Jump to content

  • Quick Navigation
Photo

2 point vs 3 point thermometer calibration

Share this

  • You cannot start a new topic
  • Please log in to reply
4 replies to this topic
- - - - -

Jackson Tsang

    Grade - Active

  • IFSQN Associate
  • 10 posts
  • 0 thanks
0
Neutral

  • Hong Kong
    Hong Kong

Posted 16 October 2014 - 12:22 AM

If I need to measure temperature of frozen, chill and cooking temperature, does it mean I need to calibrate 3 point of -18C, 0C & 100C?

I have heard of two point calibration may be somehow good enough, say 0& 100. Any suggestion?

Calibration of 18C need to do externally and cause hesitation...



Mike Green

    Grade - SIFSQN

  • IFSQN Senior
  • 355 posts
  • 75 thanks
36
Excellent

  • United Kingdom
    United Kingdom
  • Gender:Male
  • Location:Durham
  • Interests:Food(cooking & eating!) Gym, Sun, Sea,Surf,

Posted 16 October 2014 - 10:30 AM

If I need to measure temperature of frozen, chill and cooking temperature, does it mean I need to calibrate 3 point of -18C, 0C & 100C?

I have heard of two point calibration may be somehow good enough, say 0& 100. Any suggestion?

Calibration of 18C need to do externally and cause hesitation...

I think the record  low temp for multiplication  of bacteria  (generally) is -15c  (Planococcus sp)- for pathogens I believe it's closer to -1.5o c (listeria sp) -though i have heard anecdotally as low as -5 (citation needed)

 

& I personally have never encountered 3 point calib. happening outside of a research lab so....(based on that) from a safety perspective-  I wouldn't worry too much about it!

 

 

Mike


I may sound like a complete idiot...but actually there are a couple of bits missing

Charles.C

    Grade - FIFSQN

  • IFSQN Moderator
  • 20,542 posts
  • 5662 thanks
1,544
Excellent

  • Earth
    Earth
  • Gender:Male
  • Interests:SF
    TV
    Movies

Posted 16 October 2014 - 01:51 PM

Dear Mike/Jackson Tsang,

 

(shortened version sincethe forum system just deleted my first post)(Grrr).

 

I routinely use 5 point calibration, -18, 0, 10, 90, 100 (degC).

 

Method - set up one certificated master thermometer and generate sub-masters.

 

It logically also relates to the accuracy required for the intended application. For example, IMEX most TCs have  insuffiicient accuracy  for CCPs / Validation if using 0/100 degC only and at intermediate/external values.

 

(-18degC "area"  may be required to monitor freezing capabilities / validate cold rooms)

 

Rgds / Charles.C


Kind Regards,

 

Charles.C


KTD

    Grade - SIFSQN

  • IFSQN Senior
  • 264 posts
  • 94 thanks
14
Good

  • United States
    United States

Posted 24 October 2014 - 03:16 PM

I utilize both 2 and 3 point calibration checks, based on the intended device application (as Charles.C mentioned). If using a thermometer/thermocouple for a narrow temperature range (processing 'room' temp, cook temp, freezing temp) I have typically used a 2 point calibration that brackets the anticipated min/max temp range. When using a device measuring a wider range - cold and hot temps, I use a three point calibration: bracketing the extremes and then one point in or around the middle of that range. I have found this methodology supportable, ensures sufficient accuracy, and not excessively time-consuming.

 

Keith



gboskou

    Grade - Active

  • IFSQN Active
  • 3 posts
  • 2 thanks
0
Neutral

  • Greece
    Greece

Posted 04 November 2014 - 12:20 PM

better not use the same thermometer for a wide range

choose one for cold and one for hot ranges

if you are using a an accredited thermometer as reference for calibration

this is attached with an accreditation report demonstrating the temperature range of accuracy

I suggest that you prefer more practical reference temperatures, related to common practice e.g. -18 for deep freezer, 4 for refrigeration, 15 for cold cabinets, 63 for hot cabinets, 75 for pasteurization or cooking etc.

in that way your calibrated thermometer will be more related to your application

 

 

 



Thanked by 1 Member:


Share this

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users