Spray polyurethane foam is widely promoted as a green structure product for its capability to enhance energy performance. It insulates much better per inch than fiberglass or cellulose, which can mean major energy saving on heating & cooling. However, energy performance isn’t the only consideration when it comes to sustainable building. A closer look at spray foam’s chemical makeup exposes a number of substances that are known to be hazardous.

Spray polyurethane foam includes two liquid chemical parts, described as “Side A” and “Side B,” that are mixed at the website of installation. Side A is mostly made up of isocyanates, while Side B normally consists of polyol, flame retardants and amine drivers. These chemicals develop dangerous fumes during the application, which is why installers and close-by employees ought to wear individual protective equipment throughout this procedure. When the foam has totally expanded and dried, manufacturers say it is inert. If the chemicals are not effectively combined, they may not react fully and can stay hazardous.

The threats associated with the isocyanate of Side A are reasonably well-documented, however threats associated with Side B are less well comprehended. David Marlow at the Centers for Disease Control has been researching off-gassing connected with spray foam installation considering that 2010. Marlow was unavailable for an interview, the Public Affairs workplace at the CDC was able to offer details about his ongoing research study using email. These field studies intend to determine the level of exposure to all the chemical parts of spray foam, figure out a much better understanding of curing rates and establish safe reentry times, and establish engineering controls to lower the threat of direct exposure. In addition to the risks associated with setup, these chemicals can stay unreacted in the form of dust or shavings. The Environmental Protection Agency warns: “Cutting or trimming the foam as it solidifies (tack-free phase) may generate dust that may contain other chemicals and unreacted isocyanates.” 1 This is likewise an issue throughout the procedure of getting rid of foam.

Isocyanates
Isocyanates, such as methylene diphenyl diisocyanate (DMI), are discovered in the “Side A” of the spray foam mix.2 Isocyanates are also found in paints, varnishes and other types of foam. They are a known cause of occupational asthma.3 According to Dr. Yuh-Chin T. Huang, a professor at Duke University Medical Center, isocyanate-induced asthma is similar to other types of asthma, however instead of being activated by exercise, it is triggered by exposure. Re-exposure can trigger intense asthma attacks.2 as soon as somebody has ended up being sensitized.

Property owner Keri Rimel states she and her husband have both become exceptionally conscious of isocyanates and other chemical smells following exposure during spray foam installation. “He still, to this day, can stroll into any dining establishment, office, or home, and he can right away inform if there’s spray foam in a structure,” said Rimel of her husband.

According to the CDC, direct contact with isocyanates can also trigger a rash if it can be found in contact with the skin.

Amine Catalysts.
Amine drivers are among the Side B chemicals that the CDC is looking into, in an effort to comprehend the levels of exposure during installation. “Amine catalysts in [spray polyurethane foam] may be sensitizers and irritants that can trigger fuzzy vision (halo effect),” they write.4.

According to a report released by the Consumer Product Safety Commission, amine drivers can also irritate the eyes, skin, and breathing system and if consumed “may likewise cause a reversible result referred to as glaucopsia, blue haze, or halovision in the eyes.” 5.

Polyol.
Also discovered in side B, polyols are alcohols that work as drivers. They are usually made from adipic acid and ethylene glycol or propylene oxide. Some polyols are made from soy, but according to the Pharos Project, a company that advocates for constructing material transparency, the soy-based product makes up only 10 percent of the final insulation. 6.

Ethylene glycol, a chemical used to produce polyol in some spray foam, can in cases of intense direct exposure (such as swallowing) cause vomiting, convulsions and affect the central nervous system.7 According to the EPA, exposure by inhalation can trigger inflammation in the upper breathing system.

Flame Retardants.
Flame retardants are contributed to Side B to pass flammability tests in building regulations. The main fire retardants utilized in spray foam are hexabromocyclododecane (HBCD or HBCDD) and tris (1-chloro-2-propyl) phosphate (TCPP).

Bioaccumulation means that a chemical constructs up in the body much faster than it can be flushed out, so there can be a risk of chronic poisoning even if the level of exposure is low. The chemicals also build up in the ecosystem, where they go into the food chain.A paper by Vytenis Babrauskas published in the journal Building Research & Information states that, “flame retardants whose primary usage is in constructing insulation are discovered at increasing levels in household dust, human body fluids and in the environment.

The Chemical Question Mark.
In a post for the CDC, Marlow explains the components of Side B as “a chemical question mark.” 10 He described the requirement for “real-world sampling.”.

