Creative
Viewpoint |
Volume
20 |
|
Are water
sprinkler systems sufficient to contain commercial kitchen hood
fires? |
A fire triangle involves the elements of fuel, oxygen and ignition
temperature. Generally, if two elements in
the fire triangle are addressed, the fire can be effectively
contained. However for commercial kitchen hoods, the practice today
involves addressing all three elements of the triangle. This is
because fire hazards are substantially increased in a hot kitchen
environment and statistics now show that 40 percent of all kitchen
fires actually start in a hood. In
some third world countries CKP have consulted in, developers
had opted for sprinkler systems for kitchen hoods. Sprinkler
systems address only one aspect of the fire triangle. They only
address the ignition temperature
aspect.
Misting systems, which were used in the earlier generations of fire
suppression, which is now not practiced, addresses a second aspect.
They would additionally deal with the elimination of
oxygen molecules; by displacement using water molecules. This
system replaced the CO2 system which also used the displacement
principle. CO2 is now banned in the USA because it displaced
critical oxygen levels ie crucial oxygen that was needed for people
caught in a fire environment.
The chemical system was then later introduced, starting with
dry powder (hard to clean); and the subsequent evolution
of wet chemical (such as ANSUL R102) and now the sprinkler
chemical system (such as ANSUL PIRANHA). The chemical systems react
with the fuel (grease) to form a saponified substance, almost like
soap, which is hard to reignite. The latter forms a layer that
separates the underlying grease from oxygen. Therefore, this system
addresses all 3 aspects of the fire triangle. The Piranha system not
only doses chemical but then continues to sprinkle water for 15-30
seconds.
In a more recent discovery, it was noted that after a
conflagration, when reaction temperatures
are high and the fuel supply fails to turn off, reignition could
potentially occur. Therefore, continued water dispensation
prevents re-ignition. The most expensive system in the
industry for addressing kitchen fires is the Piranha System. Most
foodservice consultants tend to specify the cheaper R102, which is
the minimum standard required. In line with NFPA 96 we are
only providing nozzles for gas fired equipment and those with deep
seated fires like tandoors. For electrically operated equipment, no
nozzles will be provided. In this way we can potentially keep
the cost of the Ansul system down and are still in line with the
code. Typically for all CKP projects, we do exceed the code and
ensure that all equipment are protected, regardless of the type of
fuel employed.
It
may be the prevalent practice in some countries to go with
sprinklers and quite a bit of capital expenditure can be saved
on this as opposed to a wet chemical system. However, this may not
be deemed as sufficient to provide the required levels of fire
safety required in a hot kitchen. It may also not meet the
requirements of fire safety spelt out within the insurance
provisions of the hotel management
company. |
|
Franke’s
new coffee machine. |
Franke’s SPECTRA coffee machine series offers remarkable compactness
in terms of width, measuring only 300mm(W) x 580mm(D) x 710mm(H).
Worth mentioning is, this unit can be fitted with a maximum of 3
beans hopper (slim hoppers) on a mere 300mm width. Of the 3 hoppers,
the user has the flexibility to custom specify the sets of internal
grinders, either 3 nos. to do 3 coffee beans OR ; 2 sets of grinders
for 2 coffee beans + 1 nos. without grinder to do powdered product
(instant coffee or chocolate) (OR 1 + 2 vice versa.) The technology
advancement includes the spout, which will auto-adjust its height
upon sensing the size of the glass used. The user also has 3 choices
of control panels to be specified on the
machine. |
SPECTRA
S |
The
3 SPECTRA models under this line are: -
i)
SPECTRA S – stands for SPECTRA Specialty – For brewing specialty
coffee (comparable to EVOLUTION).
ii)
SPECTRA X – stands for SPECTRA Extra Large – It’s the market’s first
Beans-to-Pot Coffee Machine; for mass production. This is meant for
producing filtered coffee, therefore it cannot be attached with a
milk chilling system.
