EPA-15O/.1-76-OO-1
Orlober 1975
ASBESTOS
CONTAiMINATlON
OF THE AIR
*
IN PUBLIC BUILDINGS
l'.S. ENVIHOMWKM \l, PROTECTION
Office of Air ami W«*lc $iiuira«£
Office of \tr Qualat} Planning and
Rr^earrh TriangBf Park. ^iorJh (larolina 2771 I
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EPA-450/3-76-001
ASBESTOS
CONTAMINATION
OF THE AIR
IN PUBLIC BUILDINGS
by
William J. Nicholson. Arthur N. Rohl. and Irving Weinman
Mount Sinai School of Medicine
tlit> IniverMly of New York
York. N.Y.
Contract No. 68-O2-l3W>
KPA Project Officer: Alan J. Hoffman
Prepared for
ENVIRONMENTAL PROTECTION AGEN«:Y
Office of Air and Wanle Management
Office of Air Quality Planning and Standard*
Research Triangle Park. North Carolina 277 1 1
October M)7.->
-------
r
VTu MOS U')NT AMI :j-M , or, Of THE A I k
P u 11 o I r; 'i •
A: i 1 1 i CUP J -\ i , nc. s o n , e t .1 1
Mount Sinai '-ehonl o > Modi cine
P re pa red for:
Environmental Protection Agen;y
October 1975
DISTRIBUTED BY:
Kfffi
National Technical Information Service
U. S. DEPARTMENT OF COMMERCE
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TtCliN.LAl. REPOHT CA , A
.)] I
..
A.-oestos Concur, -'.it ion 01" tht> Air in hiblk: Bui Ul ings
William J. Nicholson, Arthur N. Rohl, and Irving
Wcisman
sj ORGANIZATION NAME AND ADDRESS
Mount Sinai School of Medicine
City University of New York
New York, N.Y.
12 SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
3 RE
8-Q
HFPOHT DATI
Octobei^ 197.r.
6. PERFORMING OHii«.il/A I ION CODE
B. PERFORMING ORGANIZATION Rt^Hl -;C }
10 PROGRAM ELEMENT NO.
11 CONTHACT7SWANT NO
68-12-1546
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
IS. SUPPLEMENTARY NOTES
16. ABSTRACT
From 1958 through 1973 asbestos-containing material was used extensively for fire-
proofing high-rise office buildings. Earlier use of this material for decorative and
acoustical purposes dates from the mid-1930's. Concern exists that these past uses of
asbestos may lead to current contamination of building air. This may occur either
through damage or erosion of acoustical spray materials or through erosion into
building air supply systems of asbestos fibers from spray-lined plenum spaces in
office buildings. In order to assess such possibilities, 116 samples of indoor and
outdoor air have been analyzed for asbestos. Nineteen buildings in five United States
cities were chosen to represent the various construction uses of asbestos-containing
spray materials. The results of this sampling and analysis demonstrate that signifi-
cant contamination can occur in the air supply syctems of buildings in which fibrous
type-dry spray asbestos-containing fiieproofing materials were used. Moreover, ero-
sion of similar materials applied for decorative or acoustical purposes was -ilso
found to occur. In contrast, no contamination was demonstrable in buildings in which
cementitious spray material had been used. The contamination demonstrated here was
manifest only through analysis procedures using electron microscopy. Optical
microscopic analysis of building air was found to be inappropriate.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
Air Pollution
Asbestos
Indoor Air Pollution
It. SECURITY CLASS (Thb Report/
Unclassified
COSATi Field/Croup
PRICES SUBJICT TO CHANG!
9. DISTRIBUTION STATEMENT
Release Unlimited
ai NO. OF'VAGCS
70
30 SECURITY CLASS (T*tlpaft>
Unclassified
2?
JJJO-1 |»-7J)
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This report is issued hy the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are
available f r _>e of charge to Federal employees, current contractors and
grantees, and nonprofit organisations as supplies permit from the
Air Pollution Technical Information Center, Environmental Protection
Agency, Research Triangle Park , North Carolina 27711; or, for a fee,
from the National Technical Information Service, 5285 Port Royal Road,
Springfield, Virginia 22161.
This report was furnished to the Environmental Protection Agency by
Mount Sinai School of Medicine, City University of New York , New York
N.Y. , in fulfillment of Contract No. 68-02-1346. The contents of this
report are reproduced herein as received from Mount Sinai School of
Medicine, City University of New York. The opinions, findings, and
conclusions expressed are those of the author and not necessarily those
of the Environmental Protection Agency. Mention of company or product
names is not to be considered as an endorsement by the Environmental
Protection Agency.
Publication No. EPA-450/3-76-004
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Table of Contents
Summary .................................... 1
I . Introduction .................. • . . • 2
A. Development of Asbestos-Containing
Spray Insulation Material ..... ... 2
B Extent of Use ol Asbestos Spray
Insulation .................... 3
C. Purpose of the Present Study ........... J
II . Sampling Program . ....................... 4
A. Identification and Selection of
Buildings ............................ 4
1 . New York Ci t y .................... 4
2 . Chi cago ........................ 4
3 . 3an Francisco-Berkeley ............. 4
4 . Boston ............................ 7
B. Typical Air Ventilation Systems .......... 7
1 . Equi pment Rooms .................. 7
2 . Air Supply ........................ 7
3. Ceiling Plenum and Return Air Fan . 7
4. Spill Plenum and Intake Air ....... 8
5 . D ampler Controls ................. 8
C. Buildings Sampled ...................... 8
D. Sampling Locations .................. 10
E . Sampling Procedures ................ 10
III . Results of Sample Analysis .................... 11
A. Electron Microscopic Analysis ........... 11
B. Optical Microscopic Analysis ........... 28
C. Duplicate Analysis ................... 28
D. Variability of the Data ................ 31
IV. Environmental Asbestos Exposure and
Possible Human Health Effects ................. 34
A. Historical Perspectives ................ 34
V . Conclusions and Recommendations ............... 40
A. Decorative or Acoustic Spray
Application ............................. 40
B. Cement itious Spray Fireproofing ....... 4O
C. Fibrous 'Asbestos-Containing Spray
Fireproof i ng ....................... 40
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Table »f Contents
.Summary .................................. 1
I . Introduction ....... ....... . .2
A. Development of Asbestos-Containing
Spray Insulation Material .. .. . . 2
B Extent of Use of Asbestos Spray
Insulation ......................... 3
C. Purpose of the Present Study ............ J
1 1 . Sampl ing Program ............................. 4
A. Identification and Selection of
Buildings .............................. 4
1 . New York City ..................... 4
2 . Chi cago .......................... 4
3 . 3an ^Francisco-Berkeley ............. 4
4 . Boston ............................ 7
B. Typical Air Ventilation Systems .......... 7
1 . Equi pment Rooms ................... 7
2 . Air Supply ........................ 7
3. Ceiling Plenum and Return Air Fan . 7
4. Spill Plenum and Intake Air ....... 8
5 . D ampler Controls ................. 8
C. Buildings Sampled ....................... 8
D. Sampling Locations .................... 10
E. Sampling Procedures ................ , . 10
III . Results of Sample Analysis ................. ... 11
A . Electron Microscopic Analysis ............ 11
B. Optical Microscopic Analysis ........... 28
C. Duplicate Analysis .................... 28
D. Variability of the Data .......... ..... 31
IV. Environmental Asbestos Exposure and
Possible Human Health Effects ................. 34
A. Historical Perspectives ................ 34
V . Conclusions and Recommendations .............. 40
A. Decorative or Acoustic Spray
Application ........................... 40
B. Cement itious Spray Fireproofing ....... 40
C. Fibrous 'Asbestos-Containing Spray
Fireproofing ..................... 40
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D. Specific Recommendations 40
1. Future Moni toring 4O
2. Future Control Procedures 41
VI. References 42
Appendix 1 43
Buildings Sprayed with Fireproofing Asbestos Compound
Appendix 2 ". 44
Ventilation System Emission Study
Appendix 3 49
Asbestos Sample Preparation and Analysis Methodology
Appendix 4 55
Collodion Film Method for the Determination of
Asbestos in Ambient Atmospheres
Appendix 5 56
Analysis of Air Samples - California State Department
of Health
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I llustraticns
Figure 1 5
Typical Air Plow
Figure 2 6
Cross-Section of Celing Plenum Space
Table 1
Buildinps Sampled
Table 2 12
Detailed Results of Analysis
Table 3 22
Summary of Average Asbestos Concentrations
Table 4 24
Concentration Distribution - Sprayed Asbestos
Table 5 25
Concentration Distribution - No Sprayed Asbestos
Table 6 26
Concentration Distribution - Sprayed Asbestos
Controls and Samples
Figure3 27
Concentration Distribution - Controls and Samples
Table 7 29
Comparison of Asbestos Concentrations - Electron
and Optical Microscopy
Figure 4 30
Comparison of Asbestos Concentrations - Electron
and Optical Microscopy
Table 8 32
Duplicate Analysis of Ten Ambient Air Samples
Table 9 33
Replicate Analysis of Four Ambient Air Samples
Table 10 35
Chrysotile Content of Ambient Air Samples - NAPCA
Table 11 36
Chrysotile Content of Amblert Air in New York City
by Borough
Table 12 38
Chrysotilto Air Levels near Spray Fireproofinp Sites
Table 13 39
Approximate Ranges of Asbestos Concentrations in
Different Circumstances
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Summary
From 1958 through 1973 asbestos-containing material was Msed extensively
for fireproof ing Mgh-rtse office buildings. Earlier use of this material
for decorative and acoustical purposes dates from the mid-1930's. Concern
exists that these past uses of asbestos may lead to current contamination
of building air. This may occur either through damage or erosion of
acoustical spray materials or through erosion into building air supply
systems of asbestos fibers from spray-lined plenum spaces in office build-
ings.
In order to assess such possibilities, 116 samples of indoor and outdoor
air have been analyzed for asbestos. Nineteen buildings in five United
States cities were chosen to represent the various construction uses of
asbestos-containing spray materials.
The results of this sampling and analysis demonstrate that significant
contamination can occur in the air supply systems of buildings in which
fibrous type-dry spray asbestos-containing fireproofing materials were
used. Moreover, erosion of similar materials applied for decorative or
acoustical purposes was also found to occur. In contrast, no contamina-
tion was demonstrable in buildings in which cementitious spray material
had been used. The contan-nation demonstrated here was manifest only
through analysis procedures using electron microscopy. Optical microscopic
analysis of building air was fourd to be inappropriate.
Because of possible health effects associated uith such contamination of
public buildings, it is recommended that:
1) An inspection and monitoring system be developed that
will verify the integrity of asbestos spray material used
for acoustical or decorative purposes.
2) Periodic spot sampling and analysis of air in build-
ings using cementitious fireproofing material be made to
verify continued safety.
3) Additional sampling and analysis programs be under-
taken in buildings where fibrous spray fireproofing has
been used so as to define the full extent of the problem.
4) An effective and economically feasible filtration
system be developed for those buildings now sprayed with
such fibrous materials.
5) Procedures be developed for maintenance activities
that may be required in asbestos-sprayed spaces,and
6) Procedures be developed and specified for used in
those buildings in which asbestos is to be removed because
of unacceptable contamination.
7) The suitability of proposed EPA building demolition
procedures for buildings with extensive spray asbestos be
verified.
