ASHRAE AB-10-017-2010 Combined Effects of Noise and Temperature on Human Comfort and Performance.pdf

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1、522 2010 ASHRAEThis paper is based on findings resulting from ASHRAE Research Project RP-1128.ABSTRACT This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14

2、 males) were exposed to all combinations of five thermal conditions (PMV +1 79.6F:26.4C, PMV +0.5 75.8F:24.3C, PMV 0 72.1F:22.3C, PMV -0.5 68.3F:20.2C, and PMV -1 64.6F:18.1C), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise fr

3、om building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant Survey Questionnaire, and then completed typing and number-checking tasks. There were no statistically significant effects

4、 of thermal condition, RC level, or sound quality on performance of the typing or number-checking tasks. Statistical analyses showed that thermal comfort was affected by RC noise level, while ratings of build-ing or office noise were not affected by the ambient tempera-ture. There were also differen

5、ces in the way males and females experienced the thermal and acoustical environments. Females rated lower temperatures colder than males, and higher temperatures more pleasant than males: thermal comfort composite ratings from males and females converged at about 72F (22C). INTRODUCTIONMost of our t

6、ime is spent inside buildings of one type or another, be they residential, commercial or industrial structures. The indoor environments in all these spaces will influence occu-pant health, comfort and productivity. Effective design and operation of buildings to support human activity requires under-

7、standing of the relationships between indoor environment parameters and human perception and performance.Numerous investigators working in a variety of contexts and industries have examined relationships between satisfac-tion and performance, and single indoor environmental parameters (e.g., acousti

8、cs, thermal comfort, ventilation, and lighting). In general, this work has established that poor light-ing, noisy work areas, and/or excessively warm or cold temperatures, can and will compromise productivity and satis-faction compared to more comfortable services and facilities (e.g., Banbury Bradl

9、ey 2003; Braeger Clausen et al. 1993; Fanger 1973; Fanger et al. 1980, 1989; Hancock Holmberg et al. 1993; Jones Kok et al. 1982; Kryter 1985; Kyria-kides Landstrm et al. 1991, 2002; Lewis et al. 1983; Leventhall et al. 2003; Lundquist et al. 2000; Meese et al. 1982, 1984; Muzammil Pellerin Persson

10、Waye et al. 2001; Persson Waye et al. 1997; Rea 1986; Rohles 1973; Rohles Saeki et al. 2004; Santos Shitzer et al. 1978; Veitch Wyon 1974; Wyon Wyon et al. 1972, 1979, 1975, 1978, 1982).Design recommendations based on these findings have been promulgated by the relevant professional societies (e.g.,

11、 ASHRAE 1999, 2004, 2005, 2007; CIE 1986, 1995; IESNA 2000). Because no environment will satisfy everyone, the primary focus has been to identify conditions that will be acceptable to a large percentage of occupants. The current Combined Effects of Noise and Temperature on Human Comfort and Performa

12、nceDale K. Tiller, PhD Lily M. Wang, PhD, PEMember ASHRAEAmy Musser, PhD, PE M.J. RadikAssociate Member ASHRAED.K. Tiller and L.M. Wang are associate professors in the Charles W. Durham School of Architectual Engineering and Construction, Univer-sity of Nebraska, Omaha, NE. A. Musser is principal of

13、 VandeMusser Design PLLC, Asheville, NC. M.J. Radik is senior structures designer for the Union Pacific Railroad, Omaha, NE.AB-10-017 (RP-1128)2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions (2010, Vol. 116, Par

14、t 2). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission.2010 ASHRAE 523organization of professional societies along discipline-specific lines has meant that fewer resources have been

15、 directed at integrative studies examining interactions between several indoor environment parameters and occupant percep-tion and performance.The indoor environment gestalt experienced by occupants is a mix of thermal, visual, auditory, and olfactory stimuli, and this has been recognized in a small

16、 number of integrative stud-ies. For example, Fanger et al. (1977) studied whether color and noise influence ambient temperature preference. They concluded that neither colors nor noise had significant effects on human thermal comfort. Wyon et al. (1978) investigated noise and heat stress as part of

17、 research on productivity under hot and cold conditions in South African factories. They found evidence that gender and age were important determinants of productiv-ity and accident rates, and noted that: “Noise and comfortable warmth may therefore be considered to have opposing effects, whereas noi

