Document 0LgraNNZ2JpmN2wxDGy21304J
FILE NAME Bechtel BECH
DATE 1944 June DOC BECH011 DOCUMENT DESCRIPTION Trade Journal Article
EBs
FROM
die tacit
tsnaca
448 2368
Watts
410 448 2368
kine
eee
01-10-94 01-10-94 04:26 04:26 TO
HEATING
"
ERCIAL INDUSTRIAL AND INSTITUTIONAL RIR CONDITIONING REFRIGERATION PIPHIG HEATING VENTILATION *
PLSo
Ae etepert
WAR SAVINGS BOND SERTES
/
DATE
Hoating and Steam Generation with Coat is the subject of this month's Blueprint of : Post Rcalities page 65
FROM 410 448 2368
410 448 2368
01-10-94 04:29 TO
P.17
Bombers and Balm of Battles
Out of This Heart of Cold
From producing an increasing quantity of peni
cillin to building bombers that is the range of war
jobs which you find Worthington refrigeration com-
the pressore-
heart of air conditioning and refrig-
cration systems
To make enough penicillin and quickly-Worth-
ington compressors must freeze thousands of
gallons of soluble mould to only a few pounds
of the saving drug Similarly other Worthington
stratosphere compressors help create
for the testing of bomber engines
conditions
.
Worthington makes more of the vitals ofair condi-
tioning and refrigeration systems than any other manu-
facturer ... Diesel and gas engines steam turbines
condensers Drives refrigeration valves and
fittings pumps and compressors In many installations
Worthington has taken sole responsibility for major
operating equipment from the unit that powers the 5150
of tem
to
the
compressor
at
its
heart
So alsoin hundreds chemical and petroleum prot-
esses explosives and synthetic rubber air^,, apotwer
and public machines with the world
recognized Worthington trademark are everywhere part
of the struggle for Victory and Prace Worthington
Pump and Machinery Corporation Harrison N.J. N.J.
Power Plant Equipment Refriporoting Equipment
Construction Machinery Turbinas & Generator Sais
Diesel & Gas Erginos
Porar Tennsmission Equipment ' Construction & Mining Machinery
Positioning Equipment Liquid Maters
Pumps & Compressore Air Conditioning & ~ Locomotiva foodwoter R^'otati A Welding
A WORTHINGTON WORTH Giving You More Worth for Your Tax Money and War Bonds SEE HOW PRODUCTS OF CLIMATE CONTROL GO TO WAR FROM BOMBER PLANT TO BATTLEFIELD
Sealing Out Tonk
is
made of
is synthetic manufacture manufacture synthetic synthetic
rsuyntbhetbicerrubber
.
In the tem-
peratures close synthetic below Worthington are
close
A
190 below zero
gas eo-
required Worthington Worthington a gine often drives WorthingtonWorthington com
pressor in the refrigeration system
Sex This Military Ice
tests
aircraft
from
eq1uip0me0nt
equipmenbteloiwn to room
vaabroyviengzero The WWorthoingtorn thington Mul^...-
Mul^...- Drive transmits
Worthington
conditions reproduce
compressor
which
helps-
rte
sep
ooeh
sot t.
