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AMOUNT OF MOISTURE PRODUCED INSIDE BATHROOM AND APPURTENANT CHANGING ROOM

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In recent years, the aspect and behavior inside a bathroom and an appurtenant changing room have been changing. With these changes, the thermal insulation quality of a dwelling has improved, so it seems that the amount of moisture generated in a dwelling has changed. In this study, amount of moisture produced in a bathroom and a changing room was surveyed in order to grasp the thermal and humid environment in bathroom and a changing room. From the result of the survey, it was found that the amount of moisture in bathing was bigger than before. It was considered that the amount of adhesion moisture was depended on the way of bathing, and the balance of exhausted moisture by ventilation and remaining moisture in the atmosphere was depended on of ventilation rate. The survey was conducted in two different size bathrooms (1200×1600, 1600×1600). Influence of a bathroom size was deliberated.
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AMOUNT OF MOISTURE PRODUCED INSIDE BATHROOM
AND APPURTENANT CHANGING ROOM
K. Yokoo1, S. Tanabe1, Y. Aizawa2, K. Inagaki2, D. Kawamata2, H. Amai1,
K. Watanabe1, and T. Nishimasu1
1Waseda University, Dept. of Architecture, Tokyo, Japan
2Tokyo Gas Co.Ltd.
ABSTRACT
In recent years, the aspect and behavior inside a bathroom and an appurtenant changing room have
been changing. With these changes, the thermal insulation quality of a dwelling has improved, so it
seems that the amount of moisture generated in a dwelling has changed. In this study, amount of
moisture produced in a bathroom and a changing room was surveyed in order to grasp the thermal and
humid environment in bathroom and a changing room. From the result of the survey, it was found that
the amount of moisture in bathing was bigger than before. It was considered that the amount of
adhesion moisture was depended on the way of bathing, and the balance of exhausted moisture by
ventilation and remaining moisture in the atmosphere was depended on of ventilation rate. The survey
was conducted in two different size bathrooms (1200×1600, 1600×1600). Influence of a bathroom size
was deliberated.
INTRODUCTION
In recent years, the humidity and thermal environment of the bathroom has changed dramatically with
the diversification of bathroom equipment, increasingly higher level of insulation, high airtight homes.
With the shifts in perspectives and objectives of bathing, bathing behavior has also changed (Such as
increase of bathing frequency and establishing of showering). However there are few researches of
moisture production inside a bathroom which depend on a modern Japanese life style. (Nagai et al.
2003, Ito et al. 2003, Ito et al. 2004, Otani et al. 2006) To exhaust the moisture produced inside a house
efficiently, appropriate ventilation plan, which includes an understanding of the source and the amount
of moisture production, is necessary. The objectives of this paper are to survey the humidity and
thermal environment of modern conditions of bathing and to examine the size of bathroom on humidity
and thermal environment and the moisture production.
METHOD OF EXPERIMENT
Summary of laboratory
Summary of laboratory is shown in Table 1. The experiment was performed in two of different size
bathrooms and changing rooms that are located in a controlled artificial climate room. The walls of the
unit type bathroom are composed of plastic boards, which do not absorb moisture, a section of empty
space, insulation and composite material. The ceiling and walls of the changing room are insulated and
the material of floor is wood. The dimensions of the T-1216 laboratory are width 1150mm, depth
1600mm, and height 2000mm and of the changing room are width 1200mm, depth 1200mm, height
2300mm. The dimensions of the Y-1616 are width 1600mm, depth 1600mm, and height 2100mm and
for the changing room are width 1600mm, depth 1600mm, height 2400mm. There are four vents in the
lower part of the folding door to the bathroom in T-1216 laboratory. And there are one vent in the lower
part of the sliding door to the bathroom in Y-1616. Both laboratories have a bathroom dryer on a ceiling
of bathroom.
