Transcript Module Five - Osceola County School District

Module 5:
Control Measures to
Reduce Exposures
Control Measures
Engineering Controls
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Engineering controls are those that mitigate
the dangers of accidents through the use of
design and separation. They can be placed
in three categories:
Substitution
 Isolation
 Ventilation
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Control Measures
Engineering Controls
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Substitution includes the use of a less
hazardous material, a change in the process
equipment used, or a change in the process
itself. Care must be taken to ensure that
the substitution actually does result in less
hazardous conditions.
How to Perform a Substitution.
Develop Evaluation Criteria
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It order to select a substitution chemical the teacher
must consider a variety of issues. Some of the criteria of
concern are listed below.
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Teaching objectives
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Does the alternative alter the
experiment’s teaching
objectives significantly?
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Raw material needed
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Quantity and characteristics of
the raw materials
Waste generated
Cost
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Physical state, quantity and
characteristics of the wastes
Equipment, chemicals, waste
disposal, etc.
Ease of implementation
How to Perform a Substitution.
Screen Alternatives
Some preliminary information on
each alternative will be needed
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Select favorable
alternatives
ALTERNATIVES
Ease of Implementation
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Cost
Screen using an
evaluation matrix with
the selected criteria
Waste Generated
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Raw Materials Needed
Screen the alternatives to
eliminate those that are not
feasible for the University
Teaching Objectives
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How to Perform a Substitution.
Detailed Evaluation of
Alternatives
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Quantitative/Qualitative Detailed Evaluation
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Not needed if only one alternative
remains after the initial screening
Used as a fine tuning to determine which
of the remaining alternatives might
result in the most favorable for pollution
prevention
Pilot Testing
 Test alternative before its full implementation
Example
Evaluation Criteria
Educational value
Safety risks
Input materials
Cost
Ease of implementation
Waste materials
Resources
Others
Alternatives
For Experiment A
For Experiment B
1. Chemical substitution
2. Microscale
3. Scale down
4. Alternatives 1 and 3
1. Ag identification and recovery using
ascorbic acid
2. Alternative method for Ag identification
using KI
Control Measures
Engineering Controls
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Isolation is a method of limiting exposure to those
students and teachers who are working directly
with the hazard, often by enclosing them within a
containment structure. While isolation will reduce
the risk to those outside the isolated area, it
should be accompanied by appropriate controls to
ensure that those within are not faced with an
increased exposure to the hazard.
Control Measures
Engineering Controls
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The most common example of isolation is the
elimination of anyone from the laboratory other
than those who must be there. Additional
students in the room not only create additional
distractions and opportunities for accidents but
are also potential victims should an accident
occur.
Control Measures
Engineering Controls
Ventilation is most important for the control
of airborne hazards. It involves the removal
(from the laboratory) of air that contains a
hazardous contaminant and its replacement
with uncontaminated outside air. There are
two types: local exhaust and general
dilution. A properly designed local exhaust
system can capture a contaminant where it
is generated and remove it before it is
dispersed into the work environment.
Control Measures
Engineering Controls
Local exhaust is accomplished in most laboratories with the
use of a fume hood. These devices are critical for the
removal of potentially dangerous gases and vapors for the
room.
General dilution is accomplished thorough the use of Heating
Ventilation and Air Conditioning Systems. The more air
changes occur in the laboratory the less likely that a
dangerous exposure level will occur. Experiments should
never be conducted in poorly ventilated spaces.
Engineering Controls
Fume Hoods
Space is
always an
issue but do
not use fume
hoods as
storage
cabinets. A
variety of
accidents can
happen
Engineering Controls
Fume Hoods
Fume
hoods should be
checked and certified as
functioning properly. A white
card should be placed on the
fume hood with the
certification date. (If a fume
hood is operating marginally,
a yellow caution sign should
be posted on the hood; if the
hood fails completely, a red
warning sign must be
posted.)
Engineering Controls
Fume Hoods
Many
fume hoods have
air flow alarms. However,
alarms occasionally fail or
are deliberately silenced.
One suggestion is taping
tissue to the fume hood
sash to provide a visual
indication of air flow.
