SOP FOR OPERATION AND CALIBRATION OF MUFFLE FURNANCE

1. OBJECTIVE:

1. To lay down the procedure for Operation and Calibration of Muffle Furnace

2. SCOPE: 

1. This procedure is applicable for the Operation & Calibration of Muffle Furnace in Quality Control Laboratory.

3. RESPONSIBILITY:

1. Quality Control Officer / Executive are responsible to follow procedure as per the procedure mentioned in this SOP. 

2. QC Head is responsible for implementation and compliance of the procedure as per this SOP.

4. ABBREVIATIONS

1. SOP    :    Standard Operating Procedure

2. QC    :    Quality Control

5. PROCEDURE: 

1. General Cleaning.

1. Before switching ON the instrument, cleaning should be done with clean and dry cloth. Occasionally, the exterior of the instrument may also be cleaned with a clean piece of cloth wet in a good quality mild detergent, followed by wiping with a clean dry cloth.

2. Operating Procedure:

1. Switch ON the instrument.

2. Set the temperature of the Muffle furnace at 600°C ± 50°C  using temperature setting knob.

3. Heat a silica crucible for 30 minutes, allow it to cool in a desiccator and weigh. 

4. Transfer to the crucible required amount of the sample to be examined, weigh the crucible and the contents accurately.

5. Ignite gently until the sample is thoroughly charred. Now ignite at 800º ± 25ºC otherwise specified in the standard testing procedure until all black particles have disappeared.

6. Cool the crucible in desiccators and weigh.

7. Repeat the operation until two successive weighing do not differ by more than 0.5 %.   

3. Calibration Procedure:

1. Calibration Frequency

1. Yearly and after each maintenance.

2. Calibration Procedure

1. Switch on the instrument.

2. Set the required temperature with the help temperature setter. The display will show both the set temperature and actual temperature of the furnace.

3. The display temperature indicator should be calibrated with the help of calibrated RTD calibrator at two temperatures of 300°C and 900°C.

4. Acceptance Criteria: The difference between the temperature shown by Furnace temperature display and standard RTD shall not be more than ±5°C.

Note: The calibration may be done by the external agency.

The “Calibration Record of Muffle Furnace” shall be maintained as per current Calibration of Muffle Furnace.