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Introduction
*• pavnT"'ITi^H o? Asbe»tos_-Contalning Spray Insulation Materials
Sprayed inor&anic fiber insulation was introduced in 1932 with the Limpet
process, by the J.W. Roberts Company of Great Britain. Mr. N.L. Oolbey,
Director of Research for this company, is usually acknowledged as the
pioneer developer- British Railway coach makers used the sprayed product
containing asbestos in their coaches to control condensation and noise;
it also acted as a thermal insulating material. In 1935 the spray process
was first used \n the United States. Most of the material applied during
the late 1930's was used for decorative finishes in night clubs, restau-
rants, hotels, etc.
When this material was found also to bo useful as a fireproofing agent,
such use gradually Increased, and in 1950 the National Gypsum Company ob-
tained the Underwriters Laboratories' approval of its brand of spray in-
sulation for fireprooflog. In early 1951 the Asbestospray Company also
had an inorganic fiber blend tested and approved by the Underwriters Labo-
ratories. The first use of sprayed "mineral fiber" as a fireproofing
agent in a large multiple-story building; occurred in 1958 with the erection
of the sixty-story Chase Manhattan Bank building in New York City. In
1970, well over half of all the large multistory buildings constructed in
this country made use of sprayed "inorganic fiber" as a fireproofing
agent. (1)
Mineral fiber materials containing asbestos have four major insulation
uses in the construction and shipyard industries: 1. fireproofing,
2- thermal insulation, 3. acoustical and decorative purposes, and 4.
condensation control. Fireproofing accounts for the largest amount of min-
eral fiber sprayed in the United States. Formerly, structural steel in
multistory buildings had to be encased in concrete to prevent buckling in
the event of fire. The use of sprayed mineral fiber provides adequate fire
protection, reduces installation costs, and reduces the weight load upon
structural steel components.
Because the newly applied surface of sprayed mineral fiber can be shaped,
the material not only provides good acoustical control but also can be
used for decorative ceiling and wall coatings for large areas in public
buildings, restaurants, and similar establishments.
Although the composition of the various spray products will vary with
the Intended use and the individual manufacturer, certain general formu-
lations are similar. Most are termed "mineral fiber" materials, although
naturally occurring mineral fibers are usually in a minority, and man-made
organic fibers dominate.
The material used for fireproofing in building construction usually is a
blend of 5 to 30% asbestos fiber (chrysotile), mineral wool, clay binders
(as bentonite), adhesive*, synthetic resins, and other proprietary agents.
such as oils. The material used for acoustical and decorative purposes
may contain a greater percentage of mineral wool and little or no asbes-
tos fiber. Some materials are applied as a sprayed slurry (commonly
known as cementltious spray) and will often contain vermiculite, gypsum,
and shorter asbestos fibers. Because the cementitious material has a
much greater density and increased weight per unit area, the supporting
structure must ba designed accordingly.
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There are two principal methods of applying sprayed mineral fiber In
the dry method, dry material, including binders, is dumped from a paptr
shipping bag into a large hopper, where the material is agitated and
subsequently blown into a 2- or 4-inch hose. The hose conveys the dry
material to a nozzle at the actual site of application. As the dry
material leaves the nozzle, it passes through the focus of a ring of fine
water jets. Mixing takes place at this focal point, which is usually
4 to 8 inches from the end of the nozzle, The operator is able to con-
trol the air, material, and water mix, with valves at the nozzle. This
produces a fibrous matrix held to the steel by the water-activated
binders .
The wet method differs 1" that the material is premixed with water in
the hopper, and the resu. ng slurry is pumped to the nozzle and sprayed
upon the surface to be coaled. The nozzle used is similar to that used
to apply plaster. The Portland cement and gypsum present in the ceraen-
titious wet mix provide a bond to building steelwork. Of the two Appli-
cation procedures, the surface produced by the cementitious procedure is
significantly less friable.
B Extent of Use of Asbestos Spray Insulation
The quantity of mineral fiber used for spray applications in the United
States increised steadily from 1958 through 1970. Spray industry
sources (I) estimated that 40,000 tons of material were used for fire-
proofing alone In 1968.. In 1969 and 1970, a survey of asbestos emissions
in New York City was accompanied by a survey of buildings under construc-
tion using spray fireproofIng material (see Appendix 1). These major
office buildings In Manhattan used, over a two-year period, in excess of
2,000 tons of spray fireproofing material, estimated to contain approxi-
mately 700 tons of asbestos. Smaller buildings and construction in other
boroughs would use perhaps an equal amount of asbestos material.
The majority of the spray fireproof ing material applied in New York City-
was of the fibrous, dry sprayed, type. This also found extensive use in
other eastern metropolitan areas. In contrast, on the west coast, cemen-
titious type material dominated, while in the central portions of the
country, a mix of the two occurred. Considering the use in different
areas, it is estimated that approximately equal amounts of asbestos were
applied by the two methods.
The extent of use of asbestos for decorative purposes is difficult to es-
timate. It is applied extensively in the dry fibrous form on ceilings
and walls of auditoriums, night clubs, restaurants and many public build-
ings. Additionally, asbestos is commonly added to paints which are spray-
ed in apartment and office buildings to provide a textured surface. The
extent of this use of asbestos is'unknown. It apparently continues even
today, in violation of the prohibition of sprayed asbestos containing
materials.
C. Purpose of the Present Study
At the time this study was initiated, scant information existed on possi-
ble air contamination in public buildings from the past applications of
asbestos containing fireproofing. To provide such Information, a sampling
and analysis program was initiated to determine the asbestos air concentra
tion In a variety of buildings in five major U. S. cities. Through a
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comparison of the concentrations of asbestos met»sur«-l wiihin building:- to
those measured in the ambient air, it would be possiol? v<> determine if
erosion of asbestos from spray f i : eproof ir.g occurred Moreover, the mag-
nitude of the asbestos concentrations would be useful in the assessment
of potential health effects from such contamination.
Sampling Program
A• Identification and Selection of Buildings
Surveys rere undertaken in New York City, in Chicago and *n the San
Francisco area to select buildings appropriate for this study. Addition-
ally, arrangements were made through the regional office of the Environ-
mental Protection Agency in ft ston to sample the JFK Building in that city.
In each of the three other areas, cooperation of local officials was ob-
taimxt and the building selection program wag accomplished by these local
groups.
1 . New York City
For logistical reasons, and because of its size, the greatest number
of buildings selected for sampling were in New York City. Here, the
cooperation of the Department of Air Resources was of paramount im-
portance. The New York City effort was under the direction of Harold
Romer, Consultant to the Commissioner of Air Resources. From Building
Department records, spray asbestos industry sources and architectural
firms, over 40 buildings in Mew York City were identified in which
asbestos containing spray fireproofing was used within the air supply
system or as acoustical covering, in various rooms.
A questionnaire was developed to identify use of asbestos within these
buildings (Appendix 2), The questionnaire was sent to the building
manager of each of the identified buildings. This produced only a
limited response and personal follow-up calls on each building mana-
ger were undertaken. These initial interviews obtained information
about the type of air supply system used in tiie building and the use
of asbestos fireproofing or acoustic material. Clten, however, spe-
cific Information on the brand of asbestos spray which had been used and
the brand of sealant, if any. which had been used to coat the asbestos
spray material could not be obtained. The interviews concluded with
a tour through the equipment rooms which housed the fans for the
ventilation and the air filtration systems. In all, ten bullr'ings
were selected for sampling.
2. Chi cagp
With the cooperation of the Department of Health (Dr. Murray Brown)
and the Buildings Department (Mr. John Connelly), two buildings were
selected in Chicago and a visit made to determine the suitability for
sampling.
3. San Francisco - Berkeley
Building selection in the San Francisco area was made by the sub-
contractor, the Air and Industrial Hygiene Laboratory of the State
Department of Health. Here, in order to provide a balance to the
type of buildings sampled, specific emphasis was placed on selecting
buildings in which cementitlous fireproofmg material had been used.
Six buildings were selected, including one building that hod ro as-
bestos used in Its construction. The buildings sampled were constructed
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t
SPILL DAMPERS
\\\\-—
i
INTAKE ' DAMPERS
- \\\\—
SPILL
PLENUM
X RBCIRCULATION
DAMJ* RS
RETURN AIR
H
FILTER BANK
PREHEAT COILS
CHILL COILS
Figure 1
The air tram the eelling plenuma is returned through the return air
{•v, chamber to the apill plenum. There approximately 20% la exhausted
anu the remainder recirculated. The recireulated portion la mixed with
freah air from the intake dampera, filtered, conditioned (heated or
cooled), and moved into the aupply ducta by the aupply fan.
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STBBL DECK
\
.CONCRETE FLOOR
^ ^ ^ ^ ^
'A8BBST08
RETURN AIR PLEHUM
ROOM
CEILING
1
f
Figure 2
Cross-section of ceiling plenum space showing air flow and
location of fibrous spray fireproofing covering structural members
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1U.1H through VMM.
The recent I v conwt ructod JKK Itulldttitf tn lloMton wa» Delected bv the
Kl* regional office ma a potential twit I duty for rtanpltng. The type
of building count met ton and tU« material* ui»e*t were determined local
tv and wer«» verified h v Mount Stunt u«r»onnel
! ill* v * ' * ' *' JL?U< * * * *
targe modern building*. f*»eh a* the '-M t'»» '-u> «t«»*'V offic** «HM Kl t uj;:.
til thl?« Miirvoy, linvo injuuwwiU V»HVM« wtitfh i*Kt« in Tr^sU utr
»t» at rttnit i» t-oiutt I loiitNl *t|- tv» t'Hi'U «•( IT> or 'JO »1 1 f f t»ron t t UH»»-»
.V>poi\itl««ti on iltt* uortffontiit »t»m0»»j«»»>u« of 1 hn Inn. I »U i»ii , th« equ l t«at>H <
rooiit «n«t t J .» atr »upj»lv »v*to«j* nuiv t«0 Mtvt«t t»\». thrw^, or
four |«nr«ltt*l v0rtto«l MvwItMiH whvoh M«rvtc«» »lt fftn'osU sector!* of tt»«>
liutttttiiK Tvj>t i-nt t\ , « IMU mtng wlH Ufiv.t* our v«)u(ttwot>t room «f *j>
roNtmntolv mut Ini t !•< '. UK ^levwtlou wtth it« -««>v*>r»t \Mir*Ut>t n'l r nupplv
!«v.Ht««mN, «m»t * ^(li'OMitfHiiMiWKMit fo.«w »t iht> «op-m»»»t level with il»
••rv^vs*. utr Mitpvlv Hv^ttMi* Although t!et«tt» in lnyoul varv from
but t tit iin to ImlUttiiii, the essent »«l f*»|Mve« »»f « lie «tr flow *re !tlu»wtt
tn Ktji«»"«"» I *iut i> ,
A tr
r*nn f. »r»%t» the t»re coiul 1 1 1 one»l » t r Into duct)* w*tt«> of %t»e«»t m*»t«l
which *••«' MOM«>t tmet< Unett tutttruMlly with Mc'tm.tttc fther^tuHH pmtn or
how v.1 « in ortter t.« mtutmtre the Mmouiit of f«u noise which «t»t » u>lo
the »tr duct?». The duct* 'l»*»l to vertical rt»er* which curry the *tr
«o the vnrtoitx fl»*orN f»»r »lt :»t rt hut ion by the local HU|»ply »tucts
t'hoNe are u-.unllv e\terniiltv iuMiilntett wtth f tbern l«s» *tut nlnmliuim
lot I tnmilut ton local t heraoMt at » tletermtne the amount >»f rina\
»•><«• It t>»; or heattitd of the atr before tt leave* the ducting and enters
the room 9i|«ace9« throunh louvered t^MMx
' ' *'e 1 1 n r I eiiuro a nd ln each floor, t he room atr t r> eNhau^led into the cetltng )estto« Material which
.ii.'trt M» f t ropr«..%f ing for the Meel decking of the flo»»r aln»ve 'tlie
atr e\haiiMted tntt<.lhe plenum \» thun e\p*>xe»1 to the aKbe^tt»t material
At several local toim tn each eel I ing plenum, a sheet metal duct con
d\ictn the plenum air to a vertical wttMonry duct The air t s then «•«•
lurne«l thiSMtgh thttt ma^onrv duct to the return air fan chamber which
may he lined »M t h acounttcal material wade of fiberglass hoard* The
N\irf*ce of th» board" t ••» often protected from ulieddtng into the atr
stream In -s» me tns*t al tut lon» , the protection in merely chicken wir«»
or e\j»an»U'«t uteval which pro.-tde" a co«rae physical reittrttint In
other cane" tho surface u* factory covere*! with an impregnated layer
of fiberg 'n >»ttll othera, the ftb*rgliiaa ha» a ne««prene cover
Ing to prtvk,at the f I berg las*». f rom shedding
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4. Sp' 11 Plenum and Intake Air
The return air fan exhausts into a spill plenum. Depending on the
temperature of the outside air and the building return air, the re-
turned air may be entirely apt lied to the outside, or nay be recir
culated to some degree. (8<«e Damper Controls, below.)