Engineering Controls
Fume Hoods
 Some
 Keep
rules of thumb when using fume hoods:
objects at least 6” inside the hood
 Larger objects should be up on blocks or feet to allow air
flow to travel underneath
 Too much air flow is not necessarily a good thing. Eddies
can occur which will force the contaminant back on to the
user. Call maintenance if you suspect the fume hood is
pulling too much air
 If your fume hood is loud, it may indicate that mechanical
attention is needed. Call maintenance for a hood
evaluation.
Engineering Controls
Fume Hoods
Remember -- adequate ventilation is important in any room
in which chemicals are used or stored. Inadequate
ventilation limits the kinds of activities that can be done and
the chemicals used in the laboratory. An adequate ventilation
system should change the room air 4-12 times per hour. All
air from laboratories should be exhausted outdoors and not
re-circulated in the building. The ducts should be situated so
that exhausted air does not enter fresh air intakes.
Engineering Controls
Fume Hoods
Lack of odor is not an adequate criteria of good ventilation
since many chemicals have no odor at hazardous levels. A
knowledge of the hazardous chemicals being used helps
reduce risk from exposure. If the presence of hazardous
vapors is suspected, monitoring should be done. Emergency
auxiliary ventilation should put a negative pressure on the
room so air moves into the room and prevents vapors from
being re-circulated through the building.
Engineering Controls
Fume Hoods
Chemical storerooms should have ventilation adequate to
keep atmospheric levels of chemicals below their hazardous
limits (threshold limit value (TLV) or permissible exposure
limit (PEL)). As with room ventilation, 4-12 air changes per
hour are recommended on a continuous basis to prevent
buildup of toxic or hazardous concentrations of vapors. All
ventilation systems should be regularly evaluated to ensure
they are operating properly.
Engineering Controls
Fume Hoods
Fume hoods are intended to keep flammable gases, toxic
vapors, or noxious odors from entering the general room
atmosphere. The American Conference of Government
Industrial Hygienists (ACGIH) recommends that hoods be
used when working with chemicals having a TLV of 50 ppm
or less. The concentrations of vapors in the room must be
below the TLV listed in the MSDS for the chemical(s) used.
Microscale procedures in which smaller quantities of
chemicals are used can reduce exposure to hazardous and
noxious vapors.
Mechanical Systems
Ventilation
LOCAL EXHAUST FANS
Use local exhaust fans and fume hoods to prevent air
pollutants and moisture from accumulating in, or spreading
beyond, the local area or classroom. Local exhaust fans may
be used to exhaust entire rooms (for example, bathrooms or
locker rooms). Fume hoods are appropriate for activities that
generate significant quantities of pollutants in a local area
within a room.
“Other” Control
Measures
Laboratory Maintenance and
Inspection
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Housekeeping, safety
audits, chemical
storage, container
labeling, spills, etc.
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Protective Equipment
 respirators, goggles,
gloves, lab coats
Safety Equipment
 spill kits, safety
showers, eyewashes,
fire extinguishers, first
aid kits, explosion-proof
refrigerators
“Other” Control
Measures
Laboratory Maintenance
and Inspection
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Perhaps one of the least
discussed yet most
important area of safety
management is
housekeeping.
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Clean and well organized
lab and storage areas
decrease the numbers of
opportunities for accidents.
Good housekeeping
includes proper cleaning of
glassware, orderly
arrangement of chemical
containers, pre-staged
tools and many other
measures.
Other Protective
Systems
Fire Detection Systems
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Fire Alarms and Heat/Smoke Detectors in classrooms and
storage areas provide advanced notice of an incipient fire.
Ionization and photoelectric detectors have the capability
of saving lives and property if they are installed and
maintain correctly. Some general recommendations
associated with heat and smoke detectors include:
Don’t install them in corners of walls or ceiling.
Don’t paint them.
Don’t install them in air pathways for vents.
Never cover a detector with a plastic bag or other device.
Fire Sprinkler Systems
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Fire Sprinkler systems are extremely effective tools for the
protection of life and property. They have the best safety
record of any fire control device according to the National
Fire Protection Association. A note here about how they
work.
A sprinkler head is a water outlet that is sealed closed with
a cap and a fusible device such as a glass crystal or
fusible link. They operate at a given ambient temperature
and operate one at a time directly of the seat of the fire.
They cause significantly less damage than a fire might.
Fire Sprinkler Systems
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Some simple procedures will ensure that the sprinkler
system will work effectively and not cause undue damage.
