Carbon Monoxide

Originally Posted By: Gary Reecher
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Have compiled links to sites about carbon monoxide. Hope you can find some useful information there.


http://www.essex1.com/people/mechacc/carbon%20monoxide%20links.htm



Gary Reecher, CM


HVAC Service Technician


MechAcc's Carbon Monoxide Site Links

Originally Posted By: lkage
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Excellant site for info:


http://www.coexperts.com/


--
"I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei

Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Hello Vern-


The current ASHRAE standard references the Canadian Exposure Guideline for Residential Indoor Air Quality for carbon monoxide (CO) as less than 11 ppm for an eight hour exposure. Older versions of ASHRAE referenced the WHO CO level of 2 ppm. I do not like the current ASHRAE CO reference, and I don?t use it. I much prefer the WHO reference, and I use that instead.

Although I would strictly disagree with James B?s comment that there is no safe level of CO, I would agree with the sentiment behind the comment, that if concentrations above 2 ppm are found in a home, the source should be understood. CO is normally found in outdoor air, it is simply a natural component of normal air; therefore, we know that there actually are safe levels of CO and the human body is quite able to handle these normal background levels.

Furthermore, Mr. Bushart?s comments are rather off-base, in that small amounts of CO cannot accumulate in the bloodstream. In fact, CO doesn?t ?accumulate? in the bloodstream at all. CO is in dynamic equilibrium with the breathable air, and exhibits an half-life of about 60 minutes (at sea level). Also, Mr. Bushart?s comment about CO displacing the oxygen in the blood is also incorrect ? quite the opposite, in fact. The primary metabolite of concern is carboxyhaemoglobin which upsets the ?cooperativity? of the normal haem molecule, resulting in MORE oxygen in the blood. CO causes oxygen to accumulate in the blood to unusually elevated levels. This is because the ?cooperativity? has been upset, and the blood cannot properly release the oxygen to where it is needed. That is why persons who experience CO poisoning exhibit flushed skin ? because of their oxygen rich blood. If Mr. B wants zero CO in his breathing air, he will have to move to Venus.

However, outdoor levels can be excessive in urban environments, and so I would also disagree with the comment that indoor levels should not exceed outdoor levels, since I have personally measured outdoor CO concentrations of 65 ppm in urban settings (indicating that 64 ppm in a building would be ?acceptable.?)

Brian is quite correct in that some chemicals will result in false readings. Similarly, human exposure to some chemicals can result in ?CO poisoning,? even in the absence of CO.

Vern- any gas company rep who stated that 25 ppm CO was OK in an house should, in my opinion, be removed from their current role until they have received proper training. I would have no hesitation to evacuate a school or a home if I measured 25 ppm sustained.

I would be happy to pursue the matter further.

Cheers,
Caoimh?n P. Connell
Forensic Industrial Hygienist

www.forensic-applications.com

<SMALL> (The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG </SMALL>


Originally Posted By: rwand1
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Low levels should be a concern with anyone with a heart condition, or who is pregnant or has children in the house.


From what I have heard anyway.


--
Raymond Wand
Alton, ON
The value of experience is not in seeing much,
but in seeing wisely. - Sir William Osler 1905
NACHI Member
Registered Home Inspector (OAHI)
http://www.raymondwand.ca

Originally Posted By: jhagarty
This post was automatically imported from our archived forum.



Caoimh?n P. Connell wrote:


However, outdoor levels can be excessive in urban environments, and so I would also disagree with the comment that indoor levels should not exceed outdoor levels, since I have personally measured outdoor CO concentrations of 65 ppm in urban settings (indicating that 64 ppm in a building would be ?acceptable.?)


![icon_eek.gif](upload://yuxgmvDDEGIQPAyP9sRnK0D0CCY.gif)

Where have you encountered 65 ppm Carbon Monoxide CO in an exterior environmment that made 64 ppm CO acceptable indoors??

Was this a single sampling or sampling conducted over a measured period of exposure?

You are speaking of Residential conditions encountered?


