SHANGHAI (April 23, 2:45 p.m. ET) — While China plans to open the world’s largest exhibition center in Shanghai by mid-2014, the fast-growing Chinaplas plastics and rubber exhibition is likely to remain at its current site in Pudong for its Shanghai leg at least till 2016, if not beyond.

And, for logistical reasons, it also looks to remain a four-day show for the time being, even as many push to extend the length of what is now the world’s second-largest plastics show. (The largest plastics expo, the triennial K Show in Düsseldorf, Germany, runs for eight days.)

Chinaplas – which rotates annually between Shanghai and Guangzhou in the country’s southeast – has tripled its amount of exhibition space, to 210,000 square meters (2.26 million square feet) from 77,000 square meters, since 2005, Stanley Chu, chairman of the show’s Hong Kong-based owner and organizer, Adsale Exhibitions Services Ltd., said in an interview on April 21, the show’s last day.

This year’s show, at the recently expanded Shanghai New International Expo Centre, attracted 109,858 attendees from 140 countries. Of these, more than 28,000, or just over 25 percent, came from outside China. The exhibit space filled this year represented a 17 percent increase over the 180,000 square meters at last May’s Chinaplas 2011 in Guangzhou.

The 2,700 exhibitors from 35 countries and regions – including more than 500 first-time exhibitors – filled all 17 halls, plus eight temporary, outdoor tents (which accounted for about 10,000 square meters, or about 107,000 square feet, of the space). Chu said Adsale issued about 45,000 badges for exhibitor personnel, but noted that the attendee count excludes exhibitor staff as well as media. Attendees are counted once for each day they attend.

Chu said the show could add perhaps 20,000 more square meters by installing more outdoor tents, but that it expects to need about 50,000 more square meters of space to accommodate exhibitors’ demands. Since Adsale’s goal is to add 15-20 percent new exhibitors each year, to keep it interesting for attendees, Chu now finds himself in the unusual position of having to urge some existing exhibitors to take less space than they want.

Meanwhile, China’s Ministry of Commerce in Beijing, in cooperation with the Shanghai municipal government, last December held a groundbreaking ceremony for what is likely to become the largest exhibition complex in the world. Phase one will create 400,000 square meters (4.3 million square feet) of exhibit space, with an option to expand the area by another 25 percent. This would put it on a par with the massive Hannover Messe fairgrounds in Hannover, Germany, Chu said.

Called the China Expo Center, it will be located on a 257-acre site in the western part of the 20 million person metropolis, in the Shanghai Hongqiao Central Business District – about an hour’s drive west of the Pudong expo grounds. The new facility will be very near to Hongqiao airport and railway station. The project will cost 23 billion yuan ($3.6 billion), local government officials said last fall.

Chu said the new center is due to be ready in a little over two years, just after the Chinaplas 2014 scheduled for Shanghai that spring. But even once the complex is fully operational, he said, it is likely to take some time for the surrounding area to mature in terms of hotels, services and the like. So he is not at all certain now that it would make sense for Chinaplas to shift to the new facility for its 2016 show in Shanghai.

As other shows now being held at the SNIEC fairgrounds in Pudong potentially move west to the China Expo Centre, it may give Adsale a better opportunity to extend the length of the Chinaplas. The show currently can give big exhibitors only up to five days to move in and set up equipment (versus two to three weeks at some other, major expos), and he said some of the Chinaplas halls need to be empty within 10 hours of the show’s close, to make room for the next incoming event.