POL. INDUSTRIAL EURÓPOLIS C/Copenhague No.12 Of Las Rozas (Madrid)

Transcription

1 POL. INDUSTRIAL EURÓPOLIS C/Copenhague No.12 Of Las Rozas (Madrid) AEROSOLS PRODUCTION REPORT Nº Prepared by : Marcelino Pacheco Saelices Interior Air quality Department 3rd March 2008 E?F?Q?M C/ Trespaderne, MADRID Tel: Fax: Key Member of the European Foundation for Quality Management Entidad Colaboradora de la Administración en Materia de Medio Ambiente

2 CONTENTS 1 AIM SCOPE BACKGROUND INFORMATION ASSESSMENT OF THE INSTALLATIONS AIR VELOCITY CONCLUSION...10 Page 2 of 10

3 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 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. Page 3 of 10

4 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 : 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. Page 4 of 10

5 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. Page 5 of 10

6 4 ASSESSMENT OF THE INSTALLATIONS Evaporative cooler by contact Breezair Series TBA General view of the equipment completely closed MODEL TBA 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. Page 6 of 10

7 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. Page 7 of 10

8 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. Page 8 of 10

9 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: VALUEOF REFERENCE: Measurement of the velocity in 6 points in the aspiration side of the equipment. 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 m/s IN ORDER Evaporative coolers ICON EXH 210 Velocity m/s IN ORDER Velocity m/s IN ORDER Velocity 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) Page 9 of 10

10 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 (<3m/s) recommended by ASHRAE. Evaporative cooler Breezair Series EA: An evaporative cooling by contact 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 it does not produce visible water drops entrainment, nevertheless, it must be ensured that the pad is maintained in optimum condition otherwise, there could be some occasional residual entrainment, even though the drops would be very large and visible. But under no circumstances it would produce inhaleable drops. (<4 microns) It has been verified that it complies with the maximum values of air velocity (<3m/s) recommended by ASHRAE. Evaporative cooler Breezair Series EXH 210: An evaporative cooling by contact equipment that does not produce aerosols and therefore does not fall within the scope of Royal Decree 865/2003 and the Technical Guide for the prevention and control of Legionellosis in installations. It has been verified that under normal operating conditions, the pads get wet but it does not produce visible water drops entrainment. It has been verified that it complies with the maximum values of air velocity (<3m/s) recommended by ASHRAE on the different fan settings. Madrid, 3rd March 2008 Page 10 of 10