Thermal Comfort and Indoor Air Quality Evaluation of Hospital Patient Ward in Malaysia

Transcription

1 Thermal Comfort and Indoor Air Quality Evaluation of Hospital Patient Ward in Malaysia F. AZIZPOUR, S. MOGHIMI, E. SALLEH, S.MAT, C.H.LIM, K. SOPIAN Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor. MALAYSIA. (Tell: , Abstract: - Hospital is one of the most critical buildings in indoor air quality (IAQ) and thermal comfort demand, since the proper indoor environment may effects on health and well-being of both nurse and patient. This study aims to evaluate the indoor air quality and thermal comfort of the patient ward in one of Malaysian hospitals. Indoor air quality and thermal comfort variables measured were temperature, air velocity, relative humidity, CO2, CO, Total Volitile Organic Components (TVOC), Formaldehyde and Respirable particles compared to global and Malaysian guidelines. Results showed however thermal comfort of the hospital patient ward was in the comfort range, some indoor air pollutant (chemical) such as CO2 and Formaldehyde exceed the threshold. This finding illustrates the hospital immediate demand of increasing the ventilation rate and fresh air to improve indoor air condition. Key-Words: Thermal comfort; Indoor air quality; Patient ward; hospital; Standards 1 Introduction Energy crisis in 1970s caused the engineers and building manager find ways to make the building more efficient. One of those ways was sealing up the building and less ventilation rate to reduce energy consumption [1] This strategy has led the building to have poor indoor air quality [2]. On the other hand, study shows good indoor air quality and thermal comfort enhances occupant health, comfort and workplace productivity which lead to less absenteeism [3] [4]. The hospital is one of the most critical places since the patients are more sensitive than healthy people. Furthermore, based on studies a proper indoor air condition may effect on their well being and reduce their length of stay in hospitals [5]. This current study was designed to investigate the indoor air condition of a patient ward in a Malaysian hospital by comparison to ASHRAE (American Society of Heating, Refrigerating and Air conditioning Engineers) as well as a Malaysian guildline [6] [7]. The main objectives of this study are as follows: To evaluate thermal comfort of patient ward based on Fanger model. To evaluate the indoor air quality (Chemical pollutant). 2 Methodologies 2.1 Field study description UKMMC (Universiti Kembangsaan Malaysia Medical Centre) is a typical large scale hospital which was selected as a case study of this paper. UKMMC is a teaching hospital with m 2 built up area including three blocks namely teaching,clinical and residential block. Figure 1 shows a general view of UKMMC [8] [9]. ISBN:

2 Figure 1: General view of UKMMC [8] This study was carried out in one of patient wards located in clinical block, 6 th floor. Table 1shows some specification of the patient ward (Ward 6J). Table 1: general specification of ward 6J Area (m 2 ) 923 Capacity (bed) 26 Height (m) 4.60 Orientation North Ext wall area (m) 283 Ext opening area (m) Indoor Air Quality (IAQ) To evaluate the indoor air quality three apparatuses were used as follows: AirFlow (TSI) to measure CO2,CO,TVOC (Total Volatile Organic Components) MultiRAE to measure Formaldehyde Dustrak to measure Respirble particles Figure 3 illustrates the IAQ apparatus used to measure indoor air chemical pollutant of ward 6J in December Figure 3: Indoor Air Quality equipments 2.2 Thermal comfort To measure the thermal comfort variable in this study, Thermal Comfort was used. This equipment can measure Ambient Temperature (T a ), Global Temperature (T g ), Air Velocity (V), Relative Humidity (RH), Noise and LUX level simultaneously [10]. Figure 2 shows the Thermal Comfort equipment. The data collection was in February 2012 throughout 24 hours continual. 3 3 Results and Discussion 3.1 Thermal comfort Thermal comfort of the hospital patient ward was evaluated based on Fanger model.figure 4 illustrated the operative temperature over 24 hours and it compares to ASHRAE limit as well as Malaysian guideline (DOSH). As Figure 4 shows however temperature at all the time is within the ASHRAE limit except at morning(8 am to 10 am), based on Malaysian guideline, operative temperature is higher than recommendation limit. Figure 5 shows the relative humidity level over 24 hours and standard limits. According this graph the value of RH at patient ward are within both ASHARE and Malaysian guideline at all the time [6] [7]. Figure 2: Thermal comfort measuring equipment ISBN:

