[larry lee]

Multiplaz-3500 Evaluation, Part 10: Health and Safety Issues

DISCLAIMER!
Let me emphasize that I will not be able to tell you whether the Multiplaz-3500, or any other piece of equipment, will be a good investment for you. Only you can decide that. My intent is to provide as much factual information as I can about the Multiplaz-3500 so that others in our company can make an informed decision about that. The company has no objection to my sharing the information with you as long as I leave their name out of it and make it clear that I am not endorsing any particular product.
DISCLAIMER!

Quotations from the EXECUTIVE SUMMARY
NOMINATION OF WELDING FUMES FOR TOXICITY STUDIES
National Institute for Occupational Safety and Health, February 20, 2002
(http://ntp.niehs.nih.gov/ntp/htdocs/che ... gfumes.pdf)

“ (Arc) Welding joins pieces of metal that have been made liquid by heat produced as electricity passes from one electrical conductor to another. Extremely high temperatures in the arc heat both the base metal pieces to be joined and a filler metal coming from a consumable electrode wire. Most of the materials in the welding fume comes from the consumable electrode, which is partially volatilized in the welding process. Vaporized metals react with air, producing metal oxides which condense and form fumes consisting of particles that are of respirable size.There is no material from any other source directly comparable to the composition and structure of welding fumes.

“Welding is considered a dangerous occupation because: (1) there are a multiplicity of factors that can endanger the health of a welder, such as heat, burns, radiation, noise, fumes, gases, and electrocution; and (2) the high variability in chemical composition of welding fumes which differs according to the workpiece, method employed, and surrounding environment. The particulates and gases generated during welding are considered to be the most harmful in comparison with the other byproducts of welding. (Bolding mine.)

“The composition and the rate of generation of welding fumes are characteristic of the various welding processes, and are affected by the welding current, shielding gases, and the technique and skill of the welder. The chemical properties of welding fumes can be quite complex. Most welding materials are alloy mixtures of metals characterized by different steels that may contain iron, manganese, silica, chromium, and nickel. Fumes generated from stainless steel electrodes usually contain about 20 % chromium with 10 % nickel, whereas fumes from mild steel welding are usually > 80 % iron with some manganese and no chromium or nickel present. Both chromium and nickel have been classified as human carcinogens. Exposure to high levels of manganese has caused neurological disorders in workers involved in the mining and processing of manganese ores. However, a neurotoxic effect of manganese in welders is uncertain. Several irritant gases, such as carbon monoxide, ozone, and oxides of nitrogen, may be generated in significant quantities during common arc welding processes due to different shielding gases and fluxes used.

“Neuropsychiatric symptoms have been observed in some welders. There is concern that manganese in welding fumes may be the causative agent. Epidemiology findings have not definitively proven whether manganese in welding fumes causes neurotoxicity in exposed workers. Animal studies assessing the effects of welding fumes on the central nervous system have not adequately addressed this question.”

URLs for other articles relating to welding fume toxicity that you may find of interest.

American Society of Safety Engineers:
http://www.asse.org/practicespecialties ... gfumes.php

Cambridge Toxicology Group - ToxicologySource
http://www.toxicologysource.com/scitox/ ... etals.html

Air Quality Engineering
http://www.air-quality-eng.com/weldingsafety.php

Canadian Centre for Occupational Health and Safety
http://www.ccohs.ca/oshanswers/safety_h ... fumes.html

Center to Protect Worker’s Rights (AFL-CIO)
http://www.cpwr.com/hazpdfs/kfwelding.PDF

Mother Jones Magazine
http://www.motherjones.com/politics/200 ... nd-mirrors

So, what has all of this got to do with the Multiplaz-3500?

One of the claimed advantages of the Multiplaz-3500 torches, both cutting and welding, is that the air pollution is much less than with conventional cutting and welding torches.
It is true that the pollutants from the torch plasma itself are small, probably comparable to that of a TIG torch using pure argon. However, the claims go much farther than that:

“The vapor shield that surrounds the plasma jet protects the cut or the welding puddle from the air, meaning hazardous pollutants, including nitrogen oxide, are not an issue. This vapor shield covers the whole domain under the heat treatment and also becomes a barrier for the dangerous dust that can arise from the processing surface of metal.

“This vapor shield traps and settles all particles, eliminating any exposure to the operator’s respiratory system. The shield condenses, dilutes and stops the emission of complex chemical compounds from the heat treatment domain.

