Successful Dust Capture

Source capture of nickel/chromium weld dust eliminates a health hazard. Integral halogen light improves both work and inspection in tight, hard-to-reach work areas.

• By Joe Topmiller
• Jan 01, 2005

CHALLENGE: How do you effectively capture weld dust when the work constantly moves and varies in size from small (10 liter) to large (30,000+ liter) stainless processing vessels?

Pure-Flo Precision, an ITT Industries Company, custom fabricates portable and stationary stainless steel processing vessels for use in pharmaceutical, biopharmaceutical, food, and beverage processing in a large, 125,000-square-foot facility in Springfield, Mo. Ranging in processing capacity from 10 to more than 30,000 liters, the vessels are custom fabricated to order with six departments supporting six vessel fabrication production bays.

Vessel fabrication is a complex process of cutting, prepping, rolling, forming, and welding stainless steel or exotic alloys. And, because of its intended use, it is critical that each weld seam inside the vessel be ground smooth and polished. Grinding stainless welds creates a number of worker issues:

1. Welds often have to be ground and polished in very tight, hard-to-reach spaces. For large vessels, that includes going inside through a Manway to complete the process.
2. Grinding stainless welds generates nickel and chromium dust--a potential health hazard.
3. Continuous visual inspection of the grinding work in progress is critical, but it is tough to do if weld dust is allowed to collect on the work area.
4. All vessel orders are custom. Hence, ultimate work flexibility is critical to the process as the tanks are constantly moved and rotated as they are fabricated.

While installation of traditional full-building industrial dust and smoke collection equipment might seem the obvious solution, it would not be as effective as removing the weld dust at the source of the grind. Portable source capture dust collection systems have long been available but have earned a bad reputation--not because of their effectiveness, but because workers don't use them correctly and find them inconvenient and difficult to move around. As a result, the equipment is quickly discarded and the capital investment is wasted.

"We well knew the history and reputation of portable source capture units," noted Jean Erwin, ESH manager at Pure-Flo Precision. "But we felt it important to revisit the issue because of the very tight, hard-to-reach welds our co-workers have to contend with, plus the vast range of vessel sizes that are part of our routine.

"Not only did we have to have excellent weld dust collection at the grinding source, but also we had to have the flexibility to constantly move the collection units to capture weld dust at a variety of points throughout the vessel fabrication process regardless of its size. Our large vessels can easily dwarf a co-worker. The portable units also provide us with added flexibility in terms of supporting our internal Value Based Six Sigma (VBSS) efforts and associated lean manufacturing projects. We need that flexibility as we are constantly implementing better ways of making the product and flowing it through the shop.

"Another issue was the large size of our building. We have quite a few overhead cranes and piping that would make the effectiveness of a single overall plant dust collection system difficult at best. Simply, we had to find a way to make source capture work not only in terms of dust collection, but also co-worker satisfaction."

The Selection Process
"To make a solid, informed purchase decision, we conducted a series of industrial hygiene production trials with portable source capture equipment from four of the industry's leading suppliers," Erwin explained. "Each was checked to review potential pollutant exposure and the ability to meet our CFM requirements. All did."

Next came asking co-workers for their input, likes, and dislikes for each proposed unit, she said. "In addition to ease of use, our co-workers liked the halogen light option mounted inside the source collection hood as it helped them see their work in the tight vessel work places. Based our internal testing and worker feedback, we decided to install a combination of 39 portable and self-contained dust collection units . . . . Our decision was based in large part on the portable units' compact design and the ability to pull the collection arm with its halogen light into very tight, hard-to-reach places."

The completed installation includes:

* 29 FPH2 portable weld dust collectors.
* Three FPN2 portable collectors for smoke extraction at various welding stations.
* One FJS self-contained ceiling mounted cartridge collector for smoke extraction.
* Three small SC1700 cabinet cartridge dust collectors. One unit is installed on a pipe polisher.
* Two SC3400 units installed for small parts hand polishing and dust collection and four units installed on machine polishing stations.

"Co-worker training and acceptance of the portable units," said Erwin, "was exceptionally easy. We were able to cover the operational basics in 15 minutes. A real plus was the halogen lighting in the collection arm hoods. That light source has really made their grinding and polishing of the internal vessel welds considerably easier and less time-consuming than before because they can visually inspect their work with no weld dust covering.

"Now that the majority of units have been installed and operational for the past 12 months, I can report that the dust and smoke collection units were delivered on time and as agreed," Erwin said. Workers' exposure to chromium, nickel, and total particulates was reduced by approximately 75 percent, and the average filter life has been approximately six months, she added.

This article appeared in the January 2005 issue of Occupational Health & Safety.

This article originally appeared in the January 2005 issue of Occupational Health & Safety.