In addition to those listed above, there may be other chemicals used in spray foam that are undisclosed and are protected trade tricks. “You have to tell the individual testing what you’re looking for,” says Terry Pierson Curtis, an indoor air quality expert.

Beginning a spray foam insulation business has its share of dangers, particularly when you’re simply starting. Excellent details are critical when asked to bid on a spray foam job, not only to you however to your clients also. Good management of labor and product expenses is the primary step to providing a sound bid to develop into a rewarding payday.

Know, Price, Track

Gain a good understanding of your market and your rivals. Think about calling and asking the charge rate per square foot to compare the market value range and be competitively priced.

Know your exact square video footage. Thoroughly determine the surfaces to calculate overall square video footage and determine the price and quantity of product needed to finish the job.

Compute. COST = Your rate per board foot x density (per regional building regulations or wanted by the customer) x square video (walls, ceilings, etc.).

Bidding Large Jobs: Avoid the temptation to offer a volume discount rate. Bigger tasks suggest more things that can go wrong, including weather, temperature changes, scheduling of other contractors, etc. Security and equipment accessibility can also play an element. Keep these things in mind when thinking about bidding bigger tasks and make certain to consist of a markup of 20-30% above the base rate to conquer these possible pitfalls.

Track Your Results: Data Tracking and collection systems are a great method to identify material use and labor expenses for each job with your spray foam rig. This info can then be used to confidently bid jobs based upon past product use and labor to complete similar-sized jobs.

Question: If your attic is going to have 50 bags of insulation blown into it, does it make much of a difference if it enters flat or lumpy?

Let’s look at an example. If the insulation goes in completely flat, let’s state we have a nice consistent R-value of 30 throughout the attic.

There are all kinds of methods it can enter lumpy, however let’s presume that 50% of the attic has lumps of R-50 insulation, and the other 50% is valleys with only R-10. We wish to discover the average R-value of this lumpy setup. It’s the same quantity of insulation, and the average of R-50 and R-10 is R-30. But, how does it really perform?

Let’s do the math!

Now, we can’t simply average the R-values. If we did that here, we’d get R-30, and we’d be wrong. The heat will take the path of least resistance, and the less resistance you give it, the more heat will stream. If you’ve studied physics, engineering, or structure science, you’ve probably seen the formula for heat flow by conduction:

Heat circulation formula building science
If we computed the amount of heat streaming through the lumps and valleys in this attic, we’d see that the R-10 half (red bar listed above) would allow method more heat to flow than the R-50 half (yellow bar listed above). In fact, the R-10 valleys, having one-third of the R-value, would permit 3 times more heat to flow than if it had R-30. The R-50 lumps would allow only 3/5 the heat flow as R-30.

Also, the total quantity of heat circulation is greater for the lumpy insulation than for the flat insulation As you can see below, the red and yellow parts together amount to a lot more heat flow than the orange (in fact 1.8 times as much).

Heat circulation through flat and lumpy insulation.
Due to the fact that the lumpy insulation allows more heat circulation, it’s got to have a worse average R-value. Clearly, the average R-value is going to be more influenced by the underinsulated part than by the over insulated part.

To find the average R-value the correct way, we first need to transform R-values to U-values. R represents resistance, as in resistance to heat circulation, so the greater the number the better when we’re talking about building materials. U-value, the heat transfer coefficient is the reciprocal of the R-value, so the lower the number, the better.

The equation for average U-value is:.

Average U-value formula, to find the average R-value of insulation.
Taking the attic as 1000 square feet overall and putting in 1/R for U, we get:.

average u-value for R-50 & R-10.
Taking the reciprocal of 0.06, we get the average R-value of about 17, which is much lower than the R-30 we had actually get by improperly balancing the R-values.

Conclusion.

As I stated above, heat takes the path of least resistance, so the amount of additional heat going through the R-10 half far exceeds the additional heat flow that’s stopped on the R-50 side. Instead of getting an R-30 average, the lumpy attic has an R-17 average.

In practical terms, this means that if you see an attic with lumpy insulation, act with a rake and smooth it out. In the example I simply exercised, you ‘d almost double the R-value without including any extra insulation!

Another common example of the flat-or-lumpy conundrum is an attic that’s completely insulated except for one little location, say the pull-down attic stairs. We can go through the exact same steps as above and show that an attic that has a uniform R-30 over 99% of the area and 1% at R-1 (the pull-down stairs) will have an average R-value of 23.

That’s right. Those pull-down stairs can reduce your overall R-value by 25%. One little uninsulated location can dramatically reduce the R-value.