“The purity of air during operation is the reason for its frequent use in poorly ventilated areas - underground utility lines, wells, closed spaces, vaults, garages, submarines, etc.”

http://www.multiplaz.com/eco_friendly

No scientific evidence is presented for these claims, and it is clear from my testing that
it is not true that

“The vapor shield that surrounds the plasma jet protects the cut or the welding puddle from the air”

While there is some shielding from the air, there is much more oxidation, whether cutting or welding, with the Multiplaz-3500 torches than there is using conventional technology (compressed air plasma torch or TIG with argon). This is noticeable on mild steel and more so on stainless steel (which is more sensitive to surface oxidation). It is also quite noticeable on aluminum when cutting. (As mentioned in Part 09, we did not try to weld aluminum, since flux is required.)

Nor is it true that

“This vapor shield traps and settles all particles, eliminating any exposure to the operator’s respiratory system.“

Take a look at the videos showing the welding of low-carbon steel and stainless steel and notice all of the “sparkles” boiling out of the puddle.

http://www.multiplaz.com/welding
http://www.multiplaz.com/stainless_steel_welding

Note also that the videos all show welding being done over a downdraft grate.

My main concern here is not to deal with what seem to be exaggerated claims for the performance of the Multiplaz-3500 in general (others have already pointed out that the videos never show the final weld or cut). Nor, of course, are exaggerated claims unique to Multiplaz. My concern is with the health and safety implications of the claims that the torches eliminate any exposure to hazardous fumes from the use of the torch. I am especially concerned since some of the people (non-professional welders) who have purchased the Multiplaz-3500 have stated on this and other websites that they use the torch indoors without any ventilation since there are no toxic fumes.

I wish to point out, as do many of the articles above, that the welding fume toxicity comes primarily from the gases and particles that you can’t see or smell and that it comes primarily from the consumable electrode (or filler rod) and the base material(s). Most of the particulate matter has a diameter of less than 1 micron, some down to 0.01 micron. These particulates are easily carried in the air for long periods of time and lodge in the lung when breathed in. Most of the gases and particulates are respiratory irritants (see the Canadian Centre for Occupational Health and Safety articles above for a comprehensive list), but several cause severe health effects. These are cadmium, lead, manganese, and zinc. The first 3 are cumulative toxins that effect both movement and mental capacity. The effects of excess zinc oxide appear to be reversible.

The dangers of breathing vapors of cadmium and lead compounds are by now well known. The dangers of breathing vapors of manganese compounds are also well known, but there is still much scientific (and unscientific) debate as to what the allowable working concentration should be. The issue with the regulation of manganese air concentration is that manganese is a very useful metal and is used in almost all steels and many, many other materials. The most common exposure to manganese vapor is when welding mild steel and stainless steel, both of which normally contain manganese at a concentration of about 1% by weight in the base material and up to 2.5% in the filler rod. However, the relative vapor emission is higher because the boiling point of manganese is lower than that of iron and steel. The emission of manganese vapor is high from mild steel (even more from special manganese steels); the vapor emission from stainless steel has less manganese and much more chromium and nickel.

The metal with the largest vapor emission is iron (surprise!), but the iron oxide that lodges in the lungs has no apparent toxicity. Large amounts do reduce respiratory capacity. In any event, you really don’t want any of this stuff in your lungs.

So, my point is:

Take care not to breathe the emissions from anything you weld, whether you can see a plume of smoke or not.

If you are stick welding and you can see and smell a big cloud of smoke from the burning coating, it is pretty obvious that there are fumes you don’t want to breathe (and you can see where they are). If you are using a nice clean TIG torch (or a Multiplaz-3500), there may not be anything you can see or smell to remind you that vapors are being given off that you don’t want to breathe. But in either case, you need to protect yourself by making sure that you have adequate ventilation, and that your positioning is appropriate, to keep the vapors out of your lungs. One of these years OSHA will reduce the allowable concentration of manganese (and some other compounds) by factors of from 10 to 50 from where they are now to where they should be. That will cause a great deal of readjustment because it means that even routine welding of mild steel will require a whole new level of worker protection and monitoring (or remote control). In the meantime, protect yourself by breathing as few welding fumes as you can.

to be continued

larry lee

[WerkSpace]

Thank you for the insight, Larry.
As a result of your latest post, I will cease welding of any type in my home.
Good ventilation makes sense, whether I can see or smell any fumes.
You are absolutely right, it's what we can't see that can harm us the most.

[WerkSpace]

Here's some additional reading material that I found on my favorite reference website.
http://www.scribd.com/doc/118801849/Hea ... umes-gases
http://www.scribd.com/doc/92682912/AWS- ... Gases-1979