In addition to a dust free environment temperature and humidity are important parameters that require to be controlled in the laboratory. Apart from contribution to comfort and efficiency of laboratory workers control of these parameters contributes to a high degree of reproducibility of test results.
The main reasons justifying control and monitoring of temperature and humidity are:
- Calibration and operation of sophisticated instruments
- Calibration of volumetric apparatus
- Storage of standard weights and reference materials
- Stability studies
- Microbial growth studies
- Reaction Kinetics studies
Calibration and operation of sophisticated instruments
All instrument manufacturers recommend an optimum temperature and humidity range within which the instruments should be operated. Certain instruments are sensitive to both temperature and humidity changes as such changes can influence behavior of optical coatings, electronics and mechanical components. Both calibration and routine operation can show variances resulting in non-reproducibility of results
Calibration of Volumetric Glassware
All analysis requires reproducible transfer of volumes. Glassware calibration is carried out at 25°C +/-2°C. Glass at this temperature has very low coefficient of thermal expansion but liquid medium used for calibration can show significant volume variation per degree centigrade change of temperature.
Storage of standard weights and reference materials
Standards for calibration purpose such as weights or optical filters require careful handling and storage. Variations in humidity outside permissible limits can lead to gradual corrosion damage or deterioration of reference materials. Certified results of analysis of reference materials cannot be guaranteed if temperature and humidity are not maintained.
Shelf life of pharmaceuticals and food products are dependent on temperature and humidity conditions of storage. Accelerated Stability studies on such products are conducted in specially designed stability chambers where both temperature and humidity are controlled over extended periods of time ranging from days to several months.
Studies on growth of microbe colonies on specimens of foods or pharmaceuticals requires incubation under controlled temperature and humidity for specified number of days
Reaction Kinetics Studies
The reaction rates of chemical and enzyme controlled biochemical processes are significantly altered by temperature changes. Strict control of temperature is necessary for reproducible kinetic studies of such reactions
How to monitor temperature and humidity?
Temperature and humidity are monitored by recording continuously or at least twice a day at beginning and end of the day using calibrated thermometers and hygrometers. Digital recording and data logging devices are also reliable and widely used in modern laboratories.