Pest Control - Tent Fumigation

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Tent Fumigation - Topic Update

Hawaii Fumigation

2005-06-16, 2:33 pm

I received the following 5 questions via email as a continuance of the
previous related thread. My reply to these questions follows
thereafter. The reply is long, but thorough and should make a good read
for those who are interested.

(1) How is the tent sealed at the bottom of the property? Is it just
draped to the ground?

(2) I got one company that came by. I asked him your recommended
questions. He is unsure of what "CTE" means, but told me they are
"insured". He also told me the gas they use will kill an adult in 10
seconds if I breath it. When I asked him whether it is Vikane, he said
yes.

(3) If this gas expands and expands and creeps into all the cervices
and cracks, how does these gas come back out at the end? I understand
they will "air out" the house and make sure it is safe before I
re-enter, but is this gas heavier than air or lighter? Will it stay in
some "pockets" and be potentially deadly to someone?

(4) If this gas will kill people in 10 seconds, will it be reasonable
to assume, that when they remove the tent and open the window, all
these gas will rush out of the house, and if someone walking a dog
passes by, they will die in ten seconds if they walked too close?

(5) If the air will expands and get into all the cracks, what is
stopping it from expanding and find it's way out of the tent at the
bottom of he tent? It is just soil at the foundation I assume they
will just be draped on the ground?

REPLY

Question #1: The tarps are dropped to the ground and then weighted
with sand and/or water snakes. These are similar to sand bags used for
flooding, but they are longer and more cylindrical in shape, allowing
them to conform to the terrain beneath.

Question #2: CTE is "Commitment to Excellence". This is a
recognition that is awarded to highly select companies throughout the
nation. The recognition of this title is awarded by Dow Agrosciences
(the manufacturer of Vikane) and they award these only to companies
that continuously demonstrate superior expertise and knowledge, and
consistently practice the highest standards quality workmanship.

Visit this link to learn more: Commitment to Excellence Home

There are several companies who will claim they are CTE certified. Ask
for a copy of their CTE certificate. If they don't have one, then they
are not CTE.

Question #2b: Regarding risk of death due to Vikane exposure. I will
cover this last, in conjunction to Question #4.

Question #3: Scientifically, gas is heavier than air. However, it
is important to note that gas also reacts to temperature. A properly
controlled environment enables gas to stabilize at equal levels
throughout a structure. In fumigation, this is referred to as
"equilibrium", which plays a vital role in achieving effective
treatment. The gas will expand to all voids within an enclosed
environment, but higher concentrations could occur in locations that
are colder than others. Because of this factor, achieving balanced
temperatures within and throughout the enclosed structure is important.
If balanced temperatures are not acheived, compartmentalization of the
gas will result. If this is not addressed or accounted for, the risk
of ineffective treatment increases. Why? Because a space that is 70
degrees requires a different concentration of gas and exposure time
than a space that is 80 degrees or 60 degrees.

Here is a layman's example for you: Let's suggest that during the
course of fumigation your attic averages a temperature of 80 degrees.
Your main floor averages a temperature of 75 degrees and your basement
averages a temperature of 68 degrees. Let's further suggest that
adequate measures are not taken to control and balance the temperatures
in your home, thus compartmentalization results. The fumigator
introduces a set amount of gas into the structure. The gas expands
throughout but its concentration levels in the three sections varies
because of the varying temperatures. Equilibrium never occurs. Now
there are problems with this scenario:

1. The gas will tend to move toward the coldest spot. This presents
the high risk that the concentrations that remain in the mid and upper
section are less than required.

2. The colder the spot, the higher the concentration and exposure time
needs to be. If the tarps are removed based on calculations of the
main floor temperature, the lower (colder) section may not have
received sufficient exposure time either.