la
schaeries
Bomber's made schaerschiaeris which schaeriewshich
parepeaetrrteolerumholepelppretureoleptuommrocleeeuSmsqtsreupderioadpmucmtpsreodnuctts
suscchaeries processed macfhineafmaomouuss
Worthington bearing the
we
lavesion Rations
must often be stored monthsin ad-
often vance
accret cold storage waremany of which are equipped
houses sefrigeration sys-
teass Worthington teass whosewhose heartasre Worthington
ammonis vertical
CompSCHODIT
JUNE 1944 HEATING AND VENTILATING
FROM 410 448 2368
410 448 2368
01-10-94 04:26 TO
P.1Z
Dust
as an Industrial Health Hazard
F. W. HUTCHINSON
Assistant Professor of Mechanical Engineering
University of California Berkeley Calif
THE health problem arising from dust in industry is one of increasing seriousness Socially -
economically and legally it has become evident that
-
immediate steps must be taken to combat the hazard
pneumoconiosis represented by wholesale industrial exposure to the dusts Pneumoconiosisin many of its formsis incurable Thus consideration
of the problem which it represents is based largely
on methods of dust reduction and removal andis
engineer therefore as much a responsibility of the
as
it is of the physician
Fortunately medical knowledge and engineering
equipment have progressed to such a point that recognition of hazardous conditions and availability
of methods for correcting them will now permit a
complete practical and economical solution of the
problem Unfortunately prejudice and fear have
surrounded the entire subject with such an aura of
suspicion anddistrust that neither workmen nor em-
ployers have until recently been willingto acknowl-
edge the hazard or recognize the need for preventive
measures In addition the slow action of the discase
coupled with failure on the part of many physicians to acquaint themselves with the proper diagnostic
methods has made it difficult for the worker to es-
tablish his claim for compensation in the event of
lung injury and equally difficult for the employer to
_
defend himself against fraudulent claims it has been
said that silicosis claims constitute one of the most
adoption widespread of legal rackets Workmen have bitterly opposed
of the
exacting employment qualifications and periodical
physical examinations of those exposed to dust which
are essential to medical control Yet it is essential
that persons having a predisposition to tuberculosis
or a low nasal filtering efficiency be excluded from
the dusty trades Similarly protection of the worker
exposure the demands that he be removed from
at
first indication of lung damage
adopted Employers on the other hand have
the
silicosis _ pointview most claims of
are unfair and
an unscrupulous attempt to take advantage of them
The explanation behind an employer's unwillingness
to acknowledge the hazard is not unreasonable
The ,
dust diseases are almost invariably of long duration
and frequently are not discovered until many years
after exposure has ceased Thus many employers
are now in the difficult and alarming position of fac-
ing claims for disease which is a result of exposure
to conditions that existed in their plants 10 or 15
years ago at that time they were unaware of the health hazard associated with dusty atmospheres and consequently though they might have had every
desire to furnish their employees with full protection
occupational injury from
they did not take the
special carewhichis now known to be necessary
employers Wilson states Most intentioned
may be said to have used reasonable care in past
years considering their lack of knowledge-
this is now their best defense in damage suits How-
ever from now on with the spread ... available
knowledge only special care will safeguard the
interests of employer and workman alike
Recent interest in dust diseases has built up an
extensive literature theories have been confirmed
with experimental evidence and innumerable case
histories of individuals and of entire groups are
available In contrast to the widespread ignorance
of ten years ago it would probably be difficult at the
present time to find a worker in the dusty industries
who has not at least heard of silicosis or an employ-
er who is unaware of the crippling damage suits
which will face him if his employees through failure
on his part to take the necessary preventive mea-
sures contract the discase
The cost of dust controlis often far less than the
cost of one damage suit Jury awards in silicosis cases of 10,000 17,000 22,500 25,000 and like
sums are matters of record In the St. Louis arca
alone there were some time ago over 2000 suits
pending A Missouri mining company as another _example faced claims aggregating 5,000,000 and spent 500,000 in court settlements of a few of them
is
The purpose of this article is to review the liter-
ature on the physiological effects of some of the haz-
ardous industrial dusts and to summarize present-
day criteria acceptable as a basis for the design of
dust control systems
Silicosis
Silicosis is a discase of the lungs caused by the
inhalation of dust containing free silica Some
authorities believe but this fact has not been estab-
lished that the inhalation of silicatesis also a caus-
ative factorand
Incurable and Progressive The important facts
about this disease are that for practical purposes it
is progressive and incurable The qualification for practical purposes is necessary because recent in-
vestigations suggest that uncomplicated silicosis is
not progressive however the continued existence of a case of silicosis without the onset of complications
standpoint is so rare that from the
of social consc-
quences the disease can itself be regarded as pro-
gressive In the medical literature the progressive
+
HEATING AND VENTILATING JUNE 1944
-
7
FROM 410 448 2368
410 .448 2368
01-10-94 04:27 TO
13
viewpoint is the one which has been most widely
