The Start of the Mold Problems in the U.S.

[Guest guest]

In the United States, the 1970’s saw

the extensive use of drywall (gypsum board with paper on both sides) in

both residential and commercial construction. This was mainly because

drywall construction costs 50% less than plaster construction. Thus

began the introduction of “mold friendly†building materials into

homes, commercial, and industrial buildings. The paper and glues in

drywall are organic materials that can support mold growth when they

become wet. Plaster, on the other hand, contains very little organic

matter to retain water or to support mold growth (Occasionally,

horsehair and cellulose can be found in the rough coat.) Plaster also

has a final coat of ‘lime plaster’ which is mostly calcium hydroxide.

Lime plaster is very alkaline when wet, which further inhibits

microbial growth. Therefore, drywall is much more “mold friendly†than

plaster.

The

next factor in the start of the mold problem was energy market

manipulation in the mid 1970’s. The oligopolistic major oil companies

induced a fabricated “oil shortage†by holding imported oil in tankers

off shore and creating a so-called “energy crisis.†This contrived oil

shortage was similar to the one created in the early 1920’s (see

newspapers of that time for references). The prior contrived shortage

also resulted in significantly increasing oil prices and corporate

profits. This also ushered in an era of “energy conservation†in the

US.

Note:

Another example of “repeating history when we failed to learn from itâ€

occurred in the area of ventilation standards. In December 1981, in

response to the contrived “energy crisis†mentioned above, the American

Society of Heating, Refrigeration and Air Conditioning Engineers

(ASHRAE) reduced the required amount of outside make-up air from 15 cfm

per person to only 5 cfm per person. This ventilation standard (ASHRAE

62-1981) clearly disregarded earlier research that showed a health risk

from low ventilation rates. Shortly thereafter, the indoor air quality

/sick building problems of the 1980’s began to surface. In January of

1983, ASHRAE rescinded its 62-1981 standard due to “health concerns.â€

Worse

yet, thousands of buildings continued to be built a number of years

after that using the unhealthful ASHRAE 62-1981 for. The main reason

for this continued unhealthy construction was the common practice in

the US of using the “low bidder.†Mechanical engineering firms would

win contracts by being the low bidder using the ventilation system

requirements of ASHRAE 62-1981 (5 cfm/person) over the higher bids of

competing companies using the correct, older ventilation requirements

of ASHRAE 62-1976 (15 cfm/person).

Professional

mechanical engineers, even though they were aware of the “health

concerns†statement by ASHRAE, were under no “legal†duty to inform

prospective building owner of the unhealthiness of 62-1981, since this

is only a guideline. As the same time, few building owners were unaware

that ASHRAE had retracted the newer standard. Consequently, the

practice of building poorly-ventilated buildings continued throughout

the 1980’s until the formal reissuing of this standard by ASHRAE in

1989. Many local government code bodies, also unaware that ASHRAE had

rescinded the 62-1981 standard, continued to specify these unhealthful

ventilation rates until 1990.

Consequently,

many homes and commercial buildings built during that decade were

“tightened up†to reduce heating and cooling costs. Insulation

standards increased and infiltration rates were decreased. The

consequence of this was that when drywall became wet, due to decreased

wall air infiltration and less ventilation of moisture-ladened air, it

did not dry out as quickly as it did in the past. Mold growth became a

problem after even relatively minor water intrusion events.

In the

1980’s, Canada and the Scandinavian countries, as an extension of the

concern about radon gas in homes, began to study indoor mold levels.

The computerized national healthcare record systems in these countries

made identifying mold related health symptoms an easy task. This

disease incidence data could then be compared to specific mold levels

in individual patient homes. These countries subsequently developed

“acceptable†mold standards for housing. These standards are still in

use today.

Two

of the major studies of the relationship of indoor mold to occupant

illness in homes were conducted in the Netherlands 352 and Taiwan 336

in the early 1990’s. Neither of these studies found a directly

relationship between reported symptoms and mold spore levels. However,

the reporting of “damp†conditions in the home clearly was related to

an increased risk of respiratory disease.

In

the 1990’s, the potential health implications of indoor mold growth

were finally broadly recognized in the United States. Further,

buildings containing “mold-friendly†building materials were now

widespread throughout the United States. Interestingly, Germany,

Poland, Columbia, the Czech Republic, Slovakia and many other countries

still require the use of plaster instead of drywall and coincidently do

not have as many mold problems as are found in the United States.

Note:

An interesting story regarding to the use of plaster occurred in 2000

when the Czech Republic experienced extensive flooding. The AIHA

contacted officials in that country and offered them help with mold

problems resulting from the flooding. The officials wrote back to the

AIHA and said they had very little mold problems from the flooding

because they don’t use drywall.

[Guest guest]

Good find . Confirms my desire to avoid drywall, and use plaster.

I googled a sentence to find the source, and found this,

http://www.safety-epa.com/history_mold_air_sampling.htm

which shows the history of mold sampling which was good as well.

I knew most of the theory behind mold sampling development,

but it's good to see it all in one place, even if it is not current to

present day.

Apparently, two other web sites contained the sentence I googled,

but focused on storing of water in building materials and reduce

their usage in buildings. One was a presentation in 1997, and

a firm offering computerized mold remediation. Quote:

WUFI® (Wärme und Feuchte instationär) hygrothermal modeling software

developed by Oak Ridge National Laboratory (ORNL) in the U.S. and the

Fraunhofer Institute of Building Physics in Germany.

http://www.mzaconsulting.com/services/buildingsciences/diagnostics.html

Mentions a book at the end

MZA is the author of " Mold and Moisture Damage in Building

Envelopes " in the Whole Building Design Guide, published by NIBS (the

National Institute of Building Sciences).

[Guest guest]

, thanks for adding the URL. I always add the URL, but I was in a hurry

and must have copied and pasted it incorrectly.

----- Forwarded Message ----

From: <pete-@...>

Sent: Saturday, August 22, 2009 7:35:07 PM

Subject: Re: [] The Start of the Mold Problems in the U.S.

Good find . Confirms my desire to avoid drywall, and use plaster.

I googled a sentence to find the source, and found this,

http://www.safety- epa.com/history_ mold_air_ sampling. htm

which shows the history of mold sampling which was good as well.

I knew most of the theory behind mold sampling development,

but it's good to see it all in one place, even if it is not current to

present day.

[Guest guest]

and ,

There is an extra space in the link. The corrected one is:

http://www.safety-epa.com/history_mold_air_sampling.htm

BTW, this site is by the same person who wrote the books

previously mentioned at: http://www.oehcs.com/

He is Bob s and is on the Board of and is the current

Standards Development Committee (SDC) Chair of the Indoor

Environmental Standards Organization (IESO)

http://www.indoorstandards.org/OrganizationalStructure.asp.

IESO is ANSI accredited (www.ansi.org) and is currently writing a

mold assessment standard for residential and for schools. Others

under development are a fire restoration standard, measuring

fire-related residue in HVAC systems, on-site verification of the

operation of HEPA filtration (during mold remediation, for

example), measuring low EMF radiation in residential buildings,

and the effectiveness of dehumidifiers (mostly during mold

remediation). Plus a few more.

The HEPA filtration standard was just released for public review

earlier this week. You can sign up to review it at:

http://www.indoorstandards.org/standards/index.asp

Carl Grimes

Healthy Habitats LLC

-----

>

> Good find . Confirms my desire to avoid drywall, and use plaster.

>

> I googled a sentence to find the source, and found this,

> http://www.safety- epa.com/history_mold_air_sampling.htm

> which shows the history of mold sampling which was good as well.

> I knew most of the theory behind mold sampling development,

>