If temperatures cannot be controlled and compartmentalization is
unavoidable, can an effective treatment be achieved? Yes, BUT, the
compartmentalization factor must be recognized and accounted for before
the introduction of gas. If the fumigator recognizes this, he can then
address each section individually. This would be done by calculating
gas quantities for each section based on the volume of each space and
the temperature of each space, and then introducing the appropriate
amount of gas separately in all three sections. For example one
section might require 8 pounds of gas introduction while the 2nd
section may require 14 pounds, and the third might require 17 pounds.
It can be done, but the most ideal method is to attain balanced
temperatures and equilibrium.

(Note: In cases where balanced temperatures are achieved, equilibrium
of the gas is typically reached within 1 hour (or less) of
introduction)

Question #5: First, refer to the ground sealing information answer of
Question #1. Different ground conditions offer different degrees of
sealing. A home on water (a boat/boat home) provides the best
underseal because gas will not penetrate water and the tarps are
dropped beneath the waterline. For homes on land, a house on concrete
slab provides the best seal potential as the gas will not penetrate
concrete. With concrete slabs, the tarps are dropped and sealed up
against the slab using sand and/or water snakes. For homes that are
situated on dirt, it is not uncommon for the fumigators to account for
small amounts of gas loss or they will thoroughly water the ground
around the structure and seal the tarps to that wet ground. Watering
the ground prevents and/or reduces gas loss since gas cannot penetrate
water. In the event that watering is not feasible, a knowledgable
fumigator will account for small amounts of gas seepage by introducing
a higher level of Vikane concentration into the structure.

Question 2b & 4: I have this saying that unfortunately I find I am
having to use too often. It goes: "Misinformation is just as
dangerous as misapplication".

At the levels of concentration used to fumigate homes, suggesting that
a person would be killed within 10 seconds of exposure is ludicrous and
irresponsible to say the least. Additionally, the credibility of that
statement comes into serious question if you pose the counter question
of: "If it takes only 10 seconds to kill a human, why does the home
need to be enclosed for so many hours just to kill termites?".
Afterall, typically it doesn't take more than an hour for the gas to
reach equilibrium and penetrate all the voids so what are all the other
many hours for if gas exposure equates to lethal result within 10
seconds?

I hate to bring up horror stories that occur within the fumigation
industry, but given the misinformation you were provided, the
disclosure of a real-life horror story is called for. The following
story is true and was reported nationwide.

In March 2005 (yes, this year), a woman was killed due to Vikane
expoure. The woman had been exposed to the initial concentrations of
fumigant for several hours. A fumigator re-entered the structure to
evacuate the woman who was alive at that time. She died later at the
hospital.

This is a very unfortunate event and by no means is it my intention to
play it down. However, as it pertains to your question, you can see
that 10 seconds is a drastic exaggeration. Understand that the
concentrations of gas are at its highest upon introduction. Over the
course of a fumigation, the level of concentration begins to decrease.
The female victim mentioned above had been in the structure for several
hours at the early stage of fumigation when the gas concentration was
at its highest levels. She escaped the structure alive, but later died
at the hospital. It is my assumption that her death resulted from
pulmonary and/or respiratory complications onset by the heavy exposure
over a consistent period of time.

********

As discussed previously, gas will expand to all voids. When the tarps
are removed, the ambient air outside of your home becomes an additional
void for the gas to fill and therefore, the gas dissipates to that open
air space. Because of the volume of open air outside, coupled with the
reduced concentrations of gas within the structure at the end of the
fumigation, the reduced levels of remaining gas that dissipates into
the air further "dilutes". In essence, the particles of gas released
to open air become so minute within the quantities of breathable air.

However, within the home, gas may take longer to expand out from double
walls and other small cracks and crevices. This is why your home is
required to undergo a minimum of 6 hours of aeration and a final check
before it can be posted for safe re-entry. A final check is properly
performed ONLY IF your fumigator verifies the gas levels within the
structure using an Interscan gas analyzer. This piece of equipment
measures the levels of remaining gas in the home. At this time, a
fumigator may not release the property to you until he can certify an
Interscan reading of 5 parts per million or less. In other words, his
reading must indicate that there are no more than 5 parts of Vikane gas
in your home for every one million parts of breathable air in your
home. Studies have shown that in most cases, after 6 hours of
aeration, readings are already at 0 parts per million. And in some
case, 0 parts per million is achieved in less time than 6 hours. If
any portion in the structure reads higher than 5 parts per million, the
structure is not considered safe to enter and may not be released back
to the homeowner.