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Never hang anything from a sprinkler head.
Never paint a sprinkler head.
Avoid sprinkler heads when conducting experiments
involving high heat.
Do not store anything within 18 inches of the sprinklers.
In the event a sprinkler activates accidentally, evacuate
the room (the first water at the end of the pipe is usually
filthy and stagnate) and attempt to control flooding.
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Electrical Systems
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Ground fault interrupters are designed to protect from electrical
shock by interrupting a household circuit when there is a
difference in the currents in the "hot" and neutral wires. Such a
difference indicates that an abnormal diversion of current from
the "hot" wire is occurring. Such a current might be flowing in
the ground wire, such as a leakage current from a motor or
from capacitors. More importantly, that current diversion may
be occurring because a person has come into contact with the
"hot" wire and is being shocked. When a circuit is functioning
normally, all the return current from an appliance flows through
the neutral wire, so the presence of a difference between "hot"
and neutral currents represents a malfunction which in some
circumstances could produce a dangerous or even lethal shock
hazard.
Electrical Systems
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GFCIs are sensitive and trip easily. To reset them first ensure
that there is no electrical hazard and then simply push the reset
button located in the middle of the receptacle. In some cases
normal duplex receptacles are wired to one GFCI. If this case
you will have to locate the GFCI and reset it. Any failure or a
GFCI to reset or if you cannot find it, contact facilities
maintenance.
Ground fault interrupters are subject to aging and may need
replacing after a number of years. The GFCI ordinarily trips off
and cannot be reset using the Reset button. If this occurs,
notify facilities maintenance to test and/or replace the GFCI.
Electrical Systems
To test a GFCI, press the “test”
button. The power should shut off.
Occasionally GFCIs fail to work as
designed (even though pressing the
“test” button shuts off the power).
To ensure a GFCI is working
properly, contact Maintenance for
testing.
Electrical Systems
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Extension cords are
not permitted in labs
except for temporary
(one day) use.
Check to see that all
power cords are in
good condition.
Replace or repair
those with cracked
housing, missing
grounding pugs, etc.
Electrical Systems
Electrical panels
should be labeled and
must have clear
access. Access will be
important in the event
there is an urgent
need to shut power off
to a particular
appliance of area.
Breaker panels for the
lab may be locked.
Electrical Systems
Any time rewiring or
renovation is
performed it is a good
idea to check to see
that all outlets are
grounded and that the
polarity is correct. A
simple circuit checking
tool can do this.
Emergency Shutoffs
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Florida Statutes require that “Each space equipped with
unprotected gas valves accessible to students has an
approved master cut-off readily accessible to the teacher”
The teacher should be aware of the location of the gas
shut-offs in their laboratory classroom. Shutoff is
sometimes accomplished with a quarter turn valve and
sometimes with an electrical gas valve.
Safety Inspection
Findings
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Let’s look at some photos of laboratory
inspections in schools. See how many
problems you can find.
Safety inspection findings
Safety inspection findings
Pathways blocked
by trash
Improperly disposal
of chemicals
Safety Inspection
findings
Safety Inspection
findings
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Exit door obstructed
Safety Inspection
Findings
Safety Inspection
Findings
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Chemicals, wastes & incompatible stored
together
Safety Inspection
Findings
Safety Inspection
Findings
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Extension cords should
be avoided but
certainly should never
be suspended where
the could be damaged
or might snag on a
passing cart etc..
Check
to ensure
that heavy objects
are stored no more
than five feet off the
floor.
Where appropriate,
are ladders and/or
step stools available
and in good repair?
Nothing wrong here, a
rigid container that can
be sealed should be
available for broken
glass.
Mechanical hazards
such as this open drive
belt must be guarded.
This is a tricky one.
Plastic tubing should
not extend below the
rim of a sink unless the
faucet is equipped with
an anti-siphon device
(see arrow, inset).
Soap and towels must
be readily available.
Summary
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There are a wide variety of engineering control
measures that can prevent accidents but at their
best they may not be able to control all hazards.
It is essential therefore to act is a safe manner in
support of those systems.
Most engineering solutions require some level of
maintenance, it is up to the users to ensure
proper working condition.
References
Go to the Quiz
References
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ASE (1996) Safeguards in the School Laboratory (10th ed..), Hatfield:
ASE.