The air to be recirculated passes through the recirculatioa dampers
and mixes with fresh air which has been drawn through the intake damp-
ers . The Intake air Is sometimes pre-flltered with coarse fi berg la a*
filters wh.ch are typically 24"x24 'x2'.' The mixed air Is then drawn
through the filter bank, which consists of mult 1 -pocketed bags made
of fiberglass or other fibrous materials.
5 . Dfcmpur Controls
Three sets of dampers control the degree of reclrculatlon and the a-
mount of fresh air which Is taken in. At the 100% outside air Intake
condition, all the returned air is spilled through the fully open
spill dampers. In addition,, the reclrculatlon dampers are completely
closed, and the intake dampers are completely open.
At the condition of minimum outside air Intake, which occurs when the
outside temperature is below 30 F, the spill dampers are selectively
closed down so that only a few remain open to allow a minimus of the
returned air to spill out of the return air plenum. In addition, the
reclrculatlon dampers are opened completely, and the Intake dampers
are closed down except for the minimum number which are mandated by
the building code to remain open. This minimum is in the order of
20% fresh air intake at all times.
For conditions between 100% outside air intake and minimum outside
air intake, the various dampers are modulated to permit some per-
centage of returned air to be spilled and. for the rest to be mixed
with the Intake air and recirculated.
C. Building* Sampled '•
The air in 19 buildings in the five cities was sampled. The buildings,
and their type and use of asbestos, are shown in Table 1. The ratio be-
tween cementltious and fibrous type spray reflects the reported national use of
these types of material*) Office buildings were the dominant type of
structure sampled because of the preponderance of fireproof ing material
used in these structures and because of the number of people potentially
exposed. Little spray fireproof ing was used on apartment buildings.
Additionally, a representative number of decorative and acoustic Insula-
tion uFes of asbestos were sampled. The construction periods of the
buildings ranged from 1958 through 1974, thus providing a representative
sample of the effects of time on the possible erosion of asbestos.
The cities selected for sampling were chosen because of their importance
a centers of construction activity and for travel convenience, ioughly
10% of all high-rise construction in the United States is in New York
City. Chicago is also of obvious Importance. San Pranclscio, while
having leas construction activity than other major cities, provided a
source of buildings with cementitious fireproofing (while New York pro-
vided sn extensive source of buildings with fibrous spray fireproofing)
Additionally, because of trsvel convenience, New York was the most
extensively sampled. Cement it lot •• and fibrous spray fireproofing shared
equally in national usage. With t. j cities selected, we were able to
achieve the same distribution among the buildings sampled in the cities
selected.
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Table 1
Buildings Sampled
Type of Spray
Type of Building
ons of
ound
h
s
s
Cement itious Fibrous Decorative
Acoustic
-
X
X
X
X
X
X
X
X
X
X
X
X (»)
X
X
X
X
X
X
Office Apartment
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Other
X
X
X
X
13
no spray materials used)
asbrst»«: sprav was utilized in this building
-------
D> s«»Plii Locationa
Samples were usually collected in the following locations:
1 . Inside • return a:Vr fan chamber frequently located at the Mid-building
level. (Ibis return air was most recently in contact with the fibrous
spray material.)
2. An office whose air exhausts into the return air chanber and whose
air supply is obtained from the air intake system located in the
•id-building equipment rooai.
3. An outside roof or an air intake chamber before any Mixing with
return air has taken place. This air is ultimately fed to the office.
The ambient air was usually sampled on the side of the building facing
the prevailing winds so that the exhaust air of the building itself
would not be sampled.
4. A second office at an upper lewjl of the building whose air supply
is derived from a supply system located in an upper equipment room.
Two consecutive days were aet up with the building manager for the
actual sampling time*. The aampllng equipment at each station consisted
of:
a) a Millipore filter holder and filter,
b) a 10 liter per minute critical orifice in series with the filter, and
c) a vacuum pump.
In addition to the Millipore samples, email samples of the dirty air bag
filters were taken, along with samples of the asbestos fireproof ing spray
material found in the ceiling plenums; alsor samples of the acoustical
fiberglass covering, if any, in the fan chambers or elsewhere. In all,
116 samples were collected from the buildings and ambient air-
B. Sampling Procedures
The air samples were collected on Millipore brand merbrane filters, 47m
diameter, O.tym pore sice, mounted in a Millipore filter holder equipped
with a 10 liter/bin critical orifice at the vacuum end. The collecting
surface of the filter waa fully exposed to the air.
The filter holder was taped in a horizontal position (filter surface
vertical) two or three feet above the floor, to a deak top or a chair
leg so that no dust particles* could fall directly on the filter surface.
The filter holder waa connected by means of a rubber hoae two or three
feet long to a vacuum pump which sat on the floor. Although the pumps
were equipped with silencers and filters at both inlet and discharge
ports, the pump noise wss sufficiently high to be annoying to some office
workers. The noise could be reduced somewhat by attaching a two-foot
length of rubber hose to the discharge port .
The pumps were run for six. to eight hours per sample, resultir- in an
average air volume of from 3 to 4 m3 per sample in New York, Boston^and
Chicago. Twenty-four-hour samples, with an air volume of about 7m
were collected in San Pranciaco.
-------
Results of Sample Analysis
A. Electron Microscopic Analysis
In the analysis of ambient air samplea for asbestos, the presence of other
organic and inorganic material presents significant problems. Typical
urban air nay contain 100 ug/m3 of "suspended particulates." Such mater-
ial is generally of respirable size and may include 25 to 50% of inorgan-
ic matter. In contrast, typical urban asbestos concentrations range from
about 0.1 ng/m to perhaps 100 ng/m3. Thus, asbestos may constitute only
O.OOOl to 0.1% of the particulate matter present in a given air sample.
Moreover, the asbestos found in the ambient sir includes both micron-size
fibers and numerous individual fibrils having diameters of from 20 to
4O nm and lengths of perhaps 100 nm. In many cases these fibers and
fibrils may be agglomerated with a variety of other material present in
the air sample. These considerations preclude the possibility of quant-
itative analysis of such ambient air samples by light microscopy, bulk
spectroscopic techniques, or X-ray diffraction. The only effective
analysis method has required the dispersion of minersl material, either
by grinding or by ultrasonic disruption, and use of the electron micro-
scope.
Following submission to the Environmental Protection Agency in North
Carolina and coding, the 116 samplea were analyzed using the technique
described in Appendix 3. The results sre listed in Table 2, along with
a detailed description of the buildings, and a listing of the sampling
parameters. Table 3 summarizes the aampling results by building site.
For each sample st least one grid square from four separate .--T-T grids
was scsnned. On about ten samples, usually those with except.1 v. ally high
values, eight grid squares were scsnned from two sample preparations.
In general, the scanning of additional squares yielded values approxi-
mating those originally obtained and the results were simply averaged.
On one sample (73-000-128) a large clump was found on one grid square that
yielded an extremely high mass value for the sample. Little was found
on the reaaalysis and the second value was adopted. The large clump
was probably the reault of contamination, as it would have been dispersed
had it been present on the original sample.
The processing of blank filters with each set of four samples served to
monitor contamination and provide a meaaure of laboratory background.
These analyses indicated a background level of up to 10 ng existed,
and this value was subtracted from the total mass of each sample
tabulation. The variability in this background, however, could lead to
a variation of up to 5 ng/m3 in a given sample of the sets analyzed here.
As the background is independent of the volume of air sampled, those
samples with Isrger air volumes had the lower correction value.
Considerable variability exists in the air concentrations measured in the
various buildings. Jtverage values found for the air inside buildings
range from 2.5 ng/m to 200 ng/m3, with individual measurements from 0 to
over 800 ng/m3- For the outside air, the variation for the average con-
-------
Table 2 (i)
Building
CALIFORNIA SIATC
HEALTH orauniaKT
2151 Bwrk*l*y Way
B*rk*l«y
. CasMBtitioua spray
(1966) la return air
•""""'
2150 Shattucit AVWBIM
••. •• — *
i»iMi«y
Cmmtitiaus la air
plmw.
Ail It In IftTO
.
Sanple
Location
ROOB B042
loan 2017
PlmuB
•ooa 2O17
Outald*
3 floor
•OOB 9O3
PlvnuM
•OOB 903
Outsld*.
•oof
Date
8-30-73 '
8-30
8-30
8-30
•
9-10-73
9-10
9-10
9-10
Total
Flow
<«3>
7
7
6.9
6.4
>
5.5
5.3
S.I
4.8
Totol
tost,
(ng)
103
119
18
113
40
37
13
24
Mass
Conc3 .
(ne/m )
1C-
17
2.6
18
7.3
11
2.6
5.0
f i ber
Count
5
6
•
Fiber
Coac . ^
(f/ml)
.0030
.O048
rr.*
C.ac :-'o.
73-OO3-031
-032
-034
-033
73-003-035
-036
-O38
-037
li i ii 1 1 i i
1_
:'.', J;P-. .
Co-.o .-
1
1A
IB
ID
1C
2A
2B
2D
2C
('
f
!
i
i
tc
-------
Bui Iding
STUDENT CAFETERIA
UMIV. OF CALIFORNIA
Telegraph Avenue
Berkeley
Exposed decorative
acoustic spray
Built in 1958
HARMuM'S GYM
UNIV. OF CALIFORNIA
Berkeley
No asbestos - control
building
Built in 1932
Saatnle
Location .
SW Balcony
3 floor
Serving
Area
2 floor
Serving
Area
3 floor
Roof
Room 175F
Room 91
Main Gym
East Bale.