adopted but the possible future significance of the
recent findingsis promising
With reference to the incurability of silicosis
recent work has also indicated the possibility of a
Metallica and with reference to dust warned his
readers to beware because it penetrates into the
windpipe implants away the
consump-
tion the body He called attention to the fact
that the death rate among Carpathianminers was
solution but it is as yet too soon to hold out hope
so great that a wife could often ourlive six husbands
for satisfactory medical treatment One promising
method consists in the administration of thyroxene
The passage of time has done little to alleviate the hazard The development of pacumatic tools has led
theinvestigators report that
Thyroid therapy may possibly notonly prevent
the development of silicosis but may also arrest its further progress and possibly reduce to some
already extent the degree of fibrosis
existing
The above remarks on theprogressiveness and
incurability of silicosis have been included because
they show how very far the medical profession has
_ yet to go to achieve a solution of the silicosis prob-
lem In terms of concrete present gain the sum
total of the best that medicine can now offer is not
of much value When dealing with contagious dis-
eases such as smallpox and Spanish influenza it
_
to a great increase in the dust concentrations at-
tending the grinding polishing and cutting of stone The death rate among Barre granite cutters for example increased from 1.5 per 1,000 in the year 1890
to 19.6 per 1,000 in 1924 an increase attributable to the introductioonf pneumatic equipment When one
realizes that a threshold concentration of 5 million particles per cubic footis required to constitute a silicosis hazard for dust made up 100 free silicais then evident that there are many industrial operations today which represent health baz-
ards that did not exist prior to the introduction of mechanical equipment
has been possible to achieve a satisfactory treatment as a step toward the elimination of the disease
itself the case of silicosis a contagious dis-
ease the only advance of real significance which is possible is an advance which must be brought about by the application of basic engineering principlesthe reduction of dust concentrations at the breathing
Many estimates have been made of the number of persons exposed to hazardous concentrations of silica dust but such estimates are usually based only
on industrial exposure When account is taken of
the fact that 60 of the earth's crust consists of
silica the likelihood seems great that such estimates are conservative Lanza and Vane estimated that
permitted zone to a point such that a health hazard no longer
exists onlyin this way can silicosis beeradicated
If
to run its course without complica-
tion silicosis will lead to death by suffocation
the number of industrial workers exposed to the
silica dust hazardis in excess of half a inillion in
those industries in which the processing or handling of siliceous material is of basic importance this esti-
lungs becoming incapable of maintaining a gas transfer sufficient to sustain life Usually however ter-
mate docs not take account of the many workers
exposed as a result of the industrial use of silica as
mination occurs as a result of complications such as tuberculosis or heart disease a definite correlation
hazard a filtering agent In one other respect the silicosis
has not
has been established between silicosis and tubercu-
losis but an explanation is as yet lacking With reference to tuberculosis a study of axe
grinders and polishers showed a death rate of 1,900
per 100,000 from tuberculosis as contrasted with 150
per 100,000 for the general population of the same state In this study the death rate of all workers in the dusty trades investigated was used More striking figures and more significant ones were obtained from a Massachusetts investigation in which the
tuberculosis death rate of 961 silicotic quarry workers was compared with that for the general popula-
yet been evaluated As already mentioned there is
a definite relationship between silicosis and tubercu-
losis This fact leads to the probability thaitn any community in which there's a large number of sili-
cotics there will be a decid familial tuberculosis
hazard Fortunately however his dangeris some-
what lessened as a result of the long incubation period which is found with silicosis the time a
workman's lungs have reached the stage at which
tuberculosisis most likely to set in it is more than
probable that his children will have grown past the
age at which the danger of their contracting the dis-
tion and found to be forty times as great
case is greatest
Background and Extent The name silicosis is of
That silicosis is definitely related to a particular
relatively recent origin but the existence of the
kind of occupational risk is demonstrated by the
health hazard associated with dusty work has been
data from examinations ray of 2500 workmen
ale
recognized by medical men for many centuries
from all departments of a typical heavy industry
From the literature of the period we find that the
5.8 had silicosis but
of those affected were
Awe
the 90.0 Ptolemies knew of it Pliny the Elder referred to
foundry workers The great importance of the silica
Te
the stone cutters disease and devised a crude
hazardis clearly indicated from the following com-
respirator for the protection of miners Aristotle
warned Greek workmen against the inhalation of
publication parative mortality figures from a 1933
of Hollis and Yule
dust Hippocrates thr^'e centuries before Christ
noticed that his surgical knives were dulled by dust ,
1000 for standard population all causes for _ ages 20-65
in the lungs of stone workers In the 16th century Georges Agricolaa mining engineer wrote De Re
%
1984 for silica group 967 for silica group
58
.