Borrows, P. (1992) ‘Safety in secondary schools’, in Hull, R. (ed.), ASE
Secondary Science Teachers’ Handbook, Hemel Hempstead: Simon &
Shuster. (This highlights the common accidents in labs most of which
involve chemicals in the eye or mouth or on the body; and describes
five ‘main danger areas’ such as burns from alcohol fires and alkali
metal explosions.) More recently Borrows has written: ‘Safety in
science education’, in Ratcliffe, M. (ed.) (1998).
DfEE (1996) Safety in Science Education, London: HMSO.
Everett, K. and Jenkins, E. (1991) A Safety Handbook for Science
Teachers, London: John Murray.
The MSDS Hyperglossary at http://www.ilpi.com/msds/ref/index.html
Glossary
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29 CFR 1910.1450 – OSHA’s Laboratory Standard also known as Title 29 of the Code of
Federal Regulations Part 1910, Subpart Z, Section 1450
Action Level – a concentration designated in 29 CFR part 1910 for a specific substance,
calculated as an eight hour-time weighted average (TWA), which initiates certain required
activities such as exposure monitoring and medical surveillance. Action levels are generally set at
one half the PEL but the action level may vary from standard to standard.
Acute toxicity – is the ability of a chemical to cause a harmful effect such as damage to a
target organ or death after a single exposure or an exposure of short duration.
American Conference of Governmental Industrial Hygienists (ACGIH) – a non-profit
organization consisting of a community of professionals advancing worker health and safety
through education and the development and dissemination of scientific and technical knowledge.
The ACGIH develops and publishes recommended occupational exposure limits each year called
TLVs for hundreds of chemicals, physical agents and biological exposure indices.
American National Standard Institute (ANSI) – a non-profit organization that administers
and coordinates the US voluntary standardization and conformity assessment system.
Biological Materials – Biological or biohazardous materials include all infectious organisms
(bacteria, fungi, parasites, viruses, etc.) that can cause disease in humans or cause significant
environmental or agricultural impact.
Carcinogen - A substance capable of causing cancer. Carcinogens are chronically toxic
substances; that is, they cause damage after repeated or long-duration exposure, and their
effects may become evident only after a long latency period.
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Glossary
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CAS # - Chemical Abstracts Number – a unique number assigned to a chemical by the
Chemical Abstracts Service.
CFR – Code of Federal Regulations – contains the listings of all US Federal
regulations. The CFR, compiled by the Office of the Federal Register, is divided into 50
titles, which cover broad areas subject to Federal regulation.
Chemical Hygiene Officer – an employee designated by the employer who is qualified
by training or experience to provide technical guidance in the development and
implementation of the provisions of the Chemical Hygiene Plan. Note that these duties
can be in addition to the other job functions the employee performs in the laboratory.
Chemical Hygiene Plan (CHP) – a plan that addresses specific hazards in the
laboratory and is required by OSHA’s Laboratory Standard
Corrosive – a substance which causes damage to skin, eyes or other parts of the body
on contact. Concentrated acids are examples of corrosive substances.
Embryotoxin – a substance which retards the growth or affects the development of an
unborn child up to and including deformities and death. Mercury compounds, certain
heavy metals, aflatoxin, formamide, and radiation are known embryotoxins.
Explosive – means a chemical that causes a sudden, almost instantaneous release of
pressure, gas and heat when subjected to sudden shock, pressure, or high temperature.
Face velocity – the average velocity of air drawn through the face of a chemical fume
hood and generally calculated as the total volumetric exhaust flow rate for the hood
divided by the area of the open face, less an adjustment for hood air leakage.
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Glossary
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Irritant – a chemical which may cause reversible inflammation upon contact.
Laboratory -Any facility where the "laboratory use of potentially hazardous chemicals" occurs. It is a
room where relatively small quantities of potentially hazardous chemicals are used during scientific
experimentation.
