Safety First

General Safety Rules

In a technology course, you have many opportunities to
design and build products. You can apply your creativity and
problem-solving skills. It’s very important that you also apply
common sense and practice safe work habits.

Develop a Safe Attitude

• Read and follow all posted safety rules. • Put up warning signs on things that are hot
• Take the time to do the job right. and could cause burns.
• Consider each person’s safety to be your • If you bend down to pick up an object, use
responsibility. Avoid putting others in your legs, not your back, to lift up. Keep
danger. your back straight. To keep better control,
get help to lift or move long or heavy items.
• Stay alert. Be aware of your surroundings.
• Work quietly and give your full attention to • Handle materials with sharp edges and
the task at hand. Never indulge in horseplay pointed objects carefully.
or other foolish actions. • Report accidents to your teacher at once.
• Stay out of danger zones as
much as possible. These are
usually marked with black
and yellow striped tape.

Notice the safety jackets

worn by the students working
on this solar-powered car.

1 • Safety First
Have Respect for Tools and
Equipment
• Never use any tool or machine until the
teacher has shown you how to use it and has
checked the setup.
• Before using any tool or machine, make sure
you know the safety rules and make sure
you get your teacher’s permission.
• Use equipment only when the teacher is in
the lab. Wear Appropriate Clothing and
• Do not let others distract you while working. Protective Equipment
• Do not use electrical tools or equipment if • Always wear eye protection. Special eye
the cord or plug is damaged. protection may be needed for some activi-
• Always use the right tool for the job. The ties, such as using a laser, welding, or using
wrong tool could injure you or damage the chemicals.
part you are working on.
• To avoid injury, use the right machine guard
for the job. Check with your teacher for the
appropriate guard.
• Keep hands and fingers away from all mov-
ing parts.
• Before you leave a machine, turn it off and
wait until it stops. If you are finished, clean • Wear hard shoes or boots with rubber soles.
the machine and the area around it. • Use ear protection near loud equipment.
• When you have finished working, return all • Do not wear loose clothing, jewelry, or other
tools and unused supplies to their proper items that could get caught in machinery.
places. Tie back long hair.
Prevent and • Do not wear gloves
Control Fires while operating
power tools.
• Store oily rags in a
closed metal container
to prevent fire.
• Know where the nearest
fire extinguisher is and
how to use it, if that is
your school’s policy.

Safety First • 2
 Safety First

Have Respect for Hazardous

Materials and Waste
• Products with major health risks should
have a Material Safety Data Sheet
(MSDS) available. Ask your teacher
about the MSDS before you use
materials that may be hazardous.
Know how to read the
MSDS. You can find more
information about Mate-
rial Safety Data Sheets
on page 559.
• Other common chemi-
cals will have safety
information on the labels. Check the
labels of materials before you use them.
• Wear appropriate personal protective equip-
ment (PPE) when working with hazardous
materials.
• Work in a well-ventilated area.
• Follow your teacher’s instructions for
disposal of hazardous materials and waste.

Maintain the Lab

• Keep the work area clean. Keep
the floor and aisles clean at all
times.
• If a liquid is spilled, clean it up
immediately as instructed by
the teacher.
• Always use a brush, not your
hands, to clean dry materi-
als from a table or piece of
equipment.
• Store all materials properly.

3 • Safety First
 This carpenter is nailing roof trusses. Why should eye protection be worn when using a
hammer?

Safe Use of Hand Tools

Misuse and improper maintenance pose the greatest hazards in using
hand tools. Observe the following rules when using hand tools.
• Keep all hand tools clean and in good • Always wear safety glasses or goggles.
condition. • Cutting tools should be sharp.
• Wipe tools clean before and after use. • Do not use a screwdriver on a part that is
• Use only tools that are in good condition. If being hand-held. The screwdriver can slip
a tool is damaged, tell your teacher about it. and hit your hand.
• Use a hand tool only for the purpose for • Carry sharp or pointed tools with the point
which it was designed. down and away from your body.
• Hold and use the tool in the proper way,
following manufacturer’s instructions.

Safety First • 4
 Safety First
Safe Use of Electric Power Tools
Use care and common sense when working with electric power
tools. Observe the following safety practices.

