FOCUS HEALTH & SAFETY
VENTING SAFELY
Smoke vents are a crucial part of
a building’s fire safety system
and work in conjunction with other
mechanisms such as smoke curtains
and sprinklers to protect building
occupants and the building’s
structure from damage or collapse.
How do they do this, though? In this
article, we will outline the basic
function of smoke vents and how
they work, as well as looking at
best practices for maintaining them
properly to ensure they do not fail
in case of an emergency.
In the initial stages of a fire,
temperatures tend to rise fairly slowly
and consistently until they reach
their ‘flashover point’ when the rise
in heat rapidly accelerates. Due to
the relatively slow temperature rise
when a fire starts, very large amounts
of smoke are usually produced in
the first few minutes. Without any
barriers to contain the smoke or an
exit for it to escape the building,
it can very quickly fill even a very
large space, quickly incapacitating
occupants. The limited visibility
created by the smoke also makes it
extremely di icult for firefighters to
locate the seat of the fire to put it out
quickly.
It is extremely important that
firefighters reach the fire to put it
out in the beginning stages when the
temperatures are still manageable,
because once a fire reaches its
flashover point, the likelihood of
rescuing any occupants, stock or
indeed the building itself (depending
on how large the blaze it), goes down
considerably.
Smoke vents are instrumental in
helping to keep escape routes clear
and in allowing firefighters to reach
the origin of the fire quickly, helping
them to extinguish it faster which
saves lives, stock and buildings.
HOW DO SMOKE VENTS WORK?
When a fire starts, AOVs (automatic
opening vents) will be triggered
when they sense smoke or heat in the
building. This will cause them to open
in either a roof vent or a window in
the building’s façade that will o er
the gathering smoke a way out of the
building. As well as e ectively guiding
smoke out of the building, AOVs
also generally reduce the heat in the
building, creating better conditions
that enable a safer escape for any
occupants in the building.
HOW SHOULD SMOKE VENTS BE
MAINTAINED?
For life safety equipment such as
smoke vents, the building operator/
owner is required by law to provide
a suitable system of maintenance to
maintain the system in an e icient
state, in e icient working order and in
good repair.
New guidance on smoke control in
multi-occupancy residential buildings
has been issued by The Ministry
of Housing, Communities & Local
Government. The guidance stresses
the importance of professional advice
and building owners understanding
of what type of smoke control system
they have.
It also reminds building owners that
‘Smoke control systems should be
tested weekly by the building owner
to ensure that they are operating
e ectively, with a full system
inspection and test carried out by
a suitably qualified person at least
annually.’
The BS 7346-8 is the
British Standard that gives
recommendations for the planning,
design, installation, commissioning
and maintenance of smoke
control systems, including smoke
clearance, in and around buildings.
It recommends that you get your
smoke ventilation system checked
once per year by a qualified engineer.
It is your responsibility to check that
contractors have the qualifications,
accreditations and training to work in
accordance with the regulations.
One of the biggest misconceptions
that we see when servicing smoke
vents is the misunderstanding that a
smoke test is a full service – this is not
the case. A successful smoke test will
confirm that your system is working
now, however, there may be elements
within it that are not functioning
properly or are reaching the end
of their life. Regular servicing by
qualified maintenance professionals
is vital.
For your system to be properly
tested and maintained, your service
engineer should be conducting full
motor resistance and load tests,
checking the battery charge rates
and identifying Cause and E ect of
any failures and any impact of any
failures.
Planned and regular maintenance
can extend the life of your smoke
vents, reducing the likelihood of
downtime. A scheduled maintenance
programme also allows your
equipment to be updated in line with
the latest technological advances and
standards.
Conor Logan, Technical Director at Colt explains why maintaining your smoke
vents properly is so important
It is vital that smoNe is effi cientl\
removed from buildings for the
folloZing reasons:
Smoke is comprised of
components that can be lethal
if inhaled. These components
include:
• Particles of burnt and partially
burnt substances that can
bypass the respiratory system’s
defences and enter the lungs.
• Toxic gases such as carbon
monoxide which can be deadly
even in small quantities.
• Vapours that are poisonous if
inhaled.
Fire can reduce oxygen levels
in two ways. The first, by
consuming the oxygen and
the second, by displacing the
oxygen with other gases, this is
called Hypoxia.
44 OCTOBER 2021