Flammable – means a chemical that falls into one of the following categories:
 aerosol flammable is an aerosol that when tested by the method in 16 CFR 1500.45, yields a flame
protection exceeding 18 inches at full valve opening, or a flashback (a flame extending back to the
valve) at any degree of valve opening
 gas flammable is a gas that at ambient temperature and pressure, forms a flammable mixture with
air at a concentration of 13% by volume or less or a gas that at ambient temperature and pressure,
forms a range of flammable mixtures with air wider than 12% by volume, regardless of the lower
limit.
 liquid flammable means any liquid having a flashpoint below 100°F (37.8°C), except any mixture
having components with flashpoints of 100°C or higher, the total of which make up 99 percent or
more of the total volume of the mixture.
 solid flammable means a solid, other than a blasting agent or explosive as defined in 1910.109(a),
that is liable to cause fire through friction, absorption of moisture, spontaneous chemical change,
or retained heat from manufacturing or processing, or which can be ignited readily and when
ignited burns so vigorously and persistently as to create a serious hazard. A chemical will be
considered a flammable solid if, when tested by the method described in 16 CFR 1500.44, it ignites
and burns with a self-sustained flame at a rate greater than one-tenth of an inch per second along
its major axis.
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Glossary
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FM 200 – a Halon replacement extinguishing agent which is a chemical blend
(heptafluoropropane), stored as a liquid within the agent cylinder similar to that of Halon-type
cylinders. It will not corrode sensitive electronic equipment, and contains no particulates or oily
residues. In fact, it leaves very little residue and is a quite popular extinguishing agent in use today
for the protection of computer rooms.
Fume Hood - a laboratory device, enclosed on five sides with a moveable sash or fixed partial
enclosure on the remaining side; constructed and maintained to draw air from the laboratory and to
prevent or minimize the escape of air contaminants into the laboratory; and allows chemical
manipulations to be conducted in the enclosure without insertion of any portion of the employee’s
body other than hands and arms.
Hazardous chemical – the OSHA definition is a chemical for which there is statistically significant
evidence based on at least one study conducted in accordance with established scientific principles
that acute or chronic health effects may occur in exposed employees. The term "health hazard"
includes chemicals which are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants,
corrosives, sensitizers, hepatotoxins, nephrotoxins, neurotoxins, agents which act on the
hematopoietic systems, and agents which damage the lungs, skin, eyes, or mucous membranes.
Hazard Communication Standard – 29 CFR 1910.1200 - was first enacted on November 25,
1983, by the OSHA. It was later modified with minor changes and technical amendments to take
effect March 11, 1994. The purpose of the standard is to ensure that chemical hazards in the
workplace are identified and evaluated, and that information concerning these hazards is
communicated through MSDSs and labels. This standard is also known as the Right-to-Know Law.
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Glossary
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HEPA - high efficiency particulate air filter – is a filter that is manufactured, tested and
certified to meet applicable construction and efficiency standards for high-efficiency filters. The
filters are manufactured from an ultra-fine glass-fiber medium designed to capture microscopic
particles that can easily pass through most other filters by a combination of diffusion,
interception, and inertial impaction.
Health Hazard - means a chemical for which there is statistically significant evidence based
on at least one study conducted in accordance with established scientific principles that acute
or chronic health effects may occur in exposed employees.
Inergen - It is an inert gas used for fire extinguishment. It is a mixture of three naturally
occurring atmospheric gases: 52% nitrogen, 40% argon, and 8% CO2. The Inergen gas
curtails and extinguishes fire by lowering the oxygen content beneath the level that supports
combustion. But it should be noted that due to the CO2 present in Inergen, the brain continues
to receive the same amount of oxygen in an Inergen atmosphere as it would in a normal
atmosphere, for reasonable periods of time.
Laboratory Scale - Working with substances in which the containers used for reactions,
transfers, and other handling of substances are designed to be easily and safely manipulated
by one person.
Laboratory Standard – a standard (29 CFR 1910.1450) issued by OSHA addressing
occupational exposures to hazardous chemicals in the laboratory. All laboratories must comply
with this standard.
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Glossary
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Laboratory use of Potentially Hazardous Chemicals - the handling or use of such
chemicals in which all of the following conditions are met:
1)
Use of laboratory scale.
2)
Multiple chemical procedures or chemicals used.
3)
Protective laboratory practices and equipment are available and in common use to
minimize the potential for student/teacher exposure to hazardous chemicals.
LC50 or lethal concentration 50 – this is a measure of toxicity which corresponds to the
concentration in air that kills 50% of the test population. Note that most estimates of human
toxicity are based on animal studies, which may or may not relate to human toxicity.