Roof
Date
9-14-73
9-14
9-14
9-14
,
9-18-73
9-18
9-18
9-18
Total
Flow
(ra3)
6.0
6.0
6.4
6.0
6.2
6.2
7.5
6.0
Total
Mass
22
16
0
29
74
14
55
O
Moss
Cone..
(ng/a )
3.7
2.7
C
4.3
12
2.3
7.3
O
Filler
Count
1
3
33
Fiber '.:?'. , .'•'' S: s •» • '
Cone . Co<1r ,N.) ' C'-jij .*'-, j
(f/ml)
i
i i
' ' i ... _.
I
; < *
.OOO 7
73-OO3-039 2A '
I
! i )
-040 i 3B i
t
i • !
-042 [ 3E I
: j
.0020
.OlhO
• 1 1
-041 i 3C !
! i
i i
i >
I !
1
73-OO3-O43 ' 4A ,
1
t ,
-O44 j 4B ]
1 i
-046 | -IE i
!'
|
; i
-045 4C I
i '
,
i i
! i
: L :
-------
Table 2 (11i)
Building
WKLLS FARGO BUILDING
44 Montgomery Avenue
SMI Francisco
Fibrous spray in
return air plenum
Built in 1966
.
METROPOLITAN LIFE
BUILDING
425 Market Street
San Francisco
Cenentitious spray
in return plenum
Sample
Location
Filtered
Supply
Return
Air
Room 4318
Outside
5 floor
4 floor
Open
Office
Return
Air
Plenum
Outside
Air
37 floor
j
Date
10-18-73
10-18
10-18
10-18
Total
Flow
(m3)
5.6
5.5
6.6
5.6
7.6
8.0
7.6
7.2
Total
MASS
(ng)
0
7
163
22
1372
90
101
331
Mass
Cor.c3
(ng/u )
0
1.3
25
3.9
180
11
13
46
Fiber
Count
.
1
8
9
1
Fiber
Cone .
(f/ml)
.0008
.0045
.0053
rr. ; •:• s.r,. !
Co^c No. ; C .;;" .*-. ,
1
73-O03-048 5B
t
-049 5C
(
-050
-047
74-OOO-108
-111
-109
-110
5E
5A
6A
6E
6B
6C
.
(
1
1
-------
Table 2 (iv)
:V.*lcl:n;:
TURIN HOUSE
'«O9 ColUiS.j is Avenue
Ste» York Cit;.
"partmeai Buildine
Ornamental spray paint
•;l> asbestos
JFK BUILDING
Government. Center
Boston
Cerent i ti< HIS spray in
plenum
t-ihrnus i;lass lined
'itcl s
Sample
Location
Apt. 10A
Apt . 2B
Roof
17 floor
10 floor
21 floor
(EPA-R.O.)
Air Intake
26 floor
•
Date
10-11-73
10-11-73
10-J1-73
8-16-73
8-17
8-16
8-17
8- 10
R-l^
Total t T..I--J
How
(m3)
2.H
9.6
2.7
9.6
2.7
9.6
2.3*
10.05
2.0
10.33
2.65
10.7
•
, »C> .- -t
("K>
2
70
20
167
88
34
Hi
1'i
21
12
2<.
3
Mi1-!-
C"11C2
Utg/m")
0.7
17
32
5 .'j
r. 7
!."»
10
1.2
P^
0.3
Fihr-r
Count
\ \
9
•
-
; i !«••;• ;.: '. .. > :i- ;
&.:.-• , r ;:« > L .' :' , i
O U !
'. ' i
.00-!'. Ir.'J-l'O.'l-OSl J "A-l i
i! ! -031 i '-•.-4 J
( i
-032 --
: !
.iM)4O -055 -j '
i -d53 i -''
1 i
-05fi -6 i
1
1
I
J73-O03-038 , JFV>2
-062 -r
, -<)59 -3
! -m>d - 1
!
- - 0_ ». S
: -037 ' -1
-OG] -:
|
i .
1
1
i
1
1
'
I
(
-
-------
Uuil ding
STEIXMAN BUILDING
City College of the Cit
University of New York
Hew York City
Chem. Sng. Dept.
Acoustical spray
EXXON BUILDING
1251 Ave. of America*
New York City
Offices, 54 floors
Cementitious (Mono-Kot4
on outside structural
•embers . Spray-Don (A) '
on floor decking, i.e.
fibrous asbestos spray
Sealant used, but name
unknown
Built June, 1972
Sample
Location
Room 313
Office
Room 324
Room 301
Lab
•oof
6 floor
(outside)
11 floor
Office
Room 1150
Room 2772
Computer
Room
32 floor
Vacant off
( staff nant)
Return Air
Plenum - R4
15 floor
Outside
Air
15 floor
Date
10-17-73
10-18-73
10-17-73
10-18
10-17-73
10-18
10-17-73
10-18
12-11-73
12-12
12-13
12-12-73
12-13
12-11
12-11-73
12-12
12-13
12-11-73
12-12
12-13
I
Total
Plow
(a3)
3.3
10.8
3.29
10.68
3.15
10.8
3.27
10.6
3.30
4.05
3,65
2.95
3.70
2.80
3.15
2.95
3.70
3.25
2.95
3.70
Total
Mass
(ug)
516
359
72
39
73
85
284
105
0
111
112
71
204
115
71
0
132
37
0
49
Mass
Conc3
(ng/m )
160
33
21
3.7
23
7.9
87
9.9
0
27
31
24
55
41
22
0
36
11
0
13
• i i
Fi'oer
Count
4
3
1
5
0
1
0
1
10
4
Flljcr i M'.. ' "' ... .1. . • !
t
Cone .
(f/ml)
.OO51
.0012
.0012
.0020
0
.0014
0
.001
.0114
.0046
Code X.^ .
C-HJC No '
j i
[73-003-063 ST-1
t -067 ST-5 j
-064
t
ST-2 !
-O68 ST-6 j
, 1
-065 ST-3
i
74-OOO-O15 ST-7
i
73-O03-O66
74-000-016
74-OOO-01 7
-O21
-025
-022
-O26
-018
-020
-024
-028
-019
-023
027
ST-4
ST-8
1251-1
-5
-9
-6
-10
-2
-4
-8
-12
-3
-7
-11
i
i — — . _
-------
Building
1133 Ave of Americas
Hew York City
Offices, 45 floors
Fibrous spray
No sealant
Built January. 1969
888 Seventh Avenue
New York City
Offices, 45 floors
Fibrous spray on beams
and floor decking
Mo sealant
Built in 197O
Sample
Location
Room 216
Office
32 floor
Mail Room
••turn Air
Plenum
12 floor
Outside Air
12 floor
Balcony
19 floor
45 floor
Ou+«ide Air
14 floor :
Balcony
Date
12-4-73
12-5
12-4
12-4
12-5
12-4
12-5
11-12-73
11-13
11-12
11-13
11-12
11-13
Total
Flow
(a3)
3.60
3.30
3.78
3.30
3.36
3.30
3.36
3.30
3 .35
4.85
3.05
5.00
. 3.00
4.7
To^al
Mass
(ng)
17O
184
79
47
2
119
11
50
22
213
296
34
28
66
Mass
Cone,.
(ng/m )
47
56
21
14
O.6
36
3.3
15
6.6
44
97
6.8
9.3
14
Fiber
Count
1
0
1
12
4
r t SMI-'.-.
Code >•-,> . L-'f'n :o
1 i
I
74-OOO-001
-005
-002
-OOf
-O03
-007
-004
-008
•
74-000-009
-012
-010
-O13
-Oil
-O14
'
1133-1
1133-5
-2
-6
-3
-7
-4
-8
888-1
-5
-2
-6
-3
-8
|
-
! • "
-------
Building
MCGRAW-HILL BUILDING
1221 Ave. of AwMTlcas
Mew York City
Offices. SI floors
Firebar type Ton
Cafco D C-F in plenums .
Sealant used, but name
unknown.
Building not completed
as of 12-73, but heavi-
ly occupied.
*
HIPPODROME BUILDING
1120 Ave of Aaerlcas
Hew York City
Offices, 21 floors
Fibrous asbestos spray
(floors 9-21)
Rot known whether
sealant was used.
Floors 1-8 built 1958
Floors 9-21 built 1962
Sanple
Location
6 floor
Processing
17 floor
Print Shop
Return Air
Plenum R-2
16 floor
Outside
Air
7 floor
Vacant
Office
Sewing Ra.
19 floor
Return Air
Plenum R-3
21 floor
Outside
Air
21 floor
Dale
12-14-73
12-18
12-14
12-18
12-14
12-18
12-14
12-18
2-19-74
2-20
2-19
2-20
2-20
2-19
2-20
1
Total
Flow
(m3)
3.10
3.70
3.00
3.70
3.00
3.60
2.05
3.70
3.80
3.35
3.60
3.20
2.95
3.70
2.90
Total
Kzas
(ng)
129
0
24
0
8.6
8
8
5
52
36
45
38
19
38
54
Mass
Cone..
(ng/ro )
42
0
8.0
0
2.9
2.2
2.7
1.4
14
11
12
12
6.4
10
19
i
Fiber
Count
24
24
10
18
1
FI '.,:r
Cr.i.c .
(f/ml)
0326
1. '.' . ' .,M r i
O't..c ^> i * \ r*>(\ , • *
i
r
74-000-029 1221-1
.0274
*
.0141
.0230
.0013
-033 -o !
-030 i -2
-034
-031
-6
-3
-035 ! -7
-032
-036
74-000-101
-104
-4
-8 i
i
|
1120-1
-5
-102 i -2
-105
-6
1
-106 j -7
-103
-107
-4
-8
i— . .
-------
Table 2 (vili)
Building
CKA XHSOMMCB PLAZA
31ft S. Wabasb Avenue
Chicago
Fibrous asbestos
spray (Firebar)
Built: .1974
•
0.S. GYPSUM BUILDING
101 8. Wabastt Drive
dill Ml)
Ceawntitious asbestos
•pray
Plrecode plaster
(USG Brand)
Bui?t: 1960 's
Sample
Location
9 floor
Conference
Area
8 floor
••turn Air
Mixing
Generator •>
17 floor
Exposed Fitn
Insulation
14 floor
4 floor
Outside
18 floor
Balcony
Date
3-20-74
3-21
3-20
3-21
3-20
'
3-21
3-19-74
3-19
3-19
Total
Plow
(m3)
1.60
3.95
2.46
3.00
2.40
, 3.90
3.60
3.40
3.45
Total
Mass
(ng)
140
46
115
40
507
3230
66
3
84
Uasa
Cone.
(ng/m1*)
87
12
47
13
210
830
'
18
0.9
'
24
Fiber
Count
0
1
4
4
6
18
t
'
Fiber j CPA | "f £.:-..--•; )
Cone.
(f/«l)
0
.0011
.0069
.0056
.0105
.0195
Code Xo. C.-,:!'
1
1 j
74-000-120
-123
-121
-124
-122
-125
74-000-12*
-127
-138
CKA -1
-4
-2
-5
-3
-6
U8G -1
-2
-3
«-«
-------
Building
1700 Broadway
New York City
Cementitious on
columns, concrete
facing elsewhere
Built October, 1968
TWA TFJUIIFAL
JFK Int'l Airport
Hew York City
Terminal celling is
covered wllh sprayed
fibrous material
containing asbestos.
