OSHA (Occupational Safety & Health Administration) is an organization under the United States Department of Labor that was created under the Occupational Safety and Health Act of 1970 "to assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance." More specifically, OSHA touches power transmission couplings and coupling guarding through its broad Code of Federal Regulations (CFR). Under these regulations, there exists a section, 29 CFR 1910 Subpart O, titled "Machinery and Machine Guarding".
"Machinery and Machine Guarding" (which is likely relevant to you on numerous components above and beyond just couplings) is broken out into the following subcategories:
While the concepts throughout "Machinery and Machine Guarding" are broadly applicable to couplings, it is within the last subcategory, "Mechanical power-transmission apparatus" (1910.219), that couplings are specifically called out by name. Couplings. Shaft couplings shall be so constructed as to present no hazard from bolts, nuts, setscrews, or revolving surfaces. Bolts, nuts, and setscrews will, however, be permitted where they are covered with safety sleeves or where they are used parallel with the shafting and are countersunk or else do not extend beyond the flange of the coupling."
While other sections of the regulation may not specifically call out couplings by name, the concepts of these sections (aimed at keeping workers safe from potential hazards of machinery) do still apply to the use of keeping an employee safe from the dangers posed by rotating couplings. Fully communicating the concepts covered in these other sections requires quite a bit of real estate, but, fortunately, OSHA has designed several great resources to help facilitate this information on to you. The following four links are some of their best tools:
- OSHA's Digital Book: Concepts and Techniques of Machine Safeguarding
- OSHA's Machine Guarding eTool
- OSHA's Machine Guarding Checklist
- OSHA's Machine Guarding Bibliography
OSHA does not specifically "approve" any manufacturer's coupling guarding solutions. They only issue regulations and enforce/audit facilities for compliance.) Most of these coupling guard manufacturers will tell you that they have reviewed the regulations, and, that their product, when used correctly, will allow you to be compliant with the regulations. These manufacturers (whose business is selling a better mouse trap) are well versed on the standards and can/will speak to additional standards including ANSI B11.19-201 (titled "Performance Criteria for Safeguarding") and ANSI Z535.4 (which is a Safety Signs and Labels standard).
And In Canada? Like the US, Canada has its own set of distinct coupling guarding regulations & standards. The following link is one of the better articles we found covering guarding in Canada, as it breaks out rules and regulation for each specific province... which are different. The overriding primary standard in Canada appears to be CSA Standard Z432, Safeguarding of Machinery, but please consider clicking on the first link above... to determine what specifically applies to your part of Canada... before diving into the standard.)
Recommended Follow-On Reading: Given you are on a standards roll, how about reviewing the active coupling bore & keyway standards: Active Coupling Bore and Keyway Standards - What Are They & Where Can I Find Them?