Corresponding Author: Tel: + 03 5292 5083, Fax: + 03 5292 5084
E-mail address: yoko@tanabe.arch.waseda.ac.jp
Table 1 Summary of laboratory
T-1216 Y-1616
Volume of bathroom 3.6 [m3] 5.8 [m3]
Floor space of bathroom 0.8 [m2] 1.2 [m2]
Volume of changing room 3.3 [m3] 5.8 [m3]
High 119 [m3/h]33 [ACH] 130 [m3/h] 22 [ACH]
Ventilation rate Low 65 [m3/h] 18 [ACH] 95 [m3/h] 16 [ACH]
Measurement items and ventilation quantity
Schematic of test bathrooms and measurement positions is shown in Figure 1, and the measurement
items and methods are shown in Table 2. The vertical distribution of the temperature and humidity in
the upper and lower areas of both the bathroom and changing room were measured at 3 positions. The
temperature of the ceiling and each of the walls and the humidity below the ceiling of both the bathroom
and changing room were also measured. The temperature and humidity in a vent in the doors of the
bathroom was measured in assuming that the temperature and humidity of the air entering the
bathroom and the air leaving the changing room was same. The temperature and humidity of the air
leaving the bathroom was measured in the exhaust duct connected to the ventilation fan. During the
experiment, the windows were sealed to minimize the amount of air flowing in and out through any
openings besides exhaust duct and bents in the doors. The amount of air flow for the ventilation located
on the ceiling can be switched from 119 m3/h in high ventilation to 65 m3/h in low ventilation in T-1216
laboratory, and from 130 m3/h in high ventilation to 95 m3/h in low ventilation in Y-1616 laboratory.
These values were checked by exploratory experiment (Watanabe et al. 2006).
Table 2 Measurement items and methods
Contents Measurement points and remarks
Temperature distributions 3 points in both rooms.
Humidity distributions 3 points in both rooms
The point's data hit against hot wate r during bathing was deleted.
Surface temp. 4 points in bathroom and changing room . 1point on the ceiling
Temp. and humid. of exterior 1 point in artificial climate room
Temp. and humid. of inlet-outlet a ir 1 point in exhaust duct, 1 po int in a vent of bathroom door,
1 point in a vent of changing room door
Volume rate of supply water Setting flow meter at the header of boiler
Volume rate of exhaust water Measuring weight of tank filled with exhaust water
Moisture attached to wall Measuring weight of paper used for wiping water left on surface of wall
1600 1600
1600
1600
1200
1150
W
1
W
2
W
3
W
4
W
1
W
3
W
2
W
4
1600 1200
T-1216
Y-1616
Temp. and humid. of inlet-outlet air
Tem p . FL+0.1,0.6,1.1,1.7,Humid. T-1216:FL+0.1,0.6,1.7, Y-1616:FL+0.1,0.6,1.1,1.7
Temp. and humid. of exterior
Surface temp.
Temp.and humid. on ceiling
Figure 1 Schematics of test bathrooms and measurement positions
Computational method of the amount of moisture produced
The amount of moisture produced was calculated by summing up the amount of moisture that was
contained in air and was adhered to the wall. The amount of moisture adhered to the wall was wiped off
with kitchen papers and was measured by the weight change of the papers. The amount of moisture in
air was calculated by the amount of moisture that remained in the bathroom and exhausted by
ventilation. The amount of moisture exhausted by ventilation was calculated by amount of ventilation
and air temperature and humidity at supply and exhaust openings.
Method of experiment and experiment cases
The bathing participants were total of 14 healthy men in 20’s and each bathed under various cases as
shown in Table 3. After maintaining a fully steady condition previous to the experiment, the bathing
participants entered the bathroom and bathed. To prevent any differences by participant, instructions
on how to open/close the door and the use of bathroom equipment were explained to the participants.
Ventilation during bathing was set in three levels, High, Low and Off. In cases of High and Low
ventilation the strength of ventilation was kept same both during and after bathing. In the case of Off,
the fan was switched on to the High, immediate after moving out to a changing room. Despite the
strength of ventilation, the fan was on for 20 minutes after moving out to the changing room.
The time used to open and close the door was 8 seconds in standard, and set the four type of length (4,
8, 20, 40 seconds). Quantity of moisture moved into changing room was calculated by summing up the
amount of moisture that remained in the changing room and exhausted by ventilation.
Table 3 Experiment cases
Laboratory Bathing style Temp and humid of exterior Ventilation during bathing Length of opening a door [s]
2875% High, Low, Off 8
High, Off 4
2050% Low 8
High 4
Showering
1030% Low, Off 8
2875% High, Low, Off 8
High, Off 4
2050% Low 8
High, Off 4
T-1216
Bathing in
tub
1030% Low 8
High, Low 4, 8, 20, 40
Showering Off 8
High, Low 4, 8, 20, 40
Y-1616 Bathing in
tub
2050%
Off 8
Bathing style
As shown in Figure 2,3 the scheduling and two styles of bathing (showering and bathing in tub) were
decided by using the investigated summertime average (A society for the study of bathing culture,1999,
2000). During the experiment, participants were not allowed to change the flow rate and the
temperature of hot-water for shower. Since the relative humidity of the bathroom was below 90% after
the ventilation during 20 min, it was decided to enter the bathroom to measure the water adhered to the
ceiling, walls, and floor. For showering, body washing was performed in an upright standing position for
10 min. For bathing in the bath tub, the water in the tub was not reheated and the cover for the bath tub
was opened right after the experiment participant entered the bathroom. The participant was to run the
shower for 9 minutes and stay in the bath tub for 7 minutes. The participant was to wash in a seated
position and to rinse with a shower after leaving the bath tub. Then, participant closed the cover for the
bath tub. The water in the bath tub was drained after measuring the moisture attached to the bath tub.
