Re: How long do activated charcoal filter cartridges for safety respirators last?

[Guest guest]

How would one know if mold was growing on back of wallpaper? Is it

obvious. So many things to worry about.

--- In , LiveSimply <quackadillian@...>

wrote:

>The mold was growing on the back of

> wallpaper and the entire apartment was covered in it.

>

[Guest guest]

Check out http://science.howstuffworks.com/gas-mask2.htm

http://en.wikipedia.org/wiki/Activated_carbon

then

http://en.wikipedia.org/wiki/Adsorption

with the last one skip all the equations and scroll down to the

charcoal discription.

A short version is activated charcoal looks like a labyrinth of

channels and holes under a microscope. Lots and lots of tiny

holes and channels and nooks and crannies. As gasses pass

around the charcoal particles some are adsorbed (not absorbed)

which means they " stick " to the surface of the tiny pores but don't

actually enter into it like water in a paper towel.

There are only so many locations where the molecules can

" stick. " Once filled, two things happen. 1. New molecules are not

adsorbed. 2. Some already adsorbed become " unstuck " and

pass through the filter. When you start smelling odors from the

charcoal it is time to replace it.

So to answer the question of how long charcoal will last, the

answer depends on how much charcoal is exposed to how many

molecules.

A few ounces of powder glued to a pad in an air purifier will last a

couple of weeks in a typical house with " typical " odors. Bring in

perfumes or fragranced laundry detergent or start painting the

walls and the few ounces of charcoal will become " loaded " or

" full " in a few hours.

If the purifier has pounds of charcoal, it will take longer to " fill " all

the pores because there are more of them. 5-10 pounds of

charcoal in a a typical house with " typical " odors can last as long

as a year. But, again, increase the amount of molecules

sufficiently and they won't last a month.

15 pounds of charcoal costs more to replace than a 5 ounce pad.

But by the time you replace the 5 ounce-pad 80-100 times each

year I'll guarantee you will spend more than them than for the 15

pounds. And they won't be as effective.

Charcoal in respirators is measured in ounces, not pounds.

Carl Grimes

Healthy Habitats LLC

-----

> Carl and Jeff,

>

> I just wanted to ask a technical question. Last year I remember

> reading about somebody who had to investgate a mold death scene that

> was heavily contaminated. The mold was growing on the back of

> wallpaper and the entire apartment was covered in it.

>

> He wore protective gear, obviously, full face respirator, gloves,

> tyvek suit, etc...

>

> He used HEPA cartridges with activated charcoal cartridges in the

> respirator, but the cartridges were a few weeks old.. and he got very

> sick, presumably from the MVOCs.. He said he realized that the

> cartridges were no longer good.. they had been used once before a few

> weeks earlier..

>

> Which sort of begs the question.. How long do activated charcoal

> cartridges for professional safety equipment last once the package has

> been opened?

>

> Also, does anybody know if they can be recharged by heating or

> anything like that?

>

[Guest guest]

The most likely problem is that there was leakage around the mask.

This is unavoidable.Each mask style is associated with a percentage of

leakage.

I doubt that the MVOC concentration was high enough to cause serious

illness, if anything its allergens and mycotoxins.

The lifetime of the charcoal depends on the identity of the

contaminants and the concentrations. Different substances have

differing polarities and therefore adhere with different strengths.

I think that the only way to be sure about charcoal is to test it with

something and see if it adsorbs the odor, though some manufacturer may

have tables as to the amount of a particular chemical the charcoal can

adsorb. This probably deopends on the RH though.

I don't think there is an easy answer.

Jeff

Quoting LiveSimply <quackadillian@...>:

> Carl and Jeff,

>

> I just wanted to ask a technical question. Last year I remember

> reading about somebody who had to investgate a mold death scene that

> was heavily contaminated. The mold was growing on the back of

> wallpaper and the entire apartment was covered in it.

>

> He wore protective gear, obviously, full face respirator, gloves,

> tyvek suit, etc...

>

> He used HEPA cartridges with activated charcoal cartridges in the

> respirator, but the cartridges were a few weeks old.. and he got very

> sick, presumably from the MVOCs.. He said he realized that the

> cartridges were no longer good.. they had been used once before a few

> weeks earlier..

>

> Which sort of begs the question.. How long do activated charcoal

> cartridges for professional safety equipment last once the package has

> been opened?

>

> Also, does anybody know if they can be recharged by heating or

> anything like that?

>

[Guest guest]

I used to have a fish tank and used charcoal filters for it, they

weren't cheap so I took them out and washed them often to prolong

their use my sister washes out her charcoal lined barrel too.

wouldn't ground up charcoal made into biskets/broquers like bbq

charcoal absorb more/longer? wouldn't there also be a difference

between liguid particles getting attached and dry paericles just

getting trapped and maybe wirking their way on through.

--- In , " Carl E. Grimes " <grimes@...>

wrote:

>

> Check out http://science.howstuffworks.com/gas-mask2.htm

> http://en.wikipedia.org/wiki/Activated_carbon

> then

> http://en.wikipedia.org/wiki/Adsorption

> with the last one skip all the equations and scroll down to the

> charcoal discription.

