I will traveling from Los Angeles to Bankok with a stop over in Guangzho China

for both the out going and return flights of my trip. The layover in the airport in Guangzho is approximately 4 hours. Do I need a Visa or do I qualify under the 24-Hour Direct Transit Rule.
Under the 24-hour free transit rule, no visa is required for international flight, ship, or train passengers who transit directly through mainland China and will stay for less than 24 hours.
thank you for you help

Greg