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D_Wood
First off, I am not certain if this is the correct location for this thread. I am responsible for maintaining the accreditation of our testing lab as it pertains to various client-test data programs issued by various NCB's, which are all governed by ISO 17025.
I would like to discuss the requirement of using a Black Test Corner to perform temperature testing.
In the world of compliance testing per International Safety Standards, it is becoming the norm to see reference to a "Black Test Corner" as a requirement when performing temperatrure testing (heating). Typically, this relates to wording such as "the product (appliance, etc.) and its surrounding area shall not attain excessive temperatures during normal use". The key word that seems to come into play here is "surrounding area". I'll come back to this in a moment.
For reference, a Black Test Corner consists of a draft-free corner with 3/4" (20mm) plywood on the joining walls, painted flat-black. A grid of holes, 7mm dia., spaced 100 mm apart covers the entire surface of the plywood, making it resemble pegboard. The holes are used to place blackened copper or brass discs with thermocouples attached to them. These discs are placed in only enough holes needed to cover the surface area ralative to the product being tested. The number of discs to be used in itself has led to many heated discussions throughout many industries. The thermocouples are then connected to a recording/measuring system, either a DAQ module & computer or a handful of meters.
Now, back to the "surrounding area". My arguement is that thermocouples placed on the outer surface of a product would reveal the maximum temperature rise expected from the product during normal use. These recordings would address whether a surface was too hot-to-the-touch, or hazardous to nearby walls, ceilings, etc. Thus, why would the Black Test Corner and an array of thermocouples strategically placed on a wall be necessary to determine this?
A study was performed and documented by G. Beges (and others) back in 2000. Their arguement leans toward the quest for a perfect "repeatable and traceable" testing system for accredited testing laboratories, and highly recommends the Black Test Corner along with a computer monitored DAQ setup. To me this is all fine and dandy, however, the intent of the test should not be overlooked. If there are other test methods that produce valid results and the same conclusion, then why shouldn't they be accepted as well?
I am interested in comments from others who have encountered the need to construct a Black Test Corner, and any circumstances in which your test data may have been accepted using alternate methods; such as thermocouples attached to the outer surface of the product, etc.
Thank you,
D_Wood
I would like to discuss the requirement of using a Black Test Corner to perform temperature testing.
In the world of compliance testing per International Safety Standards, it is becoming the norm to see reference to a "Black Test Corner" as a requirement when performing temperatrure testing (heating). Typically, this relates to wording such as "the product (appliance, etc.) and its surrounding area shall not attain excessive temperatures during normal use". The key word that seems to come into play here is "surrounding area". I'll come back to this in a moment.
For reference, a Black Test Corner consists of a draft-free corner with 3/4" (20mm) plywood on the joining walls, painted flat-black. A grid of holes, 7mm dia., spaced 100 mm apart covers the entire surface of the plywood, making it resemble pegboard. The holes are used to place blackened copper or brass discs with thermocouples attached to them. These discs are placed in only enough holes needed to cover the surface area ralative to the product being tested. The number of discs to be used in itself has led to many heated discussions throughout many industries. The thermocouples are then connected to a recording/measuring system, either a DAQ module & computer or a handful of meters.
Now, back to the "surrounding area". My arguement is that thermocouples placed on the outer surface of a product would reveal the maximum temperature rise expected from the product during normal use. These recordings would address whether a surface was too hot-to-the-touch, or hazardous to nearby walls, ceilings, etc. Thus, why would the Black Test Corner and an array of thermocouples strategically placed on a wall be necessary to determine this?
A study was performed and documented by G. Beges (and others) back in 2000. Their arguement leans toward the quest for a perfect "repeatable and traceable" testing system for accredited testing laboratories, and highly recommends the Black Test Corner along with a computer monitored DAQ setup. To me this is all fine and dandy, however, the intent of the test should not be overlooked. If there are other test methods that produce valid results and the same conclusion, then why shouldn't they be accepted as well?
I am interested in comments from others who have encountered the need to construct a Black Test Corner, and any circumstances in which your test data may have been accepted using alternate methods; such as thermocouples attached to the outer surface of the product, etc.
Thank you,
D_Wood