Healthy Buildings 217 Europe July 2-5, 217, Lublin, Poland Paper ID 95 ISBN: 978-83-7947-232-1 Verification of gymnasium designed by high thermal insulation considering elderly people in disaster Koki Kikuta 1,*, Hiroshi Kikuchi 2, Shiho Aoyagi 1, Hirofumi Hayama 1 1 Hokkaido University, Sapporo, Japan 2 Kona Sapporo Co., Ltd., Sapporo, Japan * Corresponding email: k-kikuta@eng.hokudai.ac.jp SUMMARY The aim of this study is to quantitatively clarify the effects of building envelope performance improvement of gymnasium designed by high thermal insulation that will contribute to the strengthening of disaster prevention. Gymnasium designed by high thermal insulation considering elderly people in a disaster was verified through a comparison with conventional gymnasiums. As a result, it was confirmed that gym H for high thermal insulation type designed by external insulation and SRC structure had the thermal insulation performance of more than twice of a present standard specification. Furthermore, it was calculated for the performance values of air leakage coefficient, air leakage exponent and effective leakage area by airtightness measurement. KEYWORDS Evacuation shelter, Room temperature, Airtightness measurement, ACH5 1 INTRODUCTION Immediately after the Great East Japan Earthquake, 622 school facilities, in particular, gymnasiums were performing the function as evacuation shelters. However, the problems such as ensuring of power and water, shortage of heating equipment, and so on occurred. On the other hand, as a measure against cold in Sapporo, Japan, it has been stockpiling a lot of sleeping bag, blanket, portable kerosene stove. Moreover, an approach to high thermal insulation for gymnasiums was shown in June 211, and it has actually been attempted from FY214. The aim of this study is to quantitatively clarify the effects of building envelope performance improvement of gymnasium designed by high thermal insulation that will contribute to the strengthening of disaster prevention. Gymnasium designed by high thermal insulation considering elderly people in a disaster is verified through a comparison with conventional gymnasiums. 2 OVERVIEW OF SCHOOL SUBJECT TO INVESTIGATION Table 1 lists overview of gymnasiums. Four gymnasiums of elementary school in Sapporo are subject to investigation. Gym H for high thermal insulation type was completed in March 214. Even if the heating at gymnasium is stopped by winter disaster, the target was set for ensuring minimum indoor environment with the only calorific value from evacuees. Concretely, it is
designed to keep room temperature more than 1 ºC during outside air temperature -1 ºC (inside-outside temperature difference more than 2 K). The calorific value from evacuees assumes about 35 kw ( 34.56 kw = 48 person 72 W/person). Solar radiation heat from window or heat from lighting and equipment contributing to the safety are not considered. Air changes per hour at the design target is expected to be.1 h -1. Gym S for standard type of subject to be compared was completed in March 212. Because the number of children is too large, total floor area is planned to be the widest. It has building envelope performance the same as a present standard specification. In addition, for the heating consumption rate of gymnasium among all school facilities, gym I for old standard type that is as low as 22 % and gym A for old standard type that is as high as 52 % are also subject to be compared. Although it is common in terms of warm air heating by city gas, it is different in terms of gym H and S of SRC structure in the 21s and gym I and A of steel structure in the 198s. Table 1. Overview of gymnasiums. Type High thermal insulation Standard Old standard Name Gym H Gym S Gym I Gym A Completed year 214 212 1987 1984 Total floor area 1,394 m 2 1,738 m 2 1,363 m 2 1,319 m 2 Structure SRC Steel Thermal Wall PF 6 mm XPS 3 mm 25 mm * Insulation spec. Roof PUF 12 mm 12 mm * 25 mm ** Window Double glazing Double glazing Single glazing spec. Investigation period (low-e Ar) (double) 7/2/214-7/17/214-1/13/212-1/1/212-3/2/215 3/12/215 5/1/213 5/1/213 * Foamed thermal insulating material, ** Cemented excelsior board 3 VERIFICATION OF THERMAL INSULATION PERFORMANCE Minimum room temperature in a severe winter season At school subject to investigation where thermal insulation performance is greatly different, minimum room temperature in a severe winter season is verified in order to compare how room temperature fell immediately after stopping heating. In the case of gym I and A for old standard type, room temperature fluctuation was very large according to intermittent heating regardless of weekdays and holidays. Room temperature remained at the high level compared to the heating temperature setting (18 ºC in gym I, 15 ºC gym A). After that, the service that gymnasium is open to the public was finished. Room temperature was rapidly dropped soon after stopping heating. A typical characteristic to be easily heated and cooled appeared. Minimum room temperature in a severe winter season of early February was recorded by 5 ºC in gym I and below the freezing point at early morning in gym A (Fig.1 (a)). In the case of gym H for high thermal insulation type and gym S for standard type, room temperature remained at the heating temperature setting around 15 ºC, and also its fluctuation range was small. Average inside-outside temperature difference on weekdays was 16.4 K in gym H and 15.1 K in gym S. However, there was no case that room temperature fell below 1 ºC in gym H (Fig.1 (b)).