iii)
SPECTRA I – stands for SPECTRA Dispenser – This is a standard dosing
machine, does not come equipped with any grinders and it is intended
for dosing instant powdered drinks only. |
|
Energy
Saving Dishwasher |
Winterhalter has recently launched its new energy saving hood type
dishwasher models - GS502, GS515 Energy and Energy+ series. With the
aid of an “exhaust air” heat exchanger, these models utilize the
transfer of heat from the exhaust air to heat up the incoming cold
water. This thermal exchange process allows the exiting exhaust air
to become cool whilst the incoming water absorbs this dissipated
heat. As this incoming water rises to its desired operational
temperature, less electrical power is required by the machine to
traditionally heat the water. In addition, the Energy+ series
utilizes an extra “waste water” heat exchanger, further reducing
power consumption. This technology would certainly be
applicable in countries with high electrical energy costs and where
incoming water temperatures do not exceed 200C. However,
if high temperature hot water services are readily available, this
technology would be inefficient and unsuitable. In short, this heat
recovery technology not only reduces the total power consumption and
operating costs, but also improves the surrounding air
quality.
Model
No |
Dimensions |
Total
Connected Load |
Standard
GS502 |
635
X 749 X 1469mm, height hood open:
1932mm |
15.5KW |
GS502
Energy |
635
X 749 X 2145mm, total system height:
2145mm |
12.5KW |
GS502
Energy+ |
635
X 749 X 2145mm, total system height:
2145mm |
0.95KW |
Standard
GS515 |
735
X 749 X 1530mm, height hood open:
2050mm |
15.6KW |
GS515
Energy |
735
X 749 X 2235mm, total system height:
2235mm |
12.6KW |
GS515
Energy+ |
735
X 749 X 2235mm, total system height:
2235mm |
09.6KW | |
|
Kitchen
Exhaust Misconception |
Most kitchen operators and owners are relying on the notion that the
greater the exhaust capacity, the better you can rid of the fumes
and contaminated grease laden air in the kitchen. That would only be
partially correct as there are many factors impacting capture
and containment. There are particular considerations whenever one is
putting up a kitchen exhaust system and one of them is
the required levels of air pressure within the
kitchen.
It was always a common issue in previous kitchen installations that
the doors leading to the dining area or sometimes service doors
leading to corridors tend to be difficult to open or to
keep closed. This is due to excessive negative pressure in
the kitchen. There has to be a minimum threshold of negative
pressure in the kitchen being created by the exhaust hood to suck
out cooking fumes and heat but not to the extent of making the doors
difficult to open or close. The latter happens when exhaust
hoods are not equipped with proper air dampers or a make up air
system thereby lending credence to the important principle of
kitchen air balance. Increasing the exhaust capacity alone does not
help beyond a certain point as this creates new problems
like increased audible air turbulence at the ductworks and fan motor
noise. A secondary but serious consequence of increasing
exhaust capacity is the resultant increase of air drafts towards the
cooking zones which act as cross currents impacting capture and
containment. One has to address ventilation on a holistic point of
view.
Latest hood designs incorporate a return air cavity at the face of
hood complete with adjustable diffusers and duct collar to allow
fresh (for temperate climates) or tempered (for tropical
climates) air supply to the kitchen. This fresh or tempered air
supply takes care first of all the air pressure balance by
replacing the air vented thru the exhaust. Although it does not
completely compensate the volume of air
loss, it does provide enough air
diffusion surrounding the cooking area creating optimum
air replacement and capture causing a laminar flow of
contaminated air and heat thru the hood and minimizing
unnecessary turbulence. By doing this the negative pressure
requirement is now more easily managed.
Increasing the exhaust capacity will also proportionately increase
your make up air volume, and by doing so will also increase your hot
or cold air tempering system and will also increase the fan
motor sizes which on the overall will be very expensive. Always
seek professional advice from relevant engineering trades
or from foodservice consultants for issues pertaining to
kitchen ventilation and equipment heat outputs.
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Creating
Forefronts in Foodservice Design
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