Study guide due sunday price is firm

Confined Spaces

EHST 3900 1

� IAQ – health and comfort

� Sources of hazardous agents in buildings

� Occupants

� Building components

� Contamination of building components

� Outdoor air/ other sources

� BRD vs SBS

� BRD – objective clinical findings

� SBS – subjective symptoms

� BRD

� Hypersensitivity diseases

� Infectious diseases

� Toxic syndromes

� Elements involved in IAQ issues

� Thermal comfort

� Relative humidity

� Odor

� HVAC systems

� Control IAQ

� Sources of pollutants

� Pollutant categories

� Chemical agents

� Biological agents

EHST 3900:

Introduction to

Occupational Health

� To define confined spaces

� To distinguish between types of confined

spaces

� To discuss confined-space hazards

� To evaluate confined-space hazards

� To assess appropriate methods for

elimination and control of confined-space

hazards

� Identification and classification of confined

spaces

� Hazards associated with confined spaces

� Confined space programs

� Rescue in confined spaces

� Hazard control in confined spaces

Confined Spaces

EHST 3900 2

� Meets all three of the following criteria:

1. It is large enough and so configured that an

employee can bodily enter the space and

perform her/his assigned work.

2. It has limited or restricted means for entry

or exit.

3. It is not designed for continuous human

occupancy.

� Confined spaces that do not contain, or do

not have the potential to contain, any hazard

capable of causing death or serious physical

harm

� Examples

� Areas above dropped ceilings

� Vented electrical vaults

� Limited or restricted means of entry and exit

may make rescue difficult in the event of an

injury or sudden illness

� Work in confined spaces frequently amplifies

hazards associated with similar work in the open

Welding in confined space Welding in open space

� Requires one to determine whether there are

health or safety hazards either

1. Present in the space or

2. Associated with the work to be conducted

in the confined space

� Identified and listed in the OSHA General

Industry regulation 1. Contains a hazardous atmosphere or may

have the reasonable potential to contain a

hazardous atmosphere

2. Contains a material that may engulf an

entrant

3. Has an internal configuration with inwardly

sloping walls or a tapering cross-section

that may allow the entrant to become

trapped or asphyxiated.

4. Contains any other serious health or safety

hazard

Confined Spaces

EHST 3900 3

� Presence of hazards may be difficult, if not

impossible, to detect by simple observation

prior to entry

� Difficulty in using normal human senses to

identify confined-space hazards

� Hazards may not develop (at least to the

same extent) every time a space is entered.

� Confined spaces that exhibit any of the

hazardous characteristics

� Storage tanks

� Process vessels

� Silos

� Boilers/fire boxes

� Open surface tanks

� Storm drains

� Pits beneath equipment

� Storage drums

� Manholes

� Cooking vessels

� Railroad tank cars

� Furnaces

Storage tank

Process vessel

Boiler

Storage drums

Storm drainsSilo Manholes

Railroad tanks

Confined Spaces

EHST 3900 4

� A permit may not be required to enter a

confined space if hazards are absent.

Welding in confined spaces

� NOTE: Tasks to be

performed in the

confined space must

be carefully

evaluated to

ascertain whether

they may create any

of these hazards in

the confined space.

1. Atmospheric hazards

2. Possible engulfment

3. Possible entrapment or asphyxiation

4. Other serious health or safety hazards

� Oxygen deficiency

� Oxygen enrichment

� Use of inert gases

� Flammable gases, vapors, mists, fibers, or dusts

� Presence of toxic gases, vapors, mists, smoke,

fibers, or dusts

� Most common atmospheric hazards associated with confined space entry

� Adverse effects of oxygen deficiency can occur with astonishing rapidity

Oxygen

conc (%)

Health effects

<16% Increased heart rate, increased breathing rate, some

decrease in coordination, increased breathing volume,

impaired attention, and impaired thought processes

<14% Abnormal fatigue on exertion, emotional upset, faulty

coordination, impaired judgment

<10% Nausea,vomiting, lethargy, inability to perform vigorous

movements, possible unconsciousness followed by death

<6% Convulsions, shortness of breath, cardiac standstill,

spasmodic breathing, death in minutes

<4% Unconsciousness within 1 or 2 breaths followed by death

� Less common than oxygen deficiency

� May be found in deep mines or when working

in caissons

� May also develop in confined spaces if a

welding torch is allowed to leak oxygen into

the workplace atmosphere

� Health effects

� Respiratory irritation

� Throat irritation

� Tracheal irritation

� Tingling of fingers and toes

� Visual impairment

� Hallucinations

� Other central nervous system disorders

Confined Spaces

EHST 3900 5

� Flammability hazards

� Increased flammability in >23.5% oxygen

� Less thermal energy required for

ignition

� Rate of flame travel is greater

Possible sources:

� Contents of confined spaces used for storage

or processing (i.e. silos)

� Coatings on the internal surfaces of the

space (i.e. paint and insulation)

� Residue from incomplete cleaning of the

internal surfaces of the space (i.e. petroleum

products in corners of tanks)

� Airborne materials evolving from tasks or

procedures taking place inside the space (i.e.

welding gases)

Problems resulting from reduced air movement:

� Increased airborne concentrations of volatile

compounds outgassing from the inner surfaces of

the space or from the contents of the space (e.g.

