Section 502 provides tabulated limits for building heights measured in stories and feet, and floor areas in square feet. Height is measured from the lowest point of elevation of the building to the highest point of roof or mechanical equipment excluding antennas. For purposes of the code, one story is considered 12.5 feet high, with most residential and commercial buildings ranging 10-14 feet per story. Type I noncombustible construction permits the greatest heights and areas, with most occupancies unlimited in both dimensions or only limited by the building's economic and practical considerations. Type IA permits unlimited height and area for some occupancies. Type IB limits height to 75 feet (approximately 6-7 stories) and area per floor to higher thresholds than other types. Type II noncombustible construction allows more modest heights and areas than Type I. Type III wood-exterior construction limits heights to 65 feet (5-6 stories). Type IV heavy timber permits 65 feet heights. Type V combustible construction is most restrictive, with heights limited to 40-65 feet and areas limited to 6,000-15,000 square feet per floor depending on occupancy. Buildings consisting of more than one occupancy must comply with the most restrictive height and area limits applicable to any occupancy present. Area increases are permitted for buildings on larger lots with frontage on public ways, with increases proportional to the frontage percentage.