INTERNATIONAL
INDOOR AIR QUALITY STANDARDS
(Chapter 1)
CHAPTER 1. History of
Indoor Air Quality standards
A. The Black Hole of
Calcutta, Prisoners-of-War and Ancient Prisons
The first well-documented
and well-publicized indoor air quality incident occurred on June 20,
1756 in Calcutta, India. This incident is known as “the
black hole of Calcutta.”
In this indoor air quality
situation, 146 captured British soldiers were imprisoned in a 14 x
18 foot prison cell. This cell only had 1 door with a
small, 1 square foot opening. Over night, most of the soldiers
died. Only 23 survived. The description of the
symptoms from the survivors was consistent with oxygen deprivation
and suffocation. Some symptoms were also consistent with acidosis
due to very high carbon dioxide exposure levels.
The British government made
this incident a rallying cry for an increased war effort against the
Nawab of Bengal, Siraj ud-Daulah. However, while claiming improper
treatment of their war prisoners, the British government practiced
similar culling methods.
American Revolutionary
Prisoners-of-War
In 1780, only 24 years
after the Black Hole of Calcutta scandal, the British had anchored a
flotilla of 12 former men-of-war ships in Brooklyn, New York,
Wallabout Bay to house prisoners from the war with the US. Prisoners
captured by the British military were crowded into these ships.
Conditions in the ships were extremely unsanitary. Further,
prisoners were given little food, no medical attention and a great
deal of abuse. This neglect was intended to motivate these
troops to change sides and join the King's Navy and fight the
colonialist revolutionary army.
Aboard these unsanitary
ships, disease was rampant. The corpses of those who died (between
11,500 and 12,500 men) were either rowed to shore and
placed in shallow
graves or unceremoniously tossed overboard by their British captors.
The worst of these prison
ships was the HMS Jersey, a decommissioned warship, on which 1,100
men were crowded together between decks. About a dozen prisoners
died each night aboard the Jersey from dysentery, typhoid, smallpox,
yellow fever,
food poisoning, starvation and torture. When the war ended in 1783
only 1,400 survivors were found on the 12 prison ships. All of
them were ill and emaciated.
Ancient Prisons
Historically, the use of
inadequately ventilated cells to cull large numbers of prisoners of
war was a common practice going back hundreds of years. Cell
overcrowding was a common prisoner reduction tool in many prisons.
Well documented cases in the literature show this technique was
routinely practiced in Istanbul and Romania.
In addition to cell
overcrowding to reduce the number of prisoners, a second technique
was also used. Ancient prisons had essentially no sanitary controls.
Ancient prisons also had many lower levels. Consequently,
human waste products would flow down to the lower levels of the
prison, producing air quality that in most cases lead to illness and
early death. Being sentenced to a lower level of a
prison was essentially a death sentence, especially with the
addition of inadequate nutrition.
B. The Londonderry
The next well-publicized
IAQ incident happened on a cruise ship called the Londonderry on
December 3, 1848. In this case, the Packet
Steamer Londonderry was
caught in a storm at sea. In order to protect the passengers,
the captain ordered that
they all go below deck.
Further, due to the high waves, he ordered that tarpaulins be placed
over the deck openings to prevent water from entering the ship.
However, the effect of placing the tarpaulins over the deck openings
was to eliminate any fresh air flow to the lower decks.
Over the next 30 hours, over half of the 174 passengers suffocated.
Sadly, “Dr Miller,
having examined the bodies, gave his opinion that
“ . . . those persons
had come by their death through many persons having been in too
small a place, and having an imperfect supply of air...the steerage
accommodation being more cramped than the Black Hole of Calcutta.”
The inquest jury found that
the passengers had died of suffocation and charged the Captain,
Alexander Johnson, as well as the first and second mates, with
manslaughter, calling for better conditions for steerage passengers.
Needless to say, the practice of closing off deck ventilation
openings during storms was no longer permitted.
C. Early Indoor
Air Quality Litigation
1. The Park Avenue
Tunnel of the New York Central Railroad
Many early railroad tunnels
lacked any specific ventilation. One such tunnel in New
York City became both an indoor air quality litigation case.
