I've been working in a block of masonettes where there's a walkway to the upstairs front doors which is open the elements to the front but is covered because the upstairs floor of the maisonettes jutts out over the walkway. My concern is this: a number of the owners have fitted a gas boiler in the hall of their homes but the balanced flues only extend about 200mm from the wall of the front door. Shouldn't the flue be extended so that it projects beyond the side of the walkway? Also, these flues are located 200-300mm from opening windows and doors. Is this ok?
have a look at. www.est.org.uk/bestpractice you want document CE30 for starters, there's also something in the building regs documents.