EPS & Mold / Fungus
Mold & Fungus – Often these terms are used
interchangeably. Though both are fungi, mold is generally used to specifically
describe unwanted growth on building materials or food. Between the two
loose distinctions, there are thousands of varieties of fungi currently
identified. Of these, only a few are particularly harmful to human health--most
are considered undesirable only for their detrimental affects on aesthetics
or structural properties.
How do they spread? - While plants often use seeds to
propagate, mold & fungi utilize spores. Much like dust mites, the
spores are everywhere--in even the cleanest kitchen, bread can go moldy
after a few days exposed to humid conditions. For the most part, the spores
do not present a problem until activated. Once activated, molds can release
mycotoxins, the real culprits in causing health problems related to mold
growth.
How are the spores activated? – Usually the two
‘W’s, “water & warmth.” Most building interiors
already meet the ‘warmth’ requirement. Where water pools or
high humidity levels result in condensation or dank conditions, spores
can be activated. This is why sources of water infiltration into buildings
MUST be eliminated. To keep the mold & fungi outside, moisture must
be kept under control. A shower can be cleaned of mold & mildew--this
is NOT the best approach for construction materials!
What are ‘treated’ or ‘preserved’ materials?
– Because some building materials are expected to endure prolonged
water exposure throughout their useful life, various methods and terminology
have been created to describe the corrective measures. Wood is often ‘preserved’
to guard against fungal rot. Caulk for showers sometimes has biocides
incorporated to ‘treat’ the material. EPS is not usually treated
in any way. Its resistance to mold or fungi growth is not due to any special
additives.
What tests are available? – As of the writing
of this bulletin, over 20 tests can be found in ASTM for mold, fungus,
and mildew resistance or damage, and more are being proposed every year.
For insulating materials, a good test is: ASTM C1338, “Standard
Test Method for Determining Fungi Resistance of Insulating Materials and
Facings.” This test uses 5 specific fungi to check for growth on
the material.
How does EPS perform against C1338? – Expanded
Polystyrene with no additives has been tested against the following inoculum,
and scored “no traces of growth” after 28 days of incubation:
• Aspergillus niger
• Aspergillus versicolor
• Penicillium funiculosum
• Chaetomium globosum
• Aspergillus flavus
Does this mean that EPS is Mold / Fungus Resistant?
– The test results above show that in a lab under ideal growth conditions,
the 5 fungi did not grow. EPS has no nutritive value. Further testing
on other fungi / mold should continue to validate that Falcon EPS does
not support growth. |
