Chengdu 72-hour visa free

In order for the 72 Hr free Transit condition to apply you must be arriving at Chengdu Shuangliu International Airport from one of the listed (Free Transit) countries, or be in transit from one the Chinese Intrnational Airports listed below, and travelling from one foreign country and departing to a different foreign county :

Beijing Capital International Airport
Shanghai Pudong Airport
Hongqiao Airport
Guangzhou Baiyun Airport
Chongqing Jiangbei International Airport
You can apply for the 72 Hr free Transit permit at a Chengdu airport after arriving from one of the above locations if you are "in transit" to another country via Chengdu. Meaning this permit does not apply to round trip tickets from your home country to Chengdu, and returning to your home country from Chengdu. To apply for a Visa-free permit you should have your passport, airline documentation of your destination country, and all other travel visas that may apply to your trip.

(this was posted on the Chengdu Airport Website)
Hope this helps to all those in need of information regarding the free transit.