passyourgas.blogspot.com/ For ACS Gas and City and Guilds Gas courses. This explains why there are rules regarding the type of terminal guard for flues. It also explains how to calculate free areas for capped flues.
I always come back to your videos, just so much info! Can't thank you enough. I have a question in regards to spillage testing, I know its done to prove POC are being taken away. But somtime I wonder what the difference is compared to a smoke bomb test. For instance on a floor standing open flue boiler or back boiler you would do a smoke bomb test under the draught diverter, this test produces a lot a smoke and if this test passes then why would you not expect a spillage done in the same location under the draught diverter to also pass, only difference i can see is the amount of smoke produced. If a lot of smoke is being pulled up then wouldn't you expecte a bit a smoke to also get pulled up? And hence POC to get pulled up too. I dont know if im making sense, Thanks
Hi Abdul… you are testing 2 completely different things. 1. The smoke bomb is carried out with the appliance OFF, it can actually be completely removed (like a gas fire). This test is to test the structure of the FLUE. It checks that there are no leaks and that flue can carry that amount of product. If the flue is cracked or not complete then you need lots of smoke to see where the leaks are. 2. The spillage test is carried out with the appliance ON and is testing that the VENTILATION AIR SUPPLY TO THE ROOM is sufficient to supply enough air for the flue to work when the appliance needs s n and all the doors and windows etc are closed (restricting the air supply) All you need to know for this test is that the ddd is sucking air in..so no need for masses of smoke. I hope this helps. Cheers
Hi Abdul… you are testing 2 completely different things. 1. The smoke bomb is carried out with the appliance OFF, it can actually be completely removed (like a gas fire). This test is to test the structure of the FLUE. It checks that there are no leaks and that flue can carry that amount of product. If the flue is cracked or not complete then you need lots of smoke to see where the leaks are. 2. The spillage test is carried out with the appliance ON and is testing that the VENTILATION AIR SUPPLY TO THE ROOM is sufficient to supply enough air for the flue to work when the appliance needs s n and all the doors and windows etc are closed (restricting the air supply) All you need to know for this test is that the ddd is sucking air in..so no need for masses of smoke. I hope this helps. Cheers
Hi pass your gas, how do you find the cross sectional area of a chimney? especially round chimneys? i see in the books it says the cross sectional area needs to be a certain size but nowhere shows you how to find this out, love the videos thanks alot
Hi Ed…it’s simply done ..here goes- square or rectangular chimneys .. measure 2 sides in cm and then multiply them together. Example.. if one side is 20cm and the other 30cm then 30 x 20 = 600cm2 … if it’s a round flue then measure in cm across the widest part … then half that number and write it down. Now whenever you’re dealing with anything circular you must use the “magic” circle number called pi. This is just a word that means 3.14 So write down 3.14 then write down the number from before twice. Multiply everything and you’ll get your answer. Example.. you measure the widest part of the flue and let’s say it’s 30cm. Half it = 15cm Use pi = 3.14 So 3.14 x 15 x 15 = 706.5cm2 I hope that helps! 😀 If you still don’t understand let me know!
