Feature
32 reliable temperature readings are necessary for producing optimal conditions in comfort , processing , storage , or industrial applications .
Sensors of this type can also be fixed or mobile / wireless to achieve tasks such as : º Spot checking of foods º Temperature monitoring of food transportation º Measuring the temperature in the centre of flue gas flow in chimneys / flue gas ducts º Surface measurements º Immersion measurement in chemical solutions º Measurement of any mechanical components
• Humidity sensors Controlling humidity in buildings is critical for occupant comfort , safety and protecting building infrastructure , production processes , stored goods , and even museum artwork . Combined temperature and humidity sensors provide a flexible and costeffective solution to achieve this . Humidity control typically adds clean steam to the airstream to raise space humidity .
Although sensors for humidification are of course as important as the humidification equipment itself , one cannot really work without the other . For regular HVAC applications , the
RACA Journal I January 2022
Bacharach
Monitoring of refrigerant gas is particularly required in confined zones such as plant rooms and where occupants may be exposed such as hotel rooms .
normal run of the mill , capacitive sensors are generally suitable as long as they are accurate within the units ’ tolerances and the sensors are importantly placed in the right position , which has been shown to sometimes be incorrect . If these minimum criteria are met these sensors becomes a forgotten component .
There are , of course , certain applications where extreme accuracy in specialised applications is demanded which in turn requires specialist devices . This would be relevant for example is a pharmaceutical production line , or in applications where particular chemicals are developed . The wrong conditions during transportation of produce as another example can result in major losses in quality , right through to a complete loss of value .
• Indoor air quality sensors Sensors that measure indoor air quality ( IAQ ) have become increasingly important , particularly over concerns by the general public over health and safety aspects and heightened awareness around airborne pathogens . The basic IAQ sensor is a carbon sensor , which detects carbon levels in the air . Carbon levels are an indicator of air circulation ( or poor air circulation ) that increases the chances that other contaminants could be present .
In an occupied office for example both carbon dioxide and carbon monoxide levels must be kept to certain maximum levels according to building standards applicable around the world . The carbon dioxide concentration and the IAQ are deemed to be the most important indicators that the quality of the indoor air
is ‘ good enough ’, when people themselves are the main source of this emission . Many studies have shown that poor indoor air quality leads to tiredness , lack of concentration and can even bring about illnesses . The CO₂ concentrations in an indoor environment should therefore not exceed 1000 parts per million ( ppm ) as a rule .
Carbon monoxide is a combustion gas ( harmful gas ) that is released when combustion processes are incomplete . The most frequent day-to-day sources of CO are petrol engines , gas ovens , heating systems and solid fuels , such as wood and charcoal that are commonly used in and around South African cities . Carbon monoxide is colourless and odourless and prevents the blood from taking up oxygen when too great a concentration is breathed in . Breathing in a CO concentration of 700 ppm in an
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