Work Safely
• Do not wear loose clothing, ties, or jewelry
that can become caught in moving parts of
machinery. Be sure to tie back long hair.
• Do not wear gloves while operating power
tools.
• Wear the appropriate personal protective
equipment (PPE), such as safety glasses or a
face shield.
• Never set a hand-held power tool down
Prevent Electric Shock while it is running or coasting.
• Do not stand in water while working on • Avoid accidental startups by keeping fingers
equipment. off the START switch when carrying a tool.
• Make sure that all electrical cords are free of • When you approach a machine, be sure it is
frays and breaks in the insulation. off and that it is not coasting.
• Pull the plug, not the cord, when you unplug • Secure the work piece with clamps or a vise.
a tool or machine. Damaging a cord may This will free both hands to operate the tool.
cause an electric shock. • Disconnect the power source before chang-
• Keep electrical cords away from sharp ing accessories such as bits, belts, and
edges. blades.
• Use only power tools that have been prop- • Keep tools as sharp and clean as possible for
erly grounded or double insulated. best performance.
• Make sure that all extension cords are the • Tell the teacher immediately if the machine
three-wire grounded type. doesn’t sound right or if you can see that
• Make sure the three-pronged plug is used in something is wrong.
a grounded receptacle.

5 • Safety First
Safe Use of Cutting Tools
Observe the following safety practices when using electric
power tools to cut materials.

Check stock before cutting it. Nails, cracks, or loose

knots could cause a power saw to kick back or send pieces
flying out at high speed. Before starting to cut, put on
safety goggles.

• Allow machines to reach full speed before • Keep your balance; don’t overreach.
starting to cut. • Support ends of long stock before cutting.
• Before working on stock (wood or other • Wait until the blade stops completely before
workpieces), check it for cracks, loose knots, removing any scraps. Use a brush, not your
and nails. fingers.
• The shortest piece of lumber that can safely
be run through most equipment is 12 inches
long.

Safety First • 6
 Safety First
Safe Use of Pneumatic Tools
Pneumatic tools are powered by compressed air. The air is fed to the tool
through a high-pressure hose connected to an air compressor.

Air Pump
Belt Drive

Belt Guard

Electric Motor

Pressure Gauge

Handle

Hose Fittings Regulator

Tank

The main parts of an air compressor are shown here.

• When using a compressed-air gun, always • Never use a pneumatic tool, such as a
wear the correct personal protective equip- compressed-air gun, to remove debris
ment (PPE). For example, wear safety from your clothing or body.
glasses or goggles and a face shield. Always • Securely position a pneumatic tool before
direct the airflow away from you. operating it. These tools operate at high
• Always carry a pneumatic tool by its frame speeds or under high pressure.
or handle, not by the air hose.
• Make sure all pneumatic tools are securely
attached to the compressed-air line.

7 • Safety First
Tool and Machine Maintenance
Tools and machines that are well maintained do a better, faster
job and are safer to use.

Hand Tool Maintenance

• Keep sharp tools properly sharpened. Blades of band saws
and other cutting tools
• Check edges, sharp points, and other work- should be cleaned
ing surfaces for cracks and other defects. regularly to remove
• Keep working surfaces and handles clean resin, pitch, and other
and free of dirt and rust. debris. A clean blade
will cut straighter and
• Check that any moving parts or mechanisms smoother.
are working properly.
• Check for loose handles and other loose parts.
• Check wood handles for splinters and other Power Tool and
damage. Machine Maintenance
• Clean the tool following use each day. • Keep sharp tools properly sharpened.
• Inspect the tool for damage at least once • Check edges, sharp points, hoses, and other
each day before use. working parts for cracks and other defects.
• Lubricate any tool parts that require it. • Keep working surfaces, handles, and hoses
• Preserve wood handles regularly with clean and free of dirt and rust.
special oils made for that purpose. • Check that any moving parts or mechanisms
• Store tools in their proper places in an are working properly.
organized way. • Check for loose handles and other loose
• Store sharp tools in a safe place with the parts.
cutting edge protected. • Check for broken plugs or lugs removed
from grounding plugs.

Clean brushes after each use to keep the

• Check for split insulation or damaged
bristles soft and in good condition.
electrical cords.
• Disconnect and clean the tool following use
each day.
• Disconnect and inspect the tool for damage
at least once each day before use.
• Lubricate any tool parts that require it.
• Store tools in their proper places in an
organized way.
• Store sharp tools in a safe place with the
cutting edge protected.

Safety First • 8
 Safety First
Safe Use of Chemicals
Follow these rules when working with paints, stains, varnishes, paint
thinners, adhesives, or other chemicals.

