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Expanding ASHRAE comfort zones

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Posted by nicksanspam on January 29, 2005, 9:21 pm
The ASHRAE 55-2004 comfort standard (based on worldwide surveys of 21,000
people) defines the winter and summer comfort zones below with equal air
and wall temperatures, equal human activity levels, and a fixed 0.1 m/s air

T (F)         RH            clo          PMV            PPD

67.3          86            1            -.4778556      9.769089
75.0          66            1             .4732535      9.676994
78.3          15            1             .5239881      10.74283
70.2          20            1            -.4779105      9.770202

74.5          67            .5           -.4747404      9.706658
80.2          56            .5            .5145492      10.53611
82.2          13            .5            .5003051      10.23146
76.5          16            .5           -.4883473      9.982468

The winter zone assumes heavier clothing with more thermal resistance
(clo=1), and the summer zone assumes lighter clothing (clo=0.5). The
zones are defined by a +/- 0.5 score on a "Predicted Mean Vote" comfort
scale that varies from -3 (very cold) to +3 (very warm.) The 4 corners
of each zone are based on high and low temperatures and humidities.
The "Percentage of People Dissatisfied" (PPD) score is based on the
PMV. Even with PMV = 0 ("comfortable"), about 6% of the people are

If people are willing to change clothing more than twice a year (early
PA farmers had one set of clothes for work and another for church, and
washed them twice a year, when they also took baths :-) and we vary air
velocity with a ceiling fan, these zones can be expanded, which can make
a solar house or one heated and cooled with the help of a whole-house fan
more efficient. We can also raise the upper comfort temperature limit
in air with lower humidity, and vice versa. The ASHRAE 55-2004 standard
contains a BASIC program to help do this. Here are some calculations based
on NREL's long-term December and August weather averages for San Diego:

20 CLO = 1'clothing insulation (clo)
30 MET=1.1'metabolic rate (met)
40 WME=0'external work (met)
50 TA.6'air temp (C)
60 TR.6'mean radiant temp (C)
70 VEL=.1'air velocity
80 RH=0'relative humidity (%)
90 DATA 68.8,0.0062,0.05,1
100 DATA 83.9,0.0062,0.5,0.5
110 DATA 67.1,0.0121,0.05,1
120 DATA 82.9,0.0121,0.5,0.5
130 FOR CASE = 1 TO 4
145 TA=(TC-32)/1.8'air temp (C)
146 TR=TA'mean radiant temp (C)
150 PA).921*3377.2/(1+.62198/WA)'water vapor pressure (Pa)
160 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa
170 IF PA=0 THEN PA=RH*10*FNPS(TA)'water vapor pressure, Pa
180 ICL=.155*CLO'clothing resistance (m^2K/W)
190 M=MET*58.15'metabolic rate (W/m^2)
200 W=WME*58.15'external work in (W/m^2)
210 MW=M-W'internal heat production
220 IF ICL<.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor
230 HCF.1*SQR(VEL)'forced convection conductance
240 TAA=TA+273'air temp (K)
250 TRA=TR+273'mean radiant temp (K)
260 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp
270 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermediate values
280 P508.7-.028*MW+P2*(TRA/100)^4
290 XN=TCLA/100
300 XF=XN
310 N=0'number of iterations
320 EPS=.00015'stop iteration when met
330 XF=(XF+XN)/2'natural convection conductance
340 HCN=2.38*ABS(100*XF-TAA)^.25
360 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)
370 N=N+1
380 IF N>150 GOTO 500
400 TCL0*XN-273'clothing surface temp (C)
410 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin
420 IF MW>58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating
430 HL3=.000017*M*(5867-PA)'latent respiration heat loss
440 HL4=.0014*M*(34-TA)'dry respiration heat loss
450 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation
460 HL6L*HC*(TCL-TA)'heat loss by convection
470 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient
480 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote
490 GOTO 510
500 PMV999!:PPD0

Dry bulb      Humidity      Air vel.      Clothing     Predicted mean
temp (F)      ratio         (m/s)         (Clo)        vote (PMV)

68.8          .0062         .05           1            -.4997552
83.9          .0062         .5            .5            .4852427
67.1          .0121         .05           1            -.491671
82.9          .0121         .5            .5            .4890098

NREL says average daily highs and lows are 48.8 and 66.1 F with w = 0.0062
pounds of water per pound of dry air in December and 67.3 and 77.8 with
w = 0.0121 in August. An airtight well-insulated house with thermal mass
and internal heat gain and a smart whole-house fan controller would barely
need heating or cooling all year. Architects call this "thermal sailing."

With inexpensive solar heating and whole-house fan heating and cooling,
it would be more efficient to make the house air temperature closer to
the upper comfort limit on an average winter day and closer to the lower
comfort limit on an average summer day, in order to store lots of thermal
energy in the mass of a house. A mean radiant (wall) temp that's less than
the house air temp in winter and greater in summer would allow raising
the upper winter air comfort temp limit and lowering the lower summer air
comfort temp limit. Occupants might also vary activity levels and wear
clothing with more or less resistance, eg a sweater as well as a long-
sleeve shirt in wintertime.