RESULTS ANALYSIS AND DISCUSSION
Thermal environment and humidity in the bathroom and changing room
The results of the average of all points measured for the temperature and the humidity inside the
bathroom and changing room, in case of bathing in tub, are shown in Figure 4. The blue colored area in
the figures shows time period of showering. The red colored area shows time period of staying in the
changing room. During bathing, the relative humidity of the bathroom reached 100% right after opening
the cover for the bath tub and letting the shower run, regardless of the operation for the ventilation and
the condition of the exterior. After the bathing, relative humidity of changing room rose with the moving
of participant to the changing room in every case. The humidity of changing room increased the most in
Off and then following in Low and in High. Increase of temperature and humidity in a bathroom and
changing room was less quickly and declination was more quickly in Y-1616 than T-1216.
The temperature in the T-1216 bathroom of the cases of bathing in tub was 2°C higher in High, 8°C
higher in Low than Y-1616, and about the same in Off. And the temperature in the T-1216 bathroom of
the cases of showering was 7°C higher in Low than Y-1616, and about the same in High and Off. But
the increase of temperature in a changing room in the cases of T-1216 was greater than Y-1616.
Supplying hot water in tub
Enter changing room.
putting off clothes [1min]
Report [1min]
Showering [9min]
Bathing in tub [7min]
Showering [1min]
(1)
(2)
(3)
(4)
(5)
(6)
Wiping body, exit [1min]
Wiping body,
putting on clothes [3min]
Ventilation [20min]
Wiping water attached
on surface
(7)
(8)
(9)
(10)
Figure 3 Schedule for showering style
(1) (2) (3) (2) (4) (5)(2)(6)(7) (8)
0 1 2 11
12
19
20
21
22
25 42
[min]
(1) (2) (3) (2) (6)(7) (8)
0 1 2 12
13
14 17 34
[min]
Supplying hot water in tub
Enter changing room.
putting off clothes [1min]
Report [1min]
Showering [9min]
Bathing in tub [7min]
Showering [1min]
(1)
(2)
(3)
(4)
(5)
(6)
Wiping body, exit [1min]
Wiping body,
putting on clothes [3min]
Ventilation [20min]
Wiping water attached
on surface
(7)
(8)
(9)
(10)
Figure 2 Schedule for bathing in tub style
Quantity of moisture attached to surface
Measurement results for the quantity of moisture attached to each surface, in the cases of bathing in
tub, are shown in Figure 5. Comparing T-1216 with Y-1616, the amount of moisture attached to the
surfaces in T-1216 was greater than Y-1616. Because of the difference of floor material, there was
difference of amount of moisture attached to floor between T-1216 and Y-1616. So the result of
calculating of the amount of moisture attached to floor of Y-1616 supposed to consist of the same
material of T-1216 (the tint part of the figure), was that the amount of moisture attached to floor of
Y-1616 was increased to 200g more and greater than T-1216.
Measurement results for the sum of quantity of moisture attached to the surfaces, in two styles of
bathing, are shown in Figure 6.The amount of moisture attached to the surfaces of T-1216 were
450-680g, while Y-1616 were 200-430g. The amount of T-1216 was 250g greater than Y-1616.
Temp. of changing room
(T1216)
Humid. of changing room
(T1216)
Temp. of changing room
(Y1616)
20
25
30
35
40
Temperature [ ˚C ]
High
0
25
50
75
100
Relative
humidity [ % ]
Low
Off
0 10 20 30 40
Time [min.]
Humid. of bathroom (Y1616) Humid. of bathroom (T1216) Temp. of bathroom (Y1616) Temp. of bathroom (T1216)
Humid. of changing room
(Y1616)
Temp. of changing room
(T1216)
Humid. of changing room
(T1216)
Temp. of changing room
(Y1616)
20
25
30
35
40
Temperature [ ˚C ]
0
25
50
75
100
Relative
humidity [ % ]
0 10 20 30 40
Humid. of bathroom (Y1616) Humid. of bathroom (T1216) Temp. of bathroom (Y1616) Temp. of bathroom (T1216)
Humid. of changing room
(Y1616)
Temp. of changing room
(T1216)
Humid. of changing room
(T1216)
Temp. of changing room
(Y1616)
20
25
30
35
40
Temperature [ ˚C ]
0
25
50
75
100
Relative
humidity [ % ]
0 10 20 30 40
Humid. of bathroom (Y1616) Humid. of bathroom (T1216) Temp. of bathroom (Y1616) Temp. of bathroom (T1216)
Humid. of changing room
(Y1616)
Figure 4 Temperature and Humidity inside the bathroom and changing room
Time [min.]