• Read and follow all label precautions. • Pay attention to others around you when
• Always wear protective clothing and working with chemicals and report any
approved eye protection. Use appropriate unusual reactions.
gloves or tongs when needed. • Clean up spills immediately.
• Many chemicals produce harmful fumes. • Clean all tools and equipment properly after
Work only in well-ventilated areas. Use a using.
respirator whenever it is required. • Avoid skin contact with chemicals. Wash
• Know where the eyewash station is and how thoroughly before leaving the area.
to use it. • Many chemicals need to be stored away
• Know where the Material Safety Data Sheets from heat or away from moisture. Follow
(MSDS) are located. label directions.
• Know where the poison-control phone • Never store chemicals in an unlabeled or
number is located. incorrectly labeled container.
• Mix chemicals only as directed. If you need • Store chemical-soaked rags in an approved
to mix acid and water, get the water first. container.
Then carefully add the acid to it. • Dispose of chemicals properly.

Use gloves to protect your hands

from contact with chemicals.

9 • Safety First
Material Safety Data Sheet
OSHA requires that workers be informed about any hazardous chemicals to
which they may be exposed. A Material Safety Data Sheet (MSDS) is a form used
to communicate information about hazards. The table at the bottom of this page
is part of an MSDS for acetylene. There are different types of Material Safety
Data Sheets, but they all must include the following kinds of information.

• The identity of the hazardous chemical, • The limit of safe exposure.

including both its chemical and common • Whether the chemical is carcinogenic
name(s). If the chemical is a mixture, the (cancer-producing).
ingredients are listed.
• Generally applicable precautions for safe
• Physical and chemical characteristics, handling and use.
such as flash point (the lowest temperature
• Generally applicable control measures, such
at which a vapor may ignite).
as personal protective equipment (PPE).
• Physical hazards, including the potential • Emergency and first-aid procedures.
for fire, explosion, and reactivity.
• The date the MSDS was prepared or last
• Health hazards, including signs and symp- updated.
toms of exposure, and any medical condi-
tions that are generally recognized as being • The contact information of the chemical
aggravated by exposure to the chemical. manufacturer, importer, employer, or
other responsible party who can serve as
• The primary route(s) of entry. For exam- a provider of additional information on
ple, a chemical may produce fumes that
the hazardous chemical and appropriate
could be inhaled.
emergency procedures, if necessary.

2. Hazard Ingredients and Identity Information

COMPONENT % VOLUME OSHA-PEL ACGIH-TLV CAS NUMBER
Acetylene 95.0 to 99.6 Not Available Simple Asphyxiant 000074-86-2
Acetone Unavailable 1000 ppm TWA 750 ppm TWA 1000 000067-64-1
ppm STEL
3. Physical and Chemical Characteristics
Boiling Point: -118.8°F Specific Gravity: 0.906 pH: N/A
Melting Point: -116°F Evaporation Rate: N/A Physical State: Gas
2
Vapor Pressure: 635 psig Solubility (H 0): Soluble
Appearance and Odor:
Pure acetylene is a colorless gas with an ethereal odor. Commercial (carbide) acetylene has a distinctive
garlic-like odor.
How to Detect This Substance: N/A
Other Physical and Chemical Data:
Liquid density at boiling point, 38.8 lb/ft3 (622 kg/m3)
Gas density at 70°F 1 atm, 0.0691 lb/ft3 (1.107 kg/m3)

Safety First • 10
 Safety First
Safety Color Codes
Safety signs and labels are color-coded to signify hazards or to identify
the location of safety-related equipment.

Color Meaning Examples

Red Danger, stop, or emergency • Fire-protection equipment
• Flammable-liquid container
• Emergency stop bars and switches

Orange Be on guard • Hazardous parts of equipment or

machines that might injure
• Safety starter buttons on equipment
or machines

Yellow Caution • Physical hazards, such as steps and

low beams
• Waste containers for combustible
materials

White Storage • Housekeeping equipment

Green First aid • Location of safety equipment, such

as first-aid kit

Blue Information or caution • Out-of-order signs on equipment

• Cautions against using out-of-order
equipment

11 • Safety First
Warning Labels
The warning labels on containers of hazardous material
may use colors and numbers to indicate the hazard level.
There are several labeling systems. One was developed by RED
the National Fire Protection Association (NFPA). Their Flammability
label consists of squares arranged into a “diamond” Hazard
shape. Each square has a different color to represent
the type of hazard. Red represents flammability, BLUE YELLOW
and yellow represents reactivity. Blue is used Health Reactivity
for health hazards, and white is for special Hazard Hazard
information. A number on a square indicates the
severity of the hazard. Numbers range from 0 to 4, WHITE
with 4 representing the greatest hazard. However, any Special
category rated 2 or higher should be considered poten- Hazard
tially dangerous.
For example, an NFPA label for toluene would have a 3
in the red square, a 2 in the blue square, and a 0 in the yel-
low square. Toluene is a chemical used in many paints, paint
thinners, lacquers, and adhesives. It is flammable, can be
harmful if inhaled or swallowed, and is not reactive when
mixed with water.

