Balance used for pipette calibrations

[ksmith]

We use a Sartorius Scale (LA120s) to calibrate laboratory pipettes.  We have a third party calibrate the scale on an annual basis.  Our currently policy states to perform in-house calibration quarterly.  

When the manufacturer does not specify how often the scale should be calibrated, is there a standard or recommendation for frequency?  Would someone be willing to share your policy/form for the calibration?

Should the weights used be sent of for calibration on a scheduled basis?

I'm new to how this scale should be maintained.  The original policy was last revised in 2003.  Someone else took care of this at the other facilities I have worked.  I appreciate any information you can provide.  

 

[Ensis01]

I am not sure how helpful this will be but my experience with scales is that your facility determines the frequency of calibration not the manufacturer because it depends on what the scale is used for and your precision and accuracy requirements. That being said one external annual calibration of a scale is good as long as there is a daily (or before use) performance check. The performance check uses your "calibrated weights".

One place I worked I got the "third party" to calibrate our weights against their very accurate high quality weights just after they finished calibrating the scale.