--
Joseph Hagarty

HouseMaster / Main Line, PA
joseph.hagarty@housemaster.com
www.householdinspector.com

Phone: 610-399-9864
Fax : 610-399-9865

HouseMaster. Home inspections. Done right.

Originally Posted By: bkelly2
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Caoimh?n P. Connell wrote:
Hello Vern-

The current ASHRAE standard references the Canadian Exposure Guideline for Residential Indoor Air Quality for carbon monoxide (CO) as less than 11 ppm for an eight hour exposure. Older versions of ASHRAE referenced the WHO CO level of 2 ppm. I do not like the current ASHRAE CO reference, and I don?t use it. I much prefer the WHO reference, and I use that instead.

Although I would strictly disagree with James B?s comment that there is no safe level of CO, I would agree with the sentiment behind the comment, that if concentrations above 2 ppm are found in a home, the source should be understood. CO is normally found in outdoor air, it is simply a natural component of normal air; therefore, we know that there actually are safe levels of CO and the human body is quite able to handle these normal background levels.

Furthermore, Mr. Bushart?s comments are rather off-base, in that small amounts of CO cannot accumulate in the bloodstream. In fact, CO doesn?t ?accumulate? in the bloodstream at all. CO is in dynamic equilibrium with the breathable air, and exhibits an half-life of about 60 minutes (at sea level). Also, Mr. Bushart?s comment about CO displacing the oxygen in the blood is also incorrect ? quite the opposite, in fact. The primary metabolite of concern is carboxyhaemoglobin which upsets the ?cooperativity? of the normal haem molecule, resulting in MORE oxygen in the blood. CO causes oxygen to accumulate in the blood to unusually elevated levels. This is because the ?cooperativity? has been upset, and the blood cannot properly release the oxygen to where it is needed. That is why persons who experience CO poisoning exhibit flushed skin ? because of their oxygen rich blood. If Mr. B wants zero CO in his breathing air, he will have to move to Venus.

However, outdoor levels can be excessive in urban environments, and so I would also disagree with the comment that indoor levels should not exceed outdoor levels, since I have personally measured outdoor CO concentrations of 65 ppm in urban settings (indicating that 64 ppm in a building would be ?acceptable.?)

Brian is quite correct in that some chemicals will result in false readings. Similarly, human exposure to some chemicals can result in ?CO poisoning,? even in the absence of CO.

Vern- any gas company rep who stated that 25 ppm CO was OK in an house should, in my opinion, be removed from their current role until they have received proper training. I would have no hesitation to evacuate a school or a home if I measured 25 ppm sustained.

I would be happy to pursue the matter further.

Cheers,
Caoimh?n P. Connell
Forensic Industrial Hygienist

www.forensic-applications.com

<SMALL> (The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG </SMALL>


We have missed your comments.


--
"I used to be disgusted, Now I try to Be amused"-Elvis Costello

Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Hello Joseph:


The 65 ppm CO concentrations were made in downtown Denver, during the winter months, and the levels were sustained. I don?t recall what the time-weighted CO average was, however, it was in the mid 30?s. The sampling monitor was literally on a busy street corner at about 16th and Broadway.

If the only criteria for CO is that indoor levels should be lower than outdoor levels, then we could have extremely elevated ?acceptable? levels. Again, I disagree with that criteria and recommend using the WHO ?level of no concern? (2 ppm) as a minimum guidance.

Cheers,
Caoimh?n P. Connell
Forensic Industrial Hygienist

www.forensic-applications.com

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG



Originally Posted By: kmcmahon
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In firefighter class, we learned the following:


Up to 100ppm No symptoms-No damage
200ppm - mild headaches
400ppm Headache after 1-2 hours
800ppm Headache after 45min; Nausea, collapse, and unconsciousness after 2 hours.

the list gets worse from here.


--
Wisconsin Home Inspection, ABC Home Inspection LLC

Search the directory for a Wisconsin Home Inspector

Originally Posted By: mthomas2
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> I call out any CO.


> I also put my CO detector right near the vent hood on water heaters (if they have them) and fire up the water heater.

