Document xz1Y6Y7vq2GNnymB7RJDg1MrG

248 CHAPTER 12 1954 Guide may. not even produce comfort on cold days; if humidity is to be main tained at 50 percent, the lower temperatures will apply. In rooms having large glass areas, when sun is not shining, or in rooms with walls having `a! high transmission coefficient,, the lowered surface tem perature will cause a feeling of coolness even though the air temperature in the room is at or 'above the temperatures indicated in the table. In rooms of this character, it[is desirable to design for even higher temperatures than those listed, unless a compensating higher temperature surface is installed A to offset the low temperature surfaces. Table 2. . Winter Inside Dry-Bulb Temperatures Usually Specified* Type op Building Deg F Ttpb op Building Deg F Schools-- - Class rooms -....................... Assembly rooms................... Gymnasiums........................ Toilets and baths................... - Wardrobe and locker rooms. . -Kitchens.. ............................. .Dining and lunch rooms...... Playrooms................................ Natatoriums............................ Hospitals-- Private rooms......... ;* Private rooms (surgical). ' Operating rooms............... and laundries.Toilets..... .................... . Bathrooms................. 70-72 68-72 55-65 70 65-68 66 65-70 60-65 75 Theaters-- Seating space.. Lounge rooms.. Toilets............. Hotels-- .... Bedrooms and baths.......... Dining rooms............ Kifrihens and laundries-- Ballrooms.............................. Toilets and service rooms.. 70-72 70-80 70-95 68 66 68 70-80 Homes..................................................... Stores...... ......... ............................... Public buildings............. ............. Warm air baths............................... Steam baths................................-- Factories and machine shops.. Foundries and boiler shops... Paint Shops........................................ 63-72 .68-72 70 70 66 65-68 68 70-72 65-68 68-72 1n2o0 60-65 50-60 * The most comfortable dry-bulb temperature to be maintained depends on the relative humidity and ; air motion. These three factors considered together constitute what is termed the effective temperature. (See Chapter 6.) When relative humidity is not controlled separately, optimum dry-bulb temperature for comfort will be slightly higher than shown in Table 2. The inside temperatures specified in Table 2 may be used for panel : heated spaces as well as for spaces heated by warm air, radiators or con-' vectors. It is true that warm panel surfaces tend to produce a comfortable >. environment at a lower room air temperature than when warm panels are;: not present, but field experience in the United States has indicated that; actual reductions in air temperature are slight in operation. Temperature at Proper Level. In making the actual heat loss compu-.: tations, however, for the various rooms in a building it is often necessary ;, to modify the temperatures given in Table 2 so that the air temperatureat the proper level will be. used. By air temperature at the proper level is: meant, in the case of walls, the air temperature at the mean height be;-' tween floor and ceiling; in the case of glass, the air temperature at the; mean height of the glass; in the case of roof or ceiling, the air temperature at the mean height of the roof or ceiling above the floor of the heated;' room; and in the case of floors, the air temperature at the floor level. 1 Temperature at Ceiling. The air temperature at the ceiling is generally:"! higher than at the breathing level due to stratification of air resulting from: the tendency of the warmer or.less dense air to rise. An allowance for this* fact should be made in calculating ceiling heat losses, particularly in thefcase of high ceilings. However, the exact allowance to be made may b3`; somewhat difficult to determine as it depends on many factors, including; (1) the type of heating system, (2) ceiling height, and (3) the insidme^. outside temperature differential The type of heating system is Heating Load 249 tieuiany important, as the temperature gradient from floor to breathinglevel to ceiling may depend to a large extent on whether direct radiation', unit heaters or warm air is used, and in the latter case, whether the air is moved mechanically or by gravity. The temperature of the heating medium is also a factor. It is impracticable to establish rigid rales for determining the temperature difference to use in all cases. However, for residences and structures hav ing ceiling heights under 10 ft, the comparatively small temperature differential between the breathing level and ceiling generally may be Ceiling Height (Ft) 10 11 12 13 14 15 16 17 18 19 20 25 30 35 40 45 50 Breathing Level Temperature (5 wt Above Floor) 60 65 70 72 74 76 113.0 3.6 4.2 4.8 5.4 6.0 3.3 3.5 3.9 4.2 4.6 4.9 6.2 5.6 5.9 6.3 6:5 - --7.0 3.6 4.3 5.0. 5.8 6.5 7.2 3.7 4.4 5.2 5.9 6.7 7.4 3.8 6.1 6.8 7.6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.3 7.4 7.6 7.6 7.7 7.5 7.6 7.7 7.8 7.9 7.7 7.8 7.9 8.0 8.1 7.0 7.5 8.0 8.5 9.0 9.5 7.5 8.0 8.5 9.0 9.5 10.0 8.0 8.5 9.0 9.5 10.0 10.5 8.2 8.7 9.2 9.7 10.2 10.7 8.4 8.9 9.4 9.9 10.4 10.9 8.6 9.1 9.6 10.1 10.6 11.1 78 3.9 3.7 5.5 6.2 7.0 7.8 8.8 9.3 9.8 10.3 10.8 11.3 80 4.0 4.8 5.6 6.4 7.2 8.0 11 8.3 8.4 8.5 9.0 9.5 10.0 10.5 11.0 11.5 85 4.3 5.1 li 7.7 8.5 8.6 8.7 8.8 . 8.9 9.0 9.5 10.0 10.5 11.0 11.5 12.0 90 4.5 5,4 6.3 7.2 8.1 9.0 9.1 9.2 9.3 9.4 9.5 10.0 10.5 11.0 11.5 12.0 12.5 percent. bating systems. or dJ-irecWt rLaUdIiWatIiBonUOoVr BgroavIIi.tywIaiurian taaibr,leinicsregaesneerv&allluveasn5n0Wpehrlc*entnt to ______ cum. ror mgner ceilings, an allowance of approximately 1 percent per foot of height above the breathing level may be made for ceiling heights up to 15 ft and approximately i o of 1 deg per foot of height above this level. The values in Table 3 are calculated on this basis. For direct radiation and gravity warm air systems, the allow ance should be increased from 50 percent to 100 percent over those given in Table 3. These rales should, however, be used with considerable dis cretion, and they do not apply to some types of heating systems such as those using panel and baseboard radiation, where very low temperature differences between the floor and the ceiling may exist. Temperature, at Floor Level. According to tests at the University of Illinois,3. * *6 the temperature at the floor level ranged from about 2 to 6 deg below that at the breathing level, or somewhat greater than the difference between the breathing level and ceiling temperatures. Tests at the University of Wisconsin1 indicated a somewhat smaller differential between the floor and breathing level temperatures. As a general rale, if the breathing level to ceiling temperature differential is neglected (as with ceiling heights under 10 ft), the breathing level to floor, differential may "so be neglected, as the two are somewhat compensating, especially where both floor and ceiling losses are calculated for the same space. In other cases, the 10 ft temperature differentials in Table 3 may be used in arriving