18、se and uncomfortable heat act in the same direction” (p. 870). A gender difference was also found by Pellerin and Candas (2003), who studied the effects of noise and temperature on human discomfort. Lightly clothed subjects were individu-ally exposed to a variety of uncomfortable ambient conditions

19、for two hours in a climatic chamber. Results suggested that males preferred less noisy conditions, while females preferred thermoneutral conditions. Clausen et al. (1993) studied the rela-tive importance of indoor air pollution, thermal load and noise on perceived discomfort, and concluded that a 1C

20、 temperature change in a space with a good air quality has, on average, the same effect on human comfort as a 3.9 dB change in noise level. Santos and Gunnarsen (1997) studied links between preferred ambient temperature and three parameters: noise, air velocity and window size. They found that warme

21、r ambient conditions were preferred when the costs associated with each of the other three parameters increased. More recently, Witterseh et al. (2004) investigated human perception and performance in an open-office type environment under three moderate to warm air temperatures and two acoustic cond

22、itions; one was quiet (35 dBA), while the other simulated open-plan office noise (55 dBA). They found that both louder noise and warmer tempera-tures increased fatigue and decreased performance. This paper describes results from an experiment designed to investigate the combined effects of noise and

23、 temperature on both human comfort and performance, involving a range of thermal and ventilation noise conditions typically found in offices. The results of this project may help optimize the design of indoor environments by verifying the appropriate-ness of individual criteria in more realistic con

24、texts of combined stimuli, and identifying any interactive effects that exist for the range of variables studied.METHODS AND PROCEDURESThirty human subjects (16 females, 14 males) were exposed twice to all combinations of five thermal conditions (PMV +1 79.6F:26.4C, PMV +0.5 75.8F:24.3C, PMV 0 72.1F

25、:22.3C, PMV -0.5 68.3F:20.2C, and PMV -1 64.6F:18.1C), three RC noise levels (RC-30, RC-40, and RC-50, where RC denotes Room Criteria (ASHRAE 2007) and two sound qualities (neutral denoted by N and rumbly denoted by R). All subjects completed a series of screening tests to ensure adequate hearing, v

26、ision and typing skill.The hearing test presented a series of tones in each ear, and subjects were asked to indicate whenever they heard a tone. A threshold of hearing less than or equal to 25 decibels was required at each of five octave frequency bands (250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz

27、). The Keystone Ophthalmic Telebinocular was used to ensure that potential subjects would be able to read the tasks presented in the exper-iment. This test presents subjects with a series of three-dimen-sional images using a stereoscopic viewer, and provides a quick measure of phorias, fusion readin

28、ess, and binocular visual efficiency at far and near, stereopsis, visual acuity and color vision. Finally, all subjects completed a commercially available typing test to ensure they could type at least 20 words per minute (WPM).Upon satisfactory completion of all three screening tests, subjects sign

29、ed an informed consent form describing the experiment, and then were scheduled for the ten two-and-a-half hour sessions required to complete the experimental protocol. Subjects were paid $14.00 for each completed session, along with a $60.00 bonus payment for completing all ten sessions (for a total

30、 of $200.00).Testing EnvironmentThe environment consisted of a test chamber, control room, and systems room. These rooms were constructed within a larger lab space in the Peter Kiewit Institute (PKI) at the University of Nebraska. Figure 1 shows the layout of the testing environment with desk and do

31、or locations. The rectangular cubes in each room show the positioning of the two workstations throughout the experiment.The testing and control rooms are 10 ft (3 m) by 10 ft 10 in (3.3 m) by 8 ft 6 in (2.6 m) with a dropped acoustical tile ceiling. The rooms are staggered metal double-stud construc

32、-tion with insulated 3/8” (1.0 cm) gypsum wall board (GWB) exterior and 3/4” (1.9 cm) GWB interior walls. The ceiling is insulated metal joist construction with 3/8” (1.0 cm) GWB underneath the insulation. Both rooms have a raised floor with gray low-pile carpet. Interior finishes include solid meta

33、l doors with acoustical gaskets and white semi-gloss paint.The design and layout of the rooms was planned so that either room could be used for testing if there was ever a need to have more than one experiment set up at the same time. Since the mechanical systems used in this experiment were capable

