Post on 25-Dec-2015
Gas, Steam, and Water
Chapter 6
(c) 2014 by John Wiley & Sons, Inc.
In this chapter, you will learn to:
Describe the uses of gas and steam in foodservice. Identify the basics of how gas and steam equipment
work. Identify energy-saving use and maintenance tips. Identify water quality problems and how to deal with
them. Identify the basic foodservice plumbing requirements. Identify the basics of installing and maintaining a
drainage system. Explain hot-water needs, and how water heaters work.
Learning Objectives
(c) 2014 by John Wiley & Sons, Inc.
Understanding Energy Use
Terminology:
Air shutter adjusts primary air coming into burner
As the burners burn, the flames also use secondary air, the air around them
When air and gas are mixed, the speed at which the flame shoots through them is called the burning speed
You may encounter incomplete combustion, when the fuel doesn’t burn fully
Yellow flames create carbon soot, making cleanup harder and clogging orifices
The ideal is flame stability, a clear blue ring of flames with a firm center cone
Gas flows from the orifice in the form of a jet
The jet causes a rush of air (called primary air)
The primary air flows into the burner tube (sometimes called a mixer tube)
(c) 2014 by John Wiley & Sons, Inc.
Types of Burners
Pipe BurnerThis is a pipe
(usually cast iron) with two or more
rows of ports drilled along its length. Found in ovens, griddles, broilers
Slotted BurnerA type of pipe
burner; pipe can be straight or circular.
Ports all aim in same direction to form a single large flame
Flame Retention
BurnerHighly efficient
slotted burner with additional ports
drilled into the pipe.
Ring BurnerWidely used on range
tops, steam tables, boilers. Standard has
1 or 2 rows of ports arranged in a circle. Made of cast iron;
comes in many sizes
Gas burners come in several shapes and sizes
(c) 2014 by John Wiley & Sons, Inc.
Types of Burners
Radiant (Infrared) Burner
A set of porous ceramic plates with about 200 holes per square inch on its surface. Super-hot
and good for broilers.
Rangetop Power BurnerPremixes gas and air
in proportion to produce high heat
and efficiency.
Infrared Jet Impingement Burner
The IR jet premixes gas and air in separate
chamber. Flames impinge (hit hard) on
pan surface. Uses less gas than conventional
burners
Gas burners come in several shapes and sizes
(c) 2014 by John Wiley & Sons, Inc.
Pilot Lights and Thermostats
New technology replaces gas pilot light with electronic spark ignition. Reduces gas consumption, as pilot is not continuously lit.
Standard gas pilot light, located near main burners of appliance, should be about ¾-inch high.
Pilot light safety feature: thermoelectric control. When a junction of two metal wires (the thermocouple) is heated by the pilot flame, a very low electric voltage is generated – just enough to fire an electromagnetic gas valve and hold it in an open position.
(c) 2014 by John Wiley & Sons, Inc.
Pilot Lights and Thermostats
The thermostat is the control used on most gas-fired equipment to maintain the desired burner temperature Most common type is a knob or dial called a
throttling control or modulating control. Some types of cooking appliances, such as deep-fat
fryers, require quick heat recovery in less than 2 minutes. In these cases, a snap-action thermostat is used, which opens fully to permit maximum heating until the desired temperature is reached. Then, it shuts off just as quickly.
(c) 2014 by John Wiley & Sons, Inc.
Maintaining Gas-Powered Equipment
Perform routine checks
Monthly Tasks
Weekly Tasks
When a new
piece is added
Clean burner parts and orifices; check
primary blower speeds; vacuum-
clean entire blower system.
Clean & adjust air
inputs/pilot lights;
calibrate thermostats; check burner
valves, balance exhaust,
make-up air
Professional test of main gas line to
ensure your hot line has
sufficient pressure
Routine checks and/or
maintenance weekly and
monthly. Document
what you’ve done
(c) 2014 by John Wiley & Sons, Inc.
