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Physical Hazard

Anita Camelia

Faculty of Public Health

UNSRI

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SPECIFIC LEARNING OBJECTIVES

The student will be able :

to identify physical hazards in the workplace environment (C2)

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References

Suma’mur, Higene Perusahaan dan Kesehatan Kerja, CV Haji Masagung, Jakarta, 1994 Hal. 57-101

Joseph LaDou J, ed. Occupational and Environmental Medicine, 2nd edition. Stamford: Appleton & Lange, 2004. Chapter : 11.

Levy & Wegman, Occupational Health, Recognizing and Preventing Work Related Disease. Third Edition. Little Broan and Company, Boston / NewYork/Toronto/London,2006. Chapter :16

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Introduction

Physical exposures that occur over time can cause human illness

Physical exposures are widespread in industry, in nature, and in various community and medical setting :

noise, vibration, thermal stress, electromagnetic radiation, Increased or decreased pressure

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The underlying science the explores measurements and intervention to reduce physical hazards exposure is based in physics

The study of the relationship between energy and matter

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Type of Physical Hazards

1. Temperature

2. Pressure

3. Noise

4. Illumination

5. Vibration

6. Radiation

* electric and magnetic fields

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1. Temperature(Extremes Temperature)

1. Heat-       lassitude, irritability, discomfort-       lowered work performance lack of concentration

lack of judgmentloss of critical thinking skills

-        skin disorders : heat rashes-         heat cramps-         heat exhaustion-         heat stroke

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2. Hypothermia- Chilblains,- Immersion Foot,

- Frostbite

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Occupational Heat Stress

There are an estimated 5 to 10 million in industries where heat stress is a potential safety and health hazards

On average, approximately 400 people die each year in the US from exposures to excessive heat in work, home, and community setting

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Heat related occupational illness, injuries and strain occur in any situation where total heat load ( environmental heat plus heat generated by the body’s metabolism)

The major modes of heat exchange between workers and their environment are : convection, conduction, radiation , evaporation

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Heat exchange

Convection Refers to the rate of heat exchange between the individual’s skin and the air immediately around the skin

Conduction The transfer of heat to the skin from direct contact with hot equipment or floors of from hot liquids

Radiation Refers to heat that is transferred between the skin and solid surfaces or object, without direct skin contact

Evaporation Evaporation of water from the surface of the skin (sweating)

Is the body’s primary method of regulating internal body temperature

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Prevention

Acclimatization Measuring environmental temperature Assessing metabolic work rates

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2. Pressure

1. Hyperbaric-Tympanic membrane rupture- Pneumothorax- Air embolism- DCS (Decompression Sickness)

2. Hypobaric- Acute Mountain Sickness (AMS)- High Altitude Pulmonary Edema(HAPE)

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Hyperbaric

Hyperbaric environment are most commonly encountered in a diving setting ,

any situation in which compressed air is required underwater tunneling

Exposure to increased atmospheric pressure (under water) leads to aseptic bone necrosis around the knee, hip and shoulder which can be detected by X ray examination

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Hyperbaric health problem

Barotrauma Middle ear trauma Pulmonary overinflation syndrome

pneumothorax

mediastinal emphysema

arterial gas embolism

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The most common health problem occurring in hyperbaric environment is known as BAROTRAUMA

Which involves an imbalance in pressure of air cavities and sinuses within the body as they are subjected to an acute change in pressure

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A classic example is Middle ear barotrauma

In which a pressure imbalance develops auma and between the middle ear and the external ear canal causing tympanic membrane trauma and acute ear pain

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A related but more serious form of barotrauma is known as Pulmonary overinflation syndrome

In which the lungs become overinflation due to expansion of the air within them during ascent

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This overinflation can reach a breaking point at which alveolar capillaeries rupture, leading to

Pneumothorax Mediastinal emphysema Arterial gas embolism

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Prevention Hyperbaric

Managing time spent at depth Carefully controlling the rate of descent

and ascent

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Arterial gas embolism, resulting from the introduction of compressed air into the bloodstream,

Has various neurologic manifestation Confusion Weakness Stroke Loss of consciousness

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Hypobaric

Hypobaric environment are commonly encountered by those in high altitude mountain setting, pilot and passengers in unpressurized aircraft

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At altitude greater than 2500m, the partial pressure of oxygen becomes significantly reduced and altitude related illness can be begin to occur

Especially in those who have not acclimatized because of ascending too rapidly

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Acute Mountain Sickness

The most common form of altitude illness

an imbalance between hypoxic induced cerebral vasodilatation and hypocarbia induced cerebral vasoconstriction

Is characterized by Headache, nausea, vomiting, fatigue, loss

appetite

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3. Noise

Definition

1. Unwanted sound

2. Unwanted,irregular,unpleasant and annoying sound

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Impairment to hearing is produced by excessive exposure to noise as well as to ototoxic chemicals

Effect of noise :damage of hearing organphysiological effects

Potential damaging effects of noise are not uniform at all frequencies

Exposure to high levels of noise can also have other adverse physiological effects

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Criteria for exposure and measurements of hazardous noise measured in decibels

In terms of human factors of hearing, the amplitude of pressure is stated in decibels (dB)

related to properties of human perception of loudness

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Noise exposure can be measured and quantified in units of pressure in relation to units of time

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Noise

Noise induced hearing loss can be detected by audiometry

Noise induced hearing loss is cumulative

Exposure outside the workplace can result in hearing impairment not predictable by workplace monitoring alone.

non occupational exposure ?