This was the Park Avenue tunnel. It was the first train tunnel
to Manhattan Island. It was 3 miles long and essentially
was unventilated. Trains traversing this tunnel
were coal fired and moved relatively slow compared to today’s
standards. This meant that people and the train spent
considerable time in this tunnel with constantly deteriorating air
quality. A traverse time of 15-20 minutes would not have been
unusual.
Below is an excerpt from
the newspaper article of Wednesday, July 27, 1901 about the
investigation of this tunnel.
"WORSE THAN
BLACK HOLE OF CALCUTTA";
Dr. Cyrus Edson's
Report on the Park Avenue Tunnel.
He describes to the
Grand Jury the sufferings of passengers
and the danger to
health they incur.
“In July 1901, during the
Grand Jury's investigation of the nuisance existing in the Park
Avenue Tunnel between Fifty- sixth and Ninety-sixth Streets, in New
York City, I was retained by the District Attorney of New York
County as engineering expert on ventilation, and in my testimony
before the Grand Jury.
In my opinion, the tunnel
is the cause of a very serious public nuisance, affecting the health
and comfort of a very large number of persons. Each car contains
less than 5,000 cubic feet of airspace, and, therefore, allows only
about 56 cubic feet of air for each person. In the case of the
'Black Hole' of Calcutta, 146 persons were thrown into a room the
size of an eighteen-foot cube at eight o'clock in the evening. The
room contained a door and two windows. The latter were open. Each
man had about 38 cubic feet of air space. The car was lighted with
oil-lamps.
On Wednesday, July 24, I
made a number of observations of cars in transit through the tunnel.
One was on the 12.15 P-M- train on the Harlem road. The temperature
of the car at starting was 86.5 degrees. Within four minutes, during
transit, it had risen to 91 degrees, and the humidity rose from 70
to 76 per cent. The air was very irritating and several persons were
seized with coughing spells. On entering the tunnel my pulse was
beating at the rate of 70 per minute. At the exit it had risen to 96
per minute.
The temperature in these
cars during the warm weather varies from 85 degrees to 105 degrees.
I have noted a temperature of 111 degrees, with a high percentage of
humidity. The gases of combustion, plainly apparent to the senses
while the cars are passing through the tunnel, are very poisonous,
and in sufficient quantities will destroy animal life.
This system of ventilating
tunnels is by no means untried or new, as you can find the
description of a similar method in the English paper, Engineering,
of April 21, 1871, where Mr. Rams- bottom (a well-known English
engineer) describes the mechanical ventilation of the Liverpool
Tunnel of the London and Northwestern Railway.
A carbon dioxide
standard in 1871
It is very interesting to
note in that Dr.Cyrus
Edson quoted Mr.
Rams-bottom’s used of a carbon dioxide exposure standard from 1871
of 800 ppm. Here is his an except from his presentation: Topic
No. 2." The Ventilation of Tunnels, Subways and Kindred
Constructions."
THE AMERICAN
SOCIETY OF HEATING And VENTILATING ENGINEERS, VOL. XL
ELEVENTH
ANNUAL MEETING, NEW YORK, JANUARY 17-19, 1905
CXL II.
TOPICAL DISCUSSIONS.
SUMMER
MEETING, CHICAGO, IL., JULY 7-8, 1905
“The amount of carbonic
acid found in the air is generally taken in ventilation work as the
index of its purity, and what is commonly considered as pure country
air ordinarily averages about 4 parts per 10,000 of carbonic acid. Eight
parts per 10,000 of carbonic acid is commonly considered as a
standard of purity in the ventilation of buildings, while in
this tunnel should the carbonic acid present occasionally reach 12
parts per 10,000, no serious inconvenience would be experienced by
the passengers, and therefore taking twelve parts per 10,000 as a
maximum allowance, with fans of sufficient capacity to exhaust all
the air from this tunnel every two minutes, this result could be
obtained.”
2. The Cole County
Courthouse Indoor Air Quality CASE
The first indoor air
quality litigation case was probably the County of Coles, Illinois
courthouse building on July 11, 1898.
A suit was filed by county
employees to justify the construction of a new courthouse. The
suit by employees to require the county to building a new building
alleged amongst other things that the air quality in the building
was a health hazard to employees. A specific mention was
the mention was the office for the county treasurer.