petroleum tanks)

� Concentration of contaminants generated by

work being performed during the entry (e.g.,

welding)

� Concentration of

contaminants produced by

decomposition or reaction

of materials within the

space (e.g., sewer)

1. Atmospheric hazards

2. Possible engulfment

3. Possible entrapment or asphyxiation

4. Other serious health or safety hazards

� Identification of possible engulfment hazards

may be more readily amenable to visual

examination than atmospheric hazards

� Silos, hoppers, bins, and similar storage

spaces contain materials that can flow (i.e.

grain, damp sand, cement, shredded wood or

bark)

� Engulfment - the surrounding and effective

capture of a person by a liquid or finely

divided solid substance that can exert

enough force on the body to cause death by

strangulation, constriction, or crushing

Confined Spaces

EHST 3900 6

� Walking on the surface of formed “bridge” or

air pocket

� Weight may cause the “bridge” to collapse

� Entrants may become engulfed in the

materials and may suffocate

� Internal configuration with inwardly sloping

walls or a tapering cross-section

� Entrants may become wedged in the

tapering, funnel-like, bottoms of cyclones

and storage spaces.

� Has resulted in asphyxiation due to

restriction of the thoracic cavity

� Noise hazards

� Animal hazards

� Insect hazards

� Risk of disease

� Ignition sources

� Skin contact with

irritant or corrosive

agents

� Temperature extremes

� National Fire Protection Association (NFPA)

� http://www.nfpa.org/assets/gallery/marketi

ng/html/confinedspaces/story.html?order_sr

c=E125

� Objective: To help identify confined spaces

most commonly found in:

� Industrial

� Agricultural

� Wind energy

� Wastewater

� Shipyards

� Petrochemical

� Breweries/wineries

http://www.cdc.gov/niosh/face/In-house/full200409.html http://www2a.cdc.gov/NIOSH-FACE/state.asp?state=ALL&Incident_Year=ALL&Category2=0004&Submit=Submit

Confined Spaces

EHST 3900 7

� Questions to ask

� “Must people enter this space?”

� “Are there alternatives to a confined-

space entry?”

� Use of confined-space hazard analysis

form (from Confined Space Entry, An AIHA

Protocol Guide)

� Provide detailed

instructions for

� Preparing a space for

entry

� The health and safety

precautions to be

taken during the

entry

� Should include the control

mechanisms for health

hazards associated with

the:

� Previous contents of the

confined space

� Material to be brought

into the confined space

for repair or maintenance

� Tasks to be performed in

the confined space

Confined Spaces

EHST 3900 8

� The means by which operations and

repair/maintenance personnel communicate

with each other to ensure that hazards are

identified and controlled prior to the start of

work

� Developed at the facility by the people who

will use them

� The IH may anticipate a central role in this

aspect of confined-space hazard control

� Inform affected workers of the health hazards

associated with the work

� Educate supervisors: Change the supervisors’

and workers’ perceptions of hazards.

1. The employer shall

provide training so that

all employees whose

work is associated with

confined spaces acquire

the understanding,

knowledge and skills

necessary for safe

performance of those

duties.

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9797

2. Training shall be provided to each affected

employee

a) Before the employee is first assigned duties

associated with the confined space

b) Before there is a change in duties

c) Whenever there is a change in the confined

space operations that presents a hazard about

which the employee has not yet been trained

d) Whenever the employer has reason to believe

that there have been changes in, or deviations

from, the confined space procedures

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9797

3. Training shall establish employee

proficiency in the duties required of each

affected employee.

4. The employer shall establish and maintain

written certification of the training.

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9797

� Primary purpose of confined-space entry

procedures:

� To identify hazards

� To either eliminate or control them for safe

entry

� Employers must

anticipate the potential

for having to rescue

entrants from confined

spaces.

Confined Spaces

EHST 3900 9

� For purposes of implementation

1. Self-rescue

2. Non-entry rescue (referred to as retrieval)

3. Entry rescue

� Plan for emergencies

� Plan for effective communication

� Cleaning the confined-space surface to

reduce hazards

� Ventilation to reduce hazards

� To allow periodic entry for inspection,

cleaning, maintenance, and/or repair

� To ensure the air inside a confined space is

breathable before it is entered

� To maintain acceptable air quality inside the

confined space

� Temporary ventilation of confined spaces is

often used to control atmospheric hazards by

removing contaminated air and replacing it

with fresh air.

� For effective ventilation of confined spaces:

mechanical ventilation must be provided by

fans or eductors (often called “air movers”).

� Some hazards cannot be completely eliminated

by using mechanical ventilation alone.

� Atmospheric testing and/or personal air

monitoring is strongly recommended to ensure

that the ventilation application is effective.

� Requirement of respiratory protection in

addition to mechanical ventilation is

determined by the results of atmospheric

testing and/or personal air monitoring for the

contaminants of concern while the work is

progressing in the confined space.

Confined Spaces

EHST 3900 10

� Confined spaces are recognized and

identified by 3 main characteristics.

� Certain hazards are typically associated

with confined space operations.

� Training, permit and rescue are included

in the basic general operating procedures

associated with confined space.

� Engineering, administrative controls and

PPE are used to eliminate and/or reduce

the risk of confined-space entry.