LD50 or lethal dose 50 – this is a measure of toxicity which corresponds to the dose
required to kill 50% of the test population. Note that most estimates of human toxicity are
based on animal studies, which may or may not relate to human toxicity. The LD50 is usually
measured in milligrams of the material per kilogram of body weight of the test animal. To
estimate a lethal dose for a human based on animal tests, the LD50 must be multiplied by the
weight of an average person.
Material Safety Data Sheets (MSDS) – is a well-established document for disseminating
health and safety information about chemical products to employees, customers, emergency
responders, and the public. Information contained in the MSDS includes potential health,
safety, and environmental hazards, safe handling practices, and applicable regulatory
information.
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Glossary
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National Fire Protection Association (NFPA) private non-profit organization, is the leading
authoritative source of technical background, data, and consumer advice on fire protection,
problems and prevention
Organic peroxide - an organic compound that contains the bivalent -OO- structure and
which may be considered to be a structural derivative of hydrogen peroxide where one or both
of the hydrogen atoms has been replaced by an organic radical. Peroxides can be very
dangerous materials and may be shock and thermal sensitive. They are also strong oxidizers.
OSHA – Occupational Safety & Health Administration http://www.osha.gov is part of
the US Department of Labor. Its mission is to save lives, prevent injuries and protect the health
of America's workers.
Particularly hazardous substance – is defined by OSHA in the Laboratory Standard and
includes “select carcinogens” (strongly indicative of causing cancer in humans), reproductive
toxins, and substances which have a high degree of acute toxicity.
Permissible exposure limit (PEL) - which represents the maximum amount or
concentration of a substance that a worker may be exposed to under OSHA regulations. There
are ceiling values (at no time should this value be exceeded) and 8-hour time weighted
averages (an average value of exposure over the course of an 8 hour work shift)
Personal Protective Equipment (PPE) – is all clothing and other work accessories
designed to create a barrier against workplace hazards. Examples include safety goggles,
respirators, lab coats, etc.
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Glossary
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Pyrophoric – a pyrophoric material is one that ignites spontaneously in air and is derived from the
Greek word meaning “fire-bearing”. Many of these materials will also react vigorously with water or
high humidity and ignite upon contact.
Physical Hazard – A hazard exhibited by certain chemicals due to their physical properties. These
chemicals fall into the following classes: combustible liquids, compressed gases, explosives,
flammable liquids or solids, organic peroxide, oxidizers, pyrophoric materials, and unstable (reactive)
or water reactive materials.
Reproductive toxins – per OSHA any chemical that affects the reproductive chemicals which
affect the reproductive capabilities including chromosomal damage/mutations and effects on fetuses
(teratogenesis).
Select carcinogens – per OSHA any substance that meets one of the following criteria:
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regulated by OSHA as a carcinogen
listed under the category, “known to be carcinogens” in the Annual Report on Carcinogens published in the
latest edition by the National Toxicology Program (NTP)
listed under Group 1 (“carcinogenic to humans”) by the International Agency for Research on Cancer
Monographs (IARC)
listed in either Group 2A or 2B by IARC or under the category, “reasonably anticipated to be carcinogens” by
NTP and causes statistically significant tumor incidence in experimental animals in accordance with any of the
following criteria: after inhalation exposure of 6-7 hours per day, 5 days per week, for a significant portion of a
lifetime to dosages of less than 10 mg/m3, after repeated skin application of less than 300 mg/kg of body
weight per week, or after oral dosages of less than 50 mg/kg of body weight per day.
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Glossary
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Sensitizer – a chemical which may lead to the development of allergic reactions after repeated
exposure.
Short term exposure limit (STEL) - which is the concentration employees can be exposed to
continuously for a short period of time without suffering from irritation, chronic or irreversible
tissue damage, or narcosis of sufficient degree to increase the likelihood of accidental injury,
impair self-rescue or materially reduce work efficiency.
Standard Operating Procedures (SOP) – is a document that describes the operations,
analyses, or actions that are commonly accepted methods or the laboratory prescribed
procedures for performing certain routine or repetitive tasks.
Target Organ - indicate which bodily organs are most likely to be affected by exposure to a
substance. Certain chemicals may bio-concentrate in the liver while other target the brain.
