-9-
-10-
-11-
solvents, adhesives, hair sprays, a er shaves ,perfumes and
some cleaning agents.
WARNING!
Your CO alarm will not be opera onal and will not
monitor for CO levels without ba ery.
WARNING!
This apparatus is designed to protect individuals
from the acute effects of carbon monoxide exposure. It will not
fully safeguard individuals with specific medical condi ons. If in
doubt consult a medical prac
oner.
7. CARBON MONOXIDE (CO) OVERVIEW
7.1 Toxic effects
Carbon monoxide (CO) is a colourless, odourless, nonirrita ng
gas classified as a chemical asphyxiant and whose toxic ac on is
a direct result of the hypoxia produced by a given exposure.
CO is rapidly absorbed through the lungs, diffuses across the
alveolar capillary membrane and is reversibly bound with
haemoglobin as carboxyhaemoglobin (COHb), however, a minute
amount is present in the plasma. The affinity of haemoglobin for
CO is over 200 mes its affinity for oxygen. This reduces the
oxygen carrying capacity of the blood, and has an effect on the
dissocia on of oxyhaemoglobin, which further reduces the
oxygen supply to the ssues. CO is chemically unchanged in the
body, and is eliminated in expired air. The elimina on is
determined by the same factors that applied during absorp on.
The half-life while breathing room air is 2h - 6,5 h depending on
the ini al COHb level. If the CO level in the inhaled air is
constant, the level of COHb in the blood will approach an
equilibrium (satura on) state a er several hours. However, the
rate at which the equilibrium is reached depends on many
factors, e.g. lung ven la on rate (physical ac vity) and alveolar
capillary transfer, cardiac parameters, blood haemoglobin
concentra on, barometric pressure, oxygen and carbon dioxide
concentra on in the inhaled air, but the two most important
factors in determining the COHb level are the CO concentra on
andthe dura on of exposure.
The effects of different satura on blood COHb levels
on healthy adults
% COHb Effects
0.3 – 0.7 Normal range in non-smokers due to endogenous
CO produc on
0.7 – 2.9 No proven physiological changes
2.9 – 4.5 Cardio-vascular changes in cardiac pa ents
4 – 6 Usual values observed in smokers, impairment in
psychomotor tests
7 – 10 Cardio-vascular changes in non-cardiac pa ents
(increased cardiac output and coronary blood flow)
10 – 20 Slight headache, weakness, poten al burden
on foetus
20 – 30 Severe headache, nausea, impairment in limb
movements
30 – 40 Severe headache, irritability, confusion, impairment
in visual acuity, nausea, muscular weakness,
dizziness
40 – 50 Convulsions and unconsciousness
60 – 70 Coma, collapse, death
Source
: U.S. Environmental Protec on Agency 1984
The rela onship between the CO concentra on and the dura on
of exposure can be calculated for a given %COHb, by
parameterising the above factors.
7.2 Chronic effects on high risk groups
Individuals with coronary artery disease exposed to lowlevels of
CO show reduced ability to exercise and the me of onset of
exercise-induced angina pectoris in such pa ents exposed to low
levels of CO is reduced. Carbon monoxide readily crosses the
placental barrier and may endanger the normal development of
the foetus. A number of high-risk groups are par cularly
sensi ve to the effects of CO because of various organ
impairments or specific changes, mainly:
a)
those whose oxygen carrying capacity is decreased due to
anaemia or other haemoglobin disorders;
b)
those with increased oxygen needs such as those
encountered in fever, hyperthyroidism or pregnancy;
c)
those with systemic hypoxia due to respiratory insufficiency;
d)
those with heart disease and any vascular insufficiency.
WHO guidance states that in order to protect non-smoking,
middle-aged and elderly popula on groups with documented or
latent coronary artery disease from acute ischaemic heart
a acks, and to protect the foetuses of non-smoking pregnant
women from untoward hypoxic effects, a COHb level of 2.5%
should not be exceeded. The following WHO guideline values
and periods of me-weighted average exposures have been
determined in such a way that the COHb level of 2.5% is not
exceeded, even when a normal subject engages in light or
moderate exercise:
100 mg/m³ (90 ppm) for 15 min.
60 mg/m³ (50 ppm) for 30 min.
30 mg/m³ (25 ppm) for 1 h.
10 mg/m³ (10 ppm) for 8 h.
7.3 Normal COHb levels
Under normal condi ons, humans typically have low levels of
COHb of between 0.3% and 0.7% present within the body. These
levels are considered neither beneficial nor harmful.
7.4 Tobacco smoking
Tobacco smokers are exposed to significant concentra ons of CO.
In cigare e smokers, the COHb concentra on varies between
5%-9%, while heavy cigar smokers may exceed 10%.
WARNING!
Exposure to high levels of carbon monoxide can be
fatal or cause permanent damage and disabili es.
WARNING!
The device may not prevent the chronic effects of
carbon monoxide exposure, and that the device will not fully
safeguard individuals at special risk.
8. SPECIFICATION
Model : CBFC28
Product standards : EN 50291-1:2018
Type of apparatus : Type B
Power Supply : 3V (2pcs AA alkaline ba ery)
Recommend ba ery type : GP GN15A or ENERGIZER E91
(The normal service life is 3years)
Sensor Type : Electrochemical
Product life : 10 years a er manufacture
Standby Current : <20μA (average)
Alarm Current : <50mA (average)
Opera on Ambient
Condi on : -10 ~ +45°C, 25 ~ 95%RH
Storage/Transport
Ambient Condi on : -20 ~ +50°C, 10 ~95%RH
Alarm sound : ≥85DB at 3m
Low Ba ery warning silence : about 9 hours
Installa on Loca on : wall
Detec on range : Max. 40 m2 within a room.
Size : 120*80*37 ± 1mm
Weight : 102 ± 5g (net)
NOTE
: This CO alarm is designed to detect carbon monoxide gas
from any source of combus on. It is not designed to detect any
other gas.
