Indoor Pollutants (1981) / Chapter Skim
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IX. Control of Indoor Pollution
IX. Control of Indoor Pollution
Pages 450-504
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From page 450... ...
Feedback control for acceptable indoor air quality is recognized and needed, but the availability of reliable and inexpensive controllers is seriously limited. Performance-oriented standards ham not been widely accepted by contractors and enforcement officials, ~~:;suse of barriers in technology transfer and increased costs of implementation and liability.
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From page 451... ...
After a building has been designed and constructed, the owner or manager usually assumes responsibility for maintaining the quality of the indoor environment, and there is normally no official enforcement. State and local building codes are normally based, directly or with modification, on one of three model building codes published in the United States: The BOCA Basic Building Code ~ s ~ ~ of the Building Officials and Code Administrators International (BOCA)
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From page 452... ...
. (In preparing proposed procedures for listing voluntary standards bodies for federal agency support and participation, the Department of Commerce held discussion.
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From page 453... ...
ASHVE Requirement ASHRAE Standard 82-73 (1973} Current Revaluation FIGURE LY-1 Historical development of ASHRAE Standard 62-73 After Klauss et al.
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From page 454... ...
'I In response to demands for energy-ef f icient buildings, ASHRAE developed a new standard, which was published in 1975: Standard 90-7S, Energy Conservation in flew Building Design. ' Through a contract with DOE, the National Conference of States on Building Codes and Standards, Inc.
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From page 455... ...
~0z i; AVERAGE SOCIOECONOMIC STATUS 200 3iO0 400 500 AIR SPACE PER PERSON ( ft3) FIGURE IX-2 ventilation rates resulting f ram the Yaglou studies .
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From page 456... ...
· The quality of outdoor air to be used for dilution and control of indoor air pollution has been defined, not only in terms of the EPA pr imary standards, but also in terms of other recognized guidelines and professional judgment. · values for minimal and recommended ventilation rates have been replaced with required values for smoking and nonsmoking areas.
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From page 458... ...
I' This model code specif ies ventilation rates for energy calculations as the minimal values in Standard 62-73 0 The ASHRAE standard, in turn, defers to other standards or codes when they have precedence and require higher ventilation rates. Domicile" As indicated in Table IX-2 ~ the two primary sources for ventilation requirements are ASHRAE standards ~ ~ and the HUD Minimum Property Standards IMPS)
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From page 459... ...
C2~15 ~ 16 ItBC 9 SBCCI55 NCSBCS 17 ~9 UBC SBCCI55 NCSBCS1 7 BoC~15 ~ 16 use 9 SBCC155 NCSBCS17 ~,oC,15, 16 UBC SBCCI55 NCSBCSi7 15,16 Usc SBCCISS NCSBCS17
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From page 460... ...
healt in-care bu ildi ng used for instruction, but not of the regin~ented classroom type; pertains more to read just~nt, such as jail ~ prison, refo rmo story, or half-way houses Warehouse: but 1 di ng used for storage of materials and supplles, such as storage facility, msintenance faclli ty, garage, airplane hangar, or bus barn Industrial: such . buildings as factories, assembly plants, foundries, mills, power plants, eelephone-exchange facllitie~, water and waste~water treatment plants, solid-refuse plants, zoos, greens houses, aviaries, arboreta - , or others requiring environmental control for process control Voluntary Standards ASHRAE ~ 9 ' ASHRAE 6, 9 ASH~69 9 Handatory Standards os~72 osHA72 Model Building Codes BoCtI5,16 UBC SBCCI55 NCSBCS17 SOCKS 5,16 UBC SBCCI55 NCSBCS17 BoC,15, 16 UBC SBCCI 55 NCSBCSl 7
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From page 461... ...
Natural ventilation is specified in the model codes as that obtainable through operable windows with areas one-twentiett~ of the floor areas; Standard 62-73 specifies minimal and recommended natural-ventilation rates of 10 and 10-15 cfm/person, respectively. Standard 62-1981 specifies required ventilation rates of 5 cfm (2.5 L/~)
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From page 462... ...
·2 ASHRAE Standard 62-73 specif ies 15 cfm/person as minimal and 20-25 cfm/person as recommended ventilation rates for spaces without animals. With animals, the minimal rate is 40 cfm/person and the recommended rate is 45-50 cfm/per~on.
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From page 463... ...
Standard 62-1981 specifies ventilation rates as required for smoking and nonsmoking areas with reductions in outdoor air allowed for mechanical ventilation as a function of filter efficiency. SUMMARY State and local building codes usually are based on one of the three model-code documents.
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From page 464... ...
0 co aC 3 ~ e <: x: 0 0 o V 1 X ~ 0 0 ~ 0 C C v V 0 o s ~ 0 0 :: i 0 ee ~ C 0 ~ ..
