Adhering To Chemical Processing Guidelines
BY RYAN SPENCER – Spray Foam Magazine and SprayFoam.com
Chemical processing parameters are essential for the proper application of spray polyurethane foam, ensuring that installation performance is maximized and the end product is installed as specified. When it comes to disseminating guidelines for the chemical processing of their products, manufacturers use a few different avenues: affixing processing parameters on chemical drums, providing technical data sheets that describe the correct processing of the material, and educating contractors in person during training sessions. So what exactly do these processing parameters entail? The specifics are essentially propriety to each manufacturer, but there are some high-level considerations worth exploring, as failing to follow the fundamentals can prove disastrous.
“Regardless of the manufacturer, you’re going to want to make sure that the material is kept in a relatively warm environment, such that the proportioner’s heating capacity is able to keep up with the correct processing temperature,” said Jose Luna, Vice President of Operations of SES Foam. Basically, you want to make sure that the material is warm enough such that the proportioner’s heaters can maintain the proper processing temperature. For example, if you have a set of material at 60° F and are spraying with a small proportioner, it’s just too limited in its ability to heat the material properly. It’s never going to be able to maintain the proper spray temperature, which can be twice as high, at around 120° F. When it comes to keeping material sets warm on the job site, drum heaters or a space heater in the spray rig will do the job just fine. It’s also a good idea to store drums of material at a manageable temperature; SES recommends maintaining drums between 70° and 90° to maintain shelf life.
While temperature may be the most significant factor with regard to chemicals, it’s also important to ensure consistency in chemical drums, particularly for open-cell foam. “You want to make sure you’re producing a good mix at the mix head,” Luna said. “We require the mixing of our half-pound material prior to application, so you want to make sure the material is mixed in the drum so there’s no separation.” With a proper mixture and temperature, the proportioner can reach the correct pressure for the proper application of the material.
While chemical considerations are crucial, it’s the spray equipment that actually does the processing, so a proper setup is similarly significant. “Proportioner selection is important,” said Luna, “If you’re in a warmer climate zone, you can probably get away with a proportioner with a smaller heater, but in northern climate zones, those proportioners will have a hard time maintaining temperature.” The critical thing is making sure your proportioner is correctly sized for your climate zone and for your materials, to get them into their correct spray temperatures. “That is more important in colder months, when you have to worry about substrate temperatures, material temperatures, and whether the hose is being dragged through snow,” said Luna. “Those are all sources of heat loss that will cause underprocessing.” As for warmer climates, temperature isn’t typically a big issue, but humidity can be a major day-to-day concern. It’s often suggested that it’s best to apply the material when humidity levels are below 80%, but this restriction can complicate applications in certain areas. “Essentially, that would mean you could almost never spray foam in Florida or the Gulf Coast, but it’s done, and it’s done successfully,” said Luna. “The way people do that is just managing the humidity with air movement through the structure. It’s apparent when a substrate is moist, and you can even use moisture meters to verify whatever substrate you have is dry enough to receive foam.” Though it’s the end of the line as far as chemical processing goes, gun configuration is also important. “If you have too large of a mix chamber, then you’re not able to maintain your pressure and you may be outrunning your heaters, which is going to result in underprocessing of the material,” explained Luna. Underprocessing can lead to various processing problems, including reduced yield, poor cell structure, and poor adhesion, and may or may not require the removal of the underprocessed foam. “For example, if they’re not maximizing yield, that’s just hurting their wallet, because that foam is still going to perform as expected,” Luna explained. “Now, if there are blatant problems with off-ratio or really poorly mixed foam, then it’s our recommendation that it should be removed.”
FOLLOWING PROCESSING PARAMETERS
Every manufacturer has developed its own specific nuances about the processing of their products, and SES is no different. Basically, the company developed its current processing guidelines the old fashioned way to maximize performance. “As a chemical manufacturer, we put our product out there and it was designed to provide superior performance, but you just have to follow our rules,” Luna said. Of course, adhering to processing guidelines involves the primary considerations discussed previously–bringing your material to the right temperature, using a properly sized proportioner, using the right configuration on your gun–but it also involves common sense precautions, like performing regular maintenance, cleaning your gun out regularly, and maintaining your air compressor and generator. Still, sometimes things can go awry, and that’s when technical service and supplier experience comes into play.
STORE IT RIGHT
Well-conditioned sets of material will store longer and make it easier for proportioners to process at optimal temperatures. “I think our service is top-notch, and our support for our contractors is one of the pillars we’re trying to build the company on…we feel that that can differentiate us in the marketplace,” said Luna. “We see other manufacturers walking away from that kind of approach, but we understand that as a chemical supplier, we’re going to have to support the needs of contractors.”