Glass Lined Hot Water Storage Tanks

Glass lined hot water storage tanks, also called vitreous enamel lined hot water tanks, are storage tanks or buffers that are normally used for domestic hot water storage(potable water), although the hot water doesn’t have to be of this quality. They are storage tanks or storage vessels manufactured in carbon steel but with glass or vitreous enamel corrosion protection of the metal surfaces in contact with the hot water.

The glass lining provides a robust internal surface for water storage tanks that must endure the wearing effects of high volume, high-temperature hot water and prevents corrosion of the storage tanks.

Our glass lined storage tank range can also be used to store cold water too, as our glass coated steel tanks can operate with cold water down to 5C (the lowest cold water mains temperature that we see in the UK)

Glass Lined Storage Tanks

Our glass lined hot water storage tanks can also be used for cold water storage too, as they are designed to withstand temperatures down to 5 degrees C. The hot water temperature limit is 95 degrees C, depending on the model of the glass lined tanks.

How is the vitreous enamelling or glass lining applied?

All interior linings of domestic hot cylinders must be “Food Grade quality” according to EU Regulation 1935/2004. Our vitreous enamelling has food grade certification at 95 °C, ensuring maximum quality at severe operating temperatures.

Using a sophisticated “surface treatment” on the carbon steel surface, combined with an automated enamel coating procedure, results in much more than a robust mechanical adhesion of the lining. A molecular interaction develops between the steel surface and the applied enamel layer during the curing process.

This maximum bonding of the enamel coating to the steel surface, along with the vitreous enamel’s high level of impermeability, and ensures the tank’s durability and keeps it from breaking down in ways that can happen with other types of coatings, like the protective coat coming off or blistering.

When to use glass lined storage tanks

These glass lined steel tanks are the most widely used for storing potable or waste water in building services or process equipment applications, but they are also suitable for dosing chemicals, numerous industrial effluents, or reagent materials since they combine the corrosion resistance of glass with the hardness of steel at a very cost-effective price.

Cathodic protection system via sacrificial anodes

A magnesium sacrificial anode in glass-lined tanks assures potable water quality. These sacrificial anodes guarantee that the domestic hot water is safe to drink by drawing contaminants from the nearby water supply. If the magnesium anode rods strike the glass while lying down, it might cause glass shattering or crazing (fine cracks on the surface of the material). It is critical that glass lined steel tanks be kept and carried upright.

The sacrificial anodes, through an electrochemical process, are designed to attract particles of limestone, iron, and other minerals present in the water and corrode instead of the glass lined tank. In simple terms, it “sacrifices” itself to help the range of glass lined storage tanks last longer.

Most glass lined storage tank manufacturers advise inspecting and evaluating the sacrificial anode’s condition every year and replacing it when it has been depleted by more than 50%. This is particularly important if you have hard water or use a water softener on your domestic hot water.

Storage Tanks Product Range

We have two ranges of glass lined water storage tanks; these are

Our Flexitank series glass lined steel tanks

This series of glass lined water storage tanks has capacities ranging from 200 litres to 5,000 litres and are the ideal choice for high volume applications, with a standard pressure of 10 BarG for the 200 to 1,000 Litre models, 8 BarG for the 1,500 to 3,000 Litre models  (10 bar optional upgrade) and a maximum operating temperature of 95 °C.

ErP rated “C” to minimize heat loss, these are glass lined steel tanks with sacrificial magnesium anode rods as standard (option of upgraded permanent electric anodes)

From 1,500 to 5,000 Litres, we have the option of either a resin synthetic lining for the steel tank, with a maximum water temperature of 70C, or a resin-ceramic nanotechnology treatment applied to the steel tank, with a maximum water temperature of 80C, for applications where up to 95C water temperature is not required e.g. lots of DHW and process hot water storage systems , do not require temperatures above 65C, thus why pay for the expense of glass lined steel water storage tanks , when resin based internal options will do the required water temperature.

These hot water storage models all benefit from an inspection and clean outdoor or manhole which is 200mm for the 200 to 5000 Litre options and a larger 400mm manhole option is available from 800 litres upwards for these glass coated steel tanks.

 

 

 

We have options of none, one or three inspection / manhole ports on this Flexitank VS range of tanks 

 

Full details are on the following brochure – 

Glass lined and Resin storage steel tanks brochure from Flexiheat UK

Our SAC series of glass glass coated steel tanks

These have capacities ranging from 300 to 5,000 litres, with a maximum water temperature of 95 °C.

With a maximum working pressure of 10 bar for the 300 to 1,000 Litre capacity models

As standard, the 1,500 to 5,000 Litre tanks are 6 Bar rated – with the option of 8 bar manufactured units.

Glass lining will cope with high temperature hot water up to 95 Degrees C.

These glass lined storage tanks come with insulation with ErP energy ratings of “B” or “C” depending on size, to minimize heat loss.

Full details on this series of glass lined storage tanks are here –

Download the Flexiheat SAC Glass Lined storage tanks or cylinders for domestic hot water storage brochure

Finished in grey PVC RAL 9006 colour lining or jacket up to 2,000 litres, and white PVC RAL 9001 above this volume.

They are manufactured to the 2014/68/UE Directive, ART. 4.3, without CE marking Standard EN 12897:2016.
These buffers are designed and built in accordance with the requirements of 2009/125/EC.

Labelling in accordance with the requirements of 2017/1369/EU and Delegated Regulation 812/2013 (EU)

Glass lining corrosion protection to DIN 4753 and come with a 5-year warranty.

Soft water areas: be aware

Glass-lined storage tanks can succumb to significant corrosive damage quickly under naturally soft water conditions, despite the use of sacrificial anodes.

Purer, soft water has poor electrical conductivity due to a lack of dissolved metal ions; therefore, the electrical flow from the anode to the cathode via the water is decreased. This has a negative influence on the chemical interaction between the sacrificial anode and the storage tank shell, resulting in less protection.

An electrically powered anode is a common substitute for the sacrificial magnesium anode rods. A powered anode, which is frequently constructed of titanium, creates a very low current in the water rather than giving up its own electrons and creating an electrolytic current. This should provide a similar level of protection for glass lined tanks while not corroding the anode. However, in soft water conditions, even an electrically powered anode may still be ineffective since the conductivity required by the anode is insufficient.

As a result, this applies to Scotland, west Wales, and the northwest and southwest regions of England, where the water is very soft, you are always going to need a stainless steel hot water storage tank.

Please see more on our range of stainless steel hot water storage tanks

Water heating

These glass lined storage tanks or buffer tanks are often used in conjunction with either tankless water heaters or suitable air source heat pumps, gas, or oil boilers that, via a plate heat exchanger, can provide the domestic hot water and space heating requirements. The glass lined storage tanks provide a buffer volume of hot water to accommodate a variety of peak demands the building or process may encounter.

Hot water system volume

With various capacities of tank sizes available, from a small 200 Litre to 6,000 litres in single glass lined steel tanks (you can also couple the units up in series should you require higher capacities), our range gives us the flexibility to cover all storage capacity requirements you may have.

Glass lined storage tanks

Should you require more product information, check stock, technical support, budget options, prices, or to place an order on our glass lined hot water storage tanks,or storage vessels then please don’t hesitate to contact our sales team on 01202 822221 or use our email contact form via the contact tab above to message us.