Sometimes, you'll know that a specific standard applies to a project - maybe you've seen in cited in the literature, or an instructor or collaborator has mentioned it.
You'll probably have some of the following information about the standard: the number, the title, and the year.
Combined, that information will look something like this: ANSI/HFES 100-2007, Human Factors Engineering of Computer Workstations.
First, focus on the acronym(s) that come before the number. These tell you what organization published the standard. Sometimes more than one organization is listed. In this case, ANSI/HFES means it's a joint standard from the American National Standards Institute and the Human Factors and Ergonomics Society. That helps us decide where to look for the standard.
If the standard is from ASTM or IEEE, you can probably access the standard online through library subscriptions. Follow one of the links below to search publications from the relevant organization.
Other standards are freely available online to everyone. These are usually standards or regulations published by a government agency.
There's some variation in how people refer to these standards. Here are a few examples referring to Food and Drug Administration regulations in the United States. When CFR is used, that refers to the Code of Federal Regulations.
If the standard starts with any other acronym - ANSI, ISO, SAE, etc - you should search for it in the library catalog.
It's a good idea to try searching for the standard by number and by title separately. Sometimes only one will bring up the relevant record. For example, to find ANSI/HFES 100-2007, Human Factors Engineering of Computer Workstations, you might search for:
When you begin a new project, you might not know what standards apply.
It's worth considering what organizations and industries are related to this work. You can often find brief discussions of relevant standards or regulations from a trade publication in the field (here's an example from Food Safety Magazine). Don't expect these to be exhaustive - there could definitely be other standards you should also consult. Anything mentioned in one of those pieces is a good place to start, though.
If you're not sure where to look, ask a librarian.