Sealed and painted .
Sample
Location
18 floor
11 floor
Return Air
Plenum
12 floor
Outside Air
12 floor
Return Air
Plenum
Passage way
Stored
Asbestos
Ambassador
Club
Lounge
Inside Air
top of roof
near, . . -
kitchen
Date
2-21-74
2-22
2-21
2-22
2-21
2-22
2-21
2-22
4-2-74
4-3
4-2
4-3
,
4-2
4-3
4-2
4-3
Total
Flow
(m3)
3.45
3.85
3.30
3.50
3.40
3.55
3.40
3.55
4.05
2.80
3.90
2.70
3.40
2.80
3.45
2.80
Tota 1
Mass
(ng)
25
45
77
20
67
5
51
12
25
32
31
510
193
8
43
40
Mass
Cone..
(ng/r, )
7.5
12
23
5.7
20
1.4
15
3.4
6.2
11
7.9'
190
57
2.9
12
14
Fiber
Count
4
2
6
Fi btr
Cone .
(f/ral)
.0051
.0024
.0094
.OO74
rrv>
Co
-------
Building
BUDDHIST CHURCH
331 Riverside Drive
Raw York City
Basesjant gym celling
fibroma aabeetoa
arterial. Sealed, but
dajsaged in spota.
Gy» air is coBple ely
exhausted to outaide.
the fiber concentra-
tion was determined by
optical microscopy
using the procedures
specified by the
National Institute. for
Occupational Safety
tuiO HeaiCn« 1 J • fuv
concentrations refer to
all fibers longer than
five Microns per
•illlliter of air
determined by phase
contrast Microscopy
at 4OOX amgnlf Icatlon .
Saaiple
Location
Chapel
Near
Altar
Baseswnt
Gym
Baseaent
Gy.
•
-
Date
3-88-74
3-29
3-28
3-29
3-28
3-29
. •
•
Total
Flow
<«3>
3.60
2.75
3.50
2.90
3.50
2.90
Total
Mass
(ng)
58
52
3
15
53
336
Mass
Cone,
(ng/oO
16
19
0.9
5*2
16
110
-
Fiber
Count
3
4
Fiber
Cone.
(f/Bl)
.0036
.0058
2 PA
Cede N'o
74-000-129
-132
-130
-133
-131
-134
-
:.:t . Sinai
Code No .
i
331-1
-4
-2
-5
-3
-6
-
-------
Table 3
Suaaary of Average Asbestos Concentrations
Average Asbestos
Concentration in
nanograHs/Beter3
Mew York
Turin Bouse
Steinaan Building
IXZOI Building
McGraw-Hill
Rippodrosw Building
1133 Ave of Americas
888 7th Avenue
1700 Broadway
TKA Terminal
Buddhist T«aple
Boston
JFK Building
Chicago
U.S. Gypsum
CNA Plaza
Berkeley
Department of Health
Great Western
OC Cafeteria
Hanson Gy»
San Francisco
425 Market Street
Building Air
8.2
41
29
9.2
11
29
77
12
17
27
2.5
9.5
200
12
7.0
2.1
7.5
8.7
68
Outside Air
18
33
8.0
2.0
14
9.2
12
9.2
5.0
24
18
5.0
4.3
0
3.9
46
-------
23
cent ration at a given sit* extends from 0 to 87 ng/m . For the large
majority of the aamplea, there was no aignlf leant difference between
the average concentration of asbestos measured within the buildings
and that Measured outolde at the same site. In several buildings, how-
ever, the possibility of Indoor air contamination exists. Three build-
ings (1251 Ave. of the Americas, 888 Seventh Ave., and 1133 Ave. of the
Americas) have average indoor air values at least three times greater
and 10 ng/m3 higher than concentrations measured outside. Additionally,
one building (CHA Plata), without a corresponding outside value, has
extremely high concentrations. Also, Isolated samples in three other
buildings (Steinmar all, 331 Riverside Dr., and TWA Terminal) suggest
the possible presence of isolated. areas of contamination.
To further consider whether indoor air contamination exists. Table 4
shows the distribution of concentration values measured inside and out-
side of buildings. In the case of fibrous spray, a significant number
of buildings have concentrations of asbestos exceeding 20 ng/m3, whereas
only one outside samp] » taken at the same time exceeded this value. In
contrast, only two out of 28 inside ssmples exceeded 20 ng/m3 of air
in buildings in which cewentitious asbestos spray had been used.
Two buildings were sampled in which no spray asbestos had been applied.
One, the Harmon Gym at the University of California, was constructed in
1932, prior to Ihe introduction of such procedures. The second, the
McGraw-Hill building in New York City, was fi reproofed with n fibrous
spray. Cafco DC-F and Firebar T, a cement itious material , which was
used on the outside of the columns. Cafco DC-F is advertised to contain
no asbestos, and this fact was verified by optical microscopic analysis
of a sample of the applied material . It is believed that Firebar T also
contains no asbestos, although a sample was not accessible for collection.
While the possibility exists that some fibrous spray material in the
building could have contained asbestos, this is thought to be unlikely,
as New York City prohibited spraying of asbestos -containing material
after February, 1972. The McGraw-Hill building was finished late in
1973, with most spraying likely to have been done in late 1972 or
early 1973. Data from these buildings and all outdoor samples taken as
controls during the sampling of buildings in which asbestos spray had
been used are tabulated in Table 5. It is seen that little difference exists
between the distribution of asbestos concentration in these two build-
ings and that of outside air
Table 6 lists the distribution of all samples according to whether they
were in areas with no asbestos present (outside air or buildings in
which no asbestos material was sprayed), buildings with fibrous asbestos
spray, or buildings with cement itious asbestos spray. These distributions
are also represented graphically in Figure 3. Also shown on Tnble | are
the number of simples having a concentration above and below 20 ng/m for
each of the three circumstances. A^£? test was a polled to these dsta and the
percentage of individual samples exceeding 20 ng/m for fibrous spray is
significantly different from those of outside air at the 0.01 level of confidence. On
the other hand, there is no significant difference in the distribution
6f air concentration in buildings usin cement! tious fireproof Ing material.
-------
The concentration distribution of
samples taken inside and outside of
buildings with sprayed asbestos
Asbestos Cone.
(ng/m3)
Used ic
inside
Number of
i Plenum
outside
samples in
material
concentration
Decorative
inside
outside
range
Tot
inside
tal
outside
Ceiuentitious Spray
0-2
2.1- 5
5.1- 20
20.1- 50
50.1-200
200.1 +
0-2
2.1- 5
5.1- 20
20.1- 50
50.1-200
200.1 +
4
2
13
1
1
0
5
0
10
13
3
2
1
2
3
2
0
0
Fibrous
1
2
7
0
0
0
2
2
3
0
0
0
r
Spray
1
2
10
3
4
0
0
2
0
1
0
0
0
0
1
0
1
0
6
4
16
1
1
0
6
2
20
16
7
2
1
4
3
3
0
0
1
2
8
0
1
0
-------
Table 3
The concentration distribution
of all outside air samples and those in
in which sprayed
Asbestos Cone.
(ng/m3)
0-2
2.1- 5
S.I- 20
20.1- 50
50.1-200
200.1 +
buildings
asbestos Material was never used
Samples in
Buildings
4
4
3
1
0
0
concentration range
Outside
2
6
11
3
1
0
Total
6
10
14
4
1
0
-------
7«blt> 6
The coucentration distributions of control sapples
and aaaplea taken in buildings with asbestos spray
Itumber and percentage of samples within range
incentratlon All control All buildings All buildings
range 3 samples with fibrous with cementitlous
aograma/m (no asbestos) aebestoe spray asbestos spray
0-2 6 17% 6 11% 6 21%
2.1- 5 10 29% 2 4% 4 14%
5.1- 20 14 40% 20 38% 16 57%
20.1- 50 4 11% 16 30% 1 4%
50.1-200 1 3% 7 13% 1 4%
200.1 + 0 0% 2 4% 0 0%
•her of samples <20ng/mZ 30 28 26
•her of samples >20ng/m 5 25 2
2
of difference between asbestos samples
and control 10.145 0.804
obability that difference is fro* chance < 0.01 M.S.
-------
60
Figure 3
The concentration distributions of
control staples and staples taken
in buildings with asbestos spray
SO —
All control buildings
(Mo asbestos spray used)
All buildings with
cecentitious asbestos spray
All buildings with
fibrous asbestos spray
5.1-20
Concentration Range
20.1-50
(nanograms/m3)
I 1
1 __ 1
2OO.U
-------
28
Of the four buildings that suggest possible contamination, two were re-
cently constructed. One (CNA), in fact, still had construction activities
taking place on upper floors. While possible contamination fro» such activi-
ties ia unlikely, they cannot be ruled out. (The construction areas were
outside the supply system sampled.) The other two buildings were also
unique in that no sealant had been applied over the asbestos spray material.
Values for some isolated samples may be the result of special circumstances.
Two T»% Terminal samplea (74-OOO-142 and -146) were near a site of stored
asbestos material, and the sample in the generator room of the CMA building
(74-OOO-125) was in a room with extensive use of sprayed asbestos on the
walls and ceiling.
Optical Microscopic Analysts
Table 7 lists the fiber concentrations measured using phase contrast optical
microscopy at 400X magnification. The technique specified by the National
Institute of Occupational Safety and Health for the analysis of asbestos
samples collected in occupational circumstances was followed. (3) All
fibers longer than five microns in 100 45 X 45-micron fields of view were
counted, and a fiber concentration calculated. These concentrations are
listed in Table 7, along with the mass, concentrations determined by electron
microscopy.
Figure 4 shows graphically the correlation between the asbestos concentrations
determined by optical and electron microscopy. It is obvious that no correlation
exists between these methods. This was to be expected* as fibers other than
asbestos are likely to be present ia the ambient air. According to the pre-
scribed technique, all objects having a 3:1 length to width ratio and a length
greater than five microns are to be counted. As many fibers present in the
ambient air are other than asbest!form minersis, enumeration of such fibers
using the NIOSH technique readily gives misleading results. In occupational
circumstances, wnere the majority of fibers are Indeed aabestiform, this
procedure has practical utility.
Duplicate Analysis
Ten randomly selected samples were sent to the Air and Industrial Hygiene
Laboratory of the California Stats Department of Health for duplicate analysis.
These were analyaed using the method described in Appendix 4, and the
results are listed in Appendix 5. Significant diffsrences existed on three
samples. Extremely high levels listed in the Appendix for samples 73-003-038,
-O46, and -054 suggested ths possibility that inadvertent contamination may
have occurred subsequent to the collection of the samples. All three of
the high values occurred in a group of four samples sent at one time. Tn
order to check this possibility, a second set of the lot of four samples
was sent to Berkeley and ths same four were reanalyzed at Mount Sinai . The
results of this reaaalysis indicated that inadvertent contamination bad occurred
at some point in the sample transfer or analysis process.
