Steel Coatings Articles

From the Rafters: Insulative Coating for Condensation

Photos courtesy of the Righter Group, Inc.
Vendor Team

Safety equipment manufacturer
3M Center
St. Paul, MN 55144
(800) 364-3577

APC Services of New England
Coatings contractors
368 Main St.
Melrose, MA 02176
(781) 665-5600

Graco Inc.
Equipment manufacturer
88 11th Ave. NE
Minneapolis, MN 55413
(612) 623-6000

Florida Power Washing Equipment & Supplies
Equipment manufacturer
671 Progress Way
Sanford, FL 32771
(407) 688-4532

Ingersoll Rand
Equipment manufacturer
800-E Beaty St.
Davidson, NC 28036
(704) 655-4000

Tnemec Company
Coatings manufacturer
6800 Corporate Dr.
Kansas City, MO 64120
(800) 863-6321

Here’s a riddle: How do you stop a condensation cycle from happening?

For the client, which wishes to remain unnamed, and the coatings contractor, APC Services of New England, that was the question. “They had an issue whereby their manufacturing plant created a lot of moisture as part of the process itself, and they have a condensation issue in that the moisture in the air would hit the cold steel above, condense, and then droplets of condensed water — mixed with whatever yuck happened to be on the ceiling — would drip down on their manufacturing process,” APC’s President Patrick Ronan said. “The manufacturing process utilized mostly closed but a few open cook kettles of the gelatin that they make there and obviously they didn’t want stuff dropping down into their kettles. So they had to find a way to prevent that from happening.”

And for them, the answer was insulation coatings.

Recipe for Success

APC has worked with this client in the past during their typical annual summertime shut-down period. It was because of this planned outage, though, that another challenge was introduced.

The floors were also to be recoated but by a different contractor. Because of that and the normal stresses to get the facility back up online as soon as possible, the APC crew had to work on a tight schedule. The crew “protected, primed, painted, Aerolon’ed so that [the client] could get it all back within that two-week timeline,” Ronan said. First they got the 1,500-square-foot (139.4 m²) room ready.

The six-person crew worked in two teams of three. One team started by covering anything they didn’t want to be over-sprayed with 6-mil (152.4 microns) plastic, including the walls, floors, pipes, and sprinklers. “Everything that you can imagine had to be masked off to protect from overspray because it was all stainless steel and couldn’t get paint on it,” Ronan said. When the eight-hour shift was done, the next team came in to finish the task. They started with “just a lot of taping and plastic wrapping the first day,” he explained.

Wearing hard hats, safety glasses, work boots, and 3M eye protection, the crew power washed all 3,400 square feet (315.9 m²) of steel surface. They used a 5,000 psi (34.5 MPa) water cannon from Florida Pressure Washing Equipment with a rotary tip. Instead of a traditional pressure washer and 20-degree straight tip, this one used a ceramic bead. “You get a conical blast pattern that allows the water to hit the surface at multiple angles at once and offers a much better cleaning action,” Ronan said. The pressure washer removed any loose rust and paint, but the crew used putty knives and wire brushes to remove any rust or coatings that still stuck to the surface.

As for the coatings, before the job started the Tnemec technician collaborated with the Righter Group, an independent representative and distributor of their coatings, to determine at what thickness the insulative coating needed to be applied. They used the average temperature and average relative humidity of the facility to come up with the necessary 60-mil (1,524.0 microns) thickness. With the plan set, the crew was cookin’ with gas!

Stack and Layer

To prime the steel, the crew spray-applied Tnemec series 1224 WB Epoxoline at 4–6 mils (101.6–152.4 microns) dry film thickness (DFT). They used a standard Graco airless spray unit. To apply the insulative coating, though, they used a special custom-made system.

Although Tnemec offered the crew suggestions on equipment, according to Ronan the APC crew decided to devise a system that would work specifically for them. To start, they used a gardening cart to keep everything in one mobile location. Then they attached a bladder pump spray unit with brackets for the hoses and an Ingersoll Rand 185 compressor. Essentially, it’s “all of the various tools that you need to make sure that everything’s working properly,” Ronan said. And they “drag” it all around for easy access.

Easy access, though, wasn’t a condition of everything on this jobsite 22 feet (6.7 m) in the air. Because the steel was up in the rafters, “everything had to be accessed through scissor lifts,” Ronan explained. They could occasionally use step ladders off the mezzanine areas, but for the most part, the work was done from the lifts.

Using the pump, they applied the 60 mils (1,524.0 microns) in two lifts. “We found that you were better off to put it on at 30 [762.0 microns] and come back at 30 [762.0 microns] again — almost wet on wet…,” Ronan said. “You could put this stuff on at 100 mils [2,540.0 microns] easily and you end up putting too much material. The guys found that it’s more accurate when you put it on in two coats.”

Because the crew was applying the coating at such a thick film, that also meant dealing with a lot of material. “At 60 mils [1,524.0 microns] you have a lot of paint cans being open, so you’d have one guy spraying, one guy filling the hopper on the spray unit, and one guy making sure the protection didn’t fall or contaminate the stainless steel because plastic does have a tendency to fall,” Ronan said.

There were a few aspects of many other coatings that the crew didn’t have to deal with, though. “There’s virtually no odor, virtually no irritation to mucous membranes,” Ronan said. “You’d be hard pressed to know you were even spraying but for the cloud in the air.” While the sprayer wore a respirator, the rest of the crew wore paper masks and everyone wore spray suits “because the stuff goes everywhere,” he continued.

The final coat applied was Tnemec Series 1029 Enduratone at approximately 3 mils (76.2 microns) DFT. “[The client] wanted a nice white reflective surface that can be cleaned. They have to constantly make sure that the place is clean because it’s a food plant,” Ronan explained.

Knead for Speed

Throughout the entire project, the crew worked with 2,000 cfm (56.6 m³/min.) negative air machines to help the coatings summertime cure. “We were working in what amounted to a basement underground level space with very poor airflow, so we had to come in with fans in order for the product to dry,” Ronan said. “The product dries through evaporation and if you have a stagnant air mass it would never dry.”

In addition to the successful application of the coatings, the client on this project was at the forefront of the minds of Ronan and his crew. “The biggest thing was the time. We had to get in and out of there so quickly, so it made it more difficult,” Ronan said. “We had to make sure everything was clean, everything was ready for the owner to go back in for production, and that’s the biggest thing.” As he continued, “You couldn’t be late; you had no choice — you’d be done. The cost of missing the deadline was thousands of dollars an hour of productivity.” So once they rolled up the protective poly, they headed out the door to allow the client to bring everything back to a boil.

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