Hi
I recently had a blockage in a combined rainwater/sewage manhole (constructed circa 1920) in back garden of terrace house. The outlet from the manhole is via a 4"x45deg clay pipe bend into a 6" clay carrier drain Y junction - pipes proved by excavation to top of pipes, but extent of bend was not traced back to manhole. When unblocked I was informed that the blockage was in a Running Trap. I have looked online at current clay pipe suppliers for details of a Clay pipe Running Trap without success and my question is - are these not currently in use and were they available/installed in the 1920s and what do they look like, and is it possible that there was a running trap between the manhole and the 45deg exit bend.
GG

Hi GG

YUP! Running traps were the norm in 1920... see images below:

Here is a link that will provide more information on these:

Do You Need Building Trap Replacement for Your Toronto Home?

Running traps were famous for clogging up at the inlet or outlet and most have been removed at this time in history as they are no longer needed (homes have installed separate PTRAPS at each fixture now)... ;)

Read the article and pop back if you have more questions, OK?

Mark

Attached Images

  

Hi Mark
Thank you for Clay Running Trap history & photos - well explained and satisfies my curiosity, and I fear the blockage (the first on since 1920 I believe) was caused by me interfering with the manhole 30 years ago to install an additional duct and not sealing properly permitting stones to enter manhole to block running trap - easily unblocked using High Pressure Water Jet not available in 1920s.
Regards
GG

Glad we could help! Thank you for popping back to share your thoughts!