A Cowbridge firefighter has paid tribute to the servicepeople of 9/11 by completing his own personal challenge.

Matt Griffiths, a firefighter of two years, climbed the 110 flights in Twin Towers stairs in full fire kit, BA and under air on Saturday 11 September, the day that marked the 20-year anniversary of the event.

His colleague David Thomas posted Matt's efforts to social media, where he was met with an overwhelming response of respect for his efforts.

"I didn't tell anybody I was going to do it," Matt told Nub News.

"It was something I wanted to do, as a small personal tribute to the firefighters who responded to 9/11.

"Of course, it's not just about the firefighters. It's everybody that was involved in that day. We've heard so many stories of civilians, as we say, that did quite awesome things.

"People were doing everything they could to help whether they were in the service, or as bystanders.

"They were ordinary people, and it was an ordinary day until it all happened. I'd like to think most people would just offer to help the person next to them," he said.

It took Matt 24 minutes to climb the full 110 flights of stairs, like so many firefighters did that day. To make his challenge as difficult and close to reality, he wore his full kit and did the challenge under air.

"I pretty much ran out of air pretty much by the time I reached the top, on the step machine," he said.

"It was literally about to give up on me as I got there. If I done that in the real world and entered the smoke-filled room at the top, I wouldn't have been able to do anything because I'd run out of air.

"From what I know, the firefighters would have gone as far up as they possibly could breathing naturally and used their air sets when they got to smoke-filled areas.

"In the real world it would have been unbearable, I imagine.

"I didn't have anything to worry about, but those guys and girls were doing their jobs, trying to get as many people as possible to safety in such an extreme situation."

David said Matt's tribute showed the calibre of Cowbridge's firefighters.