This document discusses water uses for fire protection and HVAC systems. It describes how water is effective for extinguishing fires due to its heat transfer properties. It also outlines various fire classifications and detection methods like smoke detectors, heat detectors, and flame detectors. The document discusses sprinkler systems, standpipes, and other fire suppression methods. It notes water is also well-suited for HVAC systems due to its stability, low cost, and ability to transfer heat and cool buildings effectively. Water quality is important to prevent damage to pipes and reduce microorganism growth.

1. Nate Lee W846188
November 26, 2012
Water Supply for Fire Protection and HVAC
Water is a very useful, reliable and readily available medium for extinguishing fires. The
capacity for water to carry massive amounts of heat makes it a popular fluid for use in Heating,
ventilation and air conditioning also known as HVAC. This chapter discuses water for fire
protection and water for HVAC.
Water for Fire Protection:
“Fire or combustion is a chemical reaction involving fuel, oxygen and high temperature.”
Removal of any one of the three components of a fire results in termination of this destructive
force. The NFPA ( National Fire Protection Association) has developed four different classes of
fire. These four classes are divided by the letters A, B, C and D. Class A fires has solid
combustibles such as paper or wood. These things are found commonly in households and also
make up homes themselves. “A” type fires are best extinguished using water or dry chemicals.
Flammable liquids, which are classified as “B” type fires are best put out with foam, carbon
dioxide or dry chemicals. “C” type fires, electrical fires, must be extinguished by using carbon
dioxide or dry chemicals. And, type “D” fires involve combustible metals such as titanium or
magnesium. “D” type fires must use a special dry chemical extinguisher.
Classification of Occupancy Hazards:
The occupancy hazard rating a means of classifying an occupancy and the extent to which
sprinkler systems are required. According to the NFPA, there are three divisions of hazard
occupancies. These include 1) light, 2) ordinary and 3) Extra hazard. With light hazard, the
content of combustibles are low. Light hazard occupancy are typically commercial, religious
residential and educational properties. Ordinary hazards are classified into two sub groups.
Group 1 the combustibles are not to exceed eight feet. Examples of these places would be
automobile showrooms, electronic plants and restaurant serving areas. Group to the stockpile of

2. combustible material is not to exceed 12 feet. Examples of such buildings are cereal mills,
machine shops and wood product assembly plants. Extra hazard occupation, fires may develop
rapidly. Extra hazard is also divided into two sub groups. “Group 1, buildings having hydraulic
systems with flammable or combustible hydraulic fluids under pressure. Properties with process
machinery that use flammable or combustible liquids in closed systems and those having dust
and lint in suspension are included in this group.” Group 2 has a higher amount of combustibles
than group 1.
Methods for fire detection:
The National Fire Protection Association has developed NFPA No. 74 standard for household
fire detection. To protect individuals from house fires an established criteria for manufacturing
and installing fire prevention equipment has been developed. Two types of residential fire
detection are smoke and heat detectors.
Smoke Detector:
There are two types of smoke detectors. These are ionization smoke detectors and photoelectric
smoke detector. “An ionization detector is capable of sensing microscopic particles of
combustion and is the best for detecting fire at an incipient” or beginning stage of a fire. The
photoelectric smoke detector is the best device for detecting fire at the smoldering stage. The
smoldering stage is when smoke particles are visible to the naked eye.
Heat Detector:
The NFPA standards do not require the use of heat detectors as part of a basic fire detection
method. Heat detectors come in two functions, fixed temperature and rate of rise type heat
detectors. Fixed temperature heat detectors may be self or non-self-restoring. Self-restoring
type heat detectors us a bimetallic element that when ambient temperatures reach a fixed setting
the contact is automatically closed and triggering an alarm. The contact will return to the open
position the temperature returns to normal. The non-restoring type heat detector reacts the same
as a restoring type however when the metal will melt and trips the alarm. A rate of rise type heat
detector reacts when the temperature in the immediate area rises higher than the rate of time.

3. When the temperature in the area of the detector rises quickly, air within the chamber expands
faster than the air can vent thereby tripping the alarm.
Flame Detector:
Flame detectors come in two types: infrared and Ultraviolet. Infrared or IR, is present in most
flames. The IR detector can detect a fire instantaneously. IR can sometimes cause false alarms
because there are other elements that can emit an IR. Ultraviolet or UV flame detectors operate
by detecting the UV radiation of the flame. Dual spectrum flame detectors utilize a combination
of UV and IR detection. The combination is good because it detects fires accurately without
causing false alarms.
Methods of Fire Control:
There are three things needed to create a fire. When any of these sources are taken away, then
the fire will be put out. Water, a universal medium is available in large quantities and less
expensive than any other fire suppression medium. Water also acts as a cooling agent when
introduced into fire suppression. Water may be used in manual or automatic systems. The
manual system uses hoses and standpipes while the automatic system uses sprinklers.
Sprinkler System:
Automatic sprinklers utilize a wet or dry pipe system. Automatic sprinklers consist of a network
of pipes which connect water supply to a series of sprinklers usually installed in the ceiling of a
building. For a wet pipe system, the piping holds the water until ready to use. In places where
the building is subject to freezing temperatures a dry pipe system is utilized. Dry pipe system
contains nitrogen in the pipe lines connected to the sprinkler head. In the event of a fire, the
valve connecting the pipe and water is open and the nitrogen displaced. Water is allowed to
spray through the sprinklers. A pre-action system is similar to a dry pipe system. When the
alarm is tripped the pipes fill with water and when the presence of heat is detected the sprinklers
release the water. On a deluge system, every sprinklers will dispel water simultaneously. This
system is used mostly in cases where fire is anticipated to spread quickly.
Standpipe System:

4. Standpipe systems are required for high rise buildings. These systems allow fire fighters to
access water to put out fire. There are three classes of standpipe systems. Class 1 has 2.5 hose
outlets on each floor with a minimum water supply requirement of 500 gpm for the first
standpipe and 250 for each additional one. Class 2 is to be used by the occupants of the building
for extinguishing fires. Minimum water supply is 100 gpm. Class 3 is a combination of Class 1
and Class 2.
Other Methods for Fire Suppression:
Alternative methods for fire suppression besides water are carbon dioxide, dry chemicals, foam
systems and halogenated gas. Carbon dioxide is best for confined and unventilated spaces. Dry
chemicals, when sprayed “separate the fuel from the oxygen supply and thus retards fire.” Foam
system are most effective for fighting fires that are being fueled by fluids and halogenated agents
inhibits the chemical reaction of fire.
Water for HVAC
“Water is a chemically stable, nontoxic and inexpensive fluid.” Water has an extraordinary
ability to carry heat or convey the coolness or chilled water. Water can be used for both heating
and cooling needs. How much water or the gallons per minute (gpm) needed to heat or cool a
building is calculated by the ideal temperature and the temperature difference. “HVAC piping
includes Schedule 40 steel pipe copper pipe and Schedule 80 CPVC pipe.” Water quality is
important. Mineral deposits will destroy metal pipe and microorganisms can reduce the
productivity of the overall unit. Treated water is a must for the longevity of an HVAC system.