard on Explosion Protection by Deflagration Venting.
7 NFPA 484: Standard for Combustible Metals.
8 NFPA 499: Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas.
9 NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids.
10 NFPA 704: Standard System for the Identification of Hazardous Materials for Emergency Response.
11 NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities.
12 FM Global Property Loss Prevention Data Sheet 7-76: Prevention and Mitigation of Combustible Dust Explosion and Fire.
|Standard Interpretations - Table of Contents|
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