study guide

1

 Indoor air quality

 Health, comfort and productivity

 Poor IAQ complaints

 Temperature

 Humidity

 Stuffiness or lack of air circulation

 Odors

 Physical symptoms

 Health effects of poor IAQ

 Sick building syndrome

 Building-related disease

 Legionnaire’s disease

 Causes of poor IAQ

 HVAC system

 Chemical contamination

 Microbial contamination

 IAQ as perception of air quality

 IAQ standards

 OSHA guidelines

 ASHRAE standards

 ASHRAE 62-1989: Ventilation

 ASHRAE 55-1992: Thermal Environmental Conditions

 ASHRAE 52-1992: Methods of Testing Air Cleaning

Devices

 Types of HVAC

 Constant/variable volume

 Single/ multiple zones

 HVAC-related

problems

 Inadequate outside

air intake

 Poor system design

 System or zone

modification

 Bad fresh air intake

location

 Inadequate air

distribution

 IAQ Indicators

 Carbon dioxide - air intake

 Air velocity – air distribution

 Q = VA

EHST 3700/3701:

Industrial Hygiene

 To enumerate the common complaints

associated with poor indoor air quality (IAQ)

 To describe basic HVAC systems and their

components

 To enumerate the contents of consensus

standards for IAQ

 To describe simple testing and

troubleshooting for IAQ problem evaluation

 To discuss contaminants affecting IAQ

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 Indoor air quality as a public health concern

 Heating, ventilating and air conditioning

(HVAC) systems

 Basic instruments used in IAQ studies

 Microorganism contamination and IAQ

 Radon and asbestos

Rotating vane anemometer Hot wire anemometer

Velometer

Sling psychrometer

Aspirated psychrometer

Smoke tubes

 Temperature

 Relative humidity

 Dewpoint

 Pressure

 Velocity (V)

 Volume flow (Q)

 Carbon dioxide

 Carbon monoxide

IAQ Multi-Function Instrument

3

 To ensure adequate oxygen content

 To dilute indoor air contaminants to

acceptable levels

 Carbon dioxide

 Other gases and vapors

 Dusts

 Molds

 Volume of outside air (Qoa)

 Carbon dioxide

 Percent of outside air (%OA)

 Air temperature

 Carbon dioxide

 Used as an indicator of HVAC effectiveness in

 Supplying fresh air to the building (dilution)

 Mixing the air

0

200

400

600

800

1000

1200

6:00 AM

9:00 AM

1:00 PM

5:00 PM

7:00 PM

Carbon Dioxide Level (ppm)

 CO2 inside and outside the space

Qoa= 13,000 𝑥

𝐶𝑖𝑛 − 𝐶𝑜𝑢𝑡

 Qoa – volumetric flow rate of outside air

(cfm)

 Cin – concentration of CO2 inside the space

 Cout – concentration of CO2 outside the space

 X – number of occupants

 Inside

 8 AM: 500 ppm

 1 PM: 1,200 ppm

 6 PM: 1,000 ppm

 Outside: 300 ppm

 15 workers

 Workers go home

at 5 PM.

0

200

400

600

800

1000

1200

8:00 AM

1:00 PM

6:00 PM

Indoor Carbon Dioxide Level

 Inside: 1,200 ppm

 Outside: 300 ppm

 x = 15 workers

 Qoa = 13,000 𝑥

𝐶𝑖𝑛− 𝐶𝑜𝑢𝑡

= 13,000 (15)

1,200 − 300

= 216 cfm

= 14.4 cfm/person  0

200

400

600

800

1000

1200

8:00 AM

1:00 PM

6:00 PM

Indoor Carbon Dioxide Level

Minimum ASHRAE

standard =

20 cfm/person

4

 Calculate the volume of outside air flowing

into the work space.

 CO2 outside: 370 ppm

 x = 12 workers

 Qoa = 13,000 𝑥

𝐶𝑖𝑛− 𝐶𝑜𝑢𝑡

= ?

0

100

200

300

400

500

600

700

800

900

1000

6:00 AM

8:00 AM

1:00 PM

6:00 PM

8:00 PM

20

300

950

800

40

Indoor Carbon Dioxide Level

0

100

200

300

400

500

600

700

800

900

1000

6:00 AM 8:00 AM 1:00 PM 6:00 PM 8:00 PM

20

330

970

820

80

Indoor Carbon Dioxide Level

 Temperature measurement of

 Return air (RA)

 Supplied air to the workspace (SA)

 Outside air (OA)