Steam Energy
Steam is water vapor. Steam molecules carry large quantities of heat, and they return to their original form (condense) when they come into contact with a cooler surface. The steam-jacketed kettle is a large "bowl within a bowl" used for
making sauces, soups, and stocks. Between the two bowls is an area about 2” wide into which steam is pumped, for high but uniform cooking temperatures.
A steamer is an oven-like appliance with an insulated door. Used for any cooking or thawing process that would benefit from adding moisture. Convection steamers contain a fan that circulates the warm,
moist air for quicker, more even cooking. Steam tables, often seen in cafeterias or on serving lines,
hold food above a reservoir of hot water to keep it warm Bain-marie is a hot-water bath in which a container of more
delicate foods (sauces, gravies) is immersed to stay warm.(c) 2014 by John Wiley & Sons, Inc.
Steam Energy
Steam systems and appliances work in one of three ways: Steam generators use electricity to heat water and make their
own steam. Small generators, called boilers, are located under or near the steam equipment.
Heat exchangers take steam already made from one source, circulate it through a series of coils to clean it, and use it to heat another source. Steam from a building's heating system could, for example, be captured by a heat exchanger and “recycled” to heat hot-water tanks.
Steam injectors shoot pressurized steam directly into an appliance to produce heat. This is the least efficient method, as a one-time use. Condensation is drained away, not reheated and reused.
(c) 2014 by John Wiley & Sons, Inc.
Your Water Supply
Safe, plentiful water is often taken for granted in foodservice – which is ironic when you consider what a truly scarce resource it is.
Salt water makes up 97% of all water on
earth
More than ½ % of what remains
worldwide is diverted for human use
2% percent is inaccessible,
frozen in remote ice caps and
glaciers
(c) 2014 by John Wiley & Sons, Inc.
Your Water Supply
EPA estimates that Americans use 100 gallons of water a day. EPA’s Water Alliances for Voluntary Efficiency program (WAVE) for hotels, restaurants, businesses began in 1990s, with water conservation goal of up to 30% Many water mains and pipes are more than 100 years old, long neglected, and reaching the end of their useful life
Desalination being explored as an option for increasing water supply:
Multistage flash distillation removes contaminants from seawater by boiling it, then condensing (distilling) the steam. In reverse osmosis (RO), highly pressurized seawater is pumped through a semi-permeable membrane that allows only the freshwater molecules to flow through.
(c) 2014 by John Wiley & Sons, Inc.
Water Quality Factors
EPA implements drinking water safety standards, regulations through the Safe Drinking Water Act. Concerns include:
Arsenic occurs naturally in some groundwater and is also a residue of mining and industry. At low doses, linked to cancer and diabetes; at high doses, it is poisonous.
Pathogens are bacteria that can cause gastrointestinal illnesses: Escherichia coli (E. coli O157:H7), cryptosporidium, and Yersinia enterocolitica, etc. Farm waste runoff and sewage discharge can accidentally contaminate food or water systems.
MTBE is a fuel additive designed to reduce air pollution. When spilled or leaked from storage tanks, it can contaminate water and cause liver, digestive, and nervous system disorders.
(c) 2014 by John Wiley & Sons, Inc.
Water Quality Factors
Perchlorate is used in making fireworks, weapons, and rocket fuel. It interferes with thyroid function in humans.
Trihalomethanes (THMs) are among the most common groundwater contaminants. They form when chlorine reacts with organic material such as fallen leaves. THMs may contribute to miscarriage risks and bladder cancer.
Ammonium perchlorate is an additive the National Aeronautics and Space Administration (NASA) and the Defense Department used for rocket fuel and munitions. For disposal, perchlorate often was dissolved in water and poured on the ground because defense officials did not consider low levels hazardous to humans.
(c) 2014 by John Wiley & Sons, Inc.
