- Summary-------------------------------
French
Version
-
- On this page :
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- Ammonia and latex (by Smart.Conseil)
- Ammonia
Toxicology (English version by Edouard
Bastarache)
-
- French version :
- Ammoniac et latex (par
Smart.Conseil)
-
- Ammoniac Toxicologie
(Version Française par Edouard Bastarache)
-
-
-
Ammonia
and latex
by
Smart2000
|
-
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- Ammonia-dissolved
pre-vulcanized latex is of everyday usage to make
flexible moulds and peelable protections. In this last
case, it is mainly used in ceramic decoration, to
carry out resists in the application of engobes,
glazes or colourants.
-
- The liquid latex solution is
applied with a brush to the dry area to protect in
less than 15 minutes, and then becomes rubbery. After
application and drying of the layer of engobe,
colourant or glaze, one withdraws the solidified latex
film by gently separating it from the ceramic object
with a pair of small pliers or a blade.
- The elasticity of latex
facilitates the unsticking and generally the pieces
are withdrawn as a whole and in one time.Then the
parts protected by latex appear free of engobe,
colourant or glaze.
-
- This technique is
particularly appreciated when products of very
different colours must be superimposed while being
well delimited, or if the colour of the ceramic object
or shard must appear non-coloured in the case of
application by spraying or dipping.
-
- Attention, if the porosity
of the object is too important the layer of latex will
be difficult to withdraw. Always make a test before
launching out in a long work.
- It is necessary to proceed
in a well ventilated room to avoid breathing ammonia
vapor. In the case of a daily and long use of this
technique, it will be necessary to consider means of
suitable protection and ventilation.
- Brushes must be washed
between each application and drying of
latex.
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- Smart2000.fr
©
Juillet 2005
-
FRANCE
- Écrit
et documenté par le propriétaire du site
// Contact : Smart2000@wanadoo.fr
- Document
pour CONSULTATION PRIVÉE uniquement - Toute
reproduction totale ou partielle est
interdite
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-
AMMONIA
by
Edouard Bastarache
|
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- Molecular Formula :
H3N
-
-
- Uses and
sources of emission :
-
- Ammonia is used mainly in
the manufacture of fertilizers and of many other
products in a very large variety of fields. It is used
as a cooling gas in the industry of industrial
refrigeration.
- One can also find it as a
cooling gas in arenas, and as an air contaminant in
breeding settings (examples: pigsties, henhouses).
- Ammonia is also found as
liquid ammonia which is in fact gaseous ammonia
dissolved in water (solution of ammonia at 28% or
ammonia at 28%).
-
- Hygiene and
Safety :
-
- I-Appearance
:
-
- Ammonia is a colourless gas
with a characteristic and prickly odor. It is a
suffocating gas at high concentration.
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- II-Exposure
Characteristics :
-
- Exposure to ammonia in the
work environment occurs mainly as a gas, because of
its very low boiling point and its great volatility.
The exposure to liquified ammonia generates a
significant gas concentration because of its very low
boiling point and its high volatility.
- The exposure to liquified
ammonia is increasingly frequent because of its use in
refrigeration systems. Moreover, concentrated aqueous
ammonia solutions can emit ammonia vapors at high
levels of concentration.
-
- III-Exposure to the gas :
-
- The prickly odor
characteristic of ammonia can be detected at 16,7 ppm,
which is in the same order of magnitude as the VEMP,
25 ppm or 17 mg/m³; at a VECD of 35 ppm or 24
mg/m³; at an IDLH value of 300 ppm or 209
mg/m³ and at the lower limit of explosiveness at
13 % or 13 000 ppm; so that it can be a sign of
adequate warning before the exposure becomes
dangerous.
- An olfactive fatigue occurs
following repeated exposures, therefore the odor
cannot be an adequate sign of warning to an exposure
exceeding the VEMP or the VECD. However, the olfactive
threshold is sufficiently low to prevent a situation
of IDLH.
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- IV-Exposure to the liquid
:
-
- Ammonia is a liquid at
-33,35°C. In the liquid state, it is thus
necessary to take into account all the aspects which
comprise the exposure to a liquid at low temperature.
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- Immediately dangerous to
life or health (IDLH) : 300 ppm
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- V-Inflammability and
explosiveness :
-
- A-Inflammability
:
-
- The fire hazard caused by
ammonia is relatively low, it must be put in contact
with materials or a surface having a temperature of
651°C before igniting itself
- However the presence of oil
or other combustible materials can increase the fire
hazard by lowering this temperature of autoignition.
