Cellar, Fresh Air Inlets and Sewer Vents

It sounds as if we’re describing three different types of vent here but the cellar vent, fresh air inlet and sewer vent are all the same vent. I’m sure you’ll want to know what on earth a picture of the Titanic has to do with all this but please read on…

These rather splendid looking angled vents have two uses, to ventilate cellars and below ground rooms or to allow fresh air into the sewer pipes to prevent loss of the water trap in WCs. If used as the former they are normally fitted with mesh, whilst for sewers the mesh is replaced with a flap non return valve that prevents any smells escaping.  Because many WCs were outside period properties, these vents, used as fresh air inlets were more commonly used towards the rear of the property some distance from the building – generally around knee high ( to save on expensive cast iron pipework)

You would be pressed to notice a sewer vent nowadays installed in a modern sewer system. Unsurprisingly, they’re tucked away, with the cost of plastic sewer pipes being relatively inexpensive they’re placed at a significant distance from windows and more commonly above the rainwater gutters around the roof eaves.

Another use, with a mesh front is to ventilate below pavements. There angled profile allows air to be piped below the floor level without rain water and puddles being drained into the basement – an ingenious and most attractive method of subterranean ventilation.

I’m sure that mariners, seafarers and filmgoers alike will suggest that this very same principle is very similar to the structure on the deck of steam ships that gathered fresh air from the upper deck to divert it below to cool the machinery and men working below. Our cellar vent although diminutive in size has very much the same purpose as the deck vents of ocean liners (also known as Dorade vents), but more to the point…

which came first ?