Well, it’s nothing to do with the Apple corporation! The “i” stands for the intumescent quality of our original product – suspended graphite foam.
Intumescent means it swells when exposed to heat; in this case, the swelling will be 2 -300 times its original volume once the temperature reaches approximately 230 degrees Celsius. This swelling results in a char of burnt material which hinders further combustion giving excellent FST (Fire, Smoke & Toxicity) properties.
Today, we don’t just produce graphite foam which is classed as Crib 7 foam, we also produce Crib 5 (melamine) for the transport, automotive and furniture industries.
Is it the same as the blocks of foam I can buy?
It is similar, but not exactly the same. Block foam, as the name suggests, is made in large blocks perhaps 2 metres x 1.5 metres x 30 metres or even larger. These are then cut into smaller blocks that are then sold to “convertors” to make into the shapes their customers want.
Our foam is moulded foam. A simple analogy is baking a sponge cake. You pour a mix of ingredients into a shaped tin and, after baking, the cake comes out – hopefully light and fluffy and in the same shape as the tin. This is very similar to how we make our moulded foams.
The primary differences between block and moulded foam is that the density of the moulded foam may be higher than that of block foam. This is especially so with graphite foam; complex shapes can be moulded, these moulded parts have a “skin” of thicker material on the surface (not to be confused with skinned PU components!) and there is no waste from the moulding process.
Why is graphite (Crib 7) foam more expensive than melamine (Crib 5) foam?
This is partly because you are getting more foam for your money. A piece of moulded foam measuring 500mm X 500mm X 100mm will weigh approximately 2.25 Kg whereas our Crib 5 foam will weigh approximately 1.375 Kg.
Also, the graphite foam is much more difficult to process, has a chemical formulation peculiar just to it and has a much lower demand.
What is Crib 5 and Crib 7?
BS 5852 details various fire tests for furniture starting with a lit cigarette and going up to a Crib 7 test which is the most severe. The Cribs are actually small wooden, open sided, boxes that house material that has been soaked in flammable liquids. The higher the crib number, the more severe the test.
One of these cribs is placed on a complete seat and set fire to. It must behave in a certain way to meet the requirements of the standard BS5852. In effect, it must self extinguish within a certain time period and must stop generating smoke within a certain time.
Is the foam hard or soft?
We can produce the foam to meet the hardness of the customer’s specification. We can vary the hardness of foam simply by adjusting the chemistry or amount of foam we put in the tool. Generally with block foam you will get what you are offered unless you are ordering very large volumes.
As a guide, specifying a 200 Newton foam will give a very soft and squidgy foam whereas a 1000 Newton foam will have very little give in it when, say , sitting on it.
The thickness of the foam has a significant bearing on the perceived hardness of the product. Please speak to us about the degree of hardness required for your application, it will cost you nothing the have the conversation and may save you a lot of trouble later on!
If your question is not answered here, please give us a call or send us an email as we have technical staff on site who will be able to give you objective advice and guidance on your own product specification.