Ammonia can ignite in contact with strong oxidants.
-
- B-Explosiveness
:
-
- Ammonia requires a
concentration of at least 15% and the presence of a
source of ignition to explode. Ammonia can explode in
contact with strong oxidants.
-
- Toxicology
:
-
- I-Toxicokinetics :
-
- A-Absorbtion
- Ammonia is mainly absorbed
by the respiratory tract. Absorption by other routes
is negligeable.During a short-time exposure (up to 2
minutes) at concentrations varying between 57 and 500
ppm, 83 à 92 % of the inhaled dose is retained
in the respiratory tract (mouth, lungs, etc.), among
volunteers. Following longer exposures (30 minutes)
among seven (7) volunteers exposed at 500 ppm, it has
been reported that the retention of ammonia in the
mucous membranes of the nasopharynx diminishes to 23 %
when equilibrium is achieved (after10 à 27
minutes).
-
- B-Distribution
:
- The few data available in
man suggest that only small amounts are absorbed into
the blood circulation. Blood ammonia is distributed
throughout the body where it plays an important role
the synthesis of proteins and in maintaining the
acid-base equilibrium.
-
- C-Metabolism
:
- Ammonia is an essential
constituent of the human body. It is produced during
digestion and rapidly metabolized into glutamine and
urea, mainly by the liver.
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- D-Excretion
:
- The major part of ammonia
(70-80%) dissolved in the mucous membranes of the
upper respiratory tract was excreted unchanged in the
expired air following inhalation at 500 ppm during 10
to 27 minutes by volunteers. Ammomia absorbed by the
body is excreted by the kidneys as urea and ammonia
compounds. Less than 1% of the 4 grams of ammonia
produced daily by the intestinal tract is excreted in
the feces. A certain amount may also be excreted in
sweat.
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- II-Acute Effects
:
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- Irritation and corrosion
:Ammonia being absorbed very little by the body, its
effects are limited to its irritating and corroding
capacity to the eyes, the skin and the respiratory
tract.
- Ammonia as a gas is
irritating and corrosive to the skin, the eyes and the
higher respiratory tract (nose and throat). The
severity of symptoms may vary according to the
conditions of exposure (duration of contact,
concentration of the product, etc).
- The first signs of exposure
are discomfort, dry nose, watering and a burning
sensation in the eyes.
- Exposure to high
concentrations may cause irritation of the skin,
damage to the cornea, cough, pain in the chest,
respiratory problems (dyspnea i.e. shortness of
breath) and suffocation.
- In severe cases, one
observes laryngeal oedema which may evolve to
pulmonary oedema and death by asphyxiation. The
symptoms of pulmonary oedema (mainly cough and other
respiratory difficulties) often appear after a delay
which may go up to 48 hours. Physical exertion may
worsen these symptoms.
- Rest and medical
surveillance are consequently essential.
- Accidental exposure to high
concentrations can also cause a bronchial irritation
syndrome
- (RADS, Reactive Airways
Dysfunction Syndrome, an asthma-like condition or
asthma without a latency period).
- Very high concentrations may
lead to corrosion of the skin, eyes and upper
respiratory tract.
- Contact with liquified
ammonia gas can cause frostbites as well as corrosion
of the eyes and the skin, following a direct contact.
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- III-Dose-effects
relationship :
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-
Concentration in
(ppm)
|
Probable effects
following acute exposure
|
17
|
Olfactory detection
limit.
|
20-25
|
Discomfort among
non-accustomed workers.
|
25 (VEMP)
|
(Quebec's time
weight average exposure limit.)
|
32-50 (5
mn)
|
Nose dryness, slight
irritation of the nose and throat.
|
35 (VECD)
|
(Quebec's short term
exposure limit.)
|
135 (5
mn)
|
Eye irritation,
watering. Irritation of nose and
throat.
|
300 IDLH
|
" Immediately
dangerous to life or health "
|
500 (30
mn)
|
Severe irritation of
the respiratory tract.
|
2000-3000
|
Severe
cough.
|
2500-7000 (30
mn)
|
Respiratory
troubles, bronchospasm, pulmonary
oedema.
|
5000-10.000 (30
mn)
|
Rapid death by
suffocation or by accumulation of fluids in
the lungs.
|
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- IV-Chronic effects :
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- Repeated or prolonged
exposure can generate a certain tolerance, i.e. the
irritating odor and effects will be felt at higher
concentrations.