“the office provided for
the county treasurer was….. located between the ladies’ water
closet and the main water closet; that it had no ventilation; (and)
that it was contaminated with the poisonous gases from those
closets.”
Based on this description
and the lack of stack venting on plumbing of that time, this office
must have been particularly odiferous.
D. The First Indoor Air
Quality Survey
During the early 1800s,
tuberculosis and other diseases were rampant in the poorer segment
of the population. The incidence of these diseases and
fatalities was also consistent with their unsanitary and crowded
housing conditions.
However, with the dawn of
the industrial revolution, the need for labor greatly expanded.
Sick and debilitated people did not make good workers. Hence,
significant economic interest developed to determine the reasons for
worker illness and the methods for producing healthier and more
productive workers.
Surgeon Major F. de
Chamount, M. D. began some of the initial research into the
relationship of indoor air quality and reports of ill health.
He was the first researcher to perform an “indoor air quality
survey.
Below is a copy of the
questions from his survey and the responses. Interestingly,
these questions are very similar to question found on IAQ survey’s
almost 140 years later!
INDOOR AIR QUALITY
SYMPTOM SURVEY FROM 1875
Please rate the air quality
in your room based on the following descriptions
“Fresh or not” “Rather
close” “Close” that “Very close” “Extremely
close”
differing sensi- that
is, the point is, the point that is, the point that
is, the
bly from the at which
the or- at which the at which the point at which
external air ganic
matter be- organic matter organic matter the maximum
gins
to be ap- begins to be begins to be of- point of
differen preciated by the decidedly dis- fensive
and op- tiation by the
senses. agreeable
to the pressive to the senses is
senses senses reached
Moran also measured the
carbon dioxide, temperature and absolute humidity in the surveyed
spaces.
His analysis of the carbon
dioxide concentration and humidity showed the following
relationships to the following subjective ratings:
Good Ventilation
“Fresh”
<200 ppm CO2
above outside background
absolute humidity less than
4.7 grains/ft3 (55%
RH @ 72°F)
Not good ventilation
>400 ppm CO2
above outside background
absolute humidity >4.9
grains/ft3 (56% RH @ 72 °F)
Bad Ventilation
>600 ppm CO2
above outside background
absolute humidity >4.9
grains/ft3 (56% RH @ 72 °F)
Very Bad Ventilation
>800 ppm CO2
above outside background
absolute humidity >5
grains/ft3 (57% RH @ 72 °F)
It is interesting to note
that the CO2 varied significantly more
than the absolute humidity. This is not unlike similar
research today that shows carbon dioxide concentrations to be a
better indicator of indoor air quality.
Moran’s research on the
relationship of individually reported adverse health effects lead to
the establishment of the first comprehensive ventilation standards
in England. In 1867, the first general ventilation standards were
proposed by General Morin, Director of Conservation, Imperial Art
and Meters, in England.
The table below shows
the recommended minimal ventilation standards.
Interestingly, these ventilation standards are not significantly
different that those recommended by ASHRAE today.
TABLE 1 : General Morin,
Institute of Mechanical Engineering 1867. On the Ventilation
of Public Buildings.
Ventilation
Rate Per Hour CFM/Person
Hospital for ordinary
Patients 2,000 to 24,000
Hospital for epidemic 5,000
Workshops, ordinary trades 2,000
Workshops, unhealthy trades 3,500
Prisons 1,700
Theatres 1,400 to
1,700
Meeting Halls 1,000 to
2,000
Schools for Children 400-500
Schools for Adults 800-1,000
It is ironic, that in the
almost 30 years since 1981, when financial interests resulted
in lowered ventilation rates to the point of causing sick workers
with sick building syndrome (see section ), required
ventilation rates have now returned to level recommended over 150
years ago, again to the original intent of producing healthier
working environments.
REF. Surgeon Major F. de
Chamount, M. D. On the theory of ventilation: an attempt to
establish a positive basis for calculation of the amount of Fresh
Air required for an Inhabited Air-space. Philosophical Transactions
of the Royal Society 1875 Volume 23 p. 187-200.
