Health and Safety

By: Wilmer Arellano

Overview References Health Safety Product Liability Safety Design Rules Safety Design Behaviors Health and Safety Issues of EMR

References Excerpts from the book:

John Dustin Kemper.(1993) Introduction to the Engineering Profession. 2nd Edition. [Printed]. Oxford University Press

Introduction A few years ago, the Discovery Channel's “Discovery

Journal” series aired an hour long program called “The Price of Profit.” It was about a Texas border town and the Mexican town on the other side of the U.S. - Mexico border. All towns along the border were, and still are, being tragically impacted by pollution caused by U.S. companies that moved just a few hundred yards south of the border to take advantage of Mexico's lack of environmental regulations.

The “Price of Profit” showed that many of the people in the largely female workforce for the Kemet electronics factory in Matamoros, Mexico were gravely ill. This factory used very toxic chemicals. Birth defects were common in the workers' children and a few workers were finally speaking out, even though it meant that their jobs would be at risk

http://www.ens-newswire.com/ens/oct2003/2003-10-31g.asp

Health According to the World Health

Organization “Health is a state of complete physical, mental

and social well-being and not merely the absence of disease or infirmity“

We can affect Health if our designs are not safe.

Safety Safety is the ability to enjoy life without fear of harm,

danger, or threat Safety is generally interpreted as implying a real and

significant impact on risk of death, injury or damage to property. In response to perceived risks many interventions may be

proposed with engineering responses and regulation being two of the most common.

Probably the most common individual response to perceived safety issues is insurance, which compensates for or provides restitution in the case of damage or loss

Risk management is the systematic application of policies, procedures and practices to the tasks of establishing the context, identifying, analyzing, evaluating, treating, monitoring and communicating risk

http://en.wikipedia.org/wiki/Safety

e-waste Cadmium, which in municipal waste

mostly comes from nickel-cadmium (NiCd) batteries, can cause: Birth defects Cancer Kidney and liver damage Anemia Flu-like symptoms Loss of smell

e-waste Lead, in municipal waste mainly found in the form

of leaded glass in cathode ray tubes (CRTs) of computer monitors and televisions, can cause: Birth defects Poisoning Brain, kidney and nerve damage Loss of memory Decreased fertility in both females and males Mood and personality changes Irritation of the eyes, nose, and lung Headaches Disturbed sleep

e-waste Mercury, of which some electronics

(Fluorescent Lights, IR detectors) contain recoverable amounts,, can cause: Poisoning Kidney damage Spontaneous abortion Irritation of skin and lungs

e-waste Hexavalent chromium, (Surface Coating)

Hexavalent chromium compounds are carcinogens

Hexavalent chromium is genotoxic

e-waste Polybrominated biphenyls (Flame Retardant),

It is not known for certain if PBBs could cause cancer in human beings, but it has been observed that they can lead to cancer in lab mice exposed to very high concentrations of PBBs. Based on such animal tests, the United States Department of Health and Human Services has determined that PBBs may reasonably be anticipated to be carcinogens.

The International Agency for Research on Cancer also suggests that PBBs are possibly carcinogenic to humans.

e-waste PBDE (polybrominated diphenyl ether)

(Flame Retardant), There is growing evidence that indicates these chemicals may possess: Liver toxicity Thyroid toxicity, and Neurodevelopmental toxicity

Stakeholders Client Designer (You) Final Users Employees

Product Liability Not too many years ago, the doctrine of

caveat emptor prevailed in seller-buyer relationships. Caveat emptor means “Let the buyer beware.”

In other words, once you bought something, you were stuck, whether the object was defective or not.

Today matters have shifted so far the other way that some have said the doctrine has now become: “Let the seller beware.”

Strict Liability The American Law Institute has published the following rules regarding

strict tort liability (a “tort” is a wrongful civil act committed by one person against another, other than a breach of contract):

(1) One who sells any product in a defective condition unreasonably dangerous to the user or consumer or to his property is subject to liability for physical harm thereby caused to the ultimate user or consumer, or to his property, if

(a) the seller is engaged in the business of selling such a product, and (b) it is expected to and does reach the user or consumer without substantial

change in the condition in which it is sold. (2) The rule stated in Subsection (1) applies although

(a) the seller has exercised all possible care in the preparation and sale of his product, and

b) the user or consumer has not bought the product from or entered into any contractual relation with the seller.

For example, the American Law Institute attempts to define “unreasonably dangerous” as dangerous to an extent beyond that which would be contemplated by the ordinary consumer..

Concealed Danger / Obvious Danger Concealed Danger

In a Florida case, the manufacturer of a folding aluminum lounge chair was held liable in a case in which a person lost a finger. If the chair was not fully unfolded, and if the user sat in it and simultaneously had a finger in the danger spot, the further unfolding of the chair under pressure would neatly amputate the finger.

Obvious Dangers It has already been pointed out that, for the

manufacturer of a knife, there is no duty to protect against the sharp edge because the danger is obvious. However, just because a danger is obvious does not mean that the designer is relieved of responsibility

ForeseeabiIity It sometimes seems as if the designer of a

product is expected to foresee everything and to detect every manner in which a product might be used or misused. As unfair as it may seem, this is approximately the case. One student of product liability has said:

Many engineers and designers assume their products are safe if they meet all regulations and standards and if moving parts are protected with a guard when the product leaves the factory. In fact, a review of litigation resulting from product failure shows that accidents are caused less often by mechanical failure than by the designer’s failure to consider how the product would be used.

