Ignition barriers include six permissible materials. An ignition barrier can be 1/4-inch plywood or structural panels, 1 1/2-inch mineral fiber insulation, 1/4 inch hardboard, corrosion resistant steel at least .016 inches thick, 3/8-inch gypsum board, or 3/8- inch particle board. These sizes are the minimum; code officials will approve of thicker versions of any of these six materials as ignition barriers. Like thermal barriers, equivalent materials that have been shown to have equivalent fire resistance are acceptable. Additionally, an alternate assembly can be used if the assembly has been tested by a laboratory and meets certain criteria. Insulation Spray Coating
The process typically operates at 39–120 °C to avoid thermal damage. It can induce non-thermally activated surface reactions, causing surface changes which cannot occur with molecular chemistries at atmospheric pressure. Plasma processing is done in a controlled environment inside a sealed chamber at a medium vacuum, around 13–65 Pa. The gas or mixture of gases is energized by an electrical field from DC to microwave frequencies, typically 1–500 W at 50 V. The treated components are usually electrically isolated. The volatile plasma by-products are evacuated from the chamber by the vacuum pump, and if necessary can be neutralized in an exhaust scrubber. Spray Coating
Hydraulic or air powered airless provide a more uniform pressure control since the paint piston moves at a constant speed except when it changes direction. In most direct drive piston pumps, the piston is crankshaft driven in which the piston will be constantly changing speed. The linear motors of hydraulic or compressed air drive pumps, are more efficient in converting engine power to material power, than crankshaft driven units. All types of paint can be painted by using airless method. Spray Coating Services

Thank you, Allison. We have a split system unit (actually 5) with the heat being propane. The foam guy said that it needed ventilation, so completely sealing the attic wouldn't be a good idea. It sounds like you are saying that the systems need to be vented out of the attic or replaced with some type of closed system. But I shouldn't bother spraying if the plan is to leave the soffet vents open. Is that correct?
If you're plagued with quality problems caused by uneven application of coatings or waste of costly coatings due to over-application, take a close look at our products for precision coating. You will find a wide range of nozzles, standard and heated spray headers and automated spray systems to apply all types of coatings – including thick slurries, chocolate, viscous oils and more – uniformly with minimal waste. Spray Coating

Yes, you're right that all of the problems mentioned above are related to the installer. I didn't try to hide that and even used the word 'installer' in two of the four headings. I can see how you'd think that the title is misleading, but in the end you can't separate spray foam insulation from its installation. Some people have the mistaken impression that if you get spray foam in your house, your home will outperform all others. My point here is that that's not true.

In the case you have above the installer wasn't reading his foam. They must be trained to do that as they spray. Temps and conditions are constantly changing thru out the day. Either he wasn't properly trained or if he was,he wasn't doing his job! This is a serious problem with people jumping in to the foam business. A lot of homeowners and builders are looking the best price and end up with someone who doesn't know what they are doing. Hope this info helps. Foam insulation is a great product. It just has to be done right by someone who knows what they are doing.
Allison--would be very interested in your take on the GHG issues of foams, which have received lots of smart commentary recently. To highlight a few: architect Jesse Thompson's comments on Tom's Good vs Bad post on Energy Circle, the very thorough piece by Alex Wilson on Green Building Advisor and Michael Anschel's cautionary diatribe on Remodeling. 
When using this roof coating, two coats are required. It doesn’t take much time to apply the coating. If the weather is not humid, the coating will take only a few hours to get completely dry in full sun.This coating can go over and hold strong on the sealing tapes. This feature helps you to restore your roof to brand new. It may save thousands of dollars from replacing your old roof. Spray Coating