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From page 465... ...
carbon dioxide and other contaminants for safety of the occupants {and sometimes to provide a differential in sir pressure as required by building codes or standards ~ . Ventilation air flow rates are specified in codes and standards.
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From page 466... ...
, various zones can be identified as occupied and unoccupied spaces. There is little thermal and respiratory exchange between people and the air above head level, and the space between head level and the ceiling is called Unoccupied space..
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From page 467... ...
ADPI values have been experimentally calculated for typical applications of terminal units as a function of the airflow characteristics from the units and the thermal loads of the spaces {see Tables IX-4, IX-5, and TX-6 and Figure ~X-43. From the values listed in Table IX-4, types and sizes of terminal units can be selected to provide acceptable mixing in the occupied space.
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From page 468... ...
= ~ . _ SPREAD — \ OR 0P V£RTI=L CROW SE=ION \ - SPREAD _ t job' TERMINAL VE LOCKET ENVELOPE ANGLE Of DISCHARGE \~ Plow' VIEW FIGURE {X-4 Airstream characteristics.
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From page 469... ...
469 o ~ ~ ~ ~ Cat ~ ~ ~ I` - m - ` ~ ~ _ ~ ~ e e ~ · · ~ · · · · · e ~ · - _ ~ O ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ° O ~ ~ , ~ `~` - ~ ~= == ~ A - - - 0' ~ 0 1 "- 1 ;_; oooo ;;-o To 1 1 oooo -~+ -_ He V V V _ O _ _ D i: a, O _ C)
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From page 470... ...
Drop: Dif fuser Type High-sidewal1 grille Circular ceiling diffuser Sill gr ille Ceiling slot di f fuser Light troffer diffusers Perforated, louvered celling dif fusers aReprlnted with permission from Nevins.43 Vertical distance between center line of terminal unit and point to which throw is measured. TABLE IX-6 Characteristic Dimensions for Different Air Diffusers a Characteristic Length Distance to wall perpendicular to jet Distance to closest wall or intersecting air jet Length of room in direction of jet f low Distance to wall or midplane between outlets Distance to midplane between outlets plus distance f ram ceiling to top of occupied zone Distance to wall or midplane between outlets
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From page 471... ...
· ADPI relater comfort to local air temperature and local air velocity as they deviate from a ~etpoint suitable for providing thermally comfortable conditions. This setpoint must be established by other methods, such as percentage of people dissatisfied (PPD}, 24 MU thermal sensation index, 52 and standard effective temperature (SEA)
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From page 472... ...
~ First, if the concentrations of contaminants in outdoor air are unecceptable, the outdoor air must be cleaned. Second, recirculated air from occupied spaces must be cleaned to achieve the Awe quality as specified for the outdoor air used for ventilation.
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From page 474... ...
S those generally accepted for indoor environments in the United States are ASHRAE Standard 52-76 for mass and size efficiencies.
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From page 475... ...
475 100 10 Cal at lo C~ ~ t J o MU J 6 o,ot 0.1 _ 0.001 _ 0.0001 0.001 1 / ~ O - ran Perforn - nce ~ coot/ Is, ~2~/ / ~ ~ 0,._ O~/ ~ _ , 0.01 0.1 PARTICLE SIZE,,um 10 FIGURE DY-6 Filter efficiency as a functioylof particle size tor a typical impingement filter. Adapted from Crawford.
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From page 476... ...
476 0~ :^ cat a: ~5 x ~ ~ 0 A: v ED al c-? sit :^ 0 moo moo 0 cat 0 ~ ~ t_ ~ ~ ~ up kilo oLoo ret ~ ~ ~ 0 ~ ~ ret us :, ~ 1 1 1 Z 1 1 1 1 — IN t I ~ t '_1 ~ ~ ~ O en _ TV A: O ~ O 00 ~ 1_ 0 _4 1 1 1 ~ ~ 0 00 0 3 ~ ~ ~ '_ ~5 ~ ^ a, O U)
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From page 477... ...
Electrostatic precipitators are also commonly used to remove airborne particles. The precipitation process consists of providing an electric charge on the particle, establishing an electric field, and removing the particle from the precipitator.
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From page 478... ...
478 High Vol Cage dc power supply (20-100 kY)
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From page 480... ...
. Airborne particles are polarized in the resulting f ield and electromagnetically attracted to the f ilaments of the f ilter .
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From page 481... ...
481 100 >,` 50 it c' ~L Let o Lo J J o Cat to 1 _ 1 1 1 3 4 5 O t 2 PARTICLE DIAMETER, Am 6 FIGURE X-9 Typical removal efficiency of electronic air-cleaner. After ASHORE.
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From page 483... ...
The effectiveness of disinfection depends on good mixing of the air in the upper and lower portions of the room; thus, stratification for energy conservation may be counterproductive for contamination control with W irradiation. However, the concentration of airborne organisms in the breathing zone in a uniformly mixed space can be reduced to one-tenth to one-fifth that in the absence of W radiat ion .