Safety Design Rules1. All devices using 120-V AC power shall

use copper wire of at least 14AWG to carry up to 20A, 12AWG to carry up to 25A, and 10AWG to carry up to 30A. (National Electrical Code Table 310.16)

2. All devices using 120-V AC power shall be grounded and shall use a grounded plug. (National Electrical Code 250.20(B))

Safety Design Rules3. All grounding connections shall be made using wire sized

to match the over-current protection device of the outlet: 15A protection uses 14AWG, 20A uses 12AWG, and 30 A uses 10 AWG. (National Electrical Code Table 250.122)

4. Standard 22 AWG hook-up wire can carry a maximum of 7A in unbundled applications and 0.92A in bundled applications. 30AWG “Wire-wrap wire” can carry 0.86A in unbundled applications and 0.142A in bundled applications. (Handbook of Electronic Tables and Formulas)

5. No exposed conductors shall be at more than 14V DC above ground or above any other exposed conductors. (Underwriters’ laboratory standard 1446)

Safety Design Rules6. All devices with exposed surfaces

exceeding 140°F shall be clearly marked with warning labels. (Occupational Safety and Health Administration)

Safety Design Behaviors Avoid wearing rings, metallic watchbands and

other metallic objects when working near high voltage environment

Do not work alone

Avoid working with Hot Circuits

When possible, only use one hand when working on a circuit

Avoid contact with the contents of any broken electric component

Exhale when soldering to avoid inhaling fumes

Health and Safety Issues of EMR

Thermal Effects of RF Energy Body tissues that are subjected to very high levels of RF energy

may suffer serious heat damage. These effects depend upon the frequency of the energy, the power density of the RF field that strikes the body, and even on factors such as the polarization of the wave.

At frequencies near the body's natural resonant frequency, RF energy is absorbed more efficiently, and maximum heating occurs.

In adults, this frequency usually is about 35 MHz if the person is grounded,

and about 70 MHz if the person's body is insulated from the ground. Also, body parts may be resonant; the adult head, for example is

resonant around 400 MHz, while a baby's smaller head resonates near 700 MHz.

Body size thus determines the frequency at which most RF energy is absorbed. As the frequency is increased above resonance, less RF heating generally occurs. However, additional longitudinal resonances occur at about 1 GHz near the body surface.

Athermal Effects of EMR Research about possible health effects resulting from exposure to

the lower level energy fields, the athermal effects, has been of two basic types: epidemiological research and laboratory research.

Scientists conduct laboratory research into biological mechanisms by which EMR may affect animals including humans. Epidemiologists look at the health patterns of large groups of people using statistical methods.

These epidemiological studies have been inconclusive. By their basic design, these studies do not demonstrate cause and effect, nor do they postulate mechanisms of disease. Instead, epidemiologists look for associations between an environmental factor and an observed pattern of illness.

For example, in the earliest research on malaria, epidemiologists observed the association between populations with high prevalence of the disease and the proximity of mosquito infested swamplands. It was left to the biological and medical scientists to isolate the organism causing malaria in the blood of those with the disease and identify the same organisms in the mosquito population.

Athermal Effects of EMR In the case of athermal effects, some studies have identified a weak

association between exposure to EMF at home or at work and various malignant conditions including leukemia and brain cancer.

However, a larger number of equally well designed and performed studies have found no association. A risk ratio of between 1.5 and 2.0 has been observed in positive studies (the number of observed cases of malignancy being 1.5 to 2.0 times the "expected" number in the population).

Epidemiologists generally regard a risk ratio of 4.0 or greater to be indicative of a strong association between the cause and effect under study.

For example, men who smoke one pack of cigarettes per day increase their risk for lung cancer tenfold compared to nonsmokers, and two packs per day increase the risk to more than 25 times the nonsmokers' risk.

However, epidemiological research by itself is rarely conclusive. Epidemiology only identifies health patterns in groups-it does not ordinarily determine their cause. And there are often confounding factors: Most of us are exposed to many different environmental hazards that may affect our health in various ways. Moreover, not all studies of persons likely to be exposed to high levels of EMR have yielded the same results.

http://www.arrl.org/news/rfsafety/hbkrf.html

IEEE Guideline for Recommended EM Exposure A new Institute of Electrical and Electronics Engineers (IEEE)

guideline for recommended EM exposure limits went into effect in 1991. It replaced a 1982 American National Standards Institute guideline that permitted somewhat higher exposure levels. ANSI-recommended exposure limits before 1982 were higher still.

The graph depicts the new IEEE standard. It is necessarily a complex graph because the standards differ not only for controlled and uncontrolled environments but also for electric fields (E fields) and magnetic fields (H fields). Basically, the lowest E-field exposure limits occur at frequencies between 30 and 300 MHz. The lowest H-field exposure levels occur at 100-300 MHz.

The ANSI standard sets the maximum E-field limits between 30 and 300 MHz at a power density of 1 mW/cm2 (61.4 V/m) in controlled environments-but at one-fifth that level (0.2 mW/cm2 or 27.5 V/m) in uncontrolled environments.

IEEE Guideline for Recommended EM Exposure In general, the IEEE guideline requires averaging the power

level over time periods ranging from 6 to 30 minutes for power-density calculations, depending on the frequency and other variables.

The ANSI exposure limits for uncontrolled environments are lower than those for controlled environments, but to compensate for that the guideline allows exposure levels in those environments to be averaged over much longer time periods (generally 30 minutes).

This long averaging time means that an intermittently operating RF source (such as an Amateur Radio transmitter) will show a much lower power density than a continuous-duty station for a given power level and antenna configuration.

http://www.arrl.org/news/rfsafety/hbkrf.html

Health and Safety and you Senior II Proposal Show that you care for the users and

follow practices that will protect their health and safety.

Show that you care for yourself and follow practices that will protect your health and safety.

Show that you care for liabilities and therefore you make use of foreseeability.

Use RoHS components whenever they are available

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