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- V-Sensitization
:
-
- Available data do not show
that ammonia can cause cutaneous or respiratory
sensitization
-
- Justification of effects
:
- Some reports mention
cutaneous eruption (urticaria) following exposure to
the vapors of ammonia and asthma-like reactions
following exposure to concentrations between 8 to 15
ppm of ammonia. However, these reports do not make it
possible to link these effects with a mechanism of
allergic nature.
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- VI-Effects on development
:
-
- No data concerning an effect
on the development was found in the consulted
documentary sources
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- Justification of effects
:
- Ammonia is produced by the
body. It is also an essential constituent for the
normal development of human beings. An exposure in the
work environment is not very likely to lead to an
increase in the blood ammonia level and thus, it does
not represent a hazard to development.
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- VII-Effects on
reproduction :
-
- No data concerning the
effects on reproduction was found in the consulted
documentary sources.
-
- Justification of effects
:
- Ammonia is normally produced
by the body. It is also an essential constituent for
the normal development of human beings. An exposure in
the work environment is not very likely to lead to an
increase in the blood ammonia level and thus, it does
not represent a hazard for reproduction.
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- VIII-Effects on breast
milk :
-
- It is detected in human
mother's milk.
- Justification of effects :
Ammonia is a natural component of this milk.
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- IX-Cancinogenic effects
:
-
- There was no data concerning
a cancerogenic effect found in the consulted
documentary sources.
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- X-Mutagenic effects
:
-
- The data do not make it
possible to make an adequate evaluation of the
mutagenic effect.
-
- Justification of effects
:
- A study mentions a light
increase in chromosomal aberrations and sister
chromatid exchanges in workers of a manufacture of
artificial fertilizers simultaneously exposed to
several chemicals among which ammonia.
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- First Aid :
-
- I-Inhalation
:
-
- In the event of inhalation
of gas, bring the worker in a ventilated place and
place him in semi-seated position. If he does not
breathe, give him artificial respiration. In the event
of respiratory difficulties, give him oxygen. Transfer
immediately him to the nearest medical emergency
department. The symptoms of pulmonary oedema may
appear after a delay of several hours and are worsened
by physical exertion. Rest and medical supervision are
consequently essential.
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- II-Contact with eyes
:
-
- Rinse the eyes copiously
with water for at least 20 minutes. See a doctor.
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- III-Contact with skin
:
-
- Quickly withdraw
contaminated clothing by using suitable gloves.
Abundantly rinse skin with water. See a doctor.
- In the event of a frostbite,
apply lukewarm water, rinse abundantly and see a
doctor
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- Quebec's
exposure limits :
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I-Valeur
d'exposition moyenne pondérée
(VEMP) , (TLV-TWA)
|
25 ppm 17 mg/m³
|
II-Valeur
d'exposition de courte durée (VECD) ,
(TLV-STEL)
|
35 ppm 24
mg/m³
|
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- Prevention
:
-
- When engineering measures
and modifications of working methods are not
sufficient enough to reduce the exposure to this
chemical, the wearing of individual protection
equipment may be necessary. These protection gears
must be in conformity with regulation.
-
- I-Respiratory tract :
- Wear a respiratory
protection apparatus if the concentration in the work
environment is higher than VEMP (25 ppm or 17
mg/m³) or than the VECD (35 ppm or 24
mg/m³).
- II-Skin
:
- Wear skin protection. The
selection of skin protection equipement depends on the
nature of the work to be carried out.
- III-Eyes
:
- Wear protection for the eyes
if there is a risk of splashes. The selection of
ocular protection depends on the nature of the work to
carry out and, if it is necessary, on the type of
apparatus of respiratory protection used.
-
-
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- References
:
- 1-CSST-Quebec, Repertoire
Toxicologique, 2003
- 2-Toxicologie
Industrielle et Intoxications Professionnelles,
Lauwerys R. last edition.
- 3-Sax's Dangerous
Properties of Industrial Materials, Lewis C., last
edition.
- 4-Clinical Environmental
Health and Toxic Exposures, Sullivan J.B and Krieger
G.R., last edition.
-
-
|
|
- Edouard
Bastarache M.D.
- (Occupational
& Environmental
Medicine)
-
- Author
of " Substitutions for raw ceramic
materials "
- Tracy,
Québec, CANADA
- edouardb@colba.net
|
-
-
-
- Smart2000.fr
©
Juillet 2005
-
FRANCE
- Écrit
et documenté par le propriétaire du site
et Édouard Bastarache // Contact :
Smart2000@wanadoo.fr
- Document
pour CONSULTATION PRIVÉE uniquement - Toute
reproduction totale ou partielle est
interdite
-
-
-
-
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