-------
Table 7
Comparison of
Asbestos Air Concentrations
Determined by Electron
and Optical Microscopy
EPA Sample Number
Mass Concentration
nanograms/meter3
(Electron Microscopy)
Fiber Concentration
fibers/mi Hi liter
(Optical Microscopy
E-73-O03-032 AH
-O36
-O39
-043
-046
-047
-051
-054
-055
-063
-064
-067
E-74-OOO-OO1
-002
-O07
-010
-012
-015
-O18
-022
-025
-026
-027
-028
-029
-031
-O33
-103
-105
-108
-110
-013
-119
-120
-121
-122
-123
-124
-125
-131
-134
•143
-146
17.0
10.8
3.7
11.9
7.3
3.9
0.7
7.3
17.4
156
21.2
33.2
47.2
0
36.1
97.0
43.9
7.9
41.1
24.1
30.7
55.1
13.2
35.7
41.6
2.9
0
10.3
11.9
181
64.0
23.3
1.4
87.5
46.9
211.3
11.6
13.3
828
15.1
115
56.8
188.9
.0030
.0048
.0007
.0020
.0186
.0008
.0046
0
.0040
.0051
.O012
.0012
.0012
0
.0013
.0055
.0104
.O020
.001
.0014
0
0
.0046
.0114
.0326
.014
.027
.0013
.0230
.0045
.0053
.0051
.0024
0
.0069
.0105
.0011
.0056
.0195
.0036
.0058
.0074
.0094
-------
3C
o
*:
t>
Figure 4
Fiber Concentrations by Optical Microscopy
versus
Asbestos Mass Concentrations by Electron Microscopy
50
1OO 150
Asbestos Mass Concentration (n«/m3>
200
250
-------
31
Table 8 ligta the values obtained by each laboratory for the 10 samples
Except for 74-000-003 and -O12, the agreement between laboratories is
not beyond that which might have been expected (discounting sample
73-003-046, for which inadequate analysis was performed). The possi-
bility that samples -O03 and -012 were interchanged during the coding.
shipment, and analysis procedure at one of the laboratories cannot be
discounted, as the values would be in good agreement if the data for
these two samples at one of the laboratories were interchanged.
D. Variability of the Data
Table 9 lists the two sets of remits on the four samples replicated as
mentioned in the previous section. As can be seen, reasonable agreement
exists. Additionally, as part of a previous study of asbestos ambient
air concentrations in major U.S. cities. 16 replicated samples were
analyzed. In these, the average freent deviation from the mean was found
to be 43%. Considering single samples, it 1s felt that an individual
value is accurate within a factor of two or three of a sample mean.
The inaccuracy that exists in the value obtained in a specific analysis
can result from several circumstances: a) statistical variation iu the
number of fibrils found in given grid squares, b) a much greater variation
in volume of these fibrils, c) incomplete dispersal of chrysotile bundles,
d) variability in the amount of material that may be lost during pro-
cessing, and e) low-level contamination of the sample at various points
during ints preparation and analysis.
The possibility of inadvertent sample contamination exists in spite of
adherence to rigid clean room procedures. Such contamination was found
in one ambient air sample analysed at Mount Sinai, and in one group of
samples analyzed at Berkeley. Undetected low-level contamination could
exist in some of the samples analyzed here, although blanks processed
with each set of four samples revealed no serious problem.
-------
Tabl< 8
Duplicate Analysis of TOT A*bi«nt Air Samples
Sample Nu»b«r
74-OOO-OOS
74-OOO-O12
74-000-023
74-OOO -032
73-003-038
73-O03-046
Asbestos Concentration (nanograni
Mount Sinai
0.6
44
0
2.7
2.6
7.3
•/••ter3)
Calif. 0»pt. of Health
120
0
13
0
0
< 800
.4
-------
•«Plio«t«
of ftour
A»bi«ttt Air
tntion
1st
-054
-064
0
7.6
3.3
5.3
7.1
11.4
30
2.6
7.3
7.3
21
-------
Environmental Aabeatoa Exposure and Possible Human Health Effects
A. Historical Perspectives
The first information on environmental risk from asbestos exposure came
fro. south Africa in I960. lu that year, Waguer, Sleggs and Marchand (4)
described 47 cases of mesothelioma found during a four-year period in the
northern Cape Province, an area with extensive crocidolite aabeatoa nines.
None were seen in the neighboring Transvaal Province or in 10,000 autopsy
cases of workers who had died with known exposures to silica. Of the 47
caaes, approximately half were found to have had either industrial or
mining exposures to asbestos. Virtually all of the remaining eases were
ia individuals who simply lived or worked in the vicinity of the asbestos
mines or Mills.
Confirmation of environmental asbestos-associated disease soon appeared.
Newhouse and Thompson reviewed all mesotbelioma cases at the London Hos-
pitalj(5)They corroborated the close association with asbestos, 31 of the
76 cases having had documented occupational exposure. Of the remainder,
11 had lived, decades before, within one-half mile of an asbestos factory.
A similar distribution of cases was found by Lieben and Pistawka (6) in Penn-
sylvania. On* insidious form of indirect asbestos exposure is that of
families of asbestos workers. IB the prtyiously mentioned studies, nine
of the London mesotheliomaa were in family members, as were three of the
46 Pennsylvania cases.
Additionally, evidence is accumulating that other than neoplastic disease
is present among individuals exposed only to environmental or family cir-
cumstances. A recent study by Dr. Irvine J> Sellkoff of the Mount Sinai
School of Medieln* shows that 31% of family members of a group of former asbestos
workers have X-ray abnormalities character! at ic of asbestos exposure. (7)
Unfortunately, these data on the incidence of mesotbelioma and other as-
bestos-related diseaae from environmental na? family exposure to asbestos
are severely limited. The exposures in question took place beginning 20,
30, 40, or more years ago. No knowledge exists of the associated asbestos
dust exposure levels. Thus, we hav« no dose-response information on low-
level asbestos exposure. We only nave knowledge of a potential risk of
diseaae, at exposures much below occupational ones. Obviously, additional
research and continued surveillance are highly desirable.
B< *nv*rop»«nt** Chrysotile Concentrations
In a previous study st the Mount Sinai School of medicine, 187 samples from
49 United States cities, collected by the National Air Pollution Control
Administration from their air sampling network during 1969 and 1970, were
analyzed 4) Biweekly, 24-hour samples in various three-month periods were
composited and analyzed using techniques Identical to those employed in
this research. Table 10 gives the range of values obtained in this study.
T*blellli*ts tn« results obtained from a series of single samples collected
in New York City by the Department of Air Resources at 12 sites in their
sampling network .flQHtn contrast to the NAPCA samples, which were collected
over s 24-hour period, the New York City were obtained between 9 AM and 4 PH.
At such times, of course, asbestos contributed to the ambi-
ent «i** bv nan'a Activities would have been greater.
-------
Table 10
Chryaotile Content of Aabient Air
Sample* Collected by KAPCA
Fiber Ranye , MtMber of
nanogre«a/»eter Saaplea in Range
0.1 - 0.9 61
1.6 - 4.9 102
5.0 - 9.9 12
10.0 -19.9 9
20.0 -49.9 2
50 -f 1
Total Samples 187
-------
Table 11
CHRYSOTILB GONIBNT OF AMBIWT AIR IN MPT YOU CITY BY BOBOUGH
Asbestos air level in 10"9 gr«««/»3
Sampling
Locations
Manhattan
Brooklyn
Bronx
Queens
Staten Island
Umber of
Samples
7
3
4
4
4
Range
8-65
6-39
2-25
3-18
5-14
Average
30
19
12
9
8
-------
37
*** Y°rk
all Of the,*amplea ware collected during periods when the pro-
Moure or rireproofing high-rise building, by apraying asbestos-contsining
i *i!i VI** P0"*1***** While no sampling station was known to have been
located adjacent to such site*, unusually high levels could have resulted
from theae procedure*.
To verify that construction sites were, indeed, a significant source of as-
bestos fiber, sampling was conducted in lover Manhattan about construction
sites where extensive spraying ot asbestos-containing fireproofing Material
was taking place. Table 12 shows the results of this sampling and demonstrates
that spray fireproofing can contribute significantly to asbestos air pollution.
In some instances, chrysotile asbeatos levels approximately 100 times "back-
ground are observed.
Sampling has also been done in homes of aabeatos insulation workers and ••-
bestos Kill employees in order to determine hosM air concentrations in such
circumstances. Here, also, the sampling sad analysis procedures were identi-
cal to those uaed in this study. Results indicated that air levels in the
homes of asbestos workers can range from 100 nanograms per cubic meter of
air to as high aa 5,000 nanograms per cubic miter of air- (10) It is noteworthy
that the lowest of these levels exceeds any that have been measured in the
smbient air of major U.S. cities, and the highest level is equalled oaly
by the amphlbole mass concentrations found in Silver Bay, kttnnesots near the
site of the Reserve Mining Company operation. (11)
For comparison purposes, Table 13 expresses the ranges of asbestos concen-
trations found in a variety of environmental ana occupational circumstances.
It is not possible, however, to use these ooncentratioaa as necessarily rep-
resentative of the air level* that may have been present about past factories
or in homes of workmen where asbestos-related disease has recently been mani-
fest. However, the documentation of dimaess at concentrations much lower
than occupational oaes, strongly points to the need to conrol exposures in
circumstances where they can contribute significantly to the smbient sir-
This is especially important where large populations may be exposed, such
aa waa the case about spray sites in New York City, and is the caae in the
high-rise office buildings that were constructed using asbestos-containing
spray fireproofing. Concentrations above 100 nanograna per cubic meter of
air are highly indicative of erosion and approach concentrations Measured
in workers' homes (100-5000 ng/m ) and about sites of neighborhood contamination
(to 400 ng/srX where circumstantial evidence suggests the possibility of
adverse health effects.
-------
T»bl>
oonrsoTiui A» urns MM SHUT mmoornio sins
A«b«cto« Air Ural
la 10"* s»/»
Stapling Location Staples Bang* Averts*
1/8 - 1/4 •!!• 11 0 -375 SO
1/4 - 1/2 •!!• 6 S - 54 25
1/2-1 •!!• 5 3.5- 36 18
-------
Table 13
Approximate Ranges of Asbestos Concentration* la Different Circumstances
MaSS Concentration
of Asbestos
Type of Sample Cia I "*
A«bl«nt Air
(200 Sample* In SO U.S. Citl«s) 0.1-100
Hear Astwfttos Spray Fir«prooflnc
Operations and Otter Souroaa
(1/8 - 1 •!!• distant) 10 - 1000
Silver Bay, Minnesota (Reserve
Mining Coapaay Milling Operation) 10 - SOOO
Homes of Asbestos Workmen 100 - 5000
Occupational Exposures 1000 - 100,000 +
-------
40
mutations
Decorative or Acoustic Spray Application '
Indications of contamination of public buildings from the past application
of acoustic spray exist in this study, as well as in Many isolated circum-
stances. Noteworthy in this latter category are a school in Wyoming, a Yale
library, the Lous. Beach Courthouse and a U.C.L.A. dormitory. In all cirow-
stances where significant air contamination has arisen, however, directly
visibly damage to the spray Material was evidsct. Vuus, visual monitoring
of the structural integrity of this sprayed material appears to be sufficient
to assess possible contamination. Where damas>la found, however, corrective
action should be taken. This action may extend from simply repealing the
material with an overspray, to complete removil, as has been done in the
specific caaea Mentioned above.
Cementitious Spray Flreprooflnfi
Ho evidence was developed in this study for asbestos erosion fro* cementitious
spray fireproof ing material used in the plenums of building supply systems.