E. The First Indoor Air
Quality Standards
The first indoor air
quality standard was developed in Germany by Peterkoffer.
His standard targeted carbon monoxide. The reason this
gas was targeted had to do with the technology used for indoor
lighting at that time.
During the late 18th
and 19th century, Town gas or oil lights were installed
in homes and buildings, prior to the development of electric
lighting. The gas that was burned in these interior
lights was not the natural gas that we are used to today.
In the 1800s the technology for drilling and collecting natural gas
had not been developed.
In the 1800s, the gas that
was burned was called “town gas.” Town gas was generated
by burning coal in an oxygen deficient atmosphere. The coal
would break down into methane, carbon monoxide, and a little carbon
dioxide. The health problem from Town gas occurred when the
gas pipes leaked and when the gas light would accidentally be
extinguished, but the gas would still continue to leak out of the
light fixture.
Peterkoffer researched the
health affects of carbon monoxide and recommended an exposure
standard of 50 ppm in 1849. Interestingly, the current
occupational exposure limit for carbon monoxide is essentially the
same today.
Following Peterkoffers work
others also recommended various indoor air quality standards in the
1800s. These are listed below:
• 1849
: In Germany,
Peterkoffer proposes
first known exposure standard for carbon dioxide of 1,000 ppm.
• 1860
: In England,
Moran published
ventilation standards for various occupancies based on the first
indoor air quality survey.
• 1874
: English Army Surgeon F. deChamont conducts first indoor
air quality survey relating five levels of symptoms to indoor
carbon dioxide concentrations. He proposes a carbon dioxide
IAQ standard of 200 ppm above outdoor levels, approximately 500
ppm.
• 1883
: In Germany, Max Gruber, of the Hygienic Institute at
Munich proposes the first occupational exposure standard for
carbon monoxide standard of 200 ppm.
• 1887
: In England, Carnelley, Anderson and Haldane propose
“air purity” standards for carbon dioxide, particulates,
organic matter, mold and bacteria.
< 19,355 total bacteria
(with a maximum mold level of 645 cfu/m3.)
If mold levels are higher,
the total level of culturable bacteria and mold should be no more
than 20,000 cfu/m3.
F. 1923 School
ventilation standards
During the early 1920s,
the effectiveness of public education to produce educated workers
and healthy children was of significant interest to public health
officials and educators. A consortium of research was
done on this subject involving school officials, public health
physicians and ventilation engineers. This researched involved
studying schools in NYC, Chicago, St Louis. Etc.
This research compared
heating systems, window configuration, ventilation rates, student
test scores, capital costs, and other factors. The
study concluded that a steam heating system with windows that open,
and a ventilation system that provided 30 cfm of fresh air per
student, was the most healthy and cost effective method for
constructing school. By 1924, over 60 years after the
enactment of the English ventilation standards by Morin, 30 cfm per
student of fresh air was embodied into law in 21 US states by
statutes and board regulations. 224
G. Swedish Ventilation
Standards 1500s
Sweden has always been at
the forefront of research on the general health of its population.
Sweden has been tracking the health effects of chemical exposure
since the 1500s. Though the science toxicology at that
time was not developed, Swedish Public Health researchers
clearly noted increased morbidity and mortality in workers exposed
to hazardous chemicals in various industries. Most
importantly, they noticed that in factories where ventilation was
used to expel the “bad air”, the incidence of worker
morbidity significantly decreased. Consequently, Sweden
developed and mandated specific amounts of ventilation various
industrial processes in the early 1600s. They expanded these
standards continually over the next 200 years. Eventually,
other European countries developed similar ventilation standards.
What is so interesting
about these earliest of ventilation standards is that they were
symptom based – not chemical exposure level. This meant that
if a ventilation system did produce the desired reduction in
symptoms, more ventilation would be mandated.
This was unique in that if
you had a susceptible or sensitive population, symptom relief was
mandated, not just numerical amounts of ventilation, which is the
standard today.
H. IAQ in Outer Space -
The Story of MIR
The MIR space station was
launch by Russia in 1989?. It remained in orbit for 10+?
years. During this time it was always occupied by at least 2
astronauts. During 1989 and 1990, the US also had a visiting
astronaut on this MIR space station.