William,

I've been leery of CO detection largely because of what I've read about the need for periodic recalibration of testers if inspectors are to be on firm ground in reporting such results, and about potential liability issues involved in such testing. I notice you are also in IL, can you share anything about the guidelines you are using for such testing and reporting the results, and how you developed them?


Originally Posted By: rwand1
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It is not uncommon to get spillage from natural draft water heaters when they first fire up until the flue warms and starts to draw.


As to minimum ppm at 100 what about people with breathing problems and young children?


--
Raymond Wand
Alton, ON
The value of experience is not in seeing much,
but in seeing wisely. - Sir William Osler 1905
NACHI Member
Registered Home Inspector (OAHI)
http://www.raymondwand.ca

Originally Posted By: kmcmahon
This post was automatically imported from our archived forum.



The table is not absolute because they do not take into account variations in breathing rate or length of exposure or physical condition.



Wisconsin Home Inspection, ABC Home Inspection LLC


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Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Hello Kevin -


I am going to have to strongly, but respectfully, disagree with the information you provided.

At 100 ppm, there will be very prominent signs of symptomology and there will be damage (adverse effects) to normal, healthy adults. Carbon monoxide levels of only 10 ppm (ten ppm) have been shown to degrade behavioral performance and chronic exposure to CO can lead to demyelination of nerves resulting in reduced nerve conduction (Industrial Toxicology, Williams, P.L. and Burson, J.L. Editors). Carbon monoxide levels of about 8 to 10 ppm have resulted in headaches in some people.

Upon exposure to relatively low concentrations of CO, the iron group of the P-450 isozymes (also known as the cytochromes P-450) is oxidized and the enzymes are hindered in their ability to help the body rid itself of other insults.

Since the prevalence of headaches can be observed at concentrations of 8 ppm, then I certainly would expect headaches (along with vomiting and dizziness) at 200 ppm; at 200 ppm, the building should be evacuated and emergency services notified.

I?m guessing that the concentrations to which you are referring are based on emergency responders and are geared toward emergency personnel being exposed for very short periods of time. However, these values are grossly inappropriate for describing symptomology in normal casual settings.

Just my thoughts,
Caoimh?n P. Connell
Forensic Industrial Hygienist
www.forensic-applications.com

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG



Originally Posted By: kmcmahon
This post was automatically imported from our archived forum.



Disagree all you want…I didn’t write the book, just copying the information from it.



Wisconsin Home Inspection, ABC Home Inspection LLC


Search the directory for a Wisconsin Home Inspector

Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Fair enough, Kevin -


Perhaps they need to have someone knowledgable in toxicology and exposures review their training materials before someone gets hurt, eh?

Cheers,
Caoimh?n


Originally Posted By: vmitchinson
This post was automatically imported from our archived forum.



I started this discussion and am suprised at the responce.


I follow the procedure specified by the manufacture of the tester I use It’s Kane-May model SGA91A purchased from professional equipment.


The procedure is


1 Set up and run outside for 2 minutes


2 Set reading to 0


3 take inside and run for 2 minute. Record reading.


4 Start furnace and run for 2 minutes sampling air from furnace as close to the heat exchanger as possible.


5 Record reading.


This procedure starts with the instrument at zero for the outside air. If the reading is above zero inside that means that there is something inside that is putting CO into the space.


The next reading from the furnace establishes if the furnace is adding CO


If the interior reading is the same from the furnace and the indoor air them the source is not the furnace. I them check the water heater


Following this procedure establishes weather or not the furnace and/or water heater is putting CO into the home. If they are not and the inside air has more CO them outside them I inform the buy of this situtatin and go from there.


Originally Posted By: Gary Reecher
This post was automatically imported from our archived forum.



Vern brings up a good point start up the tester outdoors and away from vehicles.


Some testers have auto zero calibration to ambient levels. You'll have to read your meters instructions as to which you have.

Bacharach's Monoxor II is a manual zero calibration and always reads ambient levels and does not auto zero. Their Monoxor III and Fyrite Tech have users choice of either manual zero calibration or auto zero.

