Smoke exhaust – it’s serious
RON BURNS
Ron Burns is currently employed at Fire Serve in Johannesburg. He has been actively involved in the air-
conditioning industry since 1987 until he found his passion for smoke and heat exhaust systems in 2000. For
the last 15 years he has embarked on a fire serve process to demystify the application of the building code and
prevent the unnecessary loss of life. He has been a member of SAIRAC for 29 years and served on the KZN
committee as chairman for 7.5 years.
HOTEL BUILDINGS:
DESIGN CONSIDERATIONS
By Ron Burns
Hotel developments are unique buildings and many times there are
errors that creep into establishing the design requirements, since not
enough attention is paid to what can go wrong.
W
e will look at two standard type “hotel
developments” in this article, appreciating that there
is the possibility that the designer goes for a more complex
approach. Should this occasion arise then understanding the
two simple options will provide the baseline for solving the
more complex development.
STANDARD SIMPLE HOTEL BUILDING
‘Simple’ is defined similar to a typical South African Road Lodge
development. Parking is external to the building and not under
cover of a building structure. There will be no requirement for
providing any smoke control to the parking.
The parking does get a little more complex when the
parking becomes part of the structure with slabs over the
parking. In South Africa we adopt the theory of a naturally
ventilated parking, and I cannot support the concept of not
providing any smoke ventilation to a parking facility, although
this is generally accepted by the local authorities.
Please note that if the building does not contain sprinklers
and is a multi-storey building, then smoke ventilation cannot
be achieved. There are people who will adopt the principle
of a “rational design”. I cannot understand this principle; it is
not possible to control the temperature of the smoke without
sprinklers and subsequently it is not possible to extract the
smoke without losing the extraction fans on temperature. It
is not possible to ventilate the lower level naturally; vertical
venting is not an acceptable solution. Therefore if fans are
required, smoke ventilation cannot be achieved without the use
of sprinklers in the building.
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Occupied floors and areas
There are a few important principles if the areas in the building
share a common ceiling void. The building may or may not have
meeting and/or function rooms. These need to be assessed in
terms of 2 000m 2 or 2 600m 2 smoke zones based on whether
the smoke ventilation system is natural or powered. A simple
building will not contain any atriums and each floor will be
separated from each other. The reception area may be double
volume and this needs to be noted as high volume extraction
areas, especially if there is a pedestrian bridge travelling over or
access to the level directly above.
Although each room is separated from the common areas,
this is not a reason to exclude evaluation of the common areas.
Investigate the area of this space and the length of travel.
Remember that smoke may not travel longer than 60m. I would
caution the exclusion of smoke control from these spaces.
There will either be a lift lobby and/or interconnecting stairs.
These need to remain smoke free. Unless the lift doors are Class
B, or equal, to an international standard and fitted with smoke
seals, the lift should be treated as an internal chimney with
potential for the fire to exit onto each floor. The chance of losing
the building through the lift shaft becomes a concern that
needs to be individually evaluated and addressed.
From a budgeting perspective, each smoke zone should be
valued at the cost of a single smoke zone and added together.
This is irrespective of the approach taken. There is no financial
saving by using ducted shafts as opposed to a set of fans on
each level per smoke zone. Generally a smoke zone comes at
a fixed price irrespective of the engineering principle used.
RACA Journal I June 2019
71