Fire Hazard Alert - is your Dryer ready to IgniteWritten by Donald Grummett
In recent years there has been many stories about dryers catching on fire. Should we be concerned? Yes of course. We should take seriously anything that may put our family at risk. Was problem dryer? Rarely. After investigating it is usually determined to have been venting within home catching on fire, and not dryer. Obviously appliance manufacturers are concerned about possibility of any dryer related fires. They have made it a policy to advise both service companies and consumers that use of plastic venting is prohibited. They have also begun issuing cautions not to exceed suggested maximums for venting length. Let me try to explain details of this problem.
The drying process ---------------------------
When clothes are being dried inside your family dryer there are two processes happening. Firstly, heat is applied to air inside dryer drum as it turns. This raises its internal temperature to approximately 175 Fahrenheit causing moisture to be driven out of clothes by evaporation. Secondly, large amounts of air is passed through clothes. Surprisingly, real trick to efficiently dry clothes is not heat, but rather this vast volume of air. Ever wonder why clothes on clothesline dry so fast on a windy day? The hero is wind. Well, same process takes place inside your family dryer. To make them dry faster air is constantly blown through clothes during drying cycle. The tumbling action of drum further exposes clothing to hot air flow. While they tumble air picks up moisture from clothes, carries it down venting, and dumps it outside home. Most people think venting is to push lint outside. Actually, its primary purpose is to dump moisture outside home. It is a process that works efficiently. That is, as long as nothing is allowed to interfere with it. Impede, slow down, or stop airflow and process quickly fails. In past homeowners who wanted to vent their dryers did it using rigid sections of venting. The sections were secured together (using screws or duct tape), and elbows were added if necessary, to connect dryer and venting to wall outlet. Although time consuming to install, straight venting sections were durable and would often outlive dryer. This was in era when laundry equipment always sat in basement, against an outside wall. Then along came flexible plastic venting. It made installations easier. It turned an hour installation into a ten minute job. The flex though tended to become brittle and break easily. Also it was prone to blockage and needed to be replaced every few years. But since plastic venting was more convenient we continued with its use. Then came a change in lifestyle. As both parents went off to work household dryer was moved to accommodate our faster paced lifestyle. To save us time it was moved from basement to a ground floor laundry room. Although moved to working level of home, it was still close to an outside wall. So you are saying, “I know all this, but what does it have to do with venting fires”. I answer, “Have patience, we are almost there”.
Taking this desire for easy access still further dryer was moved again. The laundry room is now often located near centre of home, close to family room or kitchen. If located upstairs it is often centrally located between bedrooms, allowing faster access to where most dirty laundry is produced. Easier for homeowner that is, but no longer near an outside wall. The distance from dryer to an outside wall of home is now substantially farther than it used to be. Presto, we have come to crux of our problem. The venting is too darned long. Physics and venting pipe --------------
It is a lot more difficult to push air down a long venting pipe than a short one. This is because air inside pipe has weight and volume. Obviously, air inside a longer pipe would weigh more than a shorter one. After about twenty feet of venting pipe dryer begins having difficulty pushing against all this weight. The average dryer motor does not have enough strength to overcome weight of air inside pipe. The result is that air in pipe begins to slow down. Since air slows down moisture accumulates in venting rather than being carried outside. This causes venting interior to become wet and lint traveling through pipe will cling to this wetness. This starts a vicious cycle within venting pipe. It goes something like this: The more lint in venting, more blockage; More blockage means slower air flow; Slower air flow means more moisture in venting; More moisture in venting means more lint. I think you understand scenario now. Taken to extremes lint can block venting closed. When this happens it can cause dryer to overheat. The normal drum temperature of 175 Fahrenheit can quickly shoot up to 300 Fahrenheit or higher. It may even get hot enough to allow lint in venting to ignite. If a fire of this type starts within flexible plastic venting it can quickly burn through venting and allow fire to spread. Therefore, remove any flexible plastic venting and replace with rigid, straight sections. If total length is less than fifteen feet, flexible “metal venting” is acceptable. Calculating true venting length -----------
Information and facts about graniteWritten by Joey Lewitin
Granite – Might of Stone
FORMATION Granite is generally produced by magma solidifying under extreme pressure. When magma rises, due to being lighter then surrounding rocks, it begins to cool. This cooling happens slowly, and crystals are formed beneath surface of earth. This produces a tightly interlocked structure, which is why granite is such a strong stone. It is comprised mostly of quartz, alkali feldspar, and plagioclase feldspar. Granite makes up a lot of earths crust, and is generally revealed to surface when continental shifts cause breaks in landscape that allow it to be seen.
CONTROVERSIES ON FORMATION Some evidence supports theory that there is a second way to produce Granite. Lack of evidence for contact between granite and surrounding stone, as well as evidence of sediments may demonstrate that granite can also form through metamorphic processes, by combining several minerals under pressure.