Early in its life MIR was a
very reliable space craft. However, after about 10 years, the
space because developing a number of electrical problems. The
most serious electrical problem results in a fire in one of its
pods. It also had a seal failure on one of its air locks.
This may not seem unusual
given the age of the space craft, however, age was not the cause of
the problems. The cause turned out to mutated mold and
bacteria that ate the electric wire insulation as well as attached
this silicone rubber on the air lock seals.
This was so serious of a
problem for future space travel that one of the two visits the US
made to MIR was dedicated microbial sampling. Though
much of the microbial sampling data remains secret in the US, at
least one story did appear in the literature.
The initial air sampling by
the US astronaut was done with a SAS sampler. This
sampler uses a standard culturable plate and typically samples 1 m3
of air. A typical culturable plate is then incubated for
2-3 days to let the mold and bacteria spores germinate and grow into
visible colonies.
However, this was not the
case on MIR. The next day when the US astronaut was
checking the culturable plates for any signs of growth, he
found that the plates were overgrown with mold and bacteria.
The species of mold and bacteria in the air on MIR has mutated and
were growing almost 10 times faster than the same species on earth.
This was very usual and very scary. What would happen to earth
if a common species of mold suddenly started to grow 10 times
faster? Would food rot 10 times faster? What about wood
structures in humid environments, would they decay 10 times faster?
Clearly, what was alive on
MIR could not be permitted to return to earth intact and viable and
be released into environment. This information was
never released to the public. Instead, it was decided (wisely)
to let MIR burn up in the earths atmosphere. Ironically, one
US music disc jockey made fun of the decision to let MIR up.
If he had only known what really was going on.
What the research on MIR
had shown was that water vapor in the air from the human astronauts
condensed on the interior surface of the exterior walls. This water
allowed mold and bacteria to survive on these exterior surfaces
rather than die from normal dehydration. Over time, they were
exposed to significant cosmic radiation and eventually mutated to
apparently rapidly growing species.
From an evolutionary and
survivability viewpoint, the survivability and mutation to a rapidly
growing species makes sense. The reason for this is that the
genetic material I mold and bacteria can be easily be destroyed by
radiation. This is why radiation sterilization is used on food
and medical devices. Therefore, only if a species can rapidly
reproduce and grow, will it be able to survive in an elevated
radiation environment.
One can imagine the
potential risk to food safety, if this rapid growth ability for
microbes was passed on to a pathogenic species of bacteria or mold.
This is not unlikely since bacteria “trade” DNA when they
normally pass each other in the environment.
The story does not end
there. The research on mutated mold and bacteria problems on
MIR was a fundamental design challenge in the new International
Space Station. Clearly, water vapor had to be prevented from
condensing on the exterior walls. This seems simple, just keep
the walls warmer. However, with an outside temperature that
can reach below -200 °F, this is easier said than done. The
ISS is well insulated, but one of the factors in dealing with water
condensation is the need to dry out areas where condensation has
occurred. Further, if water does spill on the ISS and it works
its way to the exterior skin, it has to somehow be forcibly
evaporated.
What the ISS designers
decided to do is build a 1” air space all round the exterior of
the ISS. Air is constantly circulates through this air space.
If any water condenses during the dark side exposure, the forced air
will evaporate the water about an hour later when the ISS enters the
sunny side of the earth on each orbit. This standard air gap design
is required for all modules of the ISS.
In mid 2009, the Russians
announced that they intend to keep their sections of the ISS in
orbit as a space station, even after the ISS is supposed to be
decommissioned around 2030. The Russians stated that
they learned a lot about maintaining a space craft for many years
and feel that even though other countries may think that their space
station modules have exceeded their useful life, Russia’s modules
can be used for many more years into the future.
I. A Cause of IAQ
Problems - ASHRAE 62-1981
Even though IAQ was an
issue during the turn of 19th century and the industrial
revolution, the benefits of the industrial revolution and its huge
leap of knowledge human capability was wasted with the mass
production of military weapons and two world wars. All of the
knowledge about IAQ that was discovered in the later 1800s was lost
and forgotten. |