FOCUS HVAC
BSRIA BEST PRACTICE BSRIA’s guide to Water Treatment for Closed Heating and Cooling Systems (BG50) has recently
been revised. Tom O’Sullivan, Head of Operations at Guardian Water Treatment explains what’s
changed and why real-time monitoring is now considered industry best-practice
BSRIA’s guide to Water Treatment for
Closed Heating and Cooling Systems
(BG50) is an important document for FMs
and their maintenance teams. It contains
the latest thinking and best practice advice
on the management and maintenance of
closed heating and cooling systems once a
building has been handed over.
This is a complex area but it’s really
worth getting it right - small adjustments
to maintenance and management
can make a huge di erence to overall
building performance, energy usage, and
consequently, cost.
The updated guidance explains common
problems, such as corrosion, scale,
34 FEBRUARY 2022
sedimentation and bifouling (biological
fouling), providing advice on how they can be
prevented through proper design, construction,
maintenance and real-time monitoring, and a
range of water treatment techniques.
In a major shi away from the previous edition,
BG50/2021 mentions real-time monitoring as a
key tool in the fight against corrosion in closed
heating and cooling systems. It highlights the
importance of eliminating the root cause of such
issues with a particular focus on minimising
levels of dissolved oxygen (DO).
What’s wrong with sampling?
Compared to sampling alone, newly
developed real-time monitoring technology
does a far superior job of keeping systems
working as they should, using less energy and
reducing maintenance and repair costs.
When BG50/2013 was first published the
technology was yet to be invented and
therefore sampling and the installation
of corrosion coupons (inline monitoring
devices) were the best option for condition
monitoring. As commercial buildings became
larger and more complex in their operations,
this technique began throwing up some
expensive and inconvenient problems.
With laboratory samples taking days or
weeks to reveal any results, hidden problems
were o en le to fester. Once data was to
hand, it revealed only a snapshot in time,
with subsequent developments unaccounted