%𝑂𝐴 = 𝑇𝑅𝐴 − 𝑇𝑆𝐴 𝑇𝑅𝐴 − 𝑇𝑂𝐴

𝑥 100%

 Calculate the %OA

 Return air temp = 74°F

 Supplied air temp = 61°F

 Outdoor air temp = 48°F

 %OA= T

RA − T

SA T

RA − T

OA

x 100%

= 74 −61

74 −48 x 100%

= 50%

 HVAC specs

 1000 cfm capacity

 15 persons

 1000 cfm * 50%

15 persons

 33.3 cfm/person

Minimum ASHRAE

standard =

20 cfm/person

 Related to HVAC system conditions

 Wet filters

 Wet duct insulation

 Standing water in any part of the systems

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 Identify and remedy uncontrolled source of

moisture

 Clean or replace the affected areas of the

system

 Legionella pneumophila

 Hanta virus

 Histoplasma fungi

 Pathogenic bacteria that cause Legionnaires'

disease

 Acquired its name after a July 1976 outbreak

of a disease that sickened 221 persons, causing

34 deaths

 First noticed among people attending a

convention of the American Legion in

Philadelphia

 Potentially fatal infectious

disease caused by the

bacteria Legionella

 Produces high fever, chills,

general aches and pains,

headache, and digestive

tract discomfort

 Cough (dry or with sputum)

 Deranged renal functions,

liver functions and

electrolytes

 Route of entry: inhalation of aerosols

containing Legionella bacteria

 Sources: contaminated water from

 Hot water systems

 Cooling towers

 Air conditioning systems

 Condensate pans

 Exposure: Work on air handling systems

 Isolated in the droppings of deer mice

 Route of entry: inhalation of airborne dust

containing virus generated by the

disturbance of droppings or nest materials

 Flu-like respiratory symptoms

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 Potentially infected materials and surfaces

neutralized by 3% hypochlorite (bleach)

 Avoiding the creation of dust during cleanup

 Use of respirators with HEPA filters

 Preventing the re-entry of the rodents

 An infectious disease, primarily affecting a

person's lungs, caused by inhaling the spores

of Histoplasma capsulatum

 Fungi found in bat guano and bird droppings

 bird-fanciers disease

 Infected individuals can exhibit a variety of

symptoms sometimes so mild they do not

realize they are infected and therefore do

not seek treatment.

 In fact, the majority of those infected do not

exhibit any apparent symptoms.

 Fever

 Chest pain

 Dry cough

 Headache

 Loss of appetite

 Shortness of breath

 Joint and muscle pains

 Chills

 Hoarseness

 Presumed ocular histoplasmosis

 Loss of vision

 Disseminated histoplasmosis

 Most rare and severe form of this disease

 Fungus spreads to organs outside the lungs

Histoplasmosis

of the lung

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Pigeon droppings in

abandoned building

 Prevent the accumulation of manure:

excluding colony of birds in a building and

sealing off all entry points to prevent their

return

 Careful removal of manure to avoid dust

creation

 Sterilize with solution of 3% hypochlorite

 Wear appropriate PPE

Asbestos

Radon

 Naturally occurring, odorless, and colorless

gas produced by the breakdown of uranium

in soil, rock, and water

 Decay product of radium-226

Uranium Radium Radon

daughters

, , 

http://www.epa.gov/radon/pdfs/zonemapcolor.pdf

 Location

 Soil porosity

 Building

foundation

porosity

 Presence of cracks or openings in building

foundation

 Air pressure of building

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 Linked to 2 decay products: polonium-218

and polonium-214 ( emitters)

 Inhalation of radon daughters has been

linked to lung cancer

 Second-leading cause of lung cancer in

the U.S. (2010)

 EPA maximum radon concentration = 4 pCi/L

 Testing involves placement of canisters of

activated charcoal  left for a week  sent

to the lab for analysis

1 pCi = 0.037

decays per second

 Aimed at reducing, removing or preventing

entry of radon gas into occupied areas of the

building

 Application of non-porous coatings on

foundations

 Increasing ventilation of basement or crawl

spaces

 Group of naturally occurring minerals that are

resistant to heat and corrosion

 Commonly used in construction before 1975

 Have been used in insulation for pipes, floor

tiles, building materials, and in vehicle brakes

and clutches

Primary concern

with asbestos:

Carcinogenic

potential of

airborne fibers,

not its mere

presence in the

building.

 Identification of ACM in the building by

building owners

 Notification of occupants of building that

ACM is present and actions to take to avoid

creating a hazard

 Posting of locations with large amounts of

ACM to alert persons in the presence of

asbestos

 Informing construction and maintenance

contractors about any asbestos

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 Simple instruments are used to gather

data on air temperature and CO2

concentration for the evaluation of

HVAC system performance.

 Microbial contamination related to

HVAC involves Legionella, Hanta virus

and Histoplasma.

 Radon and asbestos are two of the

more common IAQ concerns that may

pose serious health hazards at high

concentrations.