Threshold Limit Values (TLV) – are airborne concentrations devised by the ACGIH that
represent conditions under which it is believed that nearly all workers may be exposed day after
day with no adverse effect. TLVs are advisory exposure guidelines, not legal standards, that are
based on evidence from industrial experience, animal studies, or human studies when they exist.
There are three different types of TLV's: Time Weighted Average (TLV-TWA), Short Term
Exposure Limit (TLV-STEL) and Ceiling (TLV-C).
Tort Law – is the law of liability and negligence. It involves that plaintiff who allegedly has been
wronged and the defendant who is claimed to have perpetrated the injustice. Tort law deals with
issues of property and personal injury law. Mass tort is the process of suing a major defendant
on behalf of a large number of plaintiffs. Law suits involving drugs such as Vioxx are examples.
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Glossary
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Toxicity Characteristic Leaching Procedure (TCLP) – is a procedure (Method 1311)
performed on a sample within the laboratory to determine whether or not a waste is considered
hazardous. A sample is extracted with a buffered acid and the resulting extraction fluid or
leachate approximates the fluid that would leach from the sample if it were in a landfill.
Toxicity Characteristic (TC) – regulatory limits established for 39 compounds. If a waste
analyzed via the TCLP procedure detects any of these compounds above the regulatory limits
then the waste is said to exhibit the toxicity characteristic.
Water Reactive - these substances are dangerous when wet because they undergo a
chemical reaction with water. This reaction may release a gas that is either flammable or presents
a toxic health hazard. In addition, the heat generated when water contacts such materials is often
enough for the item to spontaneously combust or explode.

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Quiz Five
1.
The first step in using a fire blanket is to:
a.
Spread it out on a table or other flat surface
b.
Attempt to use an extinguisher first.
c.
Shake the container to mix the chemicals.
d.
Remove it from its package.
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Quiz Five
2.
Which of the following items is one of the
categories of engineering controls?
a.
Isolation
b.
Sublimation
c.
Separation
d.
Demarcation
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Quiz Five
3.
One way of continuously monitoring the proper
Functioning of fume hoods is to:
a.
Tape a ribbon of tissue to the fume sash.
b.
Listen for the sound the fan makes.
c.
Routinely test the air around the hood.
d.
Regularly measure the air flow just outside the
hood.
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Quiz Five
4.
When using a fume hood, larger items should be
placed:
b.
On blocks of feet to allow air flow to travel
underneath
In the front of the hood to get maximum effect.
c.
In the back of the hood to get maximum effect.
d.
Next to smaller items to aid in recognition
e.
None of the above
a.
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Quiz Five
5.
The ACGIH recommends that fume hoods be
used when working with chemicals
a.
That are on the extremely dangerous substances list
b.
That have a TLV of 50ppm or less.
c.
That are inflammable.
d.
That have an ignition temperature of 451ºF or
less
All of the above.
e.
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Quiz Five
6.
One important issue regarding smoke detectors in
the laboratory or classroom is they should:
a.
Never be painted.
b.
Not be installed in corners of walls or ceilings.
c.
Not be installed in the air path of a vent.
d.
Not be covered with plastic bags.
e.
All of the above.
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Quiz Five
7.
The Fire Sprinklers located in the laboratory
activate based upon heat and operate:
a.
All at once and as a deluge to drown the fire
b.
One at a time as the fusible devices operate.
c.
In groups of three to control a rapid moving fire.
d.
With relatively low effectiveness
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Quiz Five
8.
The device that is designed to protect from electrocution
by interrupting the circuit when there is a difference in the
currents in the hot and neutral wires is called a(n):
a.
Circuit Breaker
b.
Ground Fault Circuit Interrupter
c.
Bar Fuse
d.
ECG device
e.
None of the above
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Quiz Five
9.
Gas valves in laboratories are required to have
what safety feature?
a.
An emergency shutoff.
b.
A sign that reads “Gas in Use”
c.
No available means of ignition.
d.
Doors that open only in the direction of egress.
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Quiz Five
10.
Which of the following is a good practice
regarding fire sprinklers?
a.
Never hang anything from a sprinkler head.
b.
Never paint a sprinkler any color other than its
original color
Do not store anything within 22 inches of the head
c.
d.
Conduct high heat experiments directly under the
head of a sprinkler.
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answer
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Module Five Good
Job!