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Daylight savings time ends November 6, 2012.

Remember to change your smoke detector and CO detector batteries when you change your clocks!

WHY ARE THE 1984 EXTINGUISHERS OBSOLETE?

The 2007 Edition of NFPA 10 has a new requirement that states "4.4.1 Dry chemical stored pressure extinguishers manufactured prior to October 1984 shall be removed from service at the next six year maintenance interval or the next hydrotest Interval, whichever comes first."

Many distributors and end users are wondering what the reason is for this new requirement. First please understand that the addition of this requirement followed the full NFPA process; it was submitted as a proposal, and was reviewed and accepted by a two thirds majority of the NFPA 10 committee. No-one presented a challenge to this requirement at the public presentation of the revised standard.

In October of 1984 the UL 299 listing requirements for fire extinguishers changed. Many of these changes were brought about by an extensive series of fire tests that were called "Novice Fire Extinguisher Tests." In these tests, untrained people were selected to extinguish fires with fire extinguishers. Based on these tests and problems associated with the novice's use, several changes were incorporated into the listing requirements.

Underwriters Laboratories highlighted some of these changes as follow:

Two questions that are often asked are:

Do we really have to replace these extinguishers? Yes, if you want to be in compliance with the latest edition of NFPA 10 you should replace dry chemical, stored pressure fire extinguishers that were manufactured prior to October 1984, at their next scheduled six year maintenance or hydrostatic test.

Don't these older units work? If properly maintained these older units should work. However, they do not represent the current technology and user features that are now required. The argument is similar to saying that soda acid and inverting chemical foam units still work, but we know that they had to be replaced by extinguishers that provided superior fire extinguishing characteristics and operator safety. Remember that a fire extinguisher provides first line of defense to control incipient stage fires. Users of fire extinguishers have to have confidence in the units and must be able to operate them with limited training.


WHAT YOU DON'T KNOW CAN HURT YOU ...........
WASHINGTON, D.C. - The U.S. Consumer Product Safety Commission (CPSC) says consumers who hope to eliminate hazards in their homes should check what's in and what's out for a safe New Year.

WHAT YOU DON'T KNOW CAN HURT YOU www.cpsc.gov; 1-800-638-2772


DID YOU KNOW?

sprinklers.jpg (3785 bytes)

Bulb sprinklers use a bulb of glass filled with liquid glycerin. This liquid has a higher coefficient of thermal expansion than the glass bulb it is contained in. The thermal expansion coefficient describes how much a particular material will expand when exposed to heat or contract when the heat is removed. When there is a fire, both the glycerin and the bulb expand, but the glycerin does so much faster than the bulb. Eventually it reaches a point where the bulb can no longer contain the expanding liquid and it shatters, releasing the plug and the water.

A center link sprinkler replaces the bulb and liquid with two pieces of metal soldered together using what is called a 'binary eutectic alloy'. This is just a way of saying that it's a combination ('alloy') of two ('binary') metals that are easily melted ('eutectic'), When exposed to heat, the alloy melts, the two pieces of metal fall apart and the plug is released. What's interesting about this alloy is that by controlling the amount of one metal in relation to the other, you can control the melting temperature of the alloy as a whole. In other words, by adding more of one metal to the alloy you can increase the melting temperature; by adding more of the other metal you can decrease it.


smoke.gif (6463 bytes)

There are two basic types of smoke detectors, ionization and photoelectric.  Ionization detectors contain a small amount of a radioactive material called Americium. The radiation from this material makes the air in the detection chamber conductive, allowing the flow of electrical current. Smoke entering the chamber Interacts with the radioactive particles decreasing the air's conductivity and triggering the alarm.

A photoelectric detector uses a light-sensitive device called a "photoelectric cell".  In the obscuration type photoelectric detector, a light shines on the cell. Smoke entering the chamber obscures the light, triggering the alarm.  In the light-scattering type, the cell is positioned so that the light does not shine on it. Smoke entering the chamber scatters the light, sending some of it in the direction of the cell.

So which type is better? The ionization type responds slightly faster to open flaming fires while the photoelectric will respond slightly faster to smoldering fires. But both types are tested to the same standards so either type will provide more than adequate protection if properly installed, maintained and tested.


Common Myth #11

"Dry Chemical 'smothers' the fire"

Only in certain circumstances. On Class B fires, dry chemical interrupts the chain reaction. During the early stages in the development of dry chemical agents it was thought that the fire was being smothered. Regular Dry Chemical (sodium bicarbonate) and Purple-K (potassium. bicarbonate) break down in a flame front to form carbon dioxide and water vapor. However, there is neither enough carbon dioxide to extinguish the fire, nor is there enough water vapor to extinguish the fire.

On a Class B fire, dry chemical interrupts the chain reaction (kind of like a referee breaking up a fight) and extinguishes the fire. This is why it is important to look for a "flash back" when using dry chemical on a liquid fuel fire. There is still oxygen, fuel and hot surfaces present to allow the fire to re-ignite. On Class B fires, dry chemical does not cool anything down, does not take away the oxygen and does not take away the fuel.

On Class A fires, only ABC or multipurpose dry chemical is effective. ABC dry chemical (monoammonium phosphate) will start to break down at between 350 deg. F and 400 deg. F to form a molten residue that will stick to the burning embers and exclude oxygen. This is the only circumstance that dry chemical may be said to "smother" the fire.

It is also important to remember that the ABC dry chemical must be applied to the burning embers in order to have it work. It may be necessary to "break apart" a Class A fire to make sure that all of the burning surfaces are covered.

Provided courtesy of Amerex.


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