Safety First • 12
 Safety First
Fire Safety
In order for a fire to burn, three basic things must be present.
• A source of heat
• Oxygen
• Fuel
For example, what if a piece of paper comes in contact with a hot wire
and the paper burns? The hot wire provides heat, the paper is the fuel, and
oxygen is present in the air.

Most fires can be extinguished by

Reducing the heat The most common way to dioxide is contained in many fire extinguish-
reduce the heat of a fire is to throw water on ers. Keeping oxygen away is also the method
it. This has cooling action and also produces used when a person’s clothing catches fire. The
steam. The steam helps to exclude oxygen. person is wrapped in a blanket, which smoth-
However, water should not be used to extin- ers the fire.
guish some fires, such as grease or electrical
Removing the source of fuel If a gas or liquid,
fires.
such as gasoline, is feeding a fire, it can often be
Preventing oxygen from reaching the fire A turned off in some way. That removes the fuel.
fire can be deprived of oxygen by spraying it In some cases, the fuel may be allowed to burn
with an inert gas, such as carbon dioxide. Carbon until it is used up and the fire goes out.
Class of Fire Type of Flammable Material Type of Fire Extinguisher to Use

Class A Wood, paper, cloth, plastic Class A

Class A:B

Class B Grease, oil, chemicals Class A:B

Class A:B:C

Class C Electrical cords, switches, wiring Class A:C

Class B:C

Class D Combustible switches, wiring, metals, iron Class D

Class K Fires in cooking appliances involving Class K

combustible vegetable or animal oils
and fats

13 • Safety First
Developing a Fire Emergency
Plan
Your lab should have a plan for use in a fire
emergency. If your teacher has not explained it
to you, ask about it. Be sure you know where all
the exits are, where the fire extinguishers are
kept, and what your responsibilities are in case
a fire occurs. Then follow these steps to record
the fire emergency plan.
1. Draw a floor plan of the lab.
2. Locate all the fire exits and label them on
the floor plan. If the lab has no direct exit
to the outside, draw a map of your section
of the school. Show the location of the lab,
and draw arrows from the doors in the lab 7. Ask your teacher for procedures to follow
to the nearest fire exits. if a fire occurs. If time allows, this may
3. Locate and label any windows that could include such things as closing windows,
also be used for escape. (Check to be sure turning off equipment, and grabbing the
the opening will be large enough for an first-aid kit. Someone should be responsi-
adult to pass through.) ble for reporting the fire. However, human
safety is the most important consideration.
4. Locate all the fire extinguishers and label
Fires can spread quickly, and smoke can be
them on the floor plan. Indicate on the plan
just as deadly as flames. Your most impor-
the class of fire for which each extinguisher
tant responsibility is to get out alive.
can be used.
8. Be sure everyone has a chance to study the
5. Locate places where flammable or explo-
emergency plan. Then, with your teacher’s
sive materials should be stored and label
approval, post it in a prominent place
them. Be sure they are in a location far
where it can be seen easily.
away from any source of heat and that their
cabinet is fireproof. 9. Be sure that you and your classmates are
informed as to housekeeping duties that
6. Determine where you and your classmates
help prevent fires, proper handling of any
should meet after you have left the build-
materials that could catch fire, how to treat
ing. This is important so that someone can
burns, and where to report a fire.
check to be sure everyone has escaped
safely.

Safety First • 14
 Safety First
Troubleshooting
To “troubleshoot” means to follow a systematic method to find the cause
of a problem and fix it. Owner’s manuals often contain troubleshooting
charts to help users find and correct problems.
Troubleshooting begins by looking for the most likely causes. Often, the
problem is a simple one that can easily be fixed. If that turns out not to
be the case, then the troubleshooter looks for more unusual causes. It is
also a good idea to look at a system’s parts and test each part one by one.
For example, when your computer is unable to read a new CD, you might
follow a procedure like the one outlined in this table.

Symptom Possible Cause How to Check

Computer cannot read CD. 1. CD is not formatted for 1. Read label of CD for
your computer system. hardware and software
requirements.
2. CD is not properly inserted 2. Reinsert CD into drive,
in drive. being careful to place it
correctly.
3. CD is damaged. 3. Insert a different CD into
the drive to see whether it
will work.
4. CD drive damaged. 4. Replace or repair CD drive.

Here is a simple troubleshooting table to use in the school lab.

Symptom Possible Cause How to Check

Electric tool is not working. 1. Cord is not plugged in. 1. Plug in the cord.

2. Switch is turned off. 2. Turn on switch.

If the tool still does not work, report the problem to your teacher. The tool may need repairs,
or there may be a problem with the electric power supply.

15 • Safety First