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Noise Induced Hearing Loss

1. Acoustic Trauma

2. Temporary Threshold Shift (TTS)

3. Permanent Threshold Shift (PTS)

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Occupational Noise Regulation

1. Engineering control

2. Administrative control

3. Use of hearing protective devices (HPDs)

1. Ear muff

2. Ear plug

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Engineering controls for Noise

1. Reduce noise emitted by individual sources such as modifying machines or enclosing sources with acoustical shielding

2. Specify limits on noise emission for new acquisitions or replacement of sources

3. Acoustically shield4. Install acoustic absorbers5. Place partial barriers between noise

sources and workers

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Hearing Protective Device

Factors contributing to reduced performance

1. Worker discomfort2. Worker’s reluctance to wear them for a

full work shift3. The tendency to remove HPD to

readjust or clean, leading to incorrect positioning

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To achieve maximum protection, HPDs must be correctly fitted and installed

Not simple task Workers must motivated to use the

correctly

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The basic instrument for survey is the sound level meter (SLM)

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4. Radiation

1. Ionizing Radiation

2. Non-ionizing Radiation

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Terminology related to Radiation

The most important concepts to understand in the field of radiation are

1. Ionizing and non ionizing radiation

2. Exposure and dose

3. Half-life and activity

4. risk

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Ionizing Radiation Is caused when an electron is ejected from its atomic structure

Non Ionizing Radiation Does not eject electron, but causes molecules to vibrate

Exposure Represent the amount of radiation that is absorbed in air

Dose Refers to the amount of energy absorbed in a specified materials other than air, usually tissue

Half Life Is the amount of time it takes for half of the radioactive material to decay

Activity Represents the decay rate or how quickly that radioactivity material decay

Risk Is defined as the increment of some adverse health affect associated with a known amount cumulative radiation dose

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Ionizing Radiation exposures

External exposures

Occur when the body is irradiated by a radioactive sources outside the body

Internal exposures

Occur when a radioactive material enters the body via inhalation, ingestion, injection, or absorption through the skin

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Health effects of Radiation

Vary with

1. The type

2. Amount, and

3. Duration of exposure

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When radiation exposes a cell, it may1. Pass through without doing any

damage2. Interact and damage the cell, with later

repair by the cell3. Interact and damage the cell in such a

way that it continues to reproduce itself in a damaged state

4. Kill the cell

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The death of single cell may not be harmful, but if many cells are killed within an organ then that organ may not function properly

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Ionizing Radiation

1. Electromagnetic

- x-rays

- gamma rays

2. Particulate

- electrons

- protons

- neutrons

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Non-ionizing Radiation

Ultraviolet Infrared Microwave Laser radiation

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Type of Radiation Injury

Irradiation can cause many types of effect on the human body,depending on the dose and

the condition of exposure

- Mutagenic effect- Carcinogenic effect- Teratogenic effect

! : Radiation Sickness

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Prevention and Protection from radiation1. Engineering controls eliminate or

reduce the potential exposures at the source Exp. Interlocks, shielding, bonding, grounding and filtering

2. Administrative controlIncreasing the distance between the source and the worker, controlling the duration of exposure, restricting access, placing warning signs

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5. Vibration

Is a complex physical exposure, which lends itself to electro-physical measurement

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Vibration cause vascular disorders of the arms and bony changes in the small bone of the wrist

Vascular changes are difficult to detect. Test are complicated and non specific Bony changes can be detected by x ray

examination The most common finding is rarefaction of the

lunate bone

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Type of vibration :

1. Whole body vibration

2. Segmental vibration

health effects are usually related to energy transfer to the upper extremity

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Segmental vibration (hand-arm)

Vibration effects on the peripheral nerves and small vessels of the upper extremity from hand

There are variety tool types and qualities of exposure that are associated with vibration related upper extremity disorders.

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Air powered rotary tools

Grinders, sanders, cutting wheels

Gasoline powered oscillating tools

Chain saws, brush cutter

Electrical power tools

Power tools Chipping hammers, pavement breakers

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Health effects of Segmental vibration Traumatic vasospasm Vibration white fingers (VWF) Hand arm vibration syndrome (HAVS)

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Clinical presentation

1. White finger2. Peripheral neuropathy, with or without

increased cold sensitivity3. Distal compressive and demyelinating

neuropathies of digital nerves, the median nerve at the carpal tunnel, less plausibly, the ulnar nerve

4. Musculoskeletal disturbances : weakness, lancinating forearm pain, and bone and joint degeneration

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Antivibration

VWF declined 40% 5 % Hand and finger numbness 78%28%

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WHOLE BODY VIBRATION

Transmitted to the anatomic supporting surfaces, especially the legs when standing and the buttocks and back when sitting

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Source of whole body vibrationActivity Source

1. Warehousing and material handling

Forklifts

2. Construction Cranes, power shovels, bulldozers, off road trucks, tractors

3. Farming Tractors

4. Transportation Metros, buses, trains, helicopters, tractor trailers

5. Buildings Metro and rail vibration and ventilation system

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Prevention

Measurement standard and prophylactic design

Transportation Use absorbent or air ride seats

Sophisticated designs : frontback attenuation, cab isolation, vehicle suspension

Industrial environment antishock mounting of machinery, vibration isolated

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Health effects of WBV

Affecting musculoskeletal system Create chronic stress Permanent damage to the affected

organs or body parts

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