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© System Sensor 2008 I56-2634-004EN
Pittway Tecnologica S.r.l, Via Caboto 19/3, 34147 Trieste, Italy
DEUTSCH
ENGLISH
4.2: Cold Stores
Cold stores are similar to the freezer rooms with one major difference,
the temperature. The temperature in a cold store is a lot less than a
freezer and is typically just at or above 0°C.
The pipes should be kept out of the immediate airflow from a chiller unit,
if used, as its air is often significantly colder than the room itself in order
to maintain the correct temperature.
In a cold room application it is not usually necessary to use a heater
element but only a water trap to remove condensation.
4.3: High buildings
Typical examples: Atria; Cathedrals
When designing a system to fit in a very large and high room such as
an atrium or high level warehouse, it is important to consider the
various possibilities. A simple atrium design is shown below, utilising
two pipes. The smoke cloud is shown as an example of how a
stratification layer prevents the pipes at the top of the building from
detecting smoke particles. The height at which the smoke forms a layer
varies depending on temperature and therefore a vertical sampling
pipe is used to cover this. There may be no stratification layer at all if the
air in the room is at a particular temperature, especially if smoke
ventilation is needed.
Figure 4.3: Typical Atrium Example
Sampling Pipes
Sampling Holes
Aspirating
Detector
Smoke Stratification Layer
Figure 4.4.2: High Roof Example 2
Pipes Running Parallel to the Roofline
Max.
10m
Max.
10m
Pipes Run the Length of the Building (Parallel to the Roofline)
Aspirating Detectors
Figure 4.4.1: High Roof Example 1
Pipes Running Across the Width of the Roofline
Aspirating
Detector
Maximum 10m Between
Pipes at the Roof
Pipes Run the Width of the Building (across the Roofline)
The second alternative shows the pipes running in parallel along the
roof. Again to comply with UK requirements the pipes should be a
maximum distance of 10m apart, sample holes in each pipe will be 10m
from each other and the pipe serving the apex should not be further
than 600mm from the top of the roof.
4.5: Warehouses
Warehouses can be considered to be similar to supermarkets except
the same problems that can occur with high buildings need to be taken
into account as well. Vertical sampling points may be needed and the
pipe lengths should be considered carefully to ensure reasonable
response times.
4.4: Supermarkets and Storage Areas
Supermarkets and storage areas require a high level of protection due
to the possible number of people using the space at certain times of the
day and/or due to the value of the goods present.
There are two ways of applying the pipe network. The exact structure
of the roof is likely to determine the better or most appropriate solution.
The pictures below assume a simple room layout.
In one alternative the pipes will follow the contour of the roof. To comply
with UK code of practice BS5839:1, pipes will be placed at a maximum
distance of 10m from each other and sampling holes will also be sited
at a maximum of 10m from each other, with the hole serving the apex
no more than 600mm away from the roof.
