MMC 52pp M10 WEB

Heating, Ventilation & Indoor Air Quality
What’s in a
breath of
fresh air?
A breath of fresh air. A sigh of relief. An angry huff. An exultant gasp. There are many differing types of breath and as human beings
we take on average 17,000-30,000 of them per day. Coupled with this, the average person in Britain spends 92% of their time
indoors on a week day. So with less than two hours a day spent outdoors, Joe Bradbury of MMC Magazine explores the importance
of clean air and ventilation within a building.
When we are inside the home, an
indoor workplace (or any other type
of building, for that matter), we are
placing ourselves unwittingly at the mercy of
the air within that building. Any chemicals,
toxins or pollutants are drawn into our bodies
and can cause headaches, eye irritation, skin
problems, allergies and fatigue. Prolonged
exposure to more serious pollutants can even
cause certain types of cancers and other longterm
health complications. As specifiers
building structures designed for people, we
have to consider this in our projects and
ensure we do everything within our power to
protect occupants from the invisible menace
of unclean air.
According to the NHS, there are currently 5.4
million people in the UK receiving treatment
for asthma; comprising 1.1 million children (1
in 11) and 4.3 million adults (1 in 12). The UK
holds some impressive records but boasting
some of the highest rates in Europe for
Asthma is nothing to brag about; every day, the
lives of three families are devastated by the
death of a loved one to an asthma attack, and
tragically two thirds of these deaths are
preventable.
Poor indoor air quality exacerbates symptoms
of asthma in its sufferers, and plays a sinister
role in the development of asthma in
susceptible people, such as small children and
the elderly.
The construction industry is a major source of
pollution, responsible for around 4% of
22 MMC
Nov 2018 M10
particulate emissions, more water pollution
incidents than any other industry, and
thousands of noise complaints every year.
Something must be done!
Mechanical Ventilation with
Heat Recovery (MVHR)
Innovations within the field of airtightness in
buildings have happened so rapidly in recent
years and ventilation and heat recovery have
had to play catch up to keep up with the
momentum. Adequate ventilation in airtight
buildings is essential and mechanical
ventilation with heat recovery (MVHR) systems
offer that effective, efficient and clean way of
ventilation so sorely needed by people living in
poor quality air across Britain today.
MVHR (Mechanical Ventilation with Heat
Recovery) provides fresh filtered air into a
building whilst retaining most of the energy
that has already been used in heating the
building. Heat Recovery Ventilation is the
solution to the ventilation needs of energy
efficient buildings. Mechanical ventilation with
heat recovery (MVHR), heat recovery
ventilation (HRV) or Comfort ventilation are all
names for the same thing. A heat recovery
ventilation system properly fitted into a house
provides a constant supply of fresh filtered air,
maintaining the air quality whilst being
practically imperceptible.
MVHR works by extracting the air from the
polluted sources e.g. kitchen, bathroom,
toilets and utility rooms and supplying air to
the ‘living’ rooms e.g. bedrooms, living rooms,
studies etc. The extracted air is taken through
a central heat exchanger and the heat
recovered into the supply air. This works both
ways, if the air inside the building is colder
than the outside air then the building will
retain its nice and cool temperature.
Bringing the fresh air inside
Studies show that a well-sealed building
envelope combined with effective filtration of
incoming supply air can reduce particle
penetration by 78%. The positive health
implications of this are profound.
The general public understands the impact
temperature has on healthy and productive
conditions inside buildings sadly all too well;
fuel poverty and winter deaths take centre
stage in our newspapers and magazines.
Unfortunately, the fact that air quality is
equally as impactful on society is regularly
overlooked. Regardless of how hot or cold it
may be outside, people have come to expect
comfortable indoor temperatures. They
demand that from their buildings. They now
need to invoke the same demand for
protection from harmful air pollution. Get
either wrong and you run the risk of harming
your occupants.
Warmth and clean air to breathe is essential.
As an industry, we are responsible for the
comfort and wellbeing of the occupants of the
built environment. We must also ensure we
are moving forward towards renewables,
otherwise I would argue that we aren’t moving
forward at all. MVHR just might be the answer.