SOP on Monitoring of Temperature, Relative Humidity, and Pressure Differential
To lay down a procedure for monitoring temperature, relative humidity, and differential pressure in controlled areas.
This SOP is applicable for monitoring and recording the temperature (°C), Relative humidity (%), and differential pressure (Pa) in controlled areas using a wet and dry bulbs or digital hygrometers or by using Psycrometer for temperature and relative humidity and Magnehelic gauge for Differential Pressure in controlled areas of production, Quality Control, Warehouse.
Personnel of concerned department are responsible for monitoring and verification for Temperature, Relative Humidity, and Differential Pressure.
The head-Concerned department is responsible to ensure the prevailing Temperature, Relative Humidity and Differential Pressure is within limits as per SOP.
Head-Engineering/Head-Q.A shall be accountable for the implementation and compliance of SOP.
Procedure for Monitoring of Temperature, Relative Humidity by Psycrometer and Wet and Dry bulb Hygrometer.
Preparation of the Psycrometer or Wet and Dry bulb Hygrometer for Monitoring of Temperature and Relative Humidity.
Check the calibration status of the instrument.
Check and ensure that the wick is fixed on the wet bulb thermometer.
Fill the cistern with purified water at the start of the shift.
Check and ensure that the wick is wet.
Check that both thermometers are fixed properly.
Swing the Psycrometer gently for about 2 minutes and then check the reading of wet and dry bulb thermometers in the respective area and In case of dry and wet hygrometer (zeal type), check the reading directly without swinging.
Subtract the reading of the wet bulb from that of dry bulb column and the difference will give the depression value.
If the instrument show the reading in Fahrenheit (0 F) then convert the Fahrenheit reading in 0C by using formula given below. O C = (0 F-32/ 9) X 5
Refer to the Temperature and Humidity chart to locate the readings of dry bulb and the depression value given by the Psycrometer. Read the % RH at the intersection of the two columns. In case, values of dry bulb and depression of wet bulb fall as shown in example (b), interpolate the values as given below.
The following examples illustrate the method of using the table.
(a) Dry Bulb …. …. …. 30 °C , Wet Bulb …. …. …. 25 °C
Hence the depression of the Wet Bulb: 30 °C – 25 °C = 5 °C
Reading directly from the tables, the relative humidity is 65 % (intersection value of 30 °C of dry bulb and 5 °C of depression value)
(b) Dry Bulb …. …. …. 23.5 °C , Wet Bulb …. …. …. 16 °C
The depression of the wet Bulb: 23.5 °C – 16.0 °C=7.5 °C
To find the relative humidity, intersection value of 23.5 °C of dry bulb and 7.5 °C depression of wet bulb is required.
But 23.5 is not available in Temperature and Humidity chart, So, mean of intersection value of 23 °C of dry bulb and 7.5 °C depression of wet bulb and 24 °C of dry bulb and 7.5 °C depression of wet bulb is noted as below
The readings are as follows:
Dry Bulb (°C)
|Depression of Wet Bulb °C = 7.5°C|
The mean of two readings i.e. 41 and 43 is 42.Hence the relative humidity is 42%.
The dry bulb reading indicates the prevailing temperature of the respective area.
Record the Temperature and Relative Humidity at starting of the shift + 30 min and after every 4 hours ± 30 minutes for production oral, pilot plant, warehouse and 2 hours ± 15 minutes for production injection till completion of the activity or end of shift whichever is later in Format.
The temperature and relative humidity for all areas shall be maintained.
If the temperature and/or humidity is not within the limits, discontinue the activity and Inform to QA and Engineering Dept.
Engineering department along with QA shall investigate the reason for deviation in temperature and/or humidity and rectify the same. In case of major breakdown, Final decision should be taken by QA for line of action.
Maintenance of Psycrometer and Wet and Dry bulb Hygrometer:
Ensure that sufficient purified water is available in the cistern.
Ensure that the wick is clean and wet.
Ensure that the top end of the wick covers the bulb completely. (To ensure, the wick may be fastened or tied to wet bulb).
Check and ensure that no scales or deposit are observed on the wick. Replace the wick as and when required.
Psycrometer and Hygrometer should be calibrated once in year by external approved party.
Precautions to be taken During Handling of Psycrometer or Wet and Dry bulb Hygrometer :
Ensure that product in the respective area is in closed condition.
Before swinging the Psycrometer in the air, ensure that the Psycrometer will not touch with any wall, near by equipment etc.
Handle the Psycrometer and hygrometer carefully.
While handling if thermometer got damaged, inform to QA for further action.
Clean the broken mercury thermometer in the area.
Procedure for monitoring of Temperature and Relative Humidity by Digital hygrometer
Check the calibration status of the instrument.
Check the temperature and relative humidity displayed in the digital hygrometer monitor.
Record the Temperature and Relative Humidity at starting of the shift + 30 min and after every 4 hours ± 30 minutes for production oral, warehouse and 2 hours ± 15 minutes for production injection till completion of the activity or end of shift whichever is later .
Record the previous day minimum and maximum temperature and relative humidity in the format. Record the minimum and maximum at the time of observing and recording daily initial reading. Recording of minimum and maximum reading.
Record the min and max temperature and RH from hygrometer display menu by pressing “ MODE” key.
Delete the minimum and maximum reading from the memory of hygrometer that is required to leave memory space to record the next day min and max reading.
For resetting the minimum value, press “MODE” key for 3 seconds and then press “SET” key, it will reset the min value.
For resetting the maximum value, press “MODE” key for 3 seconds and then press “SET” key, it will reset the max value.