.
JUNE 1944 HEATING AND VENTILATING
FROM 410 448 2368
410 4482368 4482368
01-10-94 04:27 TO
P.14
The silica group above showed only three causes
of death diabetes appendicitis digestive diseases
which did not differ significantly from the general
group The significance of these figures is at once
apparent when it is considered that estimated
110,000 workers in the United States have silicosis SS
in some degree
required
Development of the Disease The time required
for incapacitation due to silicosis has been the sub-
ject of a great deal of attention but as yet no gen-
crally accepted conclusions have reached Ap-
parently the period of exposure preceding contrac-
tion of the disease is a function of the dust concen-
tration nature of the dust nature of the work and
individual physical idiosyncrasies From a study of 9,800 cutters in the Ruhr it is concluded that
13 years exposure are required to show slight silicosis and 20 years to cause incapacitation This
same study reveals that 63 of the deaths among silicotics occur from tuberculosis complications In
porcelain workers silicosis develops slowly but pro-
gressively the second stage is usually not . reached
until after 10 ycars Among sandstone workers the minimal exposure has been found be 11 years
while for iron miners an exposure of 4 to 5 years
may be responsible for the appearance of lung changes 4 to 8 years after the exposure has ceased In contrast to the above relatively long incubation
periods are those found among workers engaged in
blasting and in the manufacture of abrasive soaps in these occupations only 3 or 4 years may precede the onset of the disease Likewise an examination of 175 men engaged in rock drilling showed that 50 were affected in less than one year
There is a good reason for believing that under
particularly heavy dust concentrations silicosis takes
an acute form and may appear after an exposure of
only a few months Not soon forgotten will be the
case of the Hawk's Nest Hydro Plant on the New
River Some 4000 workers mostly negroes were employed for wages of 3.00 for a hour day in a relatively short time after completion of the tunnel
work 475 of them were dead and an estimated 1500
others incurably ill This case was investigated by a committee in the House of Representatives before whom witnesses testified that In the tunnel 10
drills were in op^'rationat once and you could not see ten feet ahead of you even with the headlight of the donkey engine Workmen were so thoroughly covered with a silica dust that you could not tell a
white man from that colored man 15 feet away It was this case that a senator from West Virginia described as the most horrible industrial disaster in
the history of the world It was of this case that
Representative Marcantonio of New York charged that 169 workers had been buried unidentified because the undertaker had lost his records On the basis of all evidence which has yet been brought forward it would seem to the impartial investigator that the Hawk's Nest Tunnel should remain a tragic reminder to the engineer of the need for consider-
HEATING AND VENTILATING JUNE 1944
ation of human values in the solution of engineering solution
problems | The above case is only one of a number of similar
but less sensational cases which have shown that there is a real possibility of contracting an acute
form of silicosis if work is in an atmosphere having an extremely high concentration of siliceous dust Experimentally the possibility of acute silicosis has been demonstrated by laboratory tests on animals for exposures of eight hours a day to concentrations of 200 million particles per cubic foot or more it has
been shown that the last stage of silicosis may be
expected in a relatively short timesilcosi
Size of Hazardous Dust The importance of particle size in determining the hazard associated with
dusts has received a great deal of attention Particles 25 to 30 microns in size will usually settle out
rapidly and are therefore not likely to be breathed in quantities sufficient to constitute a hazard However particles of this magnitude such as pollen of the Giant Ragweed or wood dust in carpenter shops may be responsible for hay fever or for various types of asthma In general particles greater than 10 microns are caught in the trachea large bronchi and
mucous membrane Particles around 5 microns go to the respiratory tract but few of them reach the
alveoli where the 1 micron particles are most numerOus Policard made a detailed examination of the
lungosf two silicotic miners and found that % of the particles were less than4 micron and 75 less
than I} micron his findings should be used with care however because it is very probable that the dust
distribution in the lungs is a function of the distribution of particle size in the inhaled thus Policard's findings may be applicable only for the conditions under which the men whose lungs he
examined had worked The smaller particles are obviously the most dangerous since on a weight basis they offer a much larger surface than do the larger ones For this reason dust counts are of more value in evaluating the hazard associated with a dusty environment than are gravimetric dust de-
terminations
The dust particles that are most effective in the causation of silicosis are of a magnitude so small that they are not perceptible to the human eye A micron is 1/1000 of a millimeter or about 25,000 of an inch As has been shown the particles most important in silicosis are in the neighborhood of 5 micron or 50,000 of an inch represents a di-
