Standards

Provides standard number or title/keyword searching.

Part way down the page is the Preview ASHRAE Standards and Guidelines section.
From the publisher: "You may preview the following ASHRAE Standards & Guidelines with the links below. The link will allow you to viewing access [read online] to your selection with the option to purchase your copy with the buy button."

Access to over 750,000 documents.

"The American National Standards Institute (ANSI) Incorporated by Reference (IBR) Portal provides a one-stop mechanism for access to standards that have been incorporated by reference in the U.S. Code of Federal Regulations (CFR). These standards incorporated by the U.S. government in rulemakings are offered at no cost in “read only” format and are presented for online reading. There are no print or download options.
Standards available on the ANSI IBR Portal include those developed by the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), and other standards developing organizations (SDOs) that have signed a terms and conditions agreement with ANSI. To access the standards in PDF format, go to the Hosted by ANSI tab above. All users will be required to install the FileOpen plug-in and accept an online end user license agreement prior to accessing any standards.
In addition to the standards available directly through the portal, several SDOs are offering free access via their own website. Links are provided in the Hosted by SDOs tab..."

Contains full text standards for nuclear power plants, handling radioactive waste, transporting radioactive waste, etc

Full text standards on information and communication technologies infrastructure

Contains the full text of standards, journals, conference proceedings and ebooks in electrical engineering, computer science and electronics

The National Institute of Standards and Technology (NIST) maintains a Global Standards Information website which has information concerning searching and locating standards. The NIST page also provides links to other sources for searching standards.

Provides access to over 1 million engineering standards. Free registration required to search the database.

"The majority of standards developing organizations depend on the revenue from the sale of standards to support their programs and services. But a growing number of standards organizations make access to their standards for viewing or download available for no cost."
Please note that some of the organizations list free access to members of their organizations.
This list is maintained by the United States NIST (National Institute of Standards and Technology).

The Library of Congress owns a large collection of technical reports.

Thomson Reuters database of over 400,000 codes and standards.

Includes elevator, boiler and amusement ride inspection codes; OSHA info

Free full text, digital library of federal specifications, standards and handbooks

NASA Technical Reports Server (NTRS) provides access to over 500,000 aerospace-related citations, over 300,000 full-text online documents, and over 500,000 images and videos. The types of information include: conference papers, journal articles, meeting papers, patents, research reports, images, movies, and technical videos – scientific and technical information (STI) created or funded by NASA. The databases includes NACA, NASA and NIX collections.