What ?? Black plastic sheeting
that is Fire Retardant? Why would anyone want it, and what advantages does it offer me? First, polyethylene is highly combustible in its natural form, and makes what Fire Marshal's deem a "VERY EXCITING FIRE" once it is on fire. Because polyethylene is made from oil and natural gas based compounds, it is highly flammable, and burns at very hot temperatures.
Polyethylene is used everywhere. If you keep your eyes open, you will see it every day- on construction sites, in homes and offices, black plastic at haunted houses, flea markets, warehouses are full of it, packing supplies are made from it, toys, auto parts, most foreign cars (just threw that in for giggles!), anyway you get the picture. Poly makes a fire burn much hotter and faster, and is an accelerant. This causes people to get hurt, and unfortunately, in numerous cases every year, people lose their lives because of plastic sheeting or other types of plastics. I am sure you can all remember hearing of fires in night clubs, where plastic caught fire, and many people were trapped. This is avoidable, and with some education, people can make choices that keep these tragedies from happening.
Through chemistry, the plastic industry has been able to make most polyethylene, regardless of form (even most foreign cars) using plastic that is deemed "Fire Retardant". First, let's get an idea what this term means. Making a highly combustible material, like polyethylene, Fire Retardant (FR) means that we take away its ability to contribute significantly as a fuel source in a fire. This can be done at various levels and there are countless tests available today to help certify the levels of just how FR these products have become. Some of the most popular are the NFPA 701, ASTM E-84, UL-94, California Fire Marshal Title 19, just to name a few.
To simplify this, additive packages are added to the resins used to make polyethylene products causing the finished product to be fire retardant.
Today, we are able to engineer the additive levels so that the products can pass the FR tests needed for most applications and industries. A few applications for FR polyethylene that did not even exist as little as a decade ago are such things as: Black Polyethylene Sheeting (Black Plastic Sheeting) for haunted houses, Housewraps, Vapor Retarders, Construction Tarps, Enclosure Films, Abatement Plastics, Automotive interior parts, FR tapes, Airplane Covers, Military Applications Galore, Temporary Shelters, Humanitarian Aid, Cargo Covers, Surface Protection Films, Pallet Covers, Heat Shrink Wrap, Theatrical Plastics used on stages, Dog show plastics, Industrial Plastic Sheeting, Spray booths, and the list goes on and on.
The reason for the increased popularity in FR polyethylene over such a short period of time is that the increase in fire safety is so substantial, and the cost difference is so small that it just makes sense. When fires strike, and they strike often, using FR products of any type keep the loss of property to a minimum, and more importantly the loss of life and injury as small as possible. More and more specifications are calling for FR products, and this is a great thing for all of us. After all, when was the last time you checked to find out if that housewrap they used to build the walls of your house was Fire Retardant? Please watch for future posts on this subject, because this hot topic is just heating up.
ASTM E-84 measures the flame spread and smoke index, which are considered the surface burning characteristics of a material. Depending on the numbers, materials can have classifications of Class A, B, or C according to NFPA , ANSI/NFPA No. 101, "life Safety Code" , 2006 Edition, or IBC (International Building Code), 2006 Edition, Chapter 8, Interior Finishes, Section 803, if they pass any level of this standard. The test is conducted in a fire tunnel using a 22" x 24' sample of the material. The ignition source is 7 seconds in duration, total test is 10 minutes. The flame front cannot exceed 24" during the test. Results are expressed as Flame Spread Index, and Smoke Developed Value. Following are the criteria for each level of this test, regardless of whether NFPA or IBC.
For products that pass these criteria, click here
Class A, Flame Spread 1-25, Smoke Developed Less than or equal to 450
Class B, Flame Spread 26-75, Smoke Developed Less than or equal to 450
Class C, Flame Spread 76-200, Smoke Developed Less than or equal to 450.
Please note, this test is comparable to UL 723, ANSI/NFPA No 255, and UBC No. 8-1
NFPA 701-04 Test 1 or 2 (the most recent revision of the NFPA 701) measures the mass before test, mass after test, mass loss percentage, the number of seconds of any burning drips, and the after flame of the material in seconds during and after a specified burn period at a specified flame temperature. Once the flame is extinguished the after flame in seconds is measured. 10 samples are tested, 5 in the machine direction, 5 in the cross direction (also known as warp/weft respectively). This test is a Pass/Fail test based on the following criteria. If the material fails any of the following criteria, it fails the test
Mass Loss: 40% Max Average or Average + 3 standard Deviations Max Individual
Drip Burn/Afterflame: 2 seconds Max. Avg.