Innova AirTech Instruments has an excellent comfort web site:


Posted by News on February 1, 2005, 1:05 am

Most people got married in June because they took their yearly bath in May
and were still smelling pretty good by June. However, they were starting to
smell, so brides carried a bouquet of flowers to hide the smell.

Baths equaled a big tub filled with hot water. The man of the house  had the
privilege of the nice clean water, then all the other sons and men, then the
women and finally the children. Last of all the babies. By then the water
was so dirty you could actually loose someone in it. Hence the saying,
"Don't throw the baby out with the bath water".

Houses had thatched roofs. Thick straw piled high, with no wood  underneath.
It was the only place for animals to get warm, so all the pets... dogs,
cats, and other small animals, mice, rats, bugs lived in the roof. When it
rained it became slippery and sometimes the animals would slip and fall off
the roof. Hence the saying, "It's raining cats and dogs,"

There was nothing to stop things from falling into the house. This posed a
real problem in the bedroom where bugs and other droppings could really mess
up your nice clean bed. So, they found if they made beds with big posts and
hung a sheet over the top, it addressed that problem. Hence those beautiful
big 4 poster beds with canopies.

The floor was dirt. Only the wealthy had something other than dirt, hence,
the saying "dirt poor". The wealthy had slate floors which would get
slippery in the winter when wet. So they spread thresh on the floor to help
keep their footing. As the winter wore on they kept adding more thresh until
when you opened the door it would all start slipping outside. A piece of
wood was placed at the entryway, hence a "thresh hold".

They cooked in the kitchen in a big kettle that always hung over the fire.
Every day they lit the fire and added things to the pot. They mostly ate
vegetables and didn't get much meat. They would eat the stew for dinner
leaving leftovers in the pot to get cold overnight and then start over the
next day. Sometimes the stew had food in it that had been in there for a
month. Hence the rhyme: peas porridge hot, peas porridge cold, peas porridge
in the pot nine days old."

Sometimes they could obtain pork and would feel really special when that
happened. When company came over, they would bring out some bacon and hang
it to show it off. It was a sign of wealth and that a man "could really
bring home the bacon." They would cut off a little to share with guests and
would all sit around and "chew the fat."

Those with money had plates made of pewter. Food with a high acid content
caused some of the lead to leach onto the food. This happened most often
with tomatoes, so they stopped eating tomatoes... for 400 years.

Most people didn't have pewter plates, but had trenchers - a piece of wood
with the middle scooped out like a bowl. Trencher were never washed and a
lot of times worms got into the wood. After eating off wormy trenchers, they
would get "trench mouth."

Bread was divided according to status. Workers got the burnt bottom of the
loaf, the family got the middle, and guests got the top, or the "upper

Lead cups were used to drink ale or whiskey. The combination would sometimes
knock them out for a couple of days. Someone walking along the road would
take them for dead and prepare them for burial. They were laid out on the
kitchen table for a couple of days and the family would gather around and
eat and drink and wait and see if they would wake up. Hence the custom of
holding a "wake".

Church yards started running out of places to bury people. So, they would
dig up coffins and would take their bones to a house and re-use the grave.
In reopening these coffins, one out of 25 coffins were found to have scratch
marks on the inside and they realized they had been burying people alive. So
they thought they would tie a string on their wrist and lead it through the
coffin and up through the ground and tie it to a bell. Someone would have to
sit out in the graveyard all night to listen for the bell. Hence on the
"graveyard shift" they would know that someone was "saved by the bell" or he
was a "dead ringer".

Posted by nicksanspam on February 1, 2005, 1:06 pm

They probably used soap and water and washcloths more often...

Wordorigins.org: Etymologies & Word Origins:

Dirt Poor

This term is US in origin and dates to 1937. The exact reference is
uncertain, but it is most likely to be evocative of the dust bowl and the
extreme poverty and unclean conditions in which many had to live during
the Depression.

The bit of internet lore about Life in the 1500s claims that it dates to
Shakespearian England where finished floors were rare. This is utterly false.