mension of the same order of magnitude as the wave length of that form of radiant energy which we recognize as light If one cubic inch of quartz were broken into cubes .5 micron on a side enough particles would be formed to create a silicosis hazard in a 250,000 cubic foot space
The determination of mean dust sizes was the
purpose of a series of comprehensive studies conducted by the U. S. Public Health Service exami^-ation of 18,000 outdoor dust particles showed the median size to be .5 micron all were less
59
FROM 410 448 2368
410 448 2368 .
01-10-94 04:28 TO
P.15
than 1.0 micron in contrast only % of 6,000 in-
dustrial dust particles were less than 1.0 micron the majority being between 1 and 3 microns and the
mean 1.5 microns
Hatch and Moke investigated foundry dusts and found that composition is a function of particle size
the proportion of combustible matter and acid soluble iron carbonates etc. increase with decreasing size the proportion of clay and other silicates varies without a definite trend with size the quartz be-
comes less as the size decreases and for particles un-
der 2 microns which comprises 90 of the total
number it is from 1/5 1/2o5f that found the
particles greater than 10 microns These findings emphasize the necessity of taking dust samples directly from the contaminated air and not utilizing rafter or any other kind of settlement sample
which does not contain a representative size distri-
bution
Hazardous Concentration Permissible concentra-
tions of dust vary with size composition and the dust retention characteristics of the individual The latter factor is one which offers some hope from the standpoint of preventive medicine Practically all that is known of the dust retaining characteristics of the human nose is attributable to the work of one
man Lehmann This cxperimenter has shown
that the dust fixation in the nose varics from % to 75 and is almost completely independent of such factors as the condition of the nasal secretion
the rate of air currents the degree of concentration or chemical composition of the dust the width or
narrowness of the nasal passages secmingly fixa-
tion is function of the vortex formation and re-
bound after passage through a restriction
A correlation between fixation and silicosis would
seem to follow from the following tests Of 46 stone
cutters with fixations above 40 only two were found to have silicosis of 31 stone cutters with fixa-
tions less than 29 only 2 were healthy After ex-
amining the above data Lehmann concludes that
applicants for work with poor dust fixation capacity
should not be allowed to work where a menace of
silicosis exists
-
As a result of 418 experiments with magnesium oxide and calcium carbonate Carlton E. Brown gives the following relationships between dust re-
tention and other factors
Per Cent Retention is inversely proportional to 1. Respiration rate for rates below 20 per minute An increase above 20 per minute is apparently followed by no changes in per cent retention ; 2. Minute of air breathed This prob-
ably results from increase in respiration rate with minute Per Cent Retention is unaffected by 1. Volume per respiration 2. Vital capacity 3. Relative humidity The same investigator found that the percentage of
magnesium oxide retained during normal breathing while at rest varied little from about 60 at a con-
centration of 10 mg Above 10 mg the retention
changed but little but as the concentration dropped below 10 mg the retention rapidly approached
The relation between dust concentration and the
incidence of silicosis has been studied by many in-
vestigators but no general empirical relationship
has as yet been established One commonly used
rule proposed by Drinker recommends the acccp-
tance of 5 million particles per cubic foot as the minimal permissible dust concentration for pure silica and 50 million particles per cubic foot for dusts that are very low in silica Some evidence suggests that this rule is unduly conservative for dusts which
contain little silica and an alternative which is widely
used is to limit the total dust count to a value such
that the product of the dust concentration by the percentage of silica be less than 5,000,000 this rule gives 100,000,000 particles per cubic foot as the
minimal concentration for siliceous dusts
Physiological Effect The lung condition known
as silicosis results only from the inhalation of silicabearing dusts Why silica possesses the ability to bring about this condition has been the subject of much investigation and theories of silicosis are at present responsible for considerable controversy Physiologically the effect of complica*- silicosis affects the normal functioning of the body in the same way that the formation of scale affects the efficiency of a heat transfer device In the heat exchanger the hot and cold fluids are separated by an exchange surface and the deposit of scale on this surface reduces its effectiveness as an
exchange medium If the scale becomes sufficiently heavy it will be impossible to secure the transfer of enough heat to accomplish purpose for which the exchanger was installed similarly the lung is a surface through which oxygen is transferred from the
air to the blood The formation of scar tissue rcduces the effective transfer area and eventually the
lung is unable to accomplish its purpose from
suffocation is the result
M7
Asbestosis
.