Buying and Using Water
Water is purchased in much the same way as electricity. A meter measures the amount of water that enters the water system, either in cubic feet or in hundreds of gallons
Typical home water pressure is 50 to 100 psi. An upfeed system uses excess pressure to move water through a building’s pipes. Components of typical upfeed system are Water meter. The device that records water consumption Service pipe. Main supply line between meter and building. Fixture branch. A pipe that carries water to a single fixture. It can
be vertical or horizontal and carry hot or cold water. Riser. A vertical pipe that extends 20 or more feet, and carries
hot or cold water. Fixtures. Devices (faucets, toilets, sinks) through which water is
used.
(c) 2014 by John Wiley & Sons, Inc.
Buying and Using Water
Upfeed system components (continued):
Pipes. The tubes fitted together to provide system for water to travel through. They can be copper, brass, galvanized steel, or plastic. (Building codes determine what materials are acceptable for different uses.) Copper is most expensive, but considered easy and
economical to work on. Plastic pipes are allowed only for limited, special uses. The
most common is made of polyvinyl chloride (PVC). It is inexpensive, corrosion resistant, durable.
Fittings. The joints of the pipe system fit onto the ends of pipes, allowing them to make turns and to connect to each other and to appliances or fixtures.
(c) 2014 by John Wiley & Sons, Inc.
Buying and Using Water
Upfeed system components (continued):
Valves. Valves control water flow, and are made of brass, copper, or cast iron. Use of the correct valve minimizes plumbing problems. Gate valves are used to vary water flow and allow water to go in either direction. Check valves allow water to flow only one way. They are marked with an arrow indicating the direction of flow. Safety valves are spring-loaded, operated by temperature or water pressure, to relieve excess pressure if they sense a buildup.
(c) 2014 by John Wiley & Sons, Inc.
Water Conservation
Turn off continuous flow feature of drain trays
New commercial dish machines are designed to work with water usage
well below 1 gallon per rack
Thaw food and presoak utensils in tubs or basins of water, not running
water
Boilerless steamers use least water of all steamer types
Adjust ice-making equipment to make and dispense less ice when
less is needed
Repair leaky toilets and faucets
Install aerators, spring-loaded valves, electronic sensors, or
timers on all faucets.
Replace worn-out fixtures with water-saving ones
Apply water conservation stickers on mirrors to remind
both employees and customers to turn off taps.
Kitchen & Service Areas Restrooms
(c) 2014 by John Wiley & Sons, Inc.
The How & Why of Hard Water
Hard water is unavoidable in some areas, but causes scaling,
soap scum. It can discolor dishes, clog equipment or make
it run less efficiently.
Caused by calcium carbonate, a natural mineral suspended in tap water; it builds up in appliances that use water. It is annoying but
not a health risk.
Avoid scale buildup with regular maintenance. Get expert help if necessary to test and treat hard
water.
(c) 2014 by John Wiley & Sons, Inc.
Basic Water Heating Guidelines
Hot-Water Heating
The average foodservice establishment uses roughly 5 gallons of hot water per guest. Less is needed in quick-service, with disposable utensils and
plastic ware To determine correct size of water heater needed, multiply the
five-gallons-per-guest average by the maximum number of guests you would serve at a peak mealtime
Water must, by health ordinance, reach certain temperatures for certain foodservice needs: restrooms (110-120 degrees F.); pot sinks (120-140 degrees F.); dish machines (140-160 degrees F.); final dish rinse (160 degrees F.)
(c) 2014 by John Wiley & Sons, Inc.
Hot-Water Heating
Types of Water Heaters
Self-contained storage heater
Heats and holds water up to 180°F,
delivers on demand. Most common water
heater type.
Tankless water heater
Circulating tank water
heater
Heats water immediately, only on demand. No tank is
needed.
Heats water up to 180°F, passed
immediately to a separate tank
Heat pump water heater (HPWH)
Uses “waste heat” recovered from other
appliances to heat water.
(c) 2014 by John Wiley & Sons, Inc.