34、 of conditioning only one room at a time, the room located furthest from the systems room was chosen as the test-ing room.Each room has a separate supply and return duct that run to the systems room. The supply duct in the testing room connected to a 10 in (25 cm) square ceiling diffuser located in

35、2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions (2010, Vol. 116, Part 2). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without AS

36、HRAEs prior written permission.524 ASHRAE Transactionsthe center of the ceiling. The return duct in the testing room connected to a ceiling mounted return grille located in the corner near the door. Both ducts were partially lined to achieve the desired acoustical conditions in the room. The test ch

37、amber and control rooms were furnished with two pine-finish desks and two black computer chairs each. Computer monitors, keyboards and mice located at each desk in the testing chamber were connected to processors in the control room via cable extensions. This allowed subjects in the test chamber to

38、perform computer tasks, while removing the sound generated by the processors from the chamber.The systems room is 10 ft x 5 ft x 12 ft (3m x 1.5 m x 3.7 m) with a bare concrete floor, and walls and ceiling similar to the testing and control rooms. Ducts leading to the test cham-ber and control rooms

39、 protruded from one wall. This room is accessible on two sides by solid gasketed metal doors, and is supplied with cooling if necessary by two portable air condi-tioning units vented into the larger lab space.Mechanical EquipmentThe thermal environment in the test chamber was regu-lated by equipment

40、 located in the systems room. This equip-ment provided the necessary heating, cooling, humidification, dehumidification, and ventilation required to provide the ambient thermal conditions used in the experiment. Two pieces of equipment were connected in parallel to achieve thermal control. The Mobil

41、e Building Automation System (BASMobile) is a fully controllable HVAC system on a cart that includes a chiller, a small ice storage system, a heating element, supply and return fans, a filter, humidifier, and supply, return, and outdoor air duct connections (Henze Henze et al. 2005). This custom sys

42、tem was orig-inally designed for use as an educational tool, and for supply-ing small zones with conditioned air for testing purposes. A supplementary portable cooling unit was connected in parallel with the BASMobile, to provide additional cooling capacity required to achieve some of the cooler tes

43、t conditions.Thermal ConditionsThe independent variable related to the thermal environ-ment manipulated in this experiment is the predicted mean vote (PMV). PMV was studied at the following five values in the experiment: 1.0, 0.5, 0.0, -0.5, and -1.0, corresponding to conditions that subjectively ra

44、nge from slightly warm to slightly cool on the ASHRAE thermal comfort scale. Methods outlined in ISO 7730 were used to determine the combination of conditions that were used to produce these PMV values for the experiments (ISO 1994). Subjects wore their own clothing for the tests, but were given a d

45、ress code to ensure uniform clothing insulation value throughout all tests. Subjects were asked to bring their cloth-ing to the test site and change into their test clothing after arrival. This avoided potential problems with perspiration on clothing worn in from the outdoors. The insulation value f

46、or the specified dress code was found in Annex A of ISO Stan-dard 9920 (ISO 1995). The dress code included full length cotton dress pants, a long sleeve medium thickness cotton dress shirt with collar, dress socks between ankle and calf length, rubber sole leather or soft sole canvas shoes no higher

47、 than the ankles, and undergarments. This ensemble can be worn by men and women, is typical of that worn in office envi-ronments, and has an insulating value of 0.75 clo. Effects related to the subject sitting on the chair were also considered. An additional insulation value of 0.12 clo was added (M

48、cCullough et al. 1994) for the type of chair used in the experiment. This gave an overall clothing insulation value of 0.87 for the test subjects.Several other parameters upon which PMV depends were maintained at constant or nearly constant values during the tests. The metabolic rate was taken to be

49、 equal to that measured in previous studies for sedentary activity or office work, at 1.2 met (70 W/m2) (ISO 1994). Relative humidity for the tests was maintained at approximately 50%. The local air velocity was also measured to be less than 0.1 m/s under each thermal condition. With these parameters, PMV can be correlated to opera-tive temperature using ISO Standard 7730 (ISO 1994). The desired PMV values obtained for the operative temperatures were as follows: (PMV +1 79.6F:26.4C, PMV +0.5 75.8F:24.3C, PMV 0 72.1F:22.3C, PMV