3 Weekdays 3 Weekdays 2 2 Temperature ºC 1 Temperature ºC 1-1 -1-2 1/29 1/3 1/31 2/1 2/2 2/3 2/4-2 2/1 2/2 2/3 2/4 2/5 2/6 2/7 Gym I (room) Gym A (room) Gym H (room) Gym S (room) Gym I (outside air) Gym A (outside air) (a) Gym H (outside air) Gym S (outside air) (b) Figure 1. Room temperature fluctuation in severe winter. a) Gym I and A, b) Gym H and S Room temperature fluctuation rate Room temperature fluctuation rate from 22: to 6: the next morning after the service that gymnasium is open to the public is verified in order to compare thermal insulation performance at school subject to investigation. This rate is the value dividing overall heat transmission coefficient by heat capacity. In general, it is considered desirable that this rate is as small as possible, because overall heat transmission coefficient is small when thermal insulation performance is high, and also heat capacity is large when heat storage performance is high. In gym H designed by external insulation and SRC structure, although the immediate effect of starting heating is inferior, both thermal insulation performance and heat storage performance are superior. Room temperature fluctuation rate while stopping heating equipment and ventilation equipment was 3 1-6. On the other hand, this rate in gym A was more than five times as large as that in gym H. In addition, overall heat transmission coefficient and heat capacity cannot be identified. However, it was confirmed that gym H had the thermal insulation performance of more than twice of a present standard specification in comparison with gym S (Fig. 2). 1 y=e -.3t.9 y=e -.7t y (-).8 y=e -.11t.7 y=e -.16t Figure 2. Room temperature fluctuation rate..6 7,2 14,4 21,6 28,8 Elapsed time (22:-6: the next morning) t (s) Gym H (Feb 5-6 215) Gym S (Feb 5-6 215) Gym I (Feb 2-3 212) Gym A (Feb 2-3 212) Design target The design target that inside-outside temperature difference more than 2 K was kept by only human body heat is verified. Therefore, it is necessary to evacuate many people or to input heat quantity corresponding to human body heat to a gymnasium. Then, human body heat is simulated with kerosene stoves based on grasping the effect of heating by these that are assumed to be used at an evacuation shelter. A simple method of evaluating the design target is attempted through the relationship between calorific value and inside-outside temperature difference.
For three days of January 9, 13 and 15, 215 in winter vacation, while changing the number of kerosene stoves to be used (maximum calorific value 6.59 kw/unit) to 6, 2 and 8 units, the stoves were burning for seven hours from 9:3 to 16:3. Room temperature gently rose according to the number to be used and was stable after that (Fig. 3 (a)). In particular, it became more than 15 ºC with 8 units. At that time, CO concentration and CO2 concentration were separately measured in consideration of safety. However, incomplete combustion did not occur, and 2.4 ppm and 3,69 ppm were recorded at 16:3. As a result, inside-outside temperature difference based on human body heat ensured by calorific value 34.56 kw from evacuees was 19.1 K, so it can be determined that the design target was almost achieved (Fig. 3 (b)). Temperature ºC 2 15 1 5 9:3 Room Outside air 1: 1:3 11: 11:3 12: 12:3 13: 13:3 Using the average values 14: 6 units (1/9) 2 units (1/13) 8 units (1/15) 6 units (1/9) 2 units (1/13) 8 units (1/15) (a) (b) Figure 3. Results on design target. a) Room temperature fluctuation during heating with stove, b) Relationship between calorific value and inside-outside temperature difference 4 VERIFICATION OF AIRTIGHTNESS PERFORMANCE 14:3 15: 15:3 16: 16:3 34.56 kw 1 2 3 4 Calorific value kw Overview of airtightness measurement Each performance value is verified by airtightness measurement in gymnasiums specified as an evacuation shelter. In that case, maximum four air blowers are simultaneously controlled on an airtightness measurement device, which is devised so that it can be measured in large-scale space. Two straightening cylinders with the pipe diameter of 2 mmφ are used in gym H and S of SRC structure, and four straightening cylinders with the pipe diameter of 154 mmφ are used in gym I and A of steel structure. The grating through the underfloor, the door connected to the school, and so on are sealed up (Fig. 4). Inside-outside temperature difference K 2 15 1 5 19.1 K Gym H Gym I Figure 4. Airtightness measurement of gym H and I. Effective leakage area and ACH5 When airtightness measurement based on reduced pressure method was performed, the relation of pressure difference and volume flow rate was plotted (Fig. 5). Although the number of plots
