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Winter-2019. Estimating damages and learning lessons

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This is a pretty atmosphere one can see atop St. Petersburg’s roofs – with a bird’s eye view. The classic postcard view of our city. But a serious utility problem is concealed behind this glitter.

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Anton Tsuman, reporter: “Here is a part of the water pipe – weighing about thirty kilograms – was dropped from the fourth floor, to prevent it from falling on someone in the future. It feels like they’ve done the right thing. But when the warm weather comes, all the water will run down the façade – which means damage to walls, mold and necessary renovation in 3-4 years”.

These shots became viral on the Russian web. Utility workers claim that this had to be done – to avoid a tragedy. The city’s rooftops have been a battlefield since the rough winter of 2011. It became clear back then that St. Petersburg’s rooftops represent a very fragile issue.

Anton Tsuman, reporter: “Here’s a typified sheet of metal from St. Petersburg’s roofs, half-a-millimeter in thickness. And here’s a spade which is used to de-ice those rooftops. Let’s see what happens if you accidentally hit the metal instead of ice. It’s clear that those hits can leave bumps and even holes”.

The spring is yet to come, but the Utilities Committee already has almost 200 tips about leakages. And its members name different causes for those.

Sergey Sharlaev, deputy head of Utilities Committee: “Last week we experienced 10-15 degree subzero temperatures. When a man goes on top of a roof in such weather, lock joints break and that causes leaks”.

Lock joints are junctions between sheets of metal on top of a roof. To figure out why those could be breaking, we went to a workshop with experienced roofers.

Sergey Satyukov, roofer: “This is an upward lock joint. It can do a job. Depends on a roof’s angle. It’s not sufficient when a roof is inclined. In that case you need a double lock joint”.

We repeat the same action, basically

  • “The difference is that we make the lock joint higher, and then fold it once more.

  • Well, this one is thicker. I can even feel it.

  • Yes, it is. And it is also harder to make and requires more materials”.

And this is one of the reasons why these lock joints break. To save money, single-layer ones were put in the spots which required double-layer joints. And this one can be taken apart with bare hands.

But why do we have so much ice on our roofs? Here are pictures of winter St. Petersburg from the beginning of the 20th century. You can see snow on rooftops, but almost no icicles. The solution is simple. In those days, buildings were heated by chimneys. The ice came together with central heating systems – and here is why.

Anton Tsuman, reporter: “There are two types of water heating systems. The lower feeding – when all heating pipes are located in the basement and heating goes from down up. And there’s upper feeding – when pipes run through the attic and heating goes top to bottom. In Soviet days, when Leningrad was converted to a new system, it was believed that the upper feeding system was more reliable, efficient and easy to service. But it also turned the attics into literal hot spots”.

Excessive heat at the attic warms the roof. Snow melts and the water trickles down towards the drain pipes. It turns into ice and clogs the pipe. All next portions of water go over the roof’s edge and turn into icicles. Which grow bigger and bigger.

Viktor Prusakov, engineer: “If you look at those holes, there is no ventilation there at all”.

The attic at one of the buildings at Chkalovsky Prospekt is a vivid example of how things should not be done. Ventilation holes are closed and 50-degree heating system is not sealed off properly.

  • Eighteen degrees, twenty. Is that a lot?

Viktor Prusakov, engineer: “It is a lot. The feeding system needs to be properly isolated, to keep the heat inside. But it goes up and leads to icing”.

Just to compare – these are the streets of neighboring Finland. Not a single icicle in Helsinki – even on vintage buildings. That’s despite an almost identical climate. That’s because attics are properly sealed off, while scaffoldings are heated electrically.

This kind of solution has now been looked at in St. Petersburg. Four thousand rooftops have been renovated in St. Petersburg using the “Cold Attic” technology. Including this one – at Pugacheva Street, under the management of Utility Service no2 of Krasnogvardeisky District.

Sergey Khrabryi, head of utilities at Krasnogvardeisky district: “This is the upper feeding – the root of all problems, especially at junctions. There’s a hole here – you can feel it. And now imagine that there are many here. Everything would heat up crazily and icing would be imminent”.

“And what is it sealed off?”

“Same materials – which make sure it’s all properly sealed”.

That is the main principle of a “cold attic” – when everything’s properly sealed off. The floor, ventilation and sewage system – with the corresponding materials.

And frozen pipes can actually be heated. This inventor from St. Petersburg – Anatoliy Rybkin – created a device which turns a drain pipe into a microwave.

Anatloy Rybkin, inventor: “It is installed into the drainage system. And then plugged into ordinary 220 volt AC input. It heats up for thirty seconds, then rests, then does that again”

“This one is without the device?”

“Yes”

“And this one with the device? Can I put my hand inside?”

“Of course, you won’t feel anything – all the energy is being consumed at the top”.

“There’s no ice – only water”

In short – there are many ways to fight the ice atop the roofs. Cheap and expensive. Easy and complex. But it’s high time we chose an optimal one and focused our efforts on it. Now – because otherwise next winter we could be paying the price for our inaction.

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