This conclusion, however, is a tentative one, as it is drawn from s limited
sampling program in only six building*. Prudence would suggest that periodic
sampling of ouch buildings be initinted in order to evaluate the
the results presented here.
Fibrous Asbestos-Containing Spray Fireprooflng
This study presents strong evidence for the erosion of fibers in some buildings
fireproofed with fibrous-type, dry spray, asbestos-containing material. This
was particularly evident in those buildings most recently constructed snd in
those in which no sealant was applied over the spray material. Moreover,
all buildings will, at times, have repair and maintenance activities taking
place in the plenum space that can leas) to contamination incidents. Since
visual monitoring of the integrity of the sprsy materiel In the plenum spsce
is not possible, investigation should be made of feasible filtration systems
that can be used in these buildings to remove any asbestos contamination
that may occur.
•peelfie Recommendations
1. Future Monitoring
a. An effective inspection snd monitoring program should be developed
to verify the integrity of asbestos spray material used for acoustic or
decorative purposes on the walls snd ceilings of public rooms snd build-
ings. This would be primarily a visual inspection to verify that damage
to such material was not taking place. Only in Isolated circumstances
would air sampling be necessary.
b. Periodic spot sampling snd analysis of the air In buildings using
cementitious flreprooflng whould be nade in order to verify the recilts
of this study and to assure that future air contamination of these tuildings
does not occur.
c. More extensive sampling and analysis for asbestos should be done in
those buildings where fibrous spray fireproofing has been used, in order
to define the full extent of asbestos sir contamination.
-------
---' jr> Control Procedures
*• Research wist be undertaken to determine an effective and economically
feasible filtration* system that can be uaed in buildings with air supply
plenuma aprayed with auch fibroua materials.
b. Procedurea should be developed for uaed during maintenance activities
that aay be required in aobeatos-lined plenum apace* in order to minimize
poaaible building air contamination. Consideration should be given to
syatem iaolation, area enclosure, localised wetting, and cleanup by
vacuuming.
c. Procedurea auat be developed and apedfied for uae in thoae buildings
in which the aabeetoa is to be raaoved because of unacceptable contamina-
tion. Here, consideration Bust be given'to both occupational and future
^t_M4 —«-, —M^»A _m
en vi rOfusentai
d. The suitability of proposed If* building demolition procedures for
buildings with extensive spray asbestos must be verified. The community
contamination which could possibly result from such activitiea in the
future may greatly exceed that whicn fesulted from original application
and from building use.
-------
Inferences
1. Reitse, W.B., Nicholson, W.J., Holaday, D.A. and gelikoff, I .J .
Application of Sprayed Inorganic Fiber Containing Asbestos: Occu-
pational Health Hazards. Aa. Ind. Hyg. Aaaoc. J. 33:179-191 (1972).
a. Levine, H.L. Sprayed Mineral Fiber Association. Personal consunicatioo
with W.J. Nicholson.
3. Criteria for a Recommended Standard...Occupational Exposure to A bes
p VIII-1. U.S. Department of Health, Education and Welfare, National
Institute for Occupational Safety and Health (1972).
4. Wagner, JjC., 81 eggs, C.A. and Marchand, P. Diffuse Pleursl Meso-
thelioma and Asbestos Exposure in the North Western Cape Province.
Brit. J. Ind. Hed. 17:260-271 (1960).
3. Newhouse, M.L. and Thompson, B. Meeothelioma of Pleura and Peritoneum^
Following Exposure to Asbestos in the London Area. Brit. J. Ind. Med.
22:261-269 (1969).
6. Lieben, J. and Plstawka, H. Mesothelioma and Asbestos Exposure. Arch.
Environ. Health 14:359-666 (1967)."»
7. Anderson, H. Conjugal Asbestos Neoplsstic Risk. Ann. N.TT. Acad. Scl.
(in press).
8. Nicholson, W.J. HeasureMnt of Asbestos in the Ambient Air. Final
Report to the Environmental Protection Agency, Contract CPA 70-92 (1971).
see alao: Nicholson, W.J. and Pundssck, F.L. Asbestos in the Environment
Biological Effects of Asbestos, pp 126-130, IARC, Lyon (1973).
9. Nicholson, W.J. and Rohl, AJf. Asbestos Air Pollution in New York City -
Final Report to the City of Mew York Department of Air Resources (1971).
see alao: Nicholson, W.J. and Pundsack, F.L. op cit.
10. Nicholson. WJ. (to be published).
11. Nicholson, WJ. (to be published).
-------
APPENDIX I
Bulldinns Sprayed with Fireproofing Asbestos Compound
43
Address
345 Park Avenue
7 East 42nd Street
1700 Broadwav
141 West 54th Street
IS Columbus Circle
115 Bread Street
1 New York Plaza
100 Wall Street
TOTAL
Asbestos
Compound
(LBS)
175,000
268,370
55,000
75,000
535,853
500.000
2.250.000
600.000
4/459,223
Floor
Area
(SO FT)
1,634,670
312,035
557,649
1,873,946
563,705
887.436
2.525.841
472.748
.8,828,034
Height
(FT)
681
388
503
645
583
282
664
365
No. of
Stories
44
27
41
49
46
22
50
23
Asbestos *
{LBS}
52,500
80,511
16,500
22,500
160,756
150.000
675.000
180.000
L. 337. 767
* Asbestos compound contains 30% asbestos fibers, 60% mineral wool and
10% binder.
-------
II
APPENDIX 2
TOK CITY OF Nl-W YORK
DEPARTMENT OF AIR RKSOUKCLS
51 ASTOR PLACi;, N.Y. 10003
VttJTILATION SYSTP1 CUSHIONS STUDY
44
Hate
WILDING
1. Address.
B.
Name of Building
.No. of Floors
3. Ovncr
4.
5.
6.
7.
8.
Address .
•lanapemOTit rtioup
Addre«s
-------
45
SYSTIM
1. Does the ventilation system run continuously? _ Yes
2. Daily hours of operation _ AM to _ PI.
3. Weekend hours of operation _ AM to _ PM.
.No
4. Are the same ducts used for both heating and
air conditioning?
Yes.
AIR DISTRIBUTION
1. Are any of the ducts insulated internally?
2. Describe the insulation material used.
Brand Manufacturer.
Yes.
3. Are the ducts insulated externally?
4. Describe the material ________
Brand
.Yes
Manufacturer.
RIHUTJ AIR SYSTB1
1. Is there a return air plenum? Yes No
2. Is the plenum insulated internally? *_Yes
.No
3. Type of insulation used in the plenum:
Fibrous asbestos spray?
Cementitious " " ?
Other. Descr ibe.
a sealant used?
Brand
Mfgr.
4.
Yes
No
5. Are there return air ducts? _
6. Are the ducts insulated? _
7. Insulation used:
Fibrous asbestos spray?
-Yes
-Mfgr.
No
No
Cementitious "
Other. Hescribe.
it
Brand
Brand
.Mfgr.
.No
-------
iTl^N A'Pv (Continued)
8. i'.'as a sealant used? Yes _., ' o
Brand Mfgr.
n. RLOl.V* RYM
1. Arc the internal wails insulated? Yes No
Insulation material used:
Brand ' If «r..
2. '.Vas •» sealant used? Yes _,
rand ______ ' If pr . -
I!. All HITWIflN
1. Describe t''.c filters used for the recirculated air:
Brand
2. Total urea of recirculated nir filter*
3. Filter replacement schedule
4. Hate of last filter change
5. Describe the filters used for the make-up air.
Brand Mf er •
6. Total area make-up air filters
7. 'take-up air filter rcplav. «nt schedule.
8. Date of last filter change
9. i^iat is the percentage of make-up air?
IV ra^HVATOR a'AFTS
i Are mssenger elevator shafts insulated? - Yes
Tvr? of insulation:
Fibrous asbestos
Cement itious asbestos -------- Mfgr; ___
Other __________ '«
-------
47
&EWIW SHAFTS (Continued)
2. Was a sealant used? _ Yes _ No
_________ Mfgr --
3. Are freight elevator shafts insulated?
Type of insulation:
Fibrous asbestos __ Mfgr.
Cement it ious asbestos __ Mfgr
4. Was a sealant used? _____ Yes _ No
Brand _ Mf gr
CEILINGS
1. Are the ceilings covered with acoustic material? - Yes - Mo
Type of material used - ; -- Brand
2. Are the ceilings painted? Yes No
Textured paint? Yes No. Brand
Other? . Brand.
FLOW DIAGRAM OF AIR SYSTEM
^kccc'i lir-fl^v di.i«ran showing blowers, filters, ducts, return-air
plenums, fresh-air intakes, and floors serviced.
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jjgLES NEEDED
I, Building materials
1. Plenum insulation
2. Air-duct insulation -- internal
3. Air-duct insulation -- external
4. Blower room insulation
5. Recirculating air filter
a. Filter material b. Dirt covering filter
6. Roughing filter (fresh air pre-filter)
a. Filter material b. Dirt covering filter
7. Ceiling materials
a. Acoustic spray b. acoustic tiles c. textured paint
8. Elevator shaft insulation
I. Air samples (during normal building operation)
1 1. Room air -- 3 interior stations
2. Blower room, before recirculation filters
3. External air -- upwind
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Appendix 3 **
ASBESTOS SAMPLE PREPARATION AND ANALYSIS METHODOLOGY
Ashing
Samples collected on membrane filters are prepared for
ashing by cutting a 1 cm square of the filter and placing
It, dust side down, on a clean microscope slide. Two or
three drops of acetone are added to the square to partially
dissolve the filter and to fix the material io the glass
slide. The sample is ashed in a low temperature activated
oxygen asher for 10 minutes to one hour, depending on
sample composition. (The cleaner samples will require the •
longer ashing period.) It Is best to stop the ashing be-
fore complete combustion of the filter to minimize cny loss
of sample mireral material.
*
* « *
Rubout Procedure
*
Following ashing, the samples are dispersed in a nitro-
cellulose film and mounted on formvar coated electron micro-
scope grids. The dispersal Is accompli shed by a "rubout"
technique in which asbestos fibers are broken into Individ-
ual fibrils. This procedure allows positive identification
of chrysotile asbestos to be made on the basis of morphology
alone. Moreover, large agglomerates of mineral particles,
which could obscure the presence of asbestos fibers or fi-
Krjis, and to which asbestos fibrils could be attached, are
broken into particles sufficiently small to allow all asbes-
tos fibrils to be sesn.
-------
50
The rubout is accomplished by placing a large drop of a
1% solution of nitrocellulose in amyl acetate on the ashed
residue. The flat surface near the edge of a clean watch '
glass is used to grind the residue into submicron sized
* -
particles. This grinding usually takes from 5 to 10 minutes,
depending on the amount of residue present. Typically, the
amyl acetate will evaporate in less than 5 minutes and addi-
tional drops of pure amyl acetate must be added to complete
the rubout. (Adding the 1% nitrocellulos^ solution will re-
sult in an undesirably thick film.) During the*final stages
of the rubout, the solution and residue are dispersed over
several cm of the microscope slide. After dispersing the
ashed residue, some of which still remains on the watch glass,
another drop of the nitrocellulose solution is placed on a
second clean slide. During the dispersal of this drop over
several cm of the slide, the major portion of the residue
remaining on the watch glass is removed. By this procedure,
less than 10% of the residue will remain on the watch glass.
