Fire Engineering

Construction Concerns: Sprayed-on Fireproofing

 

It has been known for nearly a hundred years that structural steel fails quickly when heated by fire. A short time later, building codes began to require protection of the structural steel in fire-resistive buildings, and rated the levels of protection as it did fire division walls (one-hour, two-hour, and so on).

The earliest forms of protection were to encase the steel columns and beams in terra-cotta (baked clay tile), concrete, or masonry. Later, gypsum plaster applied to wire lath was used, to reduce the weight of the fire protection. Multiple layers of gypsum drywall board were also used to reduce the labor required for installation. This method is still in use today.

Sprayed-on insulations were developed that could meet the Underwriters Laboratories (UL)/American Society for Testing and Materials (ASTM) fire rating tests, and became common after World War II. These materials were lightweight, provided the required heat resistance when tested in the laboratory, required less skilled labor to apply than masonry or plaster, and used asbestos fiber as the insulator and Portland cement or glue as binders.

In the 1970s, asbestos became a health concern, and was replaced in fireproofing by mineral wool and fiberglass. There is still a lot of asbestos out there in our buildings, so gross decontamination by low-pressure hoseline before removing SCBA or other personal protective equipment after interior firefighting is essential.

All sprayed-on fireproofing is not created equal. Those containing Portland cement or other inorganic binders seem more resistant to removal by fire hose streams than other types. The quality of the finished insulation depends on the cleanliness of the surface to which it is applied; the use of the right amount of water in the mixture; and the use of the correct air pressure while spraying.


Photo 1

Photo 1 shows insulation that has been sprayed onto bar joists and the underside of a fire-rated composite steel-and-concrete floor deck. A thicker layer of insulation yields more heat resistance. For higher fire ratings, additional layers can be added. For technical information on the use and application of these products, and UL Directory listings, visit www.cafco.com, the manufacturer of Isolatek and Blaze-Shield products


Photo 2

Photo 2 shows insulation that has been sprayed onto steel columns. The columns are partly exposed either because the surface of the steel (primer paint) was not clean enough, or because the batch was not evenly mixed (wet or dry spots in the spray mixer). These areas, and others like them, will have to be cleaned and resprayed before the building inspector’s next visit.

Any brands or brand names noted above are used only as examples, and the Web sites only as sources of additional information. Reference to them is not an endorsement of either product or manufacturer.

Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 30-year veteran of the fire service. He is a Wisconsin-certified fire instructor II and fire officer II, an adjunct instructor in fire service programs at Gateway Technical College, and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College and has more than 30 years of experience in facilities management and building construction.

Article and photos by Gregory Havel

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How to Remove Scale Build-up in Plumbing Pipes.

Limestone (calcium carbonate) and dolomite, which are widespread on the Earth’s surface, often enter the household water supply. Calcium carbonate is insoluble in water.

Water containing Calcium or Magnesium is called hard water, and water that is mostly free of these ions are called soft water.

In the presence of dissolved carbon dioxide from the atmosphere, calcium carbonate is converted to soluble calcium bicarbonate.

However, when water containing calcium and bicarbonate ions is heated or boiled, the solution reaction is reversed to produce calcium carbonate precipitate and gaseous carbon dioxide is driven off.

Because of this reaction, solid calcium carbonate forms and is the main component of the scale buildup that accumulates in boilers, water heaters, pipes and teakettles.  A thick layer of scale reduces heat transfer and decreases the efficiency and durability of boilers, pipes and appliances.  In household hot-water pipes, it can restrict or totally block the flow of water.

A simple method to remove scale deposits is to introduce a small amount of hydrochloric acid to the system, which reacts with the calcium carbonate and dissolves it.  In this reaction, calcium carbonate is converted to soluble calcium chloride.

Energy: its’ nature, many types and forms

Energy is usually defined as the capacity to do work in the scientific world. Though there are many types of work, in practical terms, work can be quantified to equal “force x distance”.

Brief descriptions of some types of energies that we observe and make use of are:

Radiant energy: energy from the sun, also known as solar energy; solar energy heats the atmosphere and Earth’s surface, stimulates growth of vegetation thru photosynthesis and influences global climate patterns.

Thermal energy is associated with random motion of atoms and molecules and can be measured in terms of heat temperature (generated or lost) and volume size when these molecules interact with each other.
Chemical energy is stored in the structural unit of the substance; in this case, the atom or molecule. When substances participate in a chemical reaction, chemical energy is released, stored or converted to other forms of energy.

Kinetic energy is the energy produced by a body or system that is in motion, initiated by an external force. For example, a small snowball at the top of the hill; when someone pushes the snow ball over the hill, it will roll ever faster down the hill and increase mass as more snow adheres to the snowball. As it goes downhill, it constantly picks up speed due to gravity and increased mass. The energy being created is due to the snowball being in motion.

Potential energy is energy available by virtue of an object’s position. For example, back to our snowball example; the snowball has potential energy do to the fact that is at the top of the hill and with the understanding that force of gravity can cause it to increase speed as it goes downhill. When another outside force, in this case, a person pushing the snowball, the potential energy of the snowball is realized when it is rolling downhill and increases in speed and mass. The potential energy of the snowball could not have been realized if you were at the bottom of the hill where there is not a steep slope.

All these types of energies share a central theory that relates it all together. This theory is known as the law of conservation of energy. This law states that energy is neither lost nor destroyed; it is simply converted to another form of energy. If energy is neither lost nor destroyed, but rather converted to another form of energy, it would suggest that the total quantity of energy in the universe is constant.

Relating this theory to our example of the snowball; the potential energy of the snowball is converted to kinetic energy when it starts rolling down the hill. More snow adhering to the snowball as it is rolling is chemical energy being complied or stored. As the snowball gets bigger, its’ mass and volume increase. Let’s say that the snowball stops at the bottom of the hill; exposed to the sun’s rays, the snowball melts, letting off heated vapor or thermal energy into the atmosphere causing the surrounding temperature to increase as well.

How to find True North Without a Compass Wherever you Are

Which way is north? Whether you’re lost in the woods or you’re trying to install a sundial in your yard, you’re bound to want to find true north from time to time, and chances are when the time comes you won’t have a compass.What’s more, even if you do have a compass, it will point to magnetic north, which changes with your location in the world

For the full article, click on link below.

How to Find True North without a compass

How to read your water meter

New York City properties are assessed for
water and sewer services based upon the
amount of water consumed between the
prior and current meter readings. Since
customers may want, or need, to occasionally
read their own meter, the following
information is provided to assist you.
All water meters approved for use by the
New York City Department of Environmental
Protection (DEP) read much like a car’s
odometer. Older meters may have several
dials and pointers, but they are generally
considered obsolete and, in most cases,
should be replaced based on age alone. This
brochure deals only with odometer-type
meters whose basic usage measurements
are shown below:
The three key parts of
your water meter’s register head
1) Flow Indicator
The flow indicator rotates whenever water
flows through the meter. If the triangle
turns when all water is turned off on the
property, you may have a leak, which
should be investigated.
2) Sweep Arm
Each full revolution of the sweep arm
indicates that one cubic foot of water
(about 7.48 gallons) has passed through
the meter. The markings at the dial’s
outer edge indicate tenths
and hundredths of one cubic foot.
3) The Register
The water meter register is a lot like the
mileage odometer on your car. It keeps a
running total of all the water that has
passed through the meter. The register
shown here indicates that 345,710 cubic
feet of water has passed through this
meter.

For the full specifications on how to read a DEP approved water meter, please click on the Department of Environmental Protection link below.

http://www.nyc.gov/html/dep/pdf/readmeter.pdf