CO is a killer , but CO2 is as well.

[Glenn]

CO is a killer , but CO2 is as well  by caspa

Ventilation is key. Im kinda fortunate that Ill be testing my working forge and area with a Gas analysizer for combustion products (Gas Safe Engineer). But I see quite a few photos of new guys burners in garages with the door closed. Stay Safe guys. Sorry if it sounds condescending as a new member, not meant that way.

CO2

250-350ppm Normal background concentration in outdoor ambient air

350-1,000ppm Concentrations typical of occupied indoor spaces with good air exchange

1,000-2,000ppm Complaints of drowsiness and poor air.

2,000-5,000 ppm Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.

5,000 Workplace exposure limit (as 8-hour TWA) in most jurisdictions.

>40,000 ppm Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.

 

CO

9 ppmCO Max prolonged exposure (ASHRAE standard)

35 ppmCO Max exposure for 8 hour work day (OSHA)

800 ppmCO Death within 2 to 3 hours

12,800 ppmCO Death within 1 to 3 minutes

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A CO detector is a very good idea; it can warn you about a lack of clean air in your shop, but just as important as knowing about a problem is managing it.

Don't forget to allow some air to enter between the burner pipe and the burner portal; whether the portal is a larger pipe than the burner, or just a hole through firebrick. I have noticed lots of guys stuffing ceramic fiber into the gap between the burner and the portal opening; that is acceptable way to prevent too much secondary air entertainment, only with burners that achieve complete combustion in a single flame envelope. The bulk of burners (even those that make neutral flames) have a secondary flame envelope, which requires additional air to burn.

Caution: The air that your burner induces will mostly burn in the primary flame, leaving insufficient oxygen left over to completely burn any secondary flame. Without a secondary air source to completely combust fuel gasses, carbon monoxide will form as part of the exhaust. 

Your burner will not find air within the forge for more than a few seconds unless it is provided through the burner portal's opening, by being induced by the burner's flame. It is desirable to control the introduction of excessive secondary air, for burner efficiency, but it is utterly necessary to provide sufficient secondary air to completely burn the fuel, for safety!

If your burner can't burn its fuel completely with only the air provided through its mixing tube, THEN DO NOT STUFF CERAMIC FIBER AROUND THE BURNER. A movable washer, which can provide a variable amount of secondary air for a burner that is mounted in the forge will work fine, and can be used safely; ceramic fiber cannot in this case! 

[CamCarpenter]

On 4/14/2019 at 12:23 AM, Glenn said:

 

 

On 4/14/2019 at 12:23 AM, Glenn said:

Caution: The air that your burner induces will mostly burn in the primary flame, leaving insufficient oxygen left over to completely burn any secondary flame. Without a secondary air source to completely combust fuel gasses, carbon monoxide will form as part of the exhaust. 

Your burner will not find air within the forge for more than a few seconds unless it is provided through the burner portal's opening, by being induced by the burner's flame. It is desirable to control the introduction of excessive secondary air, for burner efficiency, but it is utterly necessary to provide sufficient secondary air to completely burn the fuel, for safety!

Thank you, Glenn, for the reminder of the invisible dangers of blacksmithing. There's a lot to learn and I've been repeatedly grateful for the community here at IFI.

Does this still apply when you're using a forced-air ribbon burner? Or any other blown-air system? Or should you still have secondary air coming in through the gap between the burner and the forge?

[Frosty]

YES, any open flame produces CO as well as CO2. A propane burner is burning fuel prodigiously and making combustion products in  scary huge amounts. 

Frosty The Lucky.

 

[ThomasPowers]

A hidden danger is when you rerun exhaust mixed with air through a burner as it is lower in O2 to start with and so even more CO can be produced.  (Why I don't like vertically oriented burners, more chance of hot exhaust getting sucked into them.)

Ventilation is your friend!   My shop has 2 10'x10' roll up doors oriented along the general wind direction, it also has 10' walls and open gables.  I haven't had a CO headache since I started running a gas forge out here!