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Key Member of the European Foundation for Quality Management
Entidad Colaboradora de la Administración en Materia de Medio
Ambiente
E?F?Q?M C/ Trespaderne, 29 28042 MADRID Tel: 913138104 Fax:
913138091
Prepared by :
Marcelino Pacheco Saelices Interior Air quality Department
3rd March 2008
SSEEEELLEEYY IINNTTEERRNNAATTIIOONNAALL IIBBÉÉRRIICCAA POL.
INDUSTRIAL EURÓPOLIS
C/Copenhague No.12 Of.214 28232 Las Rozas (Madrid)
ASSESSMENT REPORT ON EVAPORATIVE COOLERS AEROSOLS
PRODUCTION
REPORT Nº 113835
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Report Nº: 113865
SEELEY INTERNATIONAL IBÉRICA
ASSESSMENT REPORT ON EVAPORATIVE COOLERS AEROSOLS PRODUCTION psw
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CONTENTS
1
AIM..........................................................................................................................................................................3
2
SCOPE....................................................................................................................................................................3
3 BACKGROUND INFORMATION
................................................................................................................4
4 ASSESSMENT OF THE INSTALLATIONS
..............................................................................................6
5 AIR
VELOCITY..................................................................................................................................................9
6 CONCLUSION
...................................................................................................................................................10
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Report Nº: 113865
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1 AIM The aim of this report is to present the results of a
field study carried out by SGS in a dwelling located in Villanueva
de la Cañada (Madrid) for the Model ICON EXH 210 and in Xátiva
(Valencia) for the models TBA and EA The aim of the study is to
assess the possible production of aerosols in three different
models of evaporative coolers.
Evaporative coolers Breezair Series TBA
Evaporative coolers Breezair Series EA
Evaporative cooler by contact ICON EXH 210
2 SCOPE This work includes the following:
? Review “in situ” of the characteristics of the different
evaporative cooling equipments in order to check the possible
production of aerosols.
? Review at the office of the technical documentation and its
associated reports.
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Report Nº: 113865
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3 BACKGROUND INFORMATION ROYAL DECREE 865/2003, dated 4th July,
which establishes the health and sanitary criteria for the
prevention and control of legionella disease, states in its article
2
Article 2. Scope of the law 1. The measures contained in this
Royal Decree shall apply to installations that use water for their
operation, producing aerosols…
Later on, it makes a classification of the installations that
present a higher or lower probability of proliferation and
dispersion of aerosols and among those specifies the following:
2.o Installations with less probability of proliferation and
dispersion of Legionella: b) Evaporative cooling equipment that
spray water, not included in point 2.1
The Technical Guide produced by the Ministry of Health for the
prevention and control of Legionellosis in installations, talks
about evaporative coolers as equipments that are not designed to
produce a spraying of water in any point of its system and
therefore their risk of transmitting Legionella is practically nil.
The temperatures reached by the water are usually low as the
renewal of the reservoir is high, except when the equipment has
been off for long periods and particularly when exposed directly to
sunlight. On the other hand, undoubtedly, these equipments put in
contact a wet surface with the current of air introduced directly
in interior spaces, therefore their maintenance has to be very
strict to avoid the possible proliferation of fungi and bacteria,
but it is very unlikely that they could become a focus of
Legionella. According to ASHRAE Guide 12-2000: Evaporative cooling
equipments are subdivided in equipments based on water spray and
equipment based on cooling by contact. Based on this double
classification and acknowledging that the operation principles and
the risks of transmitting Legionellosis are completely different
for each one of these two types of equipment, the Royal Decree 865
includes the remark “that spray water” to classify them as
dangerous or non dangerous installations. It is obvious that if
there was not acknowledgment of a difference it would only make a
generic reference to evaporative cooling equipment, as it does with
other installations.
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Report Nº: 113865
SEELEY INTERNATIONAL IBÉRICA
ASSESSMENT REPORT ON EVAPORATIVE COOLERS AEROSOLS PRODUCTION psw
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The schematic principle of the two types of equipment is as
follows:
SPRAYING CONTACT
This type of equipment has a pump, pipes and a set of sprayers
by means of which pressurized water is distributed as aerosols.
In this type of equipment there is no spraying therefore there
is no production of aerosols, the water enters the air in its
vapour phase.
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Report Nº: 113865
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ASSESSMENT REPORT ON EVAPORATIVE COOLERS AEROSOLS PRODUCTION psw
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4 ASSESSMENT OF THE INSTALLATIONS
MODEL TBA
Evaporative cooler by contact Breezair Series TBA
General view of the equipment completely
closed
One of the lateral panels was removed to see the operation of
the equipment.
Details of the water discharge. As shown, the water falls by
gravity, it is not sprayed.
Because of the geometry of the equipment, when the water falls,
it
disperses and spreads on the pad. The photograph shows the
equipment open.
Internal view of the equipment in operation :
The pad is wet but the water is kept in it. It
does not produce the entrainment of drops.
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Report Nº: 113865
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MODEL EA
Evaporative coolers by contact Breezair Series EA
General view
The principle of operation is by discharging water by gravity.
The equipment does not produce
aerosols as part of its normal operation.
View of the discharge system.
The pads must be in very good conditions otherwise loose parts
of the pad could cause a
slight entrainment of drops.
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Report Nº: 113865
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ICON MODEL
Evaporative coolers by contact ICON EXH 210
General view of the equipment completely closed
Details of the water discharge. As shown, the water falls by
gravity, it is not sprayed
Internal view of the equipment in operation :
The pad is wet but the water is kept within it. It does not
produce entrainment of drops.
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5 AIR VELOCITY The only possibility of entrainment of drops in
an evaporative cooler would be by the pushing of air in accordance
with the principles of pneumatic transport, in order for this to
occur, according to ASHRAE*, a relatively high air flow velocity is
needed, normally over 3m/s. In order to check the correct
functioning of the equipment, measurements of the air flow velocity
were carried out: TEST: Measurement of the velocity in 6 points in
the aspiration side of the
equipment. VALUEOF REFERENCE: According to ASHRAE maximum air
flow velocity: 3 m/s
Equipment Point of measurement **Measured Air Flow Velocity
Evaluation
Evaporative coolers Breezair Series TBA
2.43 m/s IN ORDER
Evaporative coolers Breezair Series EA
1.15 m/s IN ORDER
Velocity 1 0.29 m/s IN ORDER
Velocity 2 0.71 m/s IN ORDER
Velocity 3 0.27 m/s IN ORDER
Evaporative
coolers ICON EXH 210
Velocity 4 1.49 m/s IN ORDER
By design, these equipments operate with air flow velocities
relatively low as a condition to ensure a correct evaporation of
the water and therefore an adequate equipment performance. *ASHRAE:
American Society of Heating Refrigeration & Air Conditioning
Engineers ** Corresponds to the maximum speed setting of the fan
(the normal operation mode is at medium speed)
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Report Nº: 113865
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6 CONCLUSION Evaporative cooler Breezair Series TBA: An
evaporative by contact cooling equipment that does not produce
aerosols and therefore does not fall within the scope of Royal
Decree 865/2003 and Decree 173/2000. It has been verified that
under normal operating conditions, the pads get wet but there is no
visible water drops entrainment. It has been verified that it
complies with the maximum values of air velocity (