IBC – International Builders Code – (adopted by Pennsylvania, New York, Ohio, West Virginia, and most states)
Section 1029 specifies:

Bleachers, grandstands and folding and telescopic seating, that are not building elements, shall comply with ICC 300.

ICC 300 – International Code Council – Section 105 specifies:

105.2 Yearly inspections required. The owner shall cause all bleacher, folding and telescopic seating, and grandstands to be inspected at least once a year in order to verify that a structure is maintained in compliance with the provisions of this standard.  All folding and telescopic seating shall also be inspected to evaluate compliance with the manufacturer’s installation and operational instructions, including an inspection during the opening and closing of such seating.

501.2 Inspection. All existing tiered seating shall be inspected and evaluated at least once a year by a qualified person for compliance with the provisions of this chapter.  All folding and telescopic seating shall be inspected to evaluate compliance with the manufacturer’s installation and operational instructions, including an inspection during opening and closing of such seating.