•
The two slides are placed in contact and the ground res-
idue and nitrocellulose solution further dispersed. The res-
idue typically is spread over the width of the slide for a
distance of from 5 to 7 cm. The two slides are then pulled
apart. Mo pressure need be exerted during this procedure as
surface tension will hold them in contact.
-------
With practice, a uniform film is thus produced which can
be tested by viewing against a light. (We earlier did par-
ticle counts to verify uniformity, but visual appearance
proved to be as reliable an indicator of uniformity.) If
the film Is not uniform, amyl acetate can* be added and the
above procedure repeated.
Mounting
The edges of the slide with the attached film are scraped
•>
with a scalpel blade. By carefully dipping the slide in water
at an angle of from 30°-50°, the nitrocellulose film can be
floated onto the water.
Several procedures can be used to mount portions of the
film onto formvar coated electron microscope grids. (Formvar
coated grids have been found to be more stable than uncoatcd
grids In the electron microscope.) Two such procedures are:
•
1) Grids are placed on top-of the film and covered by a
portion of ordinary Whatman filter paper. This
sandwich Is then deftly flipped over and out of the
water. With some people success is achieved every
time,,with others, never.
2) Whatman filter paper is placed under the film, catch-
ing an edge of it. As the filter is withdrawn from
the water, bringing the film with it, grids are
placed at the intersection of the film and the sub-
merged filter paper.
-------
Additional procedures can be devised, depending on the
ingenuity of the technician. After drying, the grids can be
picked up from the Whatman filter paper and mounted in the
electron microscope for scanning.
^
Electron Microscope Scanning and Counting
Typically, 8 grids are prepared from each sample ashed
using material from widely separated portions of the pre-
pared films from both slides. A single square of each grid
is scanned at 40,000 X magnification to determine the quan-
tity of chrysotile present. The identification of chryso-
tile is on the basis of morphology, either that of the classic
tubular structure or that of altered chrysotile (as a result
of either beam damage or physical damage prior to collection).
Here the structure exhibits a dense, irregular, inner region,
•
some.ti-mes wi th a thin capillary, and an electron transparent
irregular outer region. To gain experience in recognizing
various forms of chrysotile, one can select an unaltered fi-
•
ber and watch it deform in the electron beam. The use of
carbon coated films can reduce this damage, but in practice
this procedure has not been found necessary.
The length and diameter of each fiber are estimated with
the aid of fiducial marks on the viewing screen and the mass
of chrysotile per grid square determined. The total area of
film prepared is used to calculate a dilution factor from the
2
rubout. (Typically, I cm of membrane filter sample is dis-
2
persed in 25 cm of film.) Knowing the air volume passed
-------
5 •<
through a given are. of filter paper, the concentration of
chrysotlle asbestos in the sampled air can be obtained.
In practice, a reasonable statistical variation exists
between the number of fibrils found on different grid squares.
The variation exceeds that expected on pure statistical
grounds as occasionally clumps of fibrils, resulting from
the incomplete dispersal of a fiber bundle, are seen. How-
ever, greater variation occurs In the volumes seen on dif-
ferent grid squares as one large fibril can contribute 100
times the volume of a small one. hence, the need for count-
ing several grid squares. Eight lOOu x lOOu squares have
proved to be sufficient. The Inaccuracies inherent in the
sample preparation do not warrant additional effort in scan-
ning.
•
Calibration
The above procedures are calibrated by processing filters
prepared with known amounts of chrysbtlla. Here both dean
membrane filters and filters previously used to collect ambient
air samples are used. Triple air jet milled chrysotile is
dispersed In HJ) to which Aerosol OT has been added. The so-
lution is subjected to ultrasonic energy and diluted so as
to produce a concentration of about 1 nanogram of chrysotile
per cc. This solution is filtered through the membrane filter
2
until 10 to 50 ngms of chrysotile is collected per cm of
filter. The above procedure is then followed as in the case
of collected air samples. Recoveries range,.typically, from
-------
30% to 50% of the added chrysotile and this factor is applied
to the data from the processed samples.
I
Clean Room Procedures
It.has been found that strict adherence to clean room
procedures must be followed. All sample processing should
take place in a filtered air environment. The water used
should be filtered through 0.22p membrane filters. Blank
controls must be run routinely to assure .absence of contam-
ination.
-------
Appendix 4
Collodion film Method for the
Determination of Asbestos in Ambient Atmospheres
Collect atmospheric samples on 0.8 micron pore size Mi 111 pore filters
for a period of about 24 hours at a rate of 10 liters per minure.
Add the collected air samples to sepaiate 10 ml Con way cells. These
tide-mouth cells expose the filters to more oxygen plasma than glass
vials in the low temperature asher (LTA), which leads to efficient ashing
of the sample.
Ash the samples in the LTA until the filters are completely decomposed.
leaving a grey to white residue consisting of inorganic material. With
our International Plasma LTA, the oxygen flow rate was set at 100 ml per
aiaute, with an RF power setting of 20O watts. The required time for
ashing was about 4 to 5 hours.
After completion of the ashing, add 1 ml of 0.25 percent collodion in
aayl acet ate to the samples contained within the glass-covered Conway
cells. Mix by hand by rotating the cells several times, and then mix
in a sonic bath for about 30 seconds to suspend and distribute the
fibers in the viscous collodion solution.
Prepare a ring of known surface area by fusing a length of 1 mm polyethylene
tubing Into a ring. Float this ring on the surface of particle-free dis-
tilled water- Drop a 0.10 ml aliquot of the collodion suspension on the
water surface inside the ring. The suspension will disperse, forming &
uniform collodion film of known srea within the ring.
Add three electron microscope grids of known mesh size to a submerged wire
icreen and draw the screen up through the cast film. Dry the grids for
•bout thirty minutes under a 100 watt incandescent bulb before electron
•icroscopic examination.
lor a 300 mesh grid, count w/enty random grid holes per grid on each of the
three grids at 4000X. Size each fiber directly on the calibrated viewing
^•ereen. Calculate the number of fibers per sample using the following formula:
,1 e A x n where
a x g x f
» - Total number of fibers (per filter)
A • Area confined by polyethylene ring
a » Total fibers counted
t• Area of one grid hole
I a Number of grid holes counted
I B Aliquot fraction
it, „., i. calculated by M . ,A x m where m is the total mass calcu-
lated fro* th* «lz«d fibers. a x g x f
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Appendix 5
Air and Industrial Hygiene Laboratory
California Deportment of Health
Analysis of Air Samples
EPA Contract No. 68-02-13UC
This attachment briefly reviews the microscopy data obtained by AIHL ar, j-art of
EPA Contra-t No. 68-02-13146. Four samples to be analy. ed were receive- 3 a' AI :L
r-n December 23, 1973 and the remaining six on Mar-h 2, 197*4.
Table I lUts the light, microscopy results. Orieinally we had intended to \-, all
ten samples by Hght microscopy as well as electron microscopy. However, this war
based on cur expectation that at least one-half of each filter woul:l be aval Labi <•
to us. However, we only received a one-fourth section for each sample. Sin.^e
one-eighth of a t liter is required for any one of the three analy: is which were
carried out, the HIOSH method, the direct clearing electron microscopy metiioj, :;n 1
th<-- rarlodion film electron microscopy method, it was decided to use some of i),f
sections for analysis by the alternate electron microscopic techniques. Thus
Table I only lists four samples. When one-eighth sections are available for the
sample:; not listed, we will be happy to analyze them by the NIOSH methou.
Table II li..ts fhe mass data obtained by calculating the mass from the size dis-
tribution measured by electron microscopy. However, the following comments shou i
be reari before addressing the table.
For samples 003, OU6, 05^, 06U and 110, numerous bundles or aggregates of fiber.
bound aid coated with a matrix material were observed. They were observed using
both the direct clearing method (DCM) and the parlodion film method (PFM.). Thus
we believe these aggregates are not an artifact of the sample preparation. The
matrix material binding these aggregates together withstands ashing in a muffle
furnace at ^50 C, and is uot soluble in organic solvent. Since asbestos mass cou: -i
not easily be estimated for the fibers contained in these bundles, the mass values
given in the table for these samples exclude the asbestos in the bundles and thus
must be considered minimum estimates of the mass.
In some cases separate measurements were made by two different AIHL microscopists.
The differences in the mass values obtained varied from a factor of 2 to 10. In
those cases where two separate determinations were made the average values are
presented in the table.
The data in the table were obtained using the PFM. Sample 038 also was done by
the DCM. The number of fibers and the corresponding mass were lower by the DCM.
Howev-r, the frequency distribution of fibers vs grid holes showed less variability
in th' iistributibn of fibers counted by PFM than by DCM. This is shown in Table
III. T!.^>> it was felt that, at least for this set of samples, the fibers may hav
fiuffi'"ifnit inhc»oeeneous distribution over the filters, to cause large error.: to
*-- in the use of DCM"
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57
Page 2
IH a telephone conversation with you it wac agreed that you would uend us all the
Reformation about the filters analyzed by AIHL, i.e. where anr both length and diameter, data which may prove invaluable in determining the
Kurce of the fibers. Thus I look forward to receiving the information from you.
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58
Table I
LIGHT MKBOaGOPY HBUUM (W10M MBBQD)
Fiber* > 5 !• In langtb
Fiber* BIT Filter
Fibers per eaa Firet *nelT*i» Second ApaXy«ia
8 fiber* per mf 8,600 0 * I, TOO
28 fiber* per »• 30,000 23,900
061» 37 fiber* per aa* 1»0,000 8,600
•ot«: fleapl* 05^ bed too cuch noo-fibrou* pertlcvil«t« aetter precent to
pervlt fiber courting.
Table II
MASS DATA AS OBIAJBBD FROM BUCTKM MXCB08COPY SIZE
003* too
012 2
023 39
032 Ho fiber* found
038 5,000 Ho fiber* fovnA
OU6 25,000* < 5700 (2 fiber*)
05l» 35,000* Ho fiber* found
06* 900* Ho fiber* found
UD 1,100
119 25
th*M Matins contained may bundl»* or eacregtto* eowlrtiag of
fiber* bow»d ead oo«te4 vlth e Htrix MtorUl, estlmte* of the MB* of
Mberto* in the earegete* ««w not mde. Thu* tte MM* given here i* a
IOMT ll»lt (cf text).
+6eoond •HOMis by direct claerlng net hod. The eoBparicon of reeulte from
tl» '— MiiljTT- Mte on fr»»b portion* of tte original sexpltt suggests a
strom pOMfbilitr of eonte«in«tion et SUB point la the proceSar* during
tt* fint
-------
TABLE III
COMPARISON BETWEEN PFM AND DCM FREQUENCY DISTRIBUTIONS
FIBERS PER GRIDHOLE FOR SAMPLE #£-073-003-038
Estimated 957,
Conf. Intv. for the
Total Number of Fibers
Direct
Clearing Method
Fibers per
Gridhole Frequency
0
1
2
3
4
5
16
59
61
104
bers
ounted
57,
£ — _ «• ^ l_ ^-_
3
2
3
1
2
1
1
1
1
1
264
16
+ 99 %
Pirlodion Film Method
Fibers per
jridhole Frequency
0
1
2
3
4
5
6
7
19
22
8
3
4
1
1
86
60
29 %
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