Asbestos dust is second only to free silica in the
magnitudoef health hazard which it represents
Asbestos is a fibrous material of varying composi-
tion but is usually made up of approximately 43 magnesia 40 silica and % water Oxide of iron
is frequently present and appears as dark particles among the translucent fibers fibers are of such length and fineness that cloth weighing less than 8
oz per square yard has been made from them The lung condition resulting from the inhalation
of this dust is known as asbestosis and resembles
silicosis in its main clinical aspects but differs duc
to the enhanced rate of development Under average`
industrial conditions the length of employment in
fatal cases is only about half that which is usual
60
JUNE 1944 HEATING AND VENTILATING
FROM 410 448 2368
410 448 2368
01-10-94 04:29 TO
P.16
for silicosis It is estimated that there are in the
United States approximately 10,000 men exposed to this hazard as a result of work in the insulating asbestos cloth and similar industries As is true of the silicosis exposure estimates this figure does not
take into account the number of persons exposed as
a result of employment the process industrics where asbestos finds use under various trade names
as a filter aid In one respect asbestosis is less dead-
ly than silicosis is there is seemingly a lower susceptibility to the supervention of pulmonary tuberculosis The danger of contracting the disease is apparently not influenced by either age or sex Like silicosis it is incurable and progressive a case is reported of a patient who was exposed to asbestos dust for one year and whose sputum showed the presence
of asbestosis bodies fourteen years later
- Very few data are available on the relation of dust concentration to the incidence of the disease No
minimal safe concentrations have yet been set up
and information is scant to the conditions in those
plants where a hazard is known to exist It has been determined however that the asbestos dust encountered in fabricating plants is free of silica when air is floated at the breathing level and that the danger of the dust increases as the quality or length
of the fibers increases
. sis of such dusts brought to light the interesting fact
that their composition is similar to that of the soil
in which the cotton was grown
Siliceous Dusts
Apparently there is a great difference of opinion
as to whether or not siliceous dusts are harmful either to normal or tubercular persons The data are so scant that a review of the literature must con-
sist essentially of a catalogue of the few and scattered investigations that have been made of particular dusts General conclusions can not be drawn and
an extension of available data to dusts of even the
same mineral family is hazardous German investigators have studied a number of
different carbon dusts and rate them in the order of
hazard which they represent lignite coal graphite
,
charcoal soot
A statistical study of the health hazard in a large
American company which manufactures artificial abrasives led to the conclusion that persons who have had pulmonary tuberculosis should not be allowed to work where they will be exposed to dust from abrasives The dust in this particular plant
was aluminum oxide combined with silicon carbide
and the incidence to tuberculosis was 1 1/2 times as great in the dusty departments as in the dusty In this connection it is interesting to note that other |
~
' Miscellaneous Siliceous Dusts
Many siliceous dusts other than quartz and asbestos have been carefully investigated Talc silicate containing 62 silica been shown to be responsible for a form of pneumoconiosis when inhaled in large quantities One group of investigators report that 50 of the tale workers whom they examined were affected and about % had tubercu-
losis The same report shows that talc containing
10 tremolite is much more dangerous than talc containing 40 tremolite but an explanation is
lacking The action of cement on the lungs is not definitely
known German investigators say that it produces only an inert deposit in the lungs but American reports show that the frequency of disability from respiratory diseases cement plants is about double that found among employees in dusty manufacturing plants absence from work was also twice as frequent , Yet animal experiments show that cement like limestone and gypsum produces an ad sorptive reaction the dust disappears from the peritoneal cavity without the production of scar
tissue
,
Slate % quartz in concentrations of 700
million particles per cubic foot produces a fibrosis
and pneumoconiosis but few cases have been known
~
to progress seriously On the other hand there is
reason for believing that clay and slate dusts are
responsible for a high incidence of tuberculosis
'
Italian investigators have studied the dust hazard
in cotton spinning mills and report that the silicosis
hazard is apparently negligible Mineralogic analy- .