Procedure for monitoring of Differential Pressure in Different Areas:
AHUs of all areas (Cubicle and adjacent area) should be started 20 to 30 minutes before starting the activity of respective areas.
Ensure that the door of the cubicle and adjacent area are in closed condition.
Read the value (differential pressure between adjacently located areas) on wall mounted Magnehelic gauge which is directly corresponding to the pointer needle, if
All the hygrometers shall be placed at the hot spots identified in each room.
List of Annexures / Formats
Reason for Revision:
Abbreviation and Definitions:
°C: Degree Centigrade
RH: Relative Humidity
A.: Quality Assurance
Annexure – I
Temperature and Relative Humidity Record by a wet and dry bulb
Department: __________________ Area: ___________________________
Frequency: At ± 30 min of starting the shift and after every 4 hours ± 30 minutes for production oral, QC, Pilot Plant and every 2 hours ± 15 minutes for production injection till completion of the activity or end of the shift whichever is later
|Date/Time||Temperature °C||Relative Humidity %|
|Dry Bulb||Wet Bulb|
Note: * Refer to ‘Table of wet and dry bulb thermometer reading with the corresponding percentage of humidity’. Mention ‘NA’ wherever not applicable.
Annexure – II
Temperature and Relative Humidity Record by a digital hygrometer
Department: __________________ Area: ___________________________
Frequency: At +./ 30 min of starting the shift and after every 4 hours ± 30 minutes for production oral, QC, Pilot Plant and every 2 hours ± 15 minutes for production injection till completion of the activity or end of the shift whichever is later. Record minimum and maximum reading at the time of observing and recording daily initial reading.
|Date||Time||Temperature °C||% Relative Humidity|
Annexure – III
Record for Differential pressure
Department: ________________ Area: _______________________
Frequency: At ± 30 min of starting the shift and after every 4 hours ± 30 minutes for production and every 2 hours ± 15 minutes for production injection till completion of the activity or end of the shift which ever is later
Annexure – IV
CLEANING UP MERCURY SPILLS
- What never to do after a Mercury spill:
- Never use a vacuum cleaner to clean up mercury. The vacuum will put mercury into the air and increase exposure.
- Never use a broom to clean up mercury. It will break the mercury into smaller droplets and spread them.
- Never pour mercury down a drain. It may lodge in the plumbing and cause future problems during plumbing repairs. If discharged, it can cause pollution of the septic tank or sewage treatment plant.
- Never wash clothing or other items that have come in contact with mercury in a washing machine, because mercury may contaminate the machine and /or pollute sewage. Clothing that has come into direct contact with mercury should be discarded. Where “direct contact”- means that mercury was spilled directly on the clothing.
- Never walk around if your shoes might be contaminated with mercury. Contaminated clothing can also spread mercury around.
- What to do if a Mercury Thermometer breaks:
- Have everyone else leave the area; don’t let anyone walk through the mercury on their way out.
- Mercury can be cleaned up easily from the following surfaces: wood, linoleum, tile and any similarly smooth surfaces.
- If a spill occurs on absorbent surfaces, these contaminated items should throw away in accordance with the disposal means outlined below.
- Items needed to clean up a small mercury spill:
- Ziplock – type bags (4-5)
- Trace bags (2-6 mm thick)
- Rubber, Nitrile or Latex gloves
- Paper towels
- Cardboard or Squeegee
- Duct tape or shaving cream and small paint brush
- Powdered sulfur (Optional)
- cleanup Instructions:
- Put on rubber, nitrile or latex gloves.
- If there are any broken pieces of glass or sharp objects, pick them up with care. Place all broken objects on a paper towel. Fold the paper towel and place in a ziplock bag. Secure the bag and label it as directed by local health or fire department.
- Locate visible mercury beads. Use a squeegee or cardboard to gather mercury beads. Use slow sweeping motions to keep mercury from becoming uncontrollable. Take a flash light, hold it at a low angle close to the floor in a darkened room and look for additional glistening beads of mercury that may be sticking to the surface or in small cracked areas of the surface.
Note: Mercury can move surprising distances on hard-flat surfaces, so be sure to inspect the entire room when searching.
- Use the eye dropper to collect or draw up the mercury beads. Slowly and carefully squeeze mercury onto a damp paper towel. Place the paper towel in a zip lock bag and secure. Make sure to label the bag as directed by local health or fire department.
- After removing larger beads, put shaving cream on top of small paint brush and gently “dot” the affected area to pick up smaller hard-to-see beads. Alternatively, use duct tape to collect smaller hard-to-see beads. Place the paint brush or duct tape in a zip lock bag and secure. Make sure to label the bag as directed by local health or fire department.
- OPTIONAL STEP: It is optional to use commercially available powdered sulfur to absorb the beads that are too small to see. The sulfur does two things, 1) it makes the mercury easier to see since there may be a color change from yellow to brown and 2) it binds the mercury so that it can be easily removed and suppresses the vapor of any missing mercury
Note: Powdered sulfur may stain fabrics a dark colour. When using powdered sulfur, do not breathe in the powder as it can be moderately toxic. Additionally, users should read and understand product information before use.
- Place all materials used with cleanup, including gloves, in a trash bag. Place all mercury beads and objects into the trash bag. Secure the trash bag and label it as directed by the local health or fire department.
- Contact the local health department, Municipal waste authority, or fire department for proper disposal in accordance with local, state, and federal laws.
- Remember to keep the area well-ventilated to the outside for at least 24 hrs after successful cleanup.