The pipe is a 21-inch pipe according to this UKPress article. 53 centimeters is about 21 inches.

The article seems to be inaccurate in at least one respect, and one comment calls the author on it: It's not a 5-foot diameter pipe. Various sources say it's either 12-inch or 21-inch, but not five feet. One source says the largest riser pipe made is 21-inches in diameter.

I am the chairman of the Board of Trustees for my church. This kind of collaborative web page is a reasonable substitute for what would be a real database and web pages if we had the money and time. One way we'd use it is to track building maintenance tasks. Any trustee might enter items as they notice them. Someone else would do the job and mark it done. Bugzilla would be ok for this and I'm sure there's other software, too, but all require a real web site.