The thing about auto zero if you go into a home and start reading negative co you can be sure you turned the unit on in the presence of co.


--
Gary Reecher, CM
HVAC Service Technician

MechAcc's Carbon Monoxide Site Links

Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Hello All-


With all the talk about CO, and due to some of the emails I?ve received, I would like to point out that many home ?CO monitors? don?t actually measure CO at all and shouldn?t be used as a field instrument to measure CO levels.

For example, in my home, I use the Nighthawk brand CO detector. In my humble opinion, these are excellent devices. There is an LED display that reads out CO in ppm. However, if I go and grab one of my (rather expensive) pieces of scientific equipment and place it side-by-side with the Nighthawk, I will see that there is a disparity between the two readings. This is because the residential monitor I have is based on a biomimetic sensor that mimics the formation of carboxyhaemoglobin in the blood, and displays the airborne CO concentration that would result in that percent saturation ? it doesn?t actually display the current concentration of CO. It?s a great idea and can help avoid false alarms due to transient spikes of CO (for example if a school bus idles outside a home for a little too long).

As such, although the Nighthawk (and similar biomimetic sensors) are excellent, they are only excellent within the context of their intended purpose, and should NOT be used as field instruments to measure CO.

Ok? you can have the soap box back again.

Cheers,
Caoimh?n P. Connell

www.forensic-applications.com

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG



Originally Posted By: rwand1
This post was automatically imported from our archived forum.



What about smokers in the house. I imagine this would elevate readings?


Thank you.


--
Raymond Wand
Alton, ON
The value of experience is not in seeing much,
but in seeing wisely. - Sir William Osler 1905
NACHI Member
Registered Home Inspector (OAHI)
http://www.raymondwand.ca

Originally Posted By: Caoimh?n P. Connell
This post was automatically imported from our archived forum.



Hello Raymond ?


The contribution of CO by smoking is often overlooked by the general public; in particular by smokers. Although it may sound ridiculous, I have often encountered smokers in office and industrial settings who complain about the possibility of low levels of CO in the air. Nonsmokers typically have less than 0.5% HbCO; smokers on the other hand may have twenty times this amount.

Whenever smokers complain about indoor air quality in an office, I really, really, really, have to exercise tremendous personal control so I don?t burst out and just laugh. (For the record, we treat all IAQ complaints equally objectively). (Shhh.... I had to put that in to keep the attorneys at bay...)

Cheers,
Caoimh?n P. Connell
Forensic Industrial Hygienist


www.forensic-applications.com

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG



Originally Posted By: kmcmahon
This post was automatically imported from our archived forum.



From a course I’m currently taking,


0 PPM (0%)

ANSI standard for appliance manufacturing. No allowable CO production.
9 PPM (0.0009%)

The maximum allowable concentration for short-term exposure in a living area according to ASHRAE.
11PPM (.0011%)

Maximum allowable concentration for exposure in an 8-hour period according to Canadian standards.
35PPM (0.0035%)

The maximum allowable concentration for continuous exposure in any 1-hour period outdoors, according to EPA.
200PPM (0.02%)

Slight headache, tiredness, dizziness, nausea after 2-3 hours. Maximum CO concentration for exposure at any time as prescribed by OSHA.
400PPM (0.04%)

Frontal headaches within 1-2hours, life-threatening after 3 hours, also maximum parts per million in flue gas according to EPA and AGA.
800PPM (0.08%)

Dizziness, nausea and convulsions within 45 minutes. Unconsciousness within 2 hours. Death possible within 2-3 hours.
1,600PPM (0.16%)

Headache, dizziness, and nausea within 20 minutes. Death possible within 1 hour.
6,400PPM (0.64%)

Headache, dizziness and nausea within 1-2 minutes. Death possible within 10-15 minutes.
12,800PPM (1.26%)

Death within 1-3 minutes.


--
Wisconsin Home Inspection, ABC Home Inspection LLC

Search the directory for a Wisconsin Home Inspector