Vented water tank - no lid

[boolie]

Some background, just bought a house and preparing to move into it - it's a very old house > 150 years old

I had a problem today which was solved due to @Mottie and @terryplumb's big brains (Thanks guys)
https://www.diynot.com/diy/threads/bought-an-old-house-water-tank-blocked.571628/

Now, whilst solving that problem I crawled into the loft and had a look at the water tank. It had a DIY polystyrene lid covered by bagged insulation. There is a big hole in the polystyrene where a copper pipe hangs into the tank (I think that must be to vent the cylinder?). The tank isn't clean and could see webs hanging off the vent pipe.

Now I want to clean it up and put a lid on it which will seal it securely. Maybe just a piece of plywood with a hole for the vent pipe? and some masking tape to cover any gaps?

I was hoping that I could buy a lid for the tank but it looks like it's designed to not have a lid? Can anyone give me any advice on all this?? I would've thought it extremely dangerous not to fully seal a water tank? Some pics below

 

[Keithmac]

To be honest all cold water taps that you'd brush your teeth with or drink from I would want to be supplied directly from the mains..

 

[CBW]

It was probably permitted, or more because local councils enforced water regulations many years ago. You might be able to fit a byelaw 30 kit, but try contacting https://www.kingspan.com/gb/en-gb/products/hot-water-cylinders/ferham-cold-water-tanks to be certain.

 

[boolie]

Thanks guys, planning on cleaning and disinfecting it today - and will do a makeshift lid - will probably use a bylaw 30 kit.Will revisit later to deal with the lid issue. Have sent an email to kingspan for advice

By the way, have taken advice from the following old thread on how to clean and disinfect. It basically says after scrubbing the tank add some household bleach to the water and flush through. Is that advice still current? From @Agile https://www.diynot.com/diy/threads/how-do-you-clean-out-a-water-tank.167037/

 

[Keithmac]

Puriclean is the popular choice for caravan water systems.

 

[boolie]

Glad today's over.. I wish I had an assistant! So after muchas trips to a very awkward loft.. here are some before and after pics of the clean up.

I made a DIY lid out of heavy duty bin liners and unibond tape. Pretty well sealed I think but feel free to take the p1ss!

 

[terryplumb]

Nice job mate.

 

[boolie]

It was probably permitted, or more because local councils enforced water regulations many years ago. You might be able to fit a byelaw 30 kit, but try contacting https://www.kingspan.com/gb/en-gb/products/hot-water-cylinders/ferham-cold-water-tanks to be certain.

In case anyone's curious this is the email response I just received from kingspan. I'm quite liking the look of their 'low level coffin' tank in the brochure (attached)
Hi,

Unfortunately your tank is now obsolete.

Please find attached sales brochure showing our current models we manufacture.

Many thanks

 

[boolie]

By the way, am planning to revamp the system - keep it as unvented. Replace the water tank with a bigger more modern one - thinking about this one
https://www.screwfix.com/p/polytank-loft-tank-kit-42gallon-uk-1185-x-503-x-503mm/46467

Also will replace the cylinder with a bigger one - not sure which cylinder to go for yet

Gonna keep the heat only boiler which looks solid (a Viesmann)