Dave Raynor, Product Manager, Watts Water Industries offers an insight into how to achieve the ultimate in system protection in the crossover from domestic water supplies and systems to small commercial installations.

Efficient and effective systems are the installers overall aim to fulfil customer expectations and an essential part of this is the need to deliver water protection – the process of bringing water into the home and premises through systems without backflow and cross-contamination.

This is generally achieved through the installation of check valves, a commonplace part of domestic installations, which allows flow in one direction and prevents contamination through flow in the other direction (backflow).

Negating backflow through the specification and installation of premium products remains a priority for water industry professionals and plumbers.  This becomes even more significantly important due to the change in requirements, testing and legislation when installers are commissioned for small commercial projects. Unknowingly, a change in fluid category risk can bring a whole new range of product and legislation obligations to support the outlined requirements.

This shift from one to the other is something that many installers tackle regularly –  but, whilst not requiring a significant change in skill set, a significant change in legislation and installer requirements is apparent.


The change in product and part specification arises when installers working on small projects, that fall outside a truly domestic environment, are obliged to ascertain the fluid category risk. Should this change from 3 (domestic) to 4, an alternative product and approach to check valves are required.

The determination of fluid category 4 is outlined as ‘fluid which represents a significant health hazard due to the concentration of toxic substances and covers fluids which contain chemical, carcinogenic substances or pesticides (including insecticides and herbicides) or environmental organisms of potential health significance.

For clarification, examples of where fluid category 4 would be attributed to the installation and therefore demand a different valve in comparison to domestic check valves, would include central heating systems other than those in a house, fire sprinkler systems using anti-freeze solution, food preparation, commercial dishwashing machines and several other applications which could be found in a smaller scale installation. And, whilst the installations may still be small the need to be aware of, and adhere to, the legislative requirements is crucial.

This is in comparison to fluid category 3 which generally pertains to domestic water usage although there are small commercial exceptions in this area too.

It is safe to say that ascertaining the correct level is of critical importance to ensure that the correct type of backflow preventer is selected and the necessary legal requirements associated with the ones required for fluid category 4 are adhered to.


Instead of the typical check valve which many installers are familiar with it may be necessary to install a BA type verifiable device which, whilst performing the same essential role, is a very different solution. To fulfil the criteria of fluid risk 4 it is necessary to notify, register and perform annual checking and testing to this valve type.

Pleasingly, local water authorities can advise on whether the premises or connection falls into the enhanced safety category and offer guidance on installation and the registration of said product.

Specifying a BA type valve will deliver enhanced backflow prevention and ensure that backflow, back siphonage and back pressure are duly managed safely and in accordance with guidelines and legal requirements.

Another point worthy of note is that once installed, it is also a requirement to annually test the product to ensure it is functioning correctly and failure to adhere to this may result in a temporary loss of supply.


A BABM backflow preventer valve with reduced pressure zones protects potable water systems against pollution caused by back pressure or back siphonage. This may be as a result of an increased demand for water, frozen pipes, pipe damage or a sudden drop in water pressure. Installation of such a valve will ensure the pressure in the system is maintained through the valve and as stated it gives protection for fluid category 4 requirements. It should be installed for easy access to permit the necessary testing to take place.


Clearly, this is an area where awareness of products and regulations is needed and in order to support installers, Watts Industries has adopted a ‘belt and braces’ approach to backflow prevention through a comprehensive range of products and literature.

Recognising the need to ensure installers had easy access to the products required to fulfil all elements of legislative requirements full consideration has been given to ensure the products were easy to install too.

Its BABM valve is a controllable backflow preventer with reduced pressure zone and is certified to EN1717 and EN 12729 9157 standards. Its maximum operating temperature is 65°C and maximum operating pressure is 10 bar.

Such products which support legislation with ease, simplicity and reliability are synonymous with the Watts brand giving installers complete peace of mind. Working closely with industry bodies and water authorities Watts continues to support installers with quality products and by sharing information to unlock the muddy waters of check valves and back flow prevention requirements.