investigators had previously reported aluminum oxide as not being a factor in the production of silicosis
thus a distinction must be drawn between the
forming ability of a particular dust and its danger through increased susceptibility to pulmonary
tuberculosis This leads to the conclusion that the
claim is unwarranted that a dust is not harmful
merely because its reaction on lung tissue is inert The U. S. Public Health Service has grouped dusts
siliceous as well as siliceous in three classifi-
cations
1. Those causing an inert reaction the amount
of dust in the peritoneal cavity remaining approxi-
mately constant soapstone carborundum jewelcr's rouge anthracite coal bituminous coal and
precipitator ash 2. Those causing a proliferative reaction nod-
ules continuing to increase in size quartz chat
and Rint
.
3. Those causing an absorptive reaction dust
disappears from the peritoneal cavity but scar
tissue is not formed calcite limestone precipitat-
ed calcium carbonate gypsum and cement
A similar list of dusts has been prepared by
Haynes who carried on a long series of animal ex-
periments He arranges them in order of toxicity as
follows precipitated silica flint slate hydroxide precipitated chalk magnesium carbonate carborundum calspar emery colloidal coal in massive
amounts All of the respiratory disorders discussed above
together with many others which are caused by the inhalation of forming dusts are grouped un-
der the one broad term Pneumoconiosis
*
HEATING AND VENTILATING JUNE 1944
61
FROM 410 448 2368
410 448 2368
-
08-16-102 12:59
15108354913
ALPHABETICAL INDEX OF ADVERTISERS
e Industries 2 .2,,....-.+5..
Conditioning Engineering Co
Air Maze Corporation
veo
Alriemp Div Chrysler Corp
43 016
40 A
Airtherm Mfg Co. ....-
. 103
Alco Valve Co. ..
eee,
11.94
Allen Corporation .............--
morican Air Filter Co. be
American Americar> wer Cork J
bene
el Steam Co.
..
American Puraps Inc. .
American Rolling Mill Co.
13 T
*
119
hd
14
Armstrong Machine Works .
10
Automatic Products C.
10
RB
Badger Mfg & Sales ( Raldor Electric Cn 2000.0... Colman Co. .. Bell & Gossett Co .Bethlehem Steel Co. Breidert G. On oo. Bronks Equipment te Bryant Heater Co Buffalo Boit C^ Bulalu More Co. Hyers A M. Co.
.
10
38
35
97
+
116 BR
" 44
&
St
Carey Philip Mfg Co.
24
Cartier Corporation :
cov,
33
Cash A. W. Valve Mfg CorpC.orp.
Rie
Chrysler Corporation Classified Advertising Continental Stert Corp. ...
4 36
.
Crune Co. .e.e- cies ee
31
Crown Iron Works Co. ..,..-..-. 115
Curtin Refrigerating Mch Div of
Curtis Mfg Co. 20...
38
19)
Detroit Lubricator Co. 6...
6
Detroit Stamping Co. ..... Dravo Corporation ... Tuuham C. A. Co.
