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Old 2007-05-28, 6:30am
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bhhco bhhco is offline
What, Me Worry?
 
Join Date: Jul 09, 2005
Location: Texas
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I think what may have happened here is relative to flameworker-torch position, and more specifically, the breathing zone relative to the thermal plume created by the torch, containing the combustion products.

First, when we use new techniques there is a natural tendency to physically move our bodies, and more specifically our face, closer to the work being done. This closes the 'safety gap' between our breathing zone and the thermal plume, potentially increasing our exposure to high concentrations of combustion products.

Second, the process of fuming requires inserting an object into the flame very close the face of the torch. The object perturbates the thermal plume which results in a backward curving plume which places it even closer to a flameworker's breathing zone - even if ergonomic postioning may be adequate for normal flamework operations.

These two factors, coupled together, can result in combustion products being respirated by a flameworker - at concentrations far greater than 'normal'.

Unfortunately, this is difficult to solve by ventilation alone. If a flameworker's breathing zone overlaps the thermal plume (or vice versa) before the plume can reach the exhaust system, then combustion products will be inhaled by the flameworker. If the concentration and time of exposure exceeds the permissible exposure limits, it can result in acute and chronic physical effects.

So... what to do? We should maintain a 'safety gap' between our breathing zone and the thermal plume. It is difficult to clearly define this gap because the thermal plume is colorless and odorless, and is not easily discerned by sight or smell - but some research has been done to define the thermal plume's 'envelope'. Additionally, it is difficult to clearly define the breathing zone, but it is relative to the nose and mouth, and can be described as a hemisphere centered on the nose tip, of nominally 6"-12" radius. Since the head is often in motion, so also is the breathing zone.

One simple guideline can help: If the nose extends over any part of the torch body... then the breathing zone and the thermal plume will overlap, and inhalation of combustion products is certain.

Me
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