Time [min.]
Quantity of moisture production during bathing
The calculated total quantity of moisture production and each value of moisture production by bathing
style, exterior conditions and ventilation conditions are shown in Figure 7. The quantity was 900-1300g
(the average was 1100g) regardless of the cases. It was greater than 403g which is a previous data
from literature (Nagai et al. 2003), because a previous data wasn’t calculated the amount of moisture
exhausted by ventilation. In Y-1616 the amount of moisture released through ventilation occupied 70%
of the quantity of moisture production, while it occupied 50% in T-1216. If the floor of Y-1616 is
supposed to consist of the same material of T-1216 (the amount of moisture attached to floor becomes
200g greater), the quantity of moisture production of Y-1616 is about the same amount of T-1216.
Remaining in ai
r
1500
1200
900
300
0
Amount of moisture
production [ g ]
600
TB YB TB TS
Y
STS
H L H L H L H L H L H L H L H L
10˚C 20˚C 28˚C10˚C20˚C 28 ˚C
Attached to surface Released through ventilation
Figure 7 The calculated total quantity of moisture production
High Low Off
Floo
r
Bath W1 W2 W3 W4 Ceilin
g
300
200
100
0
A
moun
t
o
f
mo
i
s
t
ure
attached to surface[ g ]
TB-HN=2TB-LN=1TB-ON=2
YB-HN=10YB-LN=6YB-ON=1
Fi
g
ure 5 Amount of moisture attached to each surface
Re
g
ion
Fi
g
ure 6 Amount of moisture attached to surface
High Low Off
TB YB TB TS YS TS
10˚C 20˚C 28˚C 10˚C 20˚C 28˚C
900
600
300
0
1200
Ex
p
eriment cases
A
moun
t
o
f
mo
i
s
t
ure
attached to surface[ g ]
TB:T-1216,Bathing in tub YB:Y-1616,Bathing in tub TS:T-1216.Showering
YS:
Y
-1616,Showerin
g
H:Hi
g
h L:Low O:Off
TB:T-1216,Bathing in tub YB:Y-1616,Bathing in tub TS:T-1216.Showering
YS:
Y
-1616,Showerin
g
H:Hi
g
h L:Low O:Off
Quantity of moisture moved into changing room
The calculated amount of moisture moved into changing room in the cases of Y-1616 was shown in
Figure 8. Amount of moisture moved into changing room was calculated by the sum of the amount of
moisture released through ventilation of changing room after leaving a bathroom and the amount of
moisture remaining in changing room air. The amount of moisture moved into the changing room was
20-50g. It was within 35-125g, the range of a previous simulated data (Otani et al.2006).The amount in
the bathing in tub style was more than in the showering style, especially in the case of 8 seconds used
to open and close the door. The length of the time used to open and close the door became longer, the
amount of moisture moved into changing room became greater.
CONCLUSION
The objective of this paper was to understand the thermal environment and the humidity around the
bathroom, in consideration of actual modern lifestyles. The influence of the size of bathroom and the
bathing style and the use of the ventilation to thermal environment and humidity around the bathroom
was considered. The results are follows,
1) During bathing, the relative humidity of the bathroom reached beyond 100% right after opening the
cover for the bath tub and letting the shower run. After the bathing, relative humidity of a changing
room rose with the moving of participant out to the changing room in every case. It seems that the
size of bathroom doesn’t influence much to the temperature in the bathroom. But the increase of
temperature in the changing room in the cases of T-1216 was greater than Y-1616.
2) The amount of moisture attached to the surfaces of T-1216 were 450-680g, Y-1616 were 200-430g.
Comparing T-1216 with Y-1616, the amount of moisture attached to the surfaces in T-1216 was
greater than Y-1616, because of the difference of surface material.
3) The quantity of moisture production during bathing was 900-1300g (the average was 1100g)
regardless of the cases. It was greater than 403g which is a previous data from literature. In Y-1616
the amount of moisture released through ventilation occupied 70% of the quantity of moisture
production, while it occupied 50% in T-1216.