was different, it was calculated for air leakage coefficient, air leakage exponent and effective leakage area using these measured results. Table 2 lists results on airtightness measurement. If gym A for old standard type where air leakage coefficient was the highest was used as the base, it decreased by 18 % in gym I for old standard type. Whereas, it decreased by 81 % in gym I for standard type and 86 % in gym H for high thermal insulation type. Air leakage exponent was included in the range of 1 to 2. It was as small as around 1.25 in gym H and I, so it can be determined that each air leakage was extremely narrow compared to gym I and A. Furthermore, as a result of the calculated effective leakage area, it was 85 cm 2 in gym H and 1,14 cm 2 in gym I, which is equivalent to about one-fifth and one-quarter of gym A where it was the largest. Therefore, since the performance value was almost same in gym H and S where thermal insulation performance was different, it was considered that the difference of airtight performance was greatly influenced by the differences such as mainly structure type or window sash type. On the other hand, air changes per hour at 5 Pa (ACH5) was very small, about.4 h -1 in gym H and S. In contrast, it was very large, about.9 h -1 in gym I and about 1.5 h -1 in gym A. 1, Volume flow rate m 3 /h 1, 1 1 1 Pressure difference Pa Gym H Gym S Gym I Gym A Figure 5. Relation of pressure difference and volume flow rate. Table 2. Results on airtightness measurement. Type High thermal insulation Standard Old standard Name Gym H Gym S Gym I Gym A Measurement date 1/23/214 8/8/214 2/2/212 2/27/212 Room temp. ºC 17.8 25.7 13. 12.6 Outside air temp. ºC 9.1 26.5-1.4-4.1 Wind velocity m/s 1. 2.1 3.4 3.9 Air leakage coefficient m 3 /(h Pa 1/n ) 176. 243.7 1,5.5 1,288.4 Air leakage exponent 1.22 1.26 1.7 1.54 Effective leakage area cm 2 85 1,14 2,886 4,66 ACH5 h -1.41.42.9 1.52 Ventilation rate Assuming that the gaps obtained by airtight measurement are uniformly distributed, the estimation of ventilation rate (leakage rate) using wind force and temperature difference as driving force was attempted. It was simply assumed that wind direction was perpendicular to the long side direction, wind pressure coefficients were +.6 on the windward side and -.4 on the leeward side, and the gaps were only in the long side direction. The windward and leeward side are divided into 2 at.5 m intervals in the up and down direction. The convergence calculation with room pressure as a variable is performed in order to determine ventilation rate by the influence of the gaps. By the way, in the case of wind velocity more than 4 m/s, the air
flowed in only through the windward side gaps and flowed out only through the leeward side gaps. As a result, ventilation rate was about 7-3, m 3 /h in gym H and about 2,6-1,6 m 3 /h in gym I. In reference to this rate, less than 3 m/s in gym I was almost equal to that of 1 m/s in gym H (Fig. 6). Based on the estimated ventilation rate, it was confirmed that the calculated infiltration heat loss under inside-outside temperature difference 2 K was 5.5-22.1 kw in gym H. Volume flow rate m 3 /h 12, 1, 8, 6, 4, 2, Room temp. 1 ºC Outside air temp.: -1 ºC Wind pressure coefficient (windward side): +.6 Wind pressure coefficient (leeward side): -.4 3 25 2 15 1 5 Infiltration heat loss kw 1 2 3 4 5 6 7 8 9 1 Wind velocity m/s Gym H Gym I Gym H Figure 6. Volume flow rate and infiltration heat loss. 5 CONCLUSIONS 1) There was no case that room temperature fell below 1 ºC in gym H for high thermal insulation type designed by external insulation and SRC structure. Gym H had the superior temperature characteristics of minimum room temperature and room temperature fluctuation rate compared to gym I and A for old standard type. It was confirmed that gym H had the thermal insulation performance of more than twice of a present standard specification. 2) Inside-outside temperature difference based on human body heat ensured by calorific value 34.56 kw from evacuees in gym H was 19.1 K, it can be determined that the design target was almost achieved. 3) The performance values of air leakage coefficient, air leakage exponent and effective leakage area were verified by airtightness measurement. It was considered that the difference of airtight performance was greatly influenced by the differences such as mainly structure type or window sash type. 4) Equivalent leakage area was 85 cm 2, and also ACH5 was.41 h -1 in gym H. It was confirmed that infiltration heat loss was 5.5-22.1 kw under inside-outside temperature difference 2 K and wind velocity -1 m/s. 6 REFERENCES ISO 9972: 215. Thermal performance of buildings - Determination of air permeability of buildings - Fan pressurization method JIS A 221: 23. Test method for performance of building airtightness by fan pressurization