. 119
. 93
103
E
Economy Pumps Ine ...... = -
bd
Electric Auto Co ......--...
Elgo Shutter & Manufacturing Co.
112
*
Ellsworth Pipe & Supply Co. .... 17
Emerson Electric Manufacturing
Go 4
rn
.
F
Preeman Stoker Div Alinois Iron
& Bolt
Co.
vo...
0-6.
11
G
General General
Controls Co. Electric Co.
ee 22.0.0...
we...
eee
107
*
If
Hays Corp. ....-....-.0-0-5
-.-
Henry Valve Co. vecsce ee es neces
117
*
Holcor & Hoke Mfg Co. ..--.. 39
Howel Electric Motora Co. Inside Back Cover
I
*
ilg Electric Ventilating Co. ......
Illinois Engineering Co. Inc.
*
illunis Testing Laboratories Inc. 114
fron Fireman Mfg Co. . 22... .. 101
J
Johnson Fun & Blower Corp. .... 36 Jolinson Service Co. 02... Hack Cover
K
Korfund Co. Jue
pe.
a.
eee
...
110
I
L
Ludish Drop Forge Co. ..-....---
Leland Electric Co.
...
6.
ee
Bank Co. cee ee
ee wee
29 23 10
M
Marley Co. Inc. ..... vent eeeeree
Mario Coil Co. cc...
cee e
een ee
*
41
Marsh Jas P. Corp. ..---...0eMercoid Corp. ......-- ve eetee eee McCord Radiator & Mfg Co. ..-.
19 37 117
MeDonnell & Miller oo. ..- eee
85
Minneapolis Regulator
Co. cece eeeeee . Inside Front Cover
Modine Manufacturing Co. ......
42
Mueller Brass Co. 222... .06-.0--- 26
N
Nash Englugering Co. .......56.. 50 Nelson He uanCorp. ...,...5. 18-19
.
0
Corning Fiberglas Corp
99
P
Pacific Steel Bollera 2.4...
6
Patterson Co. Inc. .
*
Peeriesa Pump Div Food Machin-
gry Corp.
oo... beeee
A -- 120
Penn Electric Switch Co. wets .
Porter 11. W. & Co. Inc. 2. 2.)
Powers Regular Co
_
Propellair Ine
.
..
44 15 417
*
:
Reznor Manufacturing Ca 0...
j
Ric Co .
.
.e
i
Sall Mountain Clo
.
is
Sarcu Company The
*
sae
Sarcotherm Controls inc 1... . 26
Smith H. Co. u^ 2...
Somers II J. Inc. Inc.
tees
A
Star Electric Motor Cu .
ose
21
Superior Sheet Steel On
bd
.
Taylor Forge & Py Works
Thrush
Poa. ae CO...
Toda Shipyards of imbus
tion Equipment Div
Trane C ..,, 2
1.
-
foes
Trerice H. 0 Co.
em
Turus Inc 2.
ee
Tuttle & Builey Tar
.
aS
%
*** 13 114 31
C. S. Machine Corp.
.
0.0...
e-
.
United States Air Conditioning
*
Corn
6
peewee ee
wees
Lee
United States Rudiator Corp i...
5
W
Wagner Electric Co. 12...
. 106
Want Advertisements ... ..
116
Webster Warren & Co.
ae
2
bd
Weeks D. H.
..--- be
nee
eens
Westinghouse Electric & -- -- ----,
facturing Co. ...., peeee en
06 .46-47
M
White Rodgers Electric Co. ....
Whitlock Manufacturing Co. -
r
Wing L. J. Mfg Co. -...,..--.. 115
Worthington Pump & Machinery
y
Warink Co. 1.0... 109-114-116 109-114-116
|
+
York Heat Div Shipley Inc.
Young Radlutor Co 2 2.
113
Advertisement appeared in girondine Gama
120
JUNE 1944 HEATING AND ENTILATING
A
rSeent
me
48
u-
vNE
vNE
NLYJo
"
ENE
T2EYEARENNARA
T2EYEARENNARA
T2EYEAREN ARA
T2EYEARENARA
T2EYEARENNARA
T2EYEAREN ARA