The Mavens' Word of the Day May 15, 2001

Sylvia Chrost wrote:

   I'm interested in the etymology of the phrase dead ringer. I heard that
its origins are tied to being buried alive and the idea of a doppelgänger or

A doppelgänger is 'a ghostly double or counterpart of a living person'; in
German it means 'double goer'. This spiritual being inhabits the works of
German romantic writers, and is typically used to symbolize a character's
internal conflict. It's also a literary device used in the horror fiction of
English language authors such as Oscar Wilde, Edgar Allan Poe, and Bram
Stoker. A doppelgänger is usually sinister and exists to haunt the living
person. An encounter with one's spiritual double may mean imminent death,
and if the double is attacked, the living person will soon die or commit

Fear of being buried alive is also a common literary theme in 18th- and
19th-century literature, first in Germany, and then in France, Britain, and
elsewhere. (Poe's "The Black Cat" and "The Fall of the House of Usher" are
American examples.) This fear was not unfounded. Until the 20th century,
medical signs and criteria of physical death were unreliable, and there are
real cases of people being buried prematurely. A widely circulated but
untrue explanation of the term dead ringer is connected to the practice of
tying a rope to the wrist of a buried person, the rope being attached to a
bell outside the coffin. If the person was indeed buried alive, the bell
could be used to signal for help. (If you want the lugubrious and humorous
details about this part of our social history, read Buried Alive: The
Terrifying History of Our Most Primal Fear, by Dr. Jan Bondeson.)

Outside of literature, the term doppelgänger is sometimes used to mean 'a
(living or dead) person who closely resembles someone else'. The term dead
ringer has the same meaning, but it's not a literary term. For example,
maybe your boyfriend is a "dead ringer" for Brad Pitt.

In this use, the adjective dead means 'perfect, absolute, exact, utmost', in
reference to death being the final step in life. Without the adjective
"dead," the noun ringer just means 'a double or counterpart'. So dead ringer
means 'exact double'.

But ringer has other pejorative meanings dating from the late 1800s. The
basic sense is 'an impostor or deceptive substitute unfairly entered into a
contest or competition'. It can refer to a superior horse entered in a race
to substitute for a slower horse, usually under an alias and with its
appearance altered to resemble the inferior horse. Or a ringer could be an
inferior horse substituted for a superior one that has been sold. Also in
sports, a ringer is a professional athlete deceptively substituted for an
amateur. In gambling games, a ringer is a marked or specially ordered deck
of cards, a loaded or otherwise modified pair of dice, a dishonest dealer,
or an expert card player posing as a novice. A counterfeit gem or coin can
be called a ringer. Other related meanings include: 'an outsider; uninvited
guest; intruder'.

The noun ringer comes from the verb ring (in), in the early 1800s meaning
'to falsify, disguise, or alter' or 'to introduce fraudulently; substitute
one person/thing for another'. In this use it's sometimes spelled "wring
(in)." Ring (in) can also mean 'to join with others, usually in an intrusive
way'. These uses of ring (in) are probably connected to the meaning 'to
announce by ringing a bell'. According to the Barnhart Dictionary of
Etymology, there is also a probable association with the slang expression
ring the changes 'to substitute counterfeit money in various ways', a pun on
the the standard sense 'to go through all the variations in ringing a peal
of bells'. As an alternative origin for ringer, Thomas L. Clark's The
Dictionary of Gambling and Gaming says it was originally a finger ring with
a small flange used for palming cards.


Copyright © 1995-2005 Random House, Inc. All rights reserved.

Questions & Answers: Saved by the bell

[Q] From a lot of people - including Mike Whitling and Lisa Smith from
the USA and Barrie J Wright from Australia:

"The following is part of a longer piece that's been making the rounds by
e-mail in recent months. Is any of it true? England is old and small and
they started running out of places to bury people. So, they would dig up
coffins and would take their bones to a house and re-use the grave. In
reopening these coffins, one out of 25 coffins were found to have scratch
marks on the inside and they realized they had been burying people alive. So
they thought they would tie a string on their wrist and lead it through the
coffin and up through the ground and tie it to a bell. Someone would have to
sit out in the graveyard all night to listen for the bell. Hence on the
'graveyard shift' they would know that someone was 'saved by the bell', or
he was a 'dead ringer'."

[A] You may not be pleased to hear that all this is complete and utter
hogwash, just like the rest of the article. It's an example of a fascinating
process (that is, from a sociolinguistic perspective) in which people
actively seek out stories to explain phrases, not really caring whether they
are true, just that they are psychologically satisfying. As a result, they
are powerful memes, strongly resisting refutation. But World Wide Words is
renowned as the home of lost causes, so I'll give it a go.Saved by the bell
is actually boxing slang, dating from the 1930s. A contestant being counted
out might be saved by the ringing of the bell for the end of the round,
giving him a minute to recover. Graveyard shift is an evocative term for the
night shift between about midnight and eight in the morning, when-no matter
how often you've worked it-your skin is clammy, there's sand behind your
eyeballs, and the world is creepily silent, like the graveyard (sailors
similarly know the graveyard watch, the midnight to four a.m. stint). The
phrase dates only from the early years of the twentieth century. The third
phrase-dead ringer-dates from roughly the same period or perhaps a decade or
two earlier. I've written about it previously, so won't explain it again.So
none of these expressions has anything to do with the burying of bodies.

World Wide Words is copyright © Michael Quinion, 1996-2005.


debunks the full hoax.


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