Silicone Sealant around a copper pipe

[docklandsuk]

Hi Guys

Yesterday I installed my first outside tap in my kitchen, it's the solid 15mm copper type which has a union backplate.

After watching a few online videos just to make sure I was doing it right I used clear general purpose silicone sealant as I pushed the copper pipe into the outside wall and around the backplate, I also used it inside to stop any creepys from coming into the house.

It was only later on when I noticed on the silicone sealant tube that it said DO NOT USE on copper.

The stuff I used is a the acetoxy stuff that smells like vinegar.

After finding out that it could corrode the pipe should I take all the tap out and remove all the silicone or will it be fine?

 

[Agile]

The acetic acid is only given off during curing.

Now you have done it its probably too late so my advice is to leave it but do keep your eye on it for green corrosion.

Did you fit the internal isolator and non return valve?

Tony

 

[docklandsuk]

Hi Tony thanks for your reply.

Yes I fitted a isolator valve and the non return valve is built into the tap.

I've just had a look tonight and there is some green staining where the silicone has contacted with the copper, the silicone has turned green too.

Trouble is I went a little mad yesterday and also filled in the gap around a 22mm gas pipe (which is inside a plastic tube) coming into the kitchen from the gas meter BUT upon seeing the warning about copper on the tube I managed to get most of it out before it was set and spray a little WD40 into the plastic tube where the gas pipe runs but on checking tonight there seems to be a lot of green corrosion already where I couldn't remove some of the silicone, I'm quite shocked on how quickly this has reacted to the copper, the 22mm gas pipe is about 10 years old and bare copper so not sure if age has anything to do with it.

Bottom line is should I be worried? also if corrosion does happen what is the worst case that can happen?

I know I've been very stupid but this is a big lesson learned.

It will be quite easy for me to replace the tap pipe but the gas one would require a pro.

 

[Agile]

I think that strictly you are meant to have a DOUBLE check valve on your garden tap!

The inbuilt one is only a single I expect.

You are very silly fiddling with the gas pipe because you don't know the regulations!

Whilst it is probably not immediately dangerous my advice is that when you have your boiler serviced you make sure you let the RGI have a look at that gas pipe and form an opinion on what, if anything, should be done about it.

Tony

 

[docklandsuk]

Hi Tony, to be fair I'm actually going to take the water pipe out and get a new one tomorrow along with a new standard tap without a double check valve and install a inline double check valve just after the isolation valve so that will be sorted.

I shall clear all of the silicone out of the hole, I haven't sleeved the hole so I don't know if that's going to be a problem also, saying that every video on youtube shown by even the pros doesn't say to sleeve the 15mm pipe with a 22mm plastic or copper sleeve, so I'm going to assume this will be ok.

As for the gas pipe, I haven't actually touched the pipe or done anything physical to it, all I did was shove some silicone sealant down the gap at the side of the pipe as cold air was coming down the pipe also allowing spiders from the gas box to come into the kitchen.

The pipe is in the corner of my kitchen and the only reason I've got access to it is due to my kitchen being fitted at the moment so I'm not sure how a gas engineer would gain access to it in the future as it will have corner cupboard around it.

I'd say that 95% of the silicone has been removed, I used a chopstick and a kitchen paper towel to remove it, the pipe wasn't touched or damaged, as i mentioned there is a little bit of green present where silicone has wedged in one corner where the gas pipe touches the plastic sleeve.

 

[BigSnoopy01]

its fine to seal the gas pipes sleeve to the wall but you should not seal the gap between the gas pipe and the sleeve outside. Inside only, this allows any gas leak inside the sleeve to escape outside.

although some plastics are allowed as a sleeve its a poor choice and tends to leave a larger gap between the two.

 

[longdogs]

You can get taps with double built in check valves.

 

[AlanE]

I think that strictly you are meant to have a DOUBLE check valve on your garden tap!

Tony

Wrong really. You need a double check valve in the supply.

Taps fitted with check valves are for replacement use only NOT new installations - Water Regs.

 

[mfarrow]

Taps fitted with check valves are for replacement use only NOT new installations - Water Regs.

Why does it matter where a backflow prevention device is fitted?

Anyway OP stop worrying it's only during curing and the oxidising metal will eat up the acid long before you pin-hole the pipe.

But next time use the builders silicone. Sanitary silicone is not designed for sealing masonary.

 

[Gasguru]

The backflow devices fitted inside the tap either jam up or fail to operate as soon as the water inside has frozen, hence they are banned for new installations. Wherever possible a double check valve should be placed inside the property. Water regs.

 

[Agile]

I think that strictly you are meant to have a DOUBLE check valve on your garden tap!

The inbuilt one is only a single I expect.

Tony

When I said " on your garden tap " I hoped you would have interpreted that is on the SUPPLY to the tap and not "in" the tap.

Its all pretty irrelevant as no one makes any inspections. Although Thames Water did say that they hoped we would report any incorrect situations.

You can add the double check valve inside and leave the single on in the tap!

The more the merrier!

The reason you should not have been touching the gas pipe was because there are strict requirements to only seal at certain positions.

It sounds as if it comes straight out of the back of a gas meter box built into the wall?

Where it should be blocked it should be something fireproof!

Tony