Now with all of that said, when the tarps are removed and the remaining
gas dissipates into open air, can you imagine how many billions of
parts of air will dilute the quantity of parts of gas? This also
explains why, when the tarps are dropped, the fumigation crew is able
to stand right there to remove their equipment.

Fumigation is often not recognized for its complexity. It requires
strong math skills, attention to details, knowledge of physics, spacial
geometry, and basic chemistry. It is not simplified to throwing a
bunch of tarps on a structure and introducing poison. So, in closing
this reply, I have to say that I'd be wary of the company/individual
who was so quick to provide you with misinformation, especially when he
has no means to quantify his statements. If he himself is so
misinformed, I cannot help but question his ability to perform the job
properly given the knowledge that is required to conduct a fumigation
effectively.

Aloha!
C. Plasman
Hawaii Fumigation & Pest Control

bugs@bugs.com

2005-06-16, 2:33 pm

Excellent reading Claudine many thanks. I feel privileged to have a friend
so knowledgeable in fumigation. You know you should teach this stuff
someday.

--
I wish you all the best
Tim Wise

www.onepest.com
www.askourpros.com

Hooligan

2005-06-19, 12:25 pm

bugs@bugs.com wrote:

quote:

> Excellent reading Claudine many thanks. I feel privileged to have a friend
> so knowledgeable in fumigation. You know you should teach this stuff
> someday.
>
> --
> I wish you all the best
> Tim Wise
>
> www.onepest.com
> www.askourpros.com

If I have a question about fumes, I got to Claudine because she give
the most acurate info.

miamicuse

2005-07-09, 11:25 pm

All:

I was the original poster, Claudine has been extremely helpful in helping me
understand the process as well as selecting a company. I had four companies
that came by to provide an estimate, and I just played dumb and ask all
sorts of questions, you cannot believe some of the answers I got, that
borderlines on comical.

Yes, one company told me the gas is so strong it will kill an adult in ten
seconds. Fifteen minutes later, he told me, by law, Florida requires tear
gas to be mixed into the gas in order to deter burglars. See the
contradiction? If it kills an adult in ten seconds, why do you need tear
gas to stop them? They won't have time to steal anything before they drop
dead!

I got three estimates, one for $850 with a $98 per year renewal, another
for $780 with a $130 per year renewal, and a $1198 with a $150 per year
renewal, all have a one year guarantee. I ended up picking the $780
company, not because of price, but because they are a CTE member and seemed
the least "sales" oriented.

There are also some differences in how they structure their prices. Some
offer lower price for tenting, but have higher renewals. Some offer limited
guarantees, but only if you call them in annually for checkup or else you
lose your guarantee (seems reasonable). Some of them offer a pre tenting
walk through, where they examine how you pack your stuff, make sure your
medicine, water, cereal boxes, snacks etc...are out of the way, make sure
shrubs and flowers near property are trimmed back etc... and others will
give you a prep sheet and say see you on the fume day. Some will provide
plastic sealer bags for free, other will sell it to you at $2 a piece.

Another company came by and offered spot treatment, and a boric acid soaking
spray in my attic. The selling point is that even though it is not 100%
guarantee kill like tenting, but the boric acid spray will PREVENT any new
termites from infecting the structure. After careful consideration, I
decided to go with the tenting so I can be sure.

I have scheduled my tenting to be done in mig August, yes it is slow, but it
is the season and they are booked up. If there is any interest, I can do a
post later after the ordeal with a play by play.

MC

"Hooligan" <loriganpestcontrol@alltel.net> wrote in message
news:1119173179.757238.112780@g49g2000cwa.googlegroups.com...

quote:

>
>
> bugs@bugs.com wrote:
friend[vbcol=seagreen]
>
>
> If I have a question about fumes, I got to Claudine because she give
> the most acurate info.
>

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