SOP on Monitoring of Temperature & Relative Humidity
1.0 Purpose: This SOP describes the method for checking the room temperature and relative humidity.
2.0 Scope: This SOP applies to Production Chemist and Stores.
3.0 Responsibility: Quality Control chemist to ensure that the procedure is followed.
4.0 Materials and Equipment:
Wet & Dry bulb hygrometer
5.01 The air conditioning system shall be in continuous operation for a period of at least 30 minutes.
5.02 The Wet & Dry bulb hygrometer is hanged in a position with a steady flow of air around the mercury bulbs.
5.03 Fill the cistern with DM water to avoid the wick becoming clogged with impurities. The wick should be changed regularly to ensure a constant flow of moisture to the wet bulb.
5.04 Allow the mercury columns remain steady.
5.05 Take the reading of the wet and dry bulb columns.
5.06 Subtract the reading of the wet bulb column from that of the dry column, thus arriving at the depression value.
5.07 In the provided table, locate the readings of the dry bulb and the depression value given by the hygrometer and at the intersection of the two columns, read off the percentage humidity.
5.08 The following example illustrate the method of using the tables –
Reading of Dry Bulb ————————– 300C
Reading of Wet Bulb ————————– 250C
Hence, the depression of the Wet Bulb —– 300C – 250C = 50C
Reading directly from the tables, the relative humidity is 65%
6.0 Reference Documents
Table of Wet and Dry Bulb Thermometer with corresponding percentages of relative humidity.