4) The amount of moisture moved into changing room was 20-50g. It was within the range of a
previous data. As the length of the time used to open and close the door became longer, the
amount of moisture moved into changing room became greater.
REFERENCES
1. Nagai Y. “A Study on Movement of Moisture Generated in Bathroom ( part 1 ) Measurement of
Moisture Generation by Bathing and Drying Process of Bathroom” Proceedings of Annual
Meeting of AIJ, 2003, pp.413-414
2. Ito Y. “A Study on Movement of Moisture Generated in Bathroom ( part 2 ) Analysis on Drying
Process of Bathroom” Proceedings of Annual Meeting of AIJ, 2003, pp.415-416
3. Ito Y. “A Study on Movement of Moisture Generated in Bathroom ( part 3) A Relation between
30
A
moun
t
o
f
mo
i
s
t
ure move
d
into changing room [ g ]
60
45
0
Length of opening a door [s]
Figure 8 Amount of moisture moved into changing room
15
4 820 40
Bath-High Shower-High Bath-Low Shower-Low
Ventilation and Evaporation Rate in Drying Bathroom” Proceedings of Annual Meeting of AIJ,
2004, pp.435-436
4. Otani T. “A study on effect of water generation in bathroom Analysis on changes in temperature
and humidity of bathroom and moisture flux from bathroom to other rooms” Proceedings of
Annual Meeting of AIJ, 2006, pp.355-356
5. Watanabe K. “Basic Unit of Amount of Moisture Produced Inside a Bathroom and Appurtenant
Dressing Room” Proceedings of Healthy Buildings 2006, vol.4, p.305-308
6. A society for the Study of Bathing Culture (1999) “A study on the investigation of consciousness
and actual situation in bathing”
7. A society for the Study of Bathing Culture (2000) “Bathing conditions of the modern people, actual
condition survey in summer”
Article
Der Artikel gibt einen Überblick über Hintergründe und Ausblicke einer nachhaltigen Entwicklung als Leitbild im Bausektor. Im Fokus steht hierbei die Notwendigkeit der Anpassung bei der Übertragung bereits generierter Erfahrungswerte in andere Klimazonen und Kulturen. Gerade in diesem Sektor liegt enormes Potential in Bezug auf eine Lösung der globalen Probleme wie Klimaerwärmung und die Endlichkeit vieler Ressourcen. Erfahrungen mit analysierten Projekten zeigen jedoch, dass häufig Technologien nicht auf regionale Bedingungen angepasst werden, um schadensfreie und gesunde Gebäude zu erstellen.
A Study on Movement of Moisture Generated in Bathroom ( part 1 ) Measurement of Moisture Generation by Bathing and Drying Process of Bathroom
  • Y Nagai
Nagai Y. "A Study on Movement of Moisture Generated in Bathroom ( part 1 ) Measurement of Moisture Generation by Bathing and Drying Process of Bathroom" Proceedings of Annual Meeting of AIJ, 2003, pp.413-414
A Study on Movement of Moisture Generated in Bathroom ( part 2 ) Analysis on Drying Process of Bathroom
  • Y Ito
Ito Y. "A Study on Movement of Moisture Generated in Bathroom ( part 2 ) Analysis on Drying Process of Bathroom" Proceedings of Annual Meeting of AIJ, 2003, pp.415-416
A study on the investigation of consciousness and actual situation in bathing " 7. A society for the Study of Bathing conditions of the modern people, actual condition survey in summer
A society for the Study of Bathing Culture (1999) " A study on the investigation of consciousness and actual situation in bathing " 7. A society for the Study of Bathing Culture (2000) " Bathing conditions of the modern people, actual condition survey in summer "
A study on effect of water generation in bathroom Analysis on changes in temperature and humidity of bathroom and moisture flux from bathroom to other rooms
  • T Otani
Otani T. "A study on effect of water generation in bathroom Analysis on changes in temperature and humidity of bathroom and moisture flux from bathroom to other rooms" Proceedings of Annual Meeting of AIJ, 2006, pp.355-356
A Study on Movement of Moisture Generated in Bathroom ( part 3) A Relation between 30
  • Y Ito
Ito Y. "A Study on Movement of Moisture Generated in Bathroom ( part 3) A Relation between 30
Shower-High Bath-Low Shower-Low Ventilation and Evaporation Rate in Drying Bathroom
  • Bath-High
Bath-High Shower-High Bath-Low Shower-Low Ventilation and Evaporation Rate in Drying Bathroom" Proceedings of Annual Meeting of AIJ, 2004, pp.435-436