Carbon Monoxide

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21

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

22

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


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23

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

24

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.

25

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

26

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

27

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

28

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

29

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

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