>

[Guest guest]

usually it bubbles up or comes loose in places.

> >The mold was growing on the back of

> > wallpaper and the entire apartment was covered in it.

> >

>

[Guest guest]

Good questions. Charcoal in water is somewhat different than

charcoal in air. Similar to how ozone in water is different than in

air; even why it is good up high but bad down low where we

breathe. Washing charcoal will remove " some " of what is

adsorbed but not much.

Charcoal for BBQ is not activated and is otherwise too dense to

do much good except on its surface. It also is not as highly

heated or as pure as charcoal for air filtering. If you have

problems with reacting to some of the best charcoal just try

Kingsford.

Charcoal will stop some particles but so will a window screen or

the air register on a heating vent. But not enough to make a

difference. Conversely, HEPA filters stop particles very well

because the particles are bigger than the pores in the filter

media. Think of sifting sand through the window screen. The big

particles are blocked but the smaller dust goes right through.

Molecures are hundreds to thousands of times smaller than the

HEPA pores so most go right on through. If the HEPA pores are

made small enough to stop molecules there would be no air flow

either because the molecules are the same size as the air. Block

one and you block them all. That's why charcoal is needed so the

tiny molecules can adhere (but are not trapped) at the tiny

spaces.

Charcoal filtering and HEPA filtering operate according to

different principles.

Carl Grimes

Healthy Habitats LLC

-----

> I used to have a fish tank and used charcoal filters for it, they

> weren't cheap so I took them out and washed them often to prolong

> their use my sister washes out her charcoal lined barrel too.

> wouldn't ground up charcoal made into biskets/broquers like bbq

> charcoal absorb more/longer? wouldn't there also be a difference

> between liguid particles getting attached and dry paericles just

> getting trapped and maybe wirking their way on through.

>

>

> >

> > Check out http://science.howstuffworks.com/gas-mask2.htm

> > http://en.wikipedia.org/wiki/Activated_carbon

> > then

> > http://en.wikipedia.org/wiki/Adsorption

> > with the last one skip all the equations and scroll down to the

> > charcoal discription.

> >

>

> ------------------------------------

>

> FAIR USE NOTICE:

>

>

[Guest guest]

Does electrostatic filters catch the smaller particles that get past

the static filter, MERV rated filter? I picture the friction causing

particles to adhere to electrostatic material but then that friction

able to leave and particle falls off again, UNLESS friction caused by

air flow is constant and keeps particles 'charged' so to speak and

clinging. Is that correct? I know you like Aprilaire which I think

has a combination filter setup.

--- In , " Carl E. Grimes " <grimes@...>

wrote:

>

> Good questions. Charcoal in water is somewhat different than

>

[Guest guest]

Barb,

This can get really complex but in simple terms your question

identifies one of the weaknesses of the self-charging electrostatic

filters. When the airflow stops the static charges begin to drop off

and previously clinging particles can now flow through the pores.

They also don't perform as well in higher humidity, again because

of the reduced (or lack of) static charge.

Constant charge filters like the electronic ones that plug in or the

hybrids like the AprilAire solve that problem but may have other

minor weaknesses.

Carl Grimes

Healthy Habitats LLC

-----

> Does electrostatic filters catch the smaller particles that get past

> the static filter, MERV rated filter? I picture the friction causing

> particles to adhere to electrostatic material but then that friction

> able to leave and particle falls off again, UNLESS friction caused by

> air flow is constant and keeps particles 'charged' so to speak and

> clinging. Is that correct? I know you like Aprilaire which I think

> has a combination filter setup.

>

>

> >

> > Good questions. Charcoal in water is somewhat different than

> >

>

>

> ------------------------------------

>

> FAIR USE NOTICE:

>

>

[Guest guest]

You sent this to me by mistake I think!

From: Carl E. Grimes <grimes@...>

Subject: Re: [] Re: How long do activated charcoal filter

cartridges for safety respirators last?

Date: Thursday, August 14, 2008, 8:29 PM

Barb,

This can get really complex but in simple terms your question

identifies one of the weaknesses of the self-charging electrostatic

filters. When the airflow stops the static charges begin to drop off

and previously clinging particles can now flow through the pores.

They also don't perform as well in higher humidity, again because

of the reduced (or lack of) static charge.

Constant charge filters like the electronic ones that plug in or the

hybrids like the AprilAire solve that problem but may have other

minor weaknesses.

Carl Grimes

Healthy Habitats LLC

-----

> Does electrostatic filters catch the smaller particles that get past

> the static filter, MERV rated filter? I picture the friction causing

> particles to adhere to electrostatic material but then that friction

> able to leave and particle falls off again, UNLESS friction caused by

> air flow is constant and keeps particles 'charged' so to speak and

> clinging. Is that correct? I know you like Aprilaire which I think

> has a combination filter setup.

>

>

> >

> > Good questions. Charcoal in water is somewhat different than

> >

>

>

> ------------ --------- --------- ------

>

> FAIR USE NOTICE:

>

>