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From page 484... ...
An application of this mechanism would be radon sorption on activated carbon. Although absorption is an important gas- or vapor~removal mechanism for industrial and military applications, IS it is seldom used for environmental control in residential or commercial buildings, but is used to control odorous gases or vapors.
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From page 485... ...
485 penetration time, is also necessary. Penetration time has also been described as the duration of adsorbent service before Saturation.
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From page 486... ...
486 TABLE LX-9 Adsorbent Impregnationsa Adsorbent Impregnant Fo11~t Action Activated Bromine Ethylene; other Conversion to dibro carbon alkenes mice, which remains on carbon Lead acetate Hydrogen sulfide Conversion to lead sulfide Phosphoric acid Adonis; aoines Neutralization Sodium silicate Hydrogen fluoride Conversion to fluorosilicates Iodine Mercury Conversion to mercuric iodide Sulfur Mercury Conversion to mercuric sulfide Sodium sulfite Fo~aldebyde Conversion to addition product Sodium carbonate Acidic vapors Neutralization or bicarbonate Oxides of copper, Oxidi sable gases, Catal ysin of air chromium, inclutlng re- oxidation vanadium, etc.; duced sulfur com noble metals pounds, such as (palladium, hydrogen sulfide, platinum) COS' and mercaptans Activated Potassium penman- Easily oxidizable Oxidation alumina ganate gases, especially formaldehyde Sodium carbonate Acidic gases Neutralization or bicarbonate 8Reprinted with permission from Turk.
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From page 487... ...
and an oxidation catalyst, Hopcalite {a mixture of cupric oxide and manganese dioxide) , has been reported to be effective,,5 although the Hopcalite must be kept scrupulously dry.
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From page 488... ...
Costs of installing and servicing these devices must also be considered. Thus, optimization techniques should be considered to decide between alternatives that will provide acceptable indoor air quality, energy consumption, and life-cycle costs.
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From page 489... ...
V Control by Source Removal A
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From page 490... ...
~ Outdoor air is brought in and dilutes the indoor-generated pollution. This strategy is in conflict with energy conservation, in that the heat and humidity of the displaced indoor air are not conserved.
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From page 491... ...
491 Exh Damper fen . ,, _ Exhale Air Oueide Air _~'x" ~ Air /////// for Air Recireulmion Air from _ , _ Owed ~ Span - SLIPPIY Fen Inlet Damper Filters' - sting, Cooling Coils FIGURE ~t-10 Schematic of conventional heating, Ventilating, a" air~condi~ioning (~AC)
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From page 492... ...
Primary air supply usual ly cons tent Primary air provides all dehu~ldif ication, 80 low~dewpoint air t8 provided 8. Not able to handle hig~exhaust applications
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From page 493... ...
Heat ing and cool ing i ndependent ly controlled b y zone 4. Individual ventilation air control 5.
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From page 495... ...
The information is inadequate to assess the magnitude of the problems or to define the amount of ventilation air needed to abate the pollutants produced by these sources. Source removal is the most effective means of controlling indoor pollution.
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From page 496... ...
Control of indoor contaminant concentrations by dilution with outdoor air will continue to be a major control strategy. Direct control of the ventilation system based on indoor contaminant concentration is the best means of achieving the optical compromise between energy conservation and pollution control.
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From page 497... ...
497 0 0 v v o a: L' a o o ~ 0 1 o x a ~ A: ~ ~ a - ; o E" 0 ~ so : v a, I: o a ~ c} :: o ~ ~ o a ~ ~ o a, ~1 v o I: a ~ 0 =e e ~ ~ ~ o Cot ~ 0 V ~ 0 0 C _.
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From page 498... ...
Education provides easy and inexpensive steps that help to improve indoor air quality. Such steps include reduction in indoor smoking, ban of potentially harmful indoor sprays, use of proper paint, changes in daily routines to evoid exposing all family members to pollutants, and the like.
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From page 499... ...
(NCS8CS) , and Southern Building Code Congress International, Inc.
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From page 500... ...
W Sijthoff International Publishing Company.
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From page 501... ...
W Sijthoff International Publishing Company, B
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From page 502... ...
A Study of the Effects of Air Changes and Outdoor Air on Interior Environment, Energy Conservation, and Construction and operating Costs: Phase ~ . Report to U.S.
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From page 503... ...
Implementation of Federal voluntary standards policy; Proposed procedure for listing voluntary standards bodies eligible for Federal agency support and participation, and for a Department sponsored voluntary dispute resolution service for procedural complaints against listed voluntary standards bodies.
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From page 504... ...
Sorption and Filtration Methods for Gas and Water Purification. NATO Advanced Study Institutes Series 8, Vol.
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