In this section the following words have the meanings indicated. “American manufactured goods” means goods that: are manufactured in the United States; or are assembled in the United States. “Emergency life safety and property safety goods” means any goods when provided for installation in, as part of, or as an addition to a system designed to: prevent, respond to, alert regarding, suppress, control, or extinguish an emergency or the cause of an emergency that threatens life or property; or assist in evacuation in the event of an emergency that threatens life or property. “Emergency life safety and property safety goods” includes: systems or items for or relating to: fire alarms; fire sprinklers; fire suppression; fire extinguishing; security; gas detection; intrusion detection; access control; video surveillance and recording; mass notification; public address; emergency lighting; patient wandering; infant tagging; and nurse call; and information technologies and telecommunications products and technologies that are used for the purposes listed in subparagraph (i) of this paragraph. “Public body” means: a unit; a county; a municipality in the State; a school district in the State; or a special district in the State. Except as provided in subsection (c) of this section, a public body shall require a contractor or subcontractor to use or supply American manufactured goods in the performance of a contract for: constructing or maintaining a public work; or buying or manufacturing machinery or equipment that is to be installed at a public work site. This section does not apply: if the head of a public body determines that: the price of the American manufactured goods exceeds the price of a similar manufactured good that is not manufactured in the United States by an unreasonable amount; the item or a similar item is not manufactured or available for purchase in the United States in reasonably available quantities; the quality of the item or a similar item manufactured in the United States is substantially less than the quality of a comparably priced, similar, and available item that is not manufactured in the United States; or the procurement of a manufactured good would be inconsistent with the public interest; or to emergency life safety and property safety goods. The Board of Public Works shall adopt regulations to define the following terms for the purposes of this section: “reasonably available”; “unreasonable amount”; and “substantially less”.