3 Figure 7 shows the Predicted Mean Vote (PMV) against Predicted People Dissatisfied (PPD). This graph demonstrates that the thermal condition of the case study is between 0 and 1 in seven-point ASHRAE where 0 is representative of neutral and 1 is slightly warm [11]. The percentage of people dissatisfied was predicted less than 20%. Figure 4: Operative temperature over 24hours Figure 5: Relative Humidity over 24 hours In this study thermal comfort was evaluated according Fanger model. Figure 6 illustrates the predicted mean vote in 24 hours based on measured environmental factor (dry temperature, global temperature, air velocity and relative humidity) and estimated personal factors ( clothing insulation value and metabolic rate). As Figure 6 shows the PMV remain within comfortable range in all 24 hours. 3.2 Indoor Air Quality (IAQ) To evaluate the indoor air quality of patient ward three mentioned equipments were used. The occupants were divided into 4 groups since there were different time of exposure between groups. The chemical contaminants were calculated based on Time Weight Average (TWA) then compared to the Malaysian guideline [7]. Furthermore, the CO2 level fluctuates in a day due to its decency to the number of people who are in a same place.. The evaluation of nurses' exposure to CO2 was according their working shifts since the number of occupants is different in visiting hour, day time and night time in a patient ward. Shift 1 is 7am to 3pm and shift 2 and 3 are 3pm to 11pm and 11pm to 7am, respectively. Table 2 illustrates the calculated variable based on exposure time. The second column shows the acceptable limit based on Malaysian guideline. According Table 2 CO and TVOC are in safe condition for all groups with different time of exposure. Figure 6:Predicted Mean Vote over 24 hours Figure 7: PMV against PPD ISBN:

4 Table 2: Indoor Air Quality (IAQ) variables in patient ward of UKMMC Indoor Air Contaminant Acceptable Limit TWA (8 Hour Base) Hourly Average UKMMC (Ward 6j) Nurse Doctor Visitor Patient Exposure Time (Hour) Chemical Contaminant 1 Carbon Monoxide (ppm) Formaldehyde (ppm) Respirable Particles (mg/m 3 ) Total Volatile Organic Compounds (TVOC) (ppm) Ventilation Performance Indicator 5 Carbon Dioxide (ppm) C 1000 Shift Shift Shift The level of Formaldehyde for nurses with 8 hours exposure and patients with at least 24 hours of exposure exceed the limit and need to be considered by hospital managers. Respirable particles however for nurses, doctors and visitors are within the limit, for patients almost cross the threshold due to their long time exposure. The CO 2 level for all groups in all the time exceed the limit except for nurses in shift 1 which is nearly cross the threshold line. 4 Conclusion The application of thermal comfort and indoor air quality audit of patient ward demonstrates the the result and recommendation. These recommendations are useful to the hospital owner and facility managers as they can plan their remedial measures such as increasing the ventilation rate. References: [1]WHO. Air Quality guidelines for Europe, second edition, WHO regional Publications,Europian series, No.91,(2000) [2] Syazwan Aizat I, Juliana J, Norhafizalina O, Azman Z. A, Khamaruzaman J. Indoor Air Quality and Sick Building Syndrome in Malaysian Buildings- Global Journal of Health Science, Volume 1, No. 2, 2009, Pages [3] Olesen, B. W. "International standards and ergonomics of the thermal environment." Journal of applied ergonomic Volume 26, Issue 4, August 1995, Pages [4] Ruey-Lung Hwanga, Tzu-Ping Linb, Ming-Jen Chengc, Jui-Hung Chiena-patient thermal comfort for hospital environment in Taiwan-Building and Environment 42 (2007) [5] Roberto z.freire, Gustavo H. C. Oliveira, Nathan Mendes Cheng, Jui-Hung Chien. Predictive controllers for thermal comfort optimization and energy saving. Energy and Buildings, Volume 40, Issue 7, 2008, Pages ISBN:

5 [6] ASHRAE. ASHRAE Standard 55: Thermal environmental conditions for human occupancy. American Society of Heating, Refrigerating and Airconditioning Engineers (2004). [7] Industry code of practice on indoor air quality, department of occupational safty anf health (DOSH), ministry of human resources, Malaysia(2012) [8] ( [9] F. Azizpour, S. Moghimi, C. Lim, S. Mat, E. Salleh, and K. Sopian, "A thermal comfort investigation of a faciliy department of a hospital in hot-humid climate: correlation between subjective and objective measurment," indoor and built environment, DOI: /142036X ( 2012). [10] Fatemeh Azizpour, S. Moghimi, C. h. Lim, S. Mat, A. Zaharim, K. Sopian. Thermal comfort assessment in large scale hospital: case study in Malaysia. Proceeding GEMESED'11 Proceedings of the 4th WSEAS international conference on Energy and development - environment - biomedicine (2011) [11] F. Azizpour, S. Moghimi, S. Mat, C. Lim, and K. Sopian, "A thermal comfort evaluation based on different occupancy levels in hospitals in a hot-humid region," presented at the Advances in Environment, Biotechnology and Biomedicine, Enagrobio, ISBN: