I had to ask Google "what is a threshold inspector?" :) Are you trying to become a threshold inspector or are you looking for useful references on special inspection?

It doesn't look like any special testing is required to become a threshold inspector provided you meet all of the other requirements. But, some of these requirements entail testing (such as becoming a PE). See the requirements at https://www.fbpe.org/index.php/component/jdownload...

In Florida, the term "Threshold Inspector" refers to a person authorized to perform Special Inspection of a "threshold" building which is a particular class of building that is more than 3 stories in height, has an assembly area that exceeds 5000 square feet or has an assembly occupancy of 500 persons or more. Any of these conditions will invoke the "threshold" building rules. These rules and the certification of Special Inspector by the State of Florida is a result of the collapse of the Harbor Cay Condominium during its construction in the early 1980's.

The Special Inspector of Record must be hired by the owner of the project and reports directly to the Building Official for inspections. The Special Inspector may delegate the on-site inspections to a qualified delegate who essentially is a graduate engineer or other person with inspection qualifications that are deemed appropriate by state law and the Special Inspector of Record. In order to be designated as a Special Inspector, you must meet certain qualifications as outlined in State Law. Special Inspection is done in accordance with a special inspection plan that the Structural Engineer of Record must develop and file with the Bulding Official.

These are the minimum qualifications:

* A currently licensed professional engineer whose principal practice is structural engineering in the State of Florida;
* Possess a current and active Florida PE license;
* Have three years verified experience in performing structural field inspections on threshold buildings;
* Have two years experience in the structural design of threshold buildings after having achieved licensure as a professional engineer; and
* Have experience in the structural inspection and/or design of at least three threshold buildings within ten calendar years preceding submittal of the application. In addition, the applicant must submit three personal references with one required to be signed by a special inspector.

If you are asking what manuals you need for testing....there is no test. You must be a licensed professional engineer with specific experience. You apply and have your experience evaluated by the Board of Engineers. If your experience is good, you can become authorized to provide the services.

I have been a designated Special Inspector in Florida since 1985.

I suggest you read Section 553.79 of the Florida Statutes and Chapter 61G15-35.003 of the Florida Administrative Code.

As crazy as this sounds, aren't architects also allowed to be threshold inspectors?

FSS...unfortunately, yes.