The standard prescriptive material that can be used as a thermal barrier is 1/2" gypsum board (a.k.a. drywall or sheetrock). Anything else has to be approved as an 'equivalent thermal barrier' by undergoing tests for temperature transmission and fire integrity. In some cases, however, you need only one test. According to the Spray Polyurethane Foam Alliance (SPFA), "Under specific conditions, the temperature transmission test can be waived if approved by building code authorities on the basis of large-scale fire testing representing actual uses." (See their pdf document, Thermal and Ignition Barriers For The SPF Industry.)
Like HVLP, low volume low pressure (LVLP) spray guns also operate at a lower pressure (LP), but they use a low volume (LV) of air when compared to conventional and HVLP equipment. This is a further effort at increasing the transfer efficiency (amount of coating that ends up on the target surface) of spray guns, while decreasing the amount of compressed air consumption.
Most electric powered airless pumps have an electric motor connected through a gear train to the paint piston pump. Pressure is achieved by stopping and starting the motor via a pressure sensor (also called a transducer); in more advanced units, this is done by digital control in which the speed of the motor varies with the demand and the difference from the pressure set-point, resulting in a very good pressure control. Some direct drive piston pumps are driven by a gasoline engine with pressure control via an electric clutch. In electric diaphragm pumps, the motor drives a hydraulic piston pump that transmits the oil displaced by the piston, to move the diaphragm. Insulation Spray Coating
Combustion spraying guns use oxygen and fuel gases. The fuel gases are potentially explosive. In particular, acetylene may only be used under approved conditions. Oxygen, while not explosive, will sustain combustion, and many materials will spontaneously ignite, if excessive oxygen levels are present. Care must be taken to avoid leakage, and to isolate oxygen and fuel gas supplies, when not in use.
There are exceptions to the thermal barrier rules. If the spray foam insulation is used as roofing or covered by concrete whichis, at least, an inch thick, then thermal barriers are not necessary. Additionally, you do not have to use a thermal barrier if the spray foam insulation is used on the interior of sill plates and rim joists, so long as the spray foam is 3 1/4 inches or less. Thermal barriers are also not necessary if the spray foam insulation is used in an attic or crawl space, as long as they are not used for storage or as living areas. In attics and crawl spaces where thermal barriers are not required, the use of ignition barriers is necessary. Insulation Spray Coating
The drawback to spray foam insulation is it's been known to cause certain health issues such irritation of the eye and the gastrointestinal and respiratory tracts. Direct contact can cause inflammation to the skin, and some individuals have been known to break out in a rash on the arms, chest and neck area. Spray foam insulation has also been linked to a few cases of hypersensitivity pneumonitis. This condition can cause:
“The true key to insulation is preventing heat load,” says J.E. Pritchett, founder and developer of SuperTherm, a ceramic coating product produced by Superior Products International. The concept is simple: Why use fiberglass insulation to slow the transfer of heat into a building when you can just prevent that heat from ever loading onto the building in the first place? If heat is kept off the structure to begin with, that fiberglass insulation becomes unnecessary. It’s a change in the way we think about insulating our homes against energy lost. “R rating is for the 20th century,” says Pritchett. “Emissivity is 21st century.”
Proper recordkeeping: One of the basic tenets of risk control is maintenance of updated health records of personnel handling spray paint products. Confidential data on biological monitoring results must be appropriately kept. Records of the schedule and result of testing procedures should also be kept. Some of the most important tests to be conducted on a regular basis are air quality testing, testing of pressure systems and electrical systems, and testing of compressor reservoir air filters. Coating Services
Note: The practice of foam insulating the attic has raised eyebrows in the building industry because "standard" roofing techniques call for the attic to be ventilated; however, in a vented attic situation it will become approximately 130 degrees in the summer. There's no reason for an air-conditioning and vent-ductwork to have to work in that type of severe conditions. By applying Icynene right on the underside of the roof deck, the severe temperatures no longer exist in the attic. In short, the attic is now a "conditioned" space of the house that is just as comfortable as any other room in the home. This is called a "Compact Roof", which means you can frame right up against it. The one drawback of using expanded foam on the inside of the roof is that this will cause the temperature of the shingles to rise, but how much is not yet known. And how much damage a rise in temperatures could cause is debatable.
Blocking heat buildup is a complicated task. Heat comes in three forms: ultra-violet (UV), visible light, and infrared (IR). A quality ceramic coating will block all three, especially IR, which is responsible for roughly 57 percent of heat load on a building. “Some ceramic paints claim to block all heat caused by UV,” says Pritchett, “but UV only accounts for three percent of heat load on a building.”
At Praxair Surface Technologies, it’s our goal to help you get more protection, more customization and more performance from your parts. To do that, we work with you to select or develop coatings based on your operating environment and production requirements. Then we combine advanced preparation services, the right application technology and post-coating operations to create optimal coating performance for any component. Coating Services
The deposition efficiency is typically low for alloy powders, and the window of process parameters and suitable powder sizes is narrow. To accelerate powders to higher velocity, finer powders (<20 micrometers) are used. It is possible to accelerate powder particles to much higher velocity using a processing gas having high speed of sound (helium instead of nitrogen). However, helium is costly and its flow rate, and thus consumption, is higher. To improve acceleration capability, nitrogen gas is heated up to about 900 °C. As a result, deposition efficiency and tensile strength of deposits increase.
In plasma spraying process, the material to be deposited (feedstock) — typically as a powder, sometimes as a liquid, suspension  or wire — is introduced into the plasma jet, emanating from a plasma torch. In the jet, where the temperature is on the order of 10,000 K, the material is melted and propelled towards a substrate. There, the molten droplets flatten, rapidly solidify and form a deposit. Commonly, the deposits remain adherent to the substrate as coatings; free-standing parts can also be produced by removing the substrate. There are a large number of technological parameters that influence the interaction of the particles with the plasma jet and the substrate and therefore the deposit properties. These parameters include feedstock type, plasma gas composition and flow rate, energy input, torch offset distance, substrate cooling, etc.
Thermal spraying can provide thick coatings (approx. thickness range is 20 microns to several mm, depending on the process and feedstock), over a large area at high deposition rate as compared to other coating processes such as electroplating, physical and chemical vapor deposition. Coating materials available for thermal spraying include metals, alloys, ceramics, plastics and composites. They are fed in powder or wire form, heated to a molten or semimolten state and accelerated towards substrates in the form of micrometer-size particles. Combustion or electrical arc discharge is usually used as the source of energy for thermal spraying. Resulting coatings are made by the accumulation of numerous sprayed particles. The surface may not heat up significantly, allowing the coating of flammable substances.
The problem was that the installer was doing his first spray foam job ever, and the thickness of the insulation varied from zero (visible roof deck) to about 9". Unfortunately, good average thickness doesn't cut it. The coverage needs to be uniform because a lot of heat will go through the under-insulated areas. (See my article on flat or lumpy insulation performance.) Insulation Spray Coating
Building code regulations typically call for the use of thermal barriers when spray polyurethane foam is installed. The code requires that the foam is separated from any living spaces by a layer of 1/2-inch drywall. As discussed earlier, any material that has been approved as being as